A question I'm often asked is "how many megapixels should I get?". Many camera salesmen present megapixels as if they are the single most important thing in your camera and sell equipment on the basis that one camera has more megapixels than the others.

In truth, megapixels shouldn't worry you at all. All modern cameras and even cameras ten years old, have more than enough megapixels for most people needs. As I've said in previous blogs, the lens, sensor; ISO, shutter speed and F number ranges are more important.

First off, let us understand what a pixel is. The name is an abbreviated version of picture element. Pictures is shortened to pics and then to pix and the first two letters of element is added. The picture element referred to is the little dots that make up an image in your camera, print, monitor, etc. These dots are tiny and so tightly packed together that the look like one continuous image and can't be seen individually, with the human eye.

So, for example, when you print an image at 300 pixels per inch or dots per inch, you have 300 pixels or dots for every inch (PPI) along the side.  A print 10 inches by 8 inches, at 300 PPI has 10 by 300 pixels on the long side, in other words, 3000 pixels and 8 by 300 pixels on the short side, 2400 pixels in total.

To find out how many pixels are in the image as a whole, simply multiply 3000 by 2400, that gives you 7,200,000 pixels. A megapixel is one million pixels, so it is 7.2 Megapixels.

A print at 300 PPI is a high resolution image. In high resolution printing it is recommended to use between 240 and 350 PPI. This standard is used for magazines, books and wall prints. If you choose to print at 240 PPI you will only need 4.6 Megapixels. 

There is also the option to use low resolution printing. Posters, for example, are printed at low resolution. This would require resolutions of 25 PPI and up. Obviously, you will need even less megapixels for one of these images. So for example, if you want to print your image at the standard poster size of 36 by 24 inches and use 50 PPI, you will have 36 by 50 pixels on the long side and 24 by 50 pixels on the short side or 1,800 by 1,200 or  2,160,000 pixels. That is less than 2.2 Megapixels.

​So far, I've written about printing but suppose you only want to display your images on a computer or smart phone screen. What do you need then? The resolution of a screen is 72 PPI. There is no point in using a higher resolution, as it will slow down you display, while it works out how to show the higher resolution, removing pixels and trying to get an accurate representation of the image, at the same time.

If you are sharing your images by email, 72 PPI is also the resolution that you will use. The gives the best representation of your images on the receiver's monitor or screen. If you're sharing images for printing, you will need to send one to match the requirements, as laid out above but usually, they are for viewing only.

Let us suppose that you are sending an image to fit the screen at the other end and the screen is 1,300 pixels by 800 pixels. That makes the screen 1,040,000 pixels or just over 1 Megapixel. If you want to know what the dimensions of the image should be in inches, simply divide the 1,300 and 800 by 72, giving you 18 inches by 11.1 inches at 72 PPI, in landscape format.

If you are posting your images on a website, there will be maximum dimensions you have to stick with. For this site the maximum is 500 pixels by 300 pixels or  150,000 pixels.  That's 0.15 Megapixels.

So, as you can see, we've come across no circumstances where you require more than 8 Megapixel in normal use. If you have an 8 Megapixel camera and you want to print a large, high resolution image, that requires 16 Megapixels, for example, there are ways of solving that problem without investing in a new camera. There are plug-ins for editing programmes that will sort that out for you easily and at low cost.

The simple answer to the question "how many Megapixels should I get?" is that it doesn't matter. All cameras on the market have more than enough Megapixels to do even professional photographers.

Scientific cameras require much higher resolution and there's a race on to be the first with the next level of high resolution. To the best of my knowledge 185 Megapixels is the highest resolution available at the moment but there are talks of a 240 Megapixel camera coming out soon.

It's a bit like motor manufacturers producing cars that can go at 380 KPH, when the speed limits in all countries are 120 KPH or lower.

In a way, all of the extra pixels are in fact a waste. They take longer to process, require more storage space and end up being dumped at the final stage of processing.

Until next time, enjoy your photography, take good care of yourselves and those you love and keep shooting. If you have any questions or comments, please feel free to contact me, by leaving a comment or emailing [email protected]

Bye bye,
​Eddie

Eddie Guiry Photography, 085 1531498 or 069 69381, email [email protected] Facebook - Eddie Guiry Photography, Viewbug -
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Hello and welcome once again to my blog. I hope you've been enjoying taking lots on photos of the autumn colours. 

Today I'm writing about how to take a good image where the light is varied, with very bright and dark patches. I'm going to use images of a church interior, St. Nicholas's Church of Ireland, in Adare, to illustrate some of the points I'm making. As usual, if you have any questions, feel free to ask in the comments section or email me directly on [email protected]

There are two settings you can use to help overcome varied light and low light conditions. In the image to the left, I used both.

The first is the ISO rating, which I've written about before and the second is the exposure compensation button, usually marked with a +/- symbol.

The image was taken in a dark church building and I didn't have a tripod with me. I hadn't planned going into the church. In fact I stopped to take some images of the main street and carried on from there. The tripod was in my van, two kilometers away.

So, the shot was going to be handheld, in low light conditions. I've explained how to pick a shutter speed before, so I'll only do it briefly here. I was using a focal length of 36 mm and needed a minimum speed of 1/36th second. Both my camera and lens are heavy and I was shooting in portrait position, so one of my elbows was in the air. To be certain of avoiding camera shake, I needed to go for a much higher speed and opted for 1/160th second. 

To get this I needed to increase my ISO rating to 1600. 

So, now I had avoided camera shake but there is the problem of capturing the light and shadow areas. The camera computer will attempt to balance the bright and dark areas of the photo, never doing a good job of it, in these conditions. There are times that your camera will do a good job but with a large bright area, surrounded by dark areas, it won't.

I needed my dark areas to remain dark, while preventing the bright areas being overexposed. This is where the exposure compensation button comes in. I selected to underexpose by -0.3. This was enough to prevent washed out shadows and whited out window details.

The next image couldn't be taken correctly without using exposure compensation. As you can see, there's a huge range of brightness, from the wall above the window to the glass on the window itself.

The camera would have tried to brighten up the wall area, if left to it's own devices. This would have blown out all detail in the glass. There would also have been a ghosting effect on the frame of the window, diminishing details there also.

I decided to use a very high shutter speed because I was hand holding the camera, in portrait mode. That one elbow being away from your body increases the likelihood of camera shake, so make extra allowances for it.

I set my camera to ISO 3200 and F7.1. To ensure I saved the detail in the glass, I underexposed by -2.0. This then gave me a shutter speed of 1/500th second, more than fast enough.

When you start doing this first, you'll have to experiment. Even when you've gotten experience at it, you'll still need to experiment, to an extent. At the start you may decide to underexpose by -0.7 first but discover it's not enough, increasing the underexposure by 1/3 stop at the time. Eventually you'll take the shot at -2.0. With experience you'll maybe go for -2.3 or -1.67 before settling on -2.0. Later again, you'll go straight for -2.0. It just takes practice.

The final example of underexposure that I'm going to give you comes from the lakes of Killarney.

This shows the detail that can be recorded by underexposing the image dramatically.

Here I went for -3.0. Any less and the sun would have been a patch of white in the sky, instead of a ball. The reflection in the water would have been larger, pure white, with no detail and the edges of the trees would have been lost to the brightness of the sun.

The final image shows an example of where I over exposed. In this case, the sun was to the side of the building and slightly behind it, leaving the facade in shadow. I would have lost details in the left side, especially in the stone building. 

I have done no editing at all to this image, apart from converting it from RAW to JPG. As you can see there is plenty of detail in the shadows, while retaining a little detail in the bright sky. Had I edited the image, I would have been able to recover full detail in the sky, using Adobe Camera Raw, while loosing no detail in the building itself.

Had I used the exposure suggested by the camera, the stone building on the left would have come out very dark and detail would have been lost. There is also some detail on the gable which may have been lost.

So, in summary, when light levels are low, increase your ISO rating and make sure you get a usable shutter speed. Go as high as needed. Also, where the light levels vary significantly in the image or there's strong shadow, where you want detail, use the exposure compensation button and either under or over expose to suit. This is also true where the area you want detail in is very bright, compared to it's surroundings.

Remember, your camera can't read your mind and doesn't know that you want to record the variation in light or detail in bright or dark areas. You have to tell it. Override the automatic settings by using the exposure compensation button. Use ISO to achieve shutter speeds that will help you avoid camera shake or blur.

Until next time, take good care of yourselves and the ones you love. Enjoy your photography. Feel free to comment or ask questions. If there's any subject you'd particularly like covered, let me know.

Bye,
Eddie

Hi everyone, I hope you all are well, healthy and happy.

I haven't written a blog in some time. The last few months have been very busy and I've been putting this on the long finger, as a result. So, now I've finally gotten down to it and the subject I've chosen to write on is why you should always back up your work. While I'm writing about photography, this rule applies to everything that you do on an electronic device.

In late August, my PC was attacked by a Crypto Locker. I had heard of them before but never met anyone who had been victim of one, so assumed that they were very rare but they are not.

What happens is, a programme infects your hard drive and enters every folder on it. Once there it encrypts everything in the folder and you are unable to open the image or file.

Two new items appear in each folder; one explains what has happened and tells you that you can't unlock the files, the other provides a link to a website, where you can pay money to the owners of the Crypto Locker, to unlock your files.

Some criminals will unlock your folders, once you've handed over the money, some will not. In my case, they were looking for €300 per folder, I have thousands of folders. Sub folders are counted as folders in this case. There was no way I could afford to pay them, even if I wanted to. There is also a very strong possibility that they wouldn't do as promised and I would still not be able to access my folders, after paying. 

The possible combinations of codes used to lock the folders runs into millions, so it wasn't feasible to sit down and figure out which combination was used, even if I could break into the programme and control it.

I had no option but to format my hard drive. Even that wasn't a guarantee that the crypto locker would be gone. I was advised to format it at least three times, just to be sure.

So this left me with a major problem. Not only was I deleting the infected folders but I was also deleting all of my programmes, including Windows. Everything had to go, as the infection could be hidden anywhere.  

You could find yourself in this situation for a number of other reasons too. A virus may wipe your hard drive clean or make it otherwise unusable. A power surge could wipe out your hard drive or destroy your device. It could be stolen. Something may be spilled on it, causing a short circuit. The list possibilities goes on and on.

What would you do? How much work and files would you loose? Could you come back from such a situation?

In many walks of life we take out insurance. You will, no doubt have your hardware insured but that will not restore lost files. The real insurance, in this case is to back up everything, regularly. I back up automatically everyday. When working on something important, like wedding images, I back up more regularly. Sometimes, every two to three hours.

You shouldn't rely on one form of back up either. A typical system is an external hard drive with your PC, one at another location and cloud back up. Nothing is infallible, so always have alternatives.

Back up several times a day onto your local external hard drive. For example, if designing a wedding book, back up every few pages. At the end of the day, ensure that all of your day's work is backed up, then disconnect the external hard drive from your device and disconnect the power. I have a fire proof storage cupboard for my cameras, my external hard drive goes in there at night. It's best to keep it in a different room to your PC or other device, when not in use.

Once a week or so, bring in the second external hard drive and back up everything new, since the last time. This should be taken away again immediately. I keep this at home. 

This gives you two extra copies of everything, one at your work place and one at a remote location. Plus you will have anything that you are working on, on your PC or other device. In the event of a fire or break in, at least one of your copies will be secure.

The final step is to use cloud backup. This is now relatively cheap and there are several trustworthy providers. I have unlimited storage for two devices, for less that €100 per year. At present I have 85 TB stored on cloud. All of my images in RAW format, all JPGs, PSDs, TIFFs, edited and unedited are there. So also are all my accounts and related documents. In fact, everything that was on my PC for more than a day is there, except the crypto locker.

It's vital that you have this set up to back up every day. When doing important work, do a manual back up every few hours also. 

How you configure this is also very important. When selecting folders and files to back up, make sure that all of your work will be backed up, completed or not. Similarly, when backing up to your external hard drives, ensure that everything is there. When you create a new set of folders be sure that they are also being backed up.

That point is where I made a major mistake. I had assumed that all new folders that I create would be backed up. That's not the case because I created some new folders outside of the range of what I had previously chosen to back up. In other words, they were not included in any of the lists selected. I should have reconfigured my back up systems, to include them, I didn't.  The result was that when I formatted my hard drive, I deleted a lot of unfinished work. I was working on seven photobooks and they were all deleted. I had to start again, from scratch.

I tell you this as a warning. I have learned from my mistake, I hope you can too and not have to go through what I did. 

The final point is that restoring your system is not easy or quick. Remember, I had to format my hard drive, so I had to restore every programme, including Windows. Some of these programmes are a few years old and the original copy had to be updated. This resulted in updates being downloaded, the PC being restarted  and the next batch of updates being downloaded, the PC being restarted and on and on. 

Eventually, you will think that it's all complete but a few days later, you do something that you haven't tried since formatting and the whole update process starts again, for hours. I'm not sure how many hours it took in total but it has put my work back some weeks.

So, that's my tale of woe. I hope it doesn't happen to you and that my story will spur you into regular, complete backups, if you are not doing it already.

Until the next time, take good care of yourself and the ones you love.

Bye,
​Eddie

We often want to take photos in low light situations but don't want to use flash. It can be done and your ISO rating is a major factor in how successful you will be.

I've already discussed ISO ratings in another blog, see What is ISO. Now I'm going to discuss a real life situation and how I handled it, which may help you.

The event was a showband concert in Shanagolden Hall, about 15 Km from where I live. The hall doesn't have it's own stage lighting system and the lights were set up by the band. There are no lighting bars to the front of the stage, so most of the lights were to the side or rear of the performers. The exception were some lights set up on top of the amps, a little to the front and side of the stage.

As you can imagine, there was very little light falling on the front of the performers. I wanted to use the ambient lights, to capture the colour and atmosphere of the event. Flash would have overpowered the stage lighting.

The most important thing in this situation was my shutter speed. Camera shake was a strong possibility and if that happened, it wouldn't matter what I did with the aperture.

The image above is the first one I took on the night. The singer was obliging enough to turn towards me, while I took the shot. This made life easier, as I could get an interesting image, while using a pillar for support.

To begin with, I increased my ISO to 5,000. I could have gone up to 6,400 but I decided not to. Why? At 5,000 I was going to have a lot of noise in my image. It would be especially noticeable where there were shadows or dark backgrounds. As you can see from the image, there are plenty of these. I knew from experience, that I could get rid of most of this with Adobe Camera Raw, at ISO 5,000 but realised that I wouldn't be as successful with a higher setting.

This is where practice is important. The better you know your camera, the less dud shots you will take. It's like using any other tool, if you don't know how to use it properly, you won't do a good job. Take your camera out and try out the different situations and settings, somewhere it doesn't count. Don't wait for an important event to experiment, do it somewhere and sometime, that you can throw away the images, if you fail.

I would like to have used F11 but this gave me a shutter speed of 1/6th of a second. Much too slow for a hand held shot. I was shooting in a dark, crowded venue, so the use of a tripod was out of the question. I didn't want to risk anyone tripping and getting hurt or knocking over my equipment. 

As in many situations, compromises had to be made and I didn't get what I wanted to but had to choose a setting that would still allow me to get a shot, without camera shake and with acceptable results.

I settled for F5.6 and a shutter speed of 1/25th of a second. This would give me a  very tight depth of field and I had to ensure that my focusing was very accurate. 

You may remember that in my blog about choosing shutter speeds, I told you that your shutter speed should be the inverse of your lens focal length. I was using a focal length of 90mm and therefore needed a shutter speed of at least 1/90th. The nearest to that on my camera but faster is 1/100th of a second, four times faster that what I was using.

All was not lost. By using a pillar for support, throwing my full weight against it, keeping my elbows tight against my body and holding my breath, while I took the shot and for a few seconds either side of it, I got a very steady image. 

The slightest movement of my body would be registered by the slow shutter speed. While 1/25th of a second may seem fast, it's surprising how much movement you can fit into it. Bracing my elbows against my body helped prevent shake in my arms. 

Holding my breath reduced movement in my chest and anything attached to it, my shoulders and arms for example. Placing my full weight against the pillar reduced the effect of any slight movement in my legs or torso and steadied me. Of course, it's vital that what you lean against can safely support your weight.  

Finally, I counted to six. On one I pressed my shutter button half way, on two I pressed it fully, the camera fired and on six I took the camera from my eye. This helps avoid camera movement, due to me taking it from my eye too quickly. It's always a good idea to allow a second or so after the shutter has fired, before moving your camera but in low light situations it's better to leave it a little longer.

The second image gives you a better idea of how dark the stage looked to the camera. Remember that your brain makes allowances and will add light to many situations, especially if you think you should know what's in the shadows. The camera records it exactly as it is.

The singer was the main subject, so I exposed for her(you've got a dirty mind). This resulted in the other band members being a little dark. Here it's no problem. Had they been as bright as the singer, they would have competed for attention.

It's important to learn how to recognise differences in light levels, so that you can choose settings to suit the most important part of the image. The audience would not be aware that there were different levels of light on the stage, they wouldn't even think about it but you have to learn to analyse the light and work accordingly.

A final point to remember. I took all these images in RAW. JPEG is fine to an extent but it involves your camera partly processing the image, before saving it. Some of the information is dumped, making it less likely that you can correct any mistakes later.  Removing digital noise is much more complicated and difficult. I was able to reduce the amount of burned out highlights on the side of the singer's head, in the first shot. This would not have been possible, had I used JPEG.

For the moment I'm not going to write any blogs about using ACR and Photoshop. I'm basing my blogs on the idea that you're a beginner photographer and I don't want to complicate things. Anything that you need to do in Photoshop can be learned from videos on Youtube and the channel I find best is Phlearn
 https://www.youtube.com/channel/UC47XN5bhLTBH5TRFyKaUpKg
and another one is Photoshop Tutorials.tv
https://www.youtube.com/channel/UC6lrxMZggMaN1u2V9N2-zrQ


They have hundreds of tutorials and present them in an easy to follow format. When you open their channels the videos may look much too advanced for a beginner but if you search, all the basic stuff is covered too, just in older uploads.

Until next time, enjoy your life and take good care of yourself and those you love.

Slan go foil,
Eddie

PS; Feel free to comment, ask questions or suggest subjects for future blogs.

All other things being equal, composition makes the difference between a good photo and an ok photo. No matter how well an image is exposed, even if it's technically perfect, a badly composed image will not work.

A number of factors need to be considered, when composing an image. The first one is the crop. Your camera can not record everything you see and so, when you compose the image, you must select what to include and exclude. Sometimes this is obvious but not always. 

In this first image of busts at UL, I've focused on one bust, the green one, the only woman's bust  in the image. This was taken with a long lens, 360mm, from a balcony, about 100 meters away. 

This is a fairly cluttered image. For one there are four more full busts and one partial bust in the image. It also includes a piece of rock and the stands that they were all displayed on, plus a large white metal frame, a glass frame, reflections on the frame and the large windows behind and distant trees and buildings. So, why does the main subject stand out?

Proper composition. First, there's the selective use of depth of field. I give more detail on this in my blog "Taking that photo". I used F10 for this, knowing that at the focal length I was using that it would give me a narrow depth of field. See my blog "What are F numbers?" for more details.

Only my main subject is in focus but with all of the clutter in the image, you may still not find her. So, where I placed her is also important. There are several rules of composition and the one I use most often, the easiest to use, is the rule of thirds.

Imagine dividing your image in three equal parts vertically and then horizontally, see the red lines in the image on the left.

This forms a grid on the image. If you place your main subject along one of these lines, it has more of an impact and stands out better. By placing your subject close to where the lines cross or at the exact point where they cross, you increase the impact further.

As you can see, my subject's face is placed along the right hand vertical line, just above where it crosses the bottom horizontal line. This is one of the most powerful positions in the image, along with the three other crossing points.

Because she is facing right, it is more common to place her on the left vertical line. This gives her space to walk into, if she could walk and the area she is facing is called positive space. The space behind her is called negative space. It is better to provide more positive space than negative but not always. This is something that you will have to learn with experience and is why it's a good  idea to analyse your own and other people's images, to see why they worked or did not work. You can gain quiet a lot from doing this.

In this case I decided to use more negative space for two reasons. It is now obvious that the busts are part of a much bigger display and not just four busts. 

There was a pillar close to the busts on the right, which would have split the image, making it look like two images combined. Even though the pillar would have only taken about 10 - 15% of the right side of the image, it would have looked like it was added in. Being white, it would also have attracted the eye away from the subject. 

I could have cropped in tighter and not include the bust on the left of the image, which I also did. That image is posted below. Both images work but in different ways.

You will also notice that the top horizontal line runs just over the top of the head of the highest bust, the horizon of the image.  It's better to place the horizon on one of the two horizontal lines, the image is more dynamic that way. You will see this in the images I've placed below. 

I've also used a leading line, the green line. Often leading lines are actual lines in an image but more often than not they are imaginary but your eye will follow them all the same. By composing the image so that the line of busts appear to be one slightly forward of the other, I've created an imaginary leading line. 

Had the white lines in the background been sharp, they would have pulled the eye away from the main subject, another reason to use a shallow depth of field. 

I chose this point of view for a number of reasons. One was that this was the least distracting background and because it was a long way away, it was easier to place it out of focus. 

Had I shot the bust head on, the background would have been much more cluttered, more busts and rocks would have been included and competed for attention. The wall behind all of this had a very colourful mosaic and a model airplane hung in front of it.

Another reason for not shooting head on was that it would have placed four busts on the same plane. They would all have been in focus and competed for attention. I could have zoomed in on one and excluded the others but I would then have lost the context of the image, which I think is important.

The blue lines between the tops of the busts indicate imaginary triangles in the  image. These are especially useful when posing a group of people. Flat lines in an image hold the eye in one place, while sloped and curved lines encourage the eye to move about the image. When your eye moves about an image, you see it as having more life and being more interesting.

Below you will see some images, with the "rule of thirds" grid marked on them, along with leading lines. Notice how I've created circles, ovals and triangles, where possible and not just lines.

What you should do next is look at my galleries and see how I've used the information above to compose my images. Then look at your own images and see where this information applies and how you may have improved your images using the above details. Finally, look at other people's images and see how they have composed their images. Ask yourself what you may have done differently. Always analyse your own images, ask yourself why they work or don't work. This will help you improve constantly. No one is ever so good that they can't improve.

Until next time, enjoy your photography and take good care of yourself and those you love. Feel free to leave comments, ask questions or suggest topics for another blog.

Slan leat,
Eddie

White balance is not a natural concept for most of us. When we see an object, the light is collected by our eyes and sent to our brain, where it is processed, to produce an image. Over time we have learned that things are usually white, green or some other colour and when we see them, our brain will adjust the actual colour to what colour it "should" be.

However, our camera does not possess the ability to learn and if there is a colour cast, our camera will record it. Digital cameras are designed to do a certain amount of correcting automatically. That's good news for us and in most situations, we can use the auto white balance. Makes life simple.

It's easy make a mistake and I would suggest that if your camera can shoot in RAW mode, you should use this mode. The reason is that if you get your white balance wrong, when shooting, it's possible to correct it, most of the time in your camera RAW processor.

So, what difference does the white balance make. In the series of images below, I have in fact edited the same image four times but changed the white balance in each.

Each image was edited in exactly the same way as the others, except I changed the white balance. As you can see, I've indicated the white balance by printing it in the top left corner. The results are very different.

This shot was taken at about 2pm, so the Daylight white balance is the more accurate. The auto, in this case got it wrong and looks more like the Shade white balance.  At least 50% of the building walls are in shadow and the river is also dark. This may have fooled the camera into thinking the subject was in the shade. I don't know for sure.

This series of images shows how choosing the correct white balance can be critical. Imagine if you shot in auto at a wedding. The brilliant white wedding dress would come out as off white.

Had I not shot the image in RAW, I would not have been able to correct the white balance. 

You've seen the effect in daylight, at night it's even more critical, especially if there is more than one light source. All artificial light has a colour cast. In public buildings and retail outlets, the fluorescent lighting is usually daylight balanced. Fluorescent lighting in the home will have a purple or green cast, depending on which standard has been used in it's manufacture. Sometimes, it may have another colour.

Tungsten lighting is usually strongly yellow, the lower the wattage, the more yellow it is. Candles and fires also give off a yellow light. We know this already but our brains will clean up the colour cast caused by them.

When we see white, what is happening is that all of the light falling on the object is reflected back and enters our eyes. If there is no colour cast in the light(it's pure white), that will mean that the object is pure white but if the light falling on the object has a yellow cast, we should see the object as yellow.

Our brain can sort that out for us but our camera has to be told how to. So, that's why you would pick a white balance to match the lighting, especially in artificial light. If you have more than one source of light, of different colours, then you must decide which is the most important.

In the image below, taken in Limerick, during Christmas 2010, you will see that there are several light sources.

The street lights have a yellow cast, as you would expect. The top of the building on the right is flood light by a light with a blue cast but we would see it as white. The tree itself also has a blue cast but again we would have seen it as white and it was described as white by newspaper articles about it. To the left of the tree you will see a window with a greenish light inside. This is a domestic fluorescent light and the it too would have looked white to those in the room.

As you look further through the image, you will notice many windows with light inside, of several different colours. However, to the occupants, each of these lights would look white.

This image has been edited in exactly the same way as the one above, except I changed the white balance to Fluorescent. Looking now you will see the the light at the top of the building on the right is white. The light inside the window to the left of the tree is also white.

The street lights are a stronger yellow, as are the lights inside many of the windows. The tree is less blue.

Again nothing has been changed, except the white balance. The tree is now white, the street lights and yellow window lights are even more yellow and the light at the top of the right hand building has changed tone.

Which one is correct? It depends on which item in the image is most important. It was taken to show the tree and it's position in relation to the water front, so, for me, the last one is correct. It's set to Flash, even though I did not fire the flash but the lights in the tree and the flash are both daylight balanced. That is why it works.

If you were to stand where I took this shot from and looked at the river bank, you would not see the lighting as being as yellow as it is in the final image. In fact, if you had been in that light for a few minutes, you would not see it as yellow, at all.

So, that's it for now. As usual, feel free to ask questions or make comments, using the comments section below or by emailing me at [email protected] Suggestions for future blogs are also welcome.

Until next time, take good care of yourself and those you love.

Bye,
Eddie

So, now that you know the three factors that effect your exposure, lets see how to use them in practice.

The image above was taken at the Way of the Cross procession, in Newcastle West, on Good Friday last. It was a cloudy day and even though it seemed bright to the human eye, light levels were low. The default ISO rating for my camera is 200 but at that level I was getting shutter speeds too slow to hand hold and avoid camera shake.

I increased my ISO rating to 500. This means that at the same F number I can get shutter speeds that are 2.5 times what I would get at 200, 500 being 2.5 times 200. With experience, I have learned to hold the camera steady at relatively slow shutter speeds, for example 1/60th or 1/125th of a second. You may need to increase your ISO to 1000 or higher, depending on how steady a hand you have.

When choosing an ISO rating, remember that you should pick the lowest rating you can get away with, so as to reduce noise levels. While it can be fixed in Photoshop and most other editors, it is always better to get is as right in camera as possible.

Next I set the camera on Aperture Priority. This is usually denoted by A on your camera's selection dial. I've already selected the ISO rating and I will now select the aperture or F number. 

The camera will then automatically select the shutter speed. This doesn't mean that I can forget completely forget about my shutter speed, it's just the the camera does the math for me. I need to be aware of the shutter speed selected because if it's slow, my images will suffer from camera shake or motion blur, neither of which can be fixed.

It's always good to take a test shot, to see what speed is selected and then look at the enlarged image on your screen, to check for camera shake. If you have some, increase your ISO again and take another test shot. Only go up one step at a time, don't jump from ISO 400 to 1600, for example, try use the lowest rating you can.

During the procession, I checked my shutter speed each time the light looked to have faded. This happened when they came into narrower streets or were in the shadow of a building, for example. I also checked it regularly over time, as light fades as the afternoon passes, anyway. I maintained my shutter speed by increasing my ISO. By the end of the procession, I was using ISO 1600.

My next decision was which aperture or F number to use. This varied from photo to photo but for this one I used F11. The woman in the image was part of a group of three and I wanted to be sure that if any part of the others came into the image, they would be out of focus. As you can see, there is a large crowd(number not weight) in the background and I wanted them out of focus also.


To pick her out from the crowd I used a 70 - 300mm zoom lens at 270mm. 


If you look closely at the image, you will notice that she is sharp, except for her far shoulder. A shoulder and head from other people, on the left side of the image and the people in the background, on the right side, are all out of focus.


The result is that the lady herself, my subject, stands out, without competition from any other element of the image. Had I used a much smaller F number, say F4, only the point of focus and a little bit around it would have been sharp, most of the woman would be out of focus.


Had I used a much larger F number, say F22, most of the image would be in focus and she would have had to compete with the people in the background and the bits of people visible in the foreground, for attention. As a portrait, it would not have worked.


I focused on her eye. In most portraits, the person's eyes are the most important. If you have sharp eyes and other parts of the face are out of focus, the image still works. However, if the eyes are out of focus, it doesn't matter how sharp the rest of the image is, it wont work.

Hi and welcome to my blog for April. If you've been following my blogs, so far, you will know that there are three settings which control exposure. By now you should know what ISO and Aperture are and how to use them to your benefit. I hope you've been experimenting and trying out various settings, to see the effect and getting more control of your images, as a result.

Today, I'm going to write about shutter speeds. I kept this until last, as I think it's the easiest to grasp. There are three problems that may arise from using the wrong shutter speed, one is under or over exposure, another is camera shake and the third is motion blur. I will deal with each one separately.

To begin with, we must understand what a camera shutter is and how it works. Your camera sensor is a light sensitive chip, sealed into a light tight chamber at the back of your camera. On the lens side of the chamber there is a shutter or door, which opens to let light through. The length of time this shutter/door is fully opened is your shutter speed. So, if the shutter/door is fully opened of 1/60th of a second your shutter speed is 1/60th of a second.

If you double your shutter speed, the door opens and closes twice as quickly and is therefore opened for half the time. If you half the speed, the shutter opens half as quickly and remain fully opened for twice as long. 

For example, if you begin with a shutter of speed of 1/30th second, your shutter is fully opened for 1/30th of a second. We'll call the quantity of light to reach your sensor X. Then increase it to 1/60th second, the shutter moves twice as quickly and remains fully open only for 1/60th of a second, half as long as at 1/30th. This means that light has only half the time to reach your sensor and only half X reaches your sensor.

Change your shutter speed to 1/15th of a second. Now your shutter is fully open for 1/15 of a second, twice as long as at 1/30th. The amount of light reaching your sensor is now 2X. 

One of the reasons we would adjust our shutter is to freeze motion. In the image above, of Charlotte dancing, I used 1/200th of a second to freeze the movement of her hair and get a sharp image. A slower shutter speed would have resulted in blurring of her hair and face. Her lower body was not moving at the same speed and would have been less blurred. As a portrait, it would not have worked. 

One of the main time you would want to freeze action is at sports events and this often requires high shutter speeds but maybe not as high as you would think. For example, if the person, horse or car is coming towards you, you can use a lower shutter speed than if it was crossing your angle of view. Sometimes the action has to slow down and lower shutter speeds are needed then also.

In the image of the rally car I picked a point where the vehicle had to slow down to get my image. It was a wet, dark day and achieving high shutter speeds would have required high ISO ratings, creating a lot of digital noise. My blog on ISO explains this. 

With an ISO of just 640 and F9, I was able to use a shutter of 1/500th. Had the car been going at full speed across my angle of view, I would have needed a much higher shutter speed, perhaps 1/4000th of a second and it the low light I would have needed ISO ratings of 6400 at least. I didn't want to use a very high ISO rating.

Another way of avoiding very high shutter speeds is to use a technique called panning. Set your camera on single focus. Pre-focus on a selected point of your choosing. You may need to use manual focus for this, otherwise your camera will try to refocus, if you relax your finger on the focus button. As you subject approaches, frame it and press your shutter part way down. This gives you an exposure reading.  Follow your subject with your camera, keeping your subject centered in the frame and just before it reaches the point where you pre-focused, press the shutter fully and continue to follow your subject until after the image is taken. This will blur the background but, if done correctly, will give you a sharp subject.

This technique takes practice, so make sure to use it often on subjects you can afford to mess up, like your dog running about. You will need a medium shutter speed for this to work, except for something like F1 motor racing.

I used this technique to take the photo of the two galloping donkeys. As you can see the background is blurred, while the black donkey (on my point of focus) is sharp.

There are times when you may want to create motion blur, as an effect, in your image. The most common example of this is running water, water falls and similar. The achieve this effect it's always better to have a tripod or place your camera on a solid base. The danger with this is that during a long exposure (slow shutter speed) you will move your camera and get camera shake, as well as motion blur. 

If you don't have a tripod, place your camera on a wall or something similar. Use a bean bag, folded jacket or similar to support you camera. This will allow you to aim your camera and if done correctly, will prevent it from tilting forward, during exposure. Use the self timer to avoid any movement caused by you pressing the shutter.

The image above, of a section of the Cascades, in Lahinch, Co. Clare was taken using 1/20th of a second. I chose to blur the water because I think it conveys the power of the falls better. I could have frozen the action, with a high shutter speed but the effect would have been completely different.

As part of the exposure triangle, your shutter speed helps control the amount of light reaching your sensor. If you choose the wrong shutter speed, you may get under or over exposure. Your camera should warn you of this. 

You will see something like this on your screen or in your viewfinder
-<........0........>+. This will indicate that the exposure is correct, as the camera sees it. You may want to under or over expose your image, for various reasons(I'll discuss this in a later blog) but lets assume you want to have balanced or correct exposure.

The chart here shows you the different ways the symbol above is use to let you know if your exposure is correct. If you are using shutter priority mode, the camera will make the correction automatically, by changing one of the other settings. You only have to worry about it if you are using fully manual.

With practice you will learn how to compensate for under or over exposure by changing the ISO or aperture. 

You'll experience camera shake when you use slow to medium shutter speeds, if you don't stand correctly or if you move during exposure. Holding your camera correctly is also important to avoid camera shake.

My next blog will be about how to hold your camera correctly and how to choose shutter speeds to suit your lens and subject.

Thank you for reading. I hope you find it helpful and as usual, if you have any questions, feel free to ask, using the comments section below.

Until next time, take good care of yourself and those you love.

Bye,
Eddie 

So, now that we've discussed one corner of the exposure triangle, it's time move on and discuss another. For this blog I'm going to tell you F numbers or aperture and what effects they have on your photography.

The aperture of you camera is the hole in the lens, through which light enters and reaches the sensor or film. In all but the cheapest of cameras, this aperture is variable in size. In some cameras there are a limited number of options, for example, there may only be three settings; called close up, portrait and landscape. In more expensive cameras there is a much wider range of options, which can be selected automatically by your camera or manually selected by you.

This aperture not only controls the amount of light entering the camera over any given time but also controls the 'depth of field' in your image. I will give more detail on this soon.

The size of your aperture is indicated by the F numbers and they work in reverse order. In other words, larger F numbers indicate smaller apertures and smaller F numbers indicate larger apertures. This may seem odd but the F numbers are in ratio to the 'depth of field' of the image, which is the inverse of the aperture size.

The chart above shows the relative size of different apertures and the F numbers than indicate them, in the top line. The scale in the lower line indicates the size of the depth of field, assuming that you are focusing on the same point with each aperture. It is not to scale, as the depth of field also depends on the lens being used. In most cases it is at infinity when using F22 and would therefore, be impossible to show to scale, as you would expect.

So what is Depth of Field and how do you use it, I hear you ask? (Must get something done about those voices in my head).

The 'depth of field' is the area of the image that appears sharp. When you focus on a subject at, for example, 3 meters, everything in the image that is 3 meters from the sensor is sharp. This forms an arc in the image. Nothing else is sharp, the items at 2.99 m and 3.01 meters are out of focus. However, they are so slightly out of focus that we can't tell. 

As we move further from the 3 meter point, objects get more and more out of focus, until eventually we reach a point where they are so out of focus we can see it. Depth of field is a measure of the distance from that point in front of your subject to the similar point behind your subject. This will vary, depending on what aperture you use.

In the image on the left I needed a wide 'depth of field'. I needed both the boat, in the foreground and the mountains, in the background, looking sharp. 

Checking the chart above, you will see that larger F numbers give wider depth of field. This image was taken at F 28, not in the chart. At this setting, the depth of field extends from the camera's minimum focus point to infinity. The minimum focus point on most cameras is at about 1.4 meters but depending on the lens you are using, this may be different, as it's the lens that controls it.

When using large F numbers, the way to get the widest depth of field is to focus on a point about 15 to 16 meters from the camera. Don't focus on a point much further away, as you will have objects near the camera out of focus. The depth of field extends from the point of focus, not the camera, so it's possible to have an obviously out of focus area close to your camera. You can, however, use this fact to create a sense of depth in an image. I will discuss this in a later blog.

In this image of my wife, you will notice that the curtains  and even her far shoulder are out of focus. Also, if you look closely, you will see that some of her near shoulder is out of focus.

This is the result of using a small F number, F 6.3 in this case. The resulting depth of field is very narrow, barely enough to include her head. This ensures that all of the attention is on the subject and not something in front or behind her.

As you would expect, a narrow depth of field is ideal for portraits or any image where there is a lot of distracting detail. It is vital that, when using a small F number, you focus on the most important item in the image. In the case of portraits, that is the eyes. When working with a narrow depth of field it's important to ensure that your subject is sharp and draws all of the attention.

Now you have seen how the two extremes of F numbers effect your image and what they suit best, go out and experiment. People will tell you that the rule is - "use a small F number for portraits, use a large F number for landscapes" but there are no rules in photography, just guidelines. The best way to learn is to use the guidelines until you are confident with them and then break the rules and have fun.

In the image on the left, I used an aperture of F 9. Why? I hear you ask (those voices again).  Well, you have to balance the three points in the exposure triangle, namely - ISO, Aperture and Shutter Speed. I had chosen an ISO rating of 640, a compromise between speed and grain (see ISO blog, for details). To get a shutter speed that would allow me avoid camera shake, I need a wider aperture or smaller F number(the same thing, as you know by now). At F 9 the waves would all appear in focus and I was able to use a shutter speed of 1/250 second.

You will need to experiment with your camera and lens, as the depth of field will vary depending on what lens you use and how far out your are focusing. Stick with the "rules" until you're comfortable with what you're doing, then go crazy.

The size of the aperture will always be the same. The effect is changed by the lens and the position of the glass within it.