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.