Understanding Layers

Many people have problems getting to grips with Layers, they don't understand what a Layer is or how to use one. Yet the Layers Palette is probably the most powerful and useful tool in Photoshop.

So what exactly is a layer?

To understand exactly what a Layer is imagine you have a photograph on the table in front of you, now cover it with a thin piece of perfectly clear plastic. Ta Daa! You have just created a Layer. Two Layers to be more precise, your photo is a Background Layer and the sheet of plastic is an editable Layer. You can draw on the plastic with a marker pen, paint on it or whatever you want but the photo below remains totally unmarked and unchanged. Put another sheet on top of the first and draw or paint on it too, you can see the changes you are making but neither the Layer below nor the photograph are changed.

It is exactly the same in Photoshop. You can create as many layers as you want, do what you want with them and see the changes as you make them but the photo at the bottom of the Layer Stack remains untouched. You can turn a Layer on or off by clicking on the eye icon beside it so you can quickly and easily compare the changes you have made with an earlier version of your image.

Adjustment Layers

An Adjustment Layer is just an even more flexible Layer. When you create an Adjustment Layer by clicking on the black and white circle in the Layers Palette, in addition to the New Layer icon you will see a small white rectangle and this is the key to the usefulness of the Adjustment Layer.  Lets say you have used Layers to change your image to black and white but would like to keep some colour. Click on the white rectangle and select a paint brush making sure your foreground colour is black. Anything you paint over will now appear in colour, in effect you are selectively"rubbing out" the black and white layer and allowing the colour below to show through.


Got it now? Don't panic if it all seems a bit much, it really is one of those things that is harder to explain than to do. I'm working on a quick tutorial which will appear later this week which will make it all much easier to understand.

Go to www.imagesbygeorge.co.uk to see more of my work.

Macro Lenses

I suppose the first question is "What is a macro lens?" There are several answers to this, or at least several variations on the answer but in its simplest form the answer is this: If it allows you to make a life-size image without enlarging and allows you to get physically closer to the subject but still maintain sharp focus, then it's a macro lens. I can already hear the ifs and buts, I did say this was the simplest answer. There are other factors to be taken into account including sensor size and native resolution but these can be ignored for most purposes.

What do I use it for and do I need one?

Well, the answer to the second question very much depends on the answer to the first. Macro lenses are typically used to photograph insects and other tiny animals as well as close-ups of flowers, fungi and the like. Of course the number of uses you can put one to is limited only by your imagination. So, are you going to take loads of images like those I've mentioned? If so then to get the best image quality you will indeed need a macro lens.

Can I get by without one?

Absolutely. Providing you are willing to compromise a bit you can get great close up images by simply zooming in. Images captured this way may lack the ultimate sharpness and bokeh  (the out-of-focus area) of those taken with a true macro lens but there is no reason that you can't get "macro" images to be proud of.

These images were taken with my new Nikon 28-300 zoom. The rusty bolt has not been cropped at all, the insect image has been cropped in to about half its original size to enlarge the little bugs. A true Macro lens would allow you to nearly fill the frame with one of these little critters.

Finally, where can I get one and how much do they cost? Here we have some good news. Macro lenses are very popular, all the big names make their own macro lenses with many different specifications. There are cheap offerings from Tamron for example costing a little over £100, a fast f2.8 Nikon 60mm Micro (Nikonese for Macro) will cost well under £300.

Go to www.imagesbygeorge.co.uk to see more of my work.

ISO plus Aperture plus Shutter Speed equals Exposure

Okay, some of you have asked me to explain the relationship between ISO, aperture and shutter speed so here goes. As it says in the title bar, all three of these added together equals exposure. Too much or too little of any of the three elements will give you an over or under-exposed photo. You will normally find information about these settings in your camera view-finder or LCD panel. Before I go any further, it's important to understand what these things are and what they do, we'll go for the easiest first.

Shutter speed as the name implies is the speed at which your cammera's shutter opens and closes. More accurately, it is a measure of how long your shutter is open. A shutter speed of 1/125 of a second means that for 1/125th of a second your camera's shutter is open allowing light to fall on the sensor, or film for the non digital among you, and so creating an image.

Aperture which is denoted by f numbers, f3.6, f11 etc refers to how much light is allowed to enter your camera as opposed to for how long. There is a series of blades in your lens which open and close as you adjust the aperture setting, a wider setting for example f1.8 will let in much more light than a small setting, say f22. On a zoom lens you will see something like f3.5 - f5.6, this tells you the widest available aperture at both ends of the zoom, f3.5 at the wide angle and f5.6 at the highest magnification. This means that you will not have such a wide aperture available when zooming in and so you will need to use a slower shutter speed. A single number for example f2.8 means that this aperture is available throughout the lens' range and is normally only found on expensive pro lenses.

ISO is the joker in the pack. It doesn't directly control the light entering the camera, but how the camera reacts with the light. Most cameras start at ISO 100 and many can be adjusted to go higher than ISO 1600. But what does this mean? The ISO setting controls how sensitive your sensor is to light. Lets say that the exposure settings for a particular shot are 1/60 at F8 and ISO 100, but you need a faster shutter speed, 1/250, because you are photographing horses running, or a dog getting dry, and you want to keep the aperture at F8 to keep most of your shot in reasonably sharp focus. Your only option here is to increase the ISO, that is to make the camera more sensitive to light, in this case to ISO 400. This will give you exactly the same exposure but will allow you to use the faster shutter speed you require.

So why not use the highest available ISO and widest aperture setting all the time? After all you could then use faster shutter speeds which in turn would mean no more lost shots due to camera shake, right? Well yes, but there are other factors to be considered. The amount of digital noise or graininess in your photos will increase rapidly the higher you push the ISO. Try taking the same photo at the lowest and highest ISO settings on your camera, the chances are that the highest setting will give you an image that is all but unuseable. In addition the wider the aperture, the less of the image is in sharp focus, great in a close-up portrait but not usually much good in a landscape shot!

Confused yet? The good news is that there is no reason to jump from the pre-programmed settings you have become comfortable with to full manual control all at once. Ease yourself in gently. Many cameras have an auto ISO setting, letting you mess around with aperture and shutter speed while the camera ensures the ISO is high enough to get a good exposure. I suggest you start with Aperture Priority mode, usually A or AP on your control dial or menu. This means that you choose the aperture and the camera sets the shutter speed required. If you notice that the shutter speed is too low then simply adjust the ISO setting until you get the shutter speed you need. In low light you may decide that the ISO is too high to give you the image quality you want. In this case you will want to use either a wider aperture and/or a slower shutter speed. You have to find a compromise you are comfortable with.

I hope this helps you understand your camera a little better. I have deliberately simplified my explanations, but only a little. Stick with it and you'll soon wonder what all the fuss was about.

Go to www.imagesbygeorge.co.uk to see more of my work.

Kit lens vs Professional

Okay, I seem to have opened a can of worms with my comment about kit lenses, " in good light at average settings there will be very little visible difference between the typical kit lenses offered with many cameras and the most expensive glass on the market". If kit lenses are as good as professional ones why should anybody pay the prices asked for professional glass? The key here is good light and average settings. Any decent lens is capable of producing a great image in ideal shooting conditions at f8 to f11 ( I will cover f stops in a later post ). When conditions are less favourable the difference becomes clearer.

I don't want to get into too much technical detail, I'm not a scientist so I would probably explain it badly, but expensive lenses have better glass in them and this results in better images particularly at wider apertures. The availability of a wider aperture allows the use of faster shutter speeds, vital if you are photographing sports for example. You can compensate of course by using a higher ISO but the trade off is increased noise in your images. A wider aperture (lower f number) also results in more bokeh, the out of focus area in an image, used to great effect in portraits where the subject is in sharp focus and stands out from a lovely soft background.

How much do you need to spend on one of these lenses? Surprisingly little is the answer, provided that you don't need a zoom lens. Nikon make a 50mm f1.8 lens which you can buy for about £100 and this lens is as sharp as anything on the market. There are similar offerings from all the major camera brands.

This post barely scratches the surface of the issue. As ever in photography, whether or not you need to spend a small fortune on lenses depends entirely on the use you intend to put them to.

Go to www.imagesbygeorge.co.uk to see more of my work.