Thursday, 18 April 2013 12:19

A GLASS AND A HALF Lenses Part 3

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People always ask me what camera they should buy and I then ask them what lens they intend using on the camera. The lens is more important than the camera and only the most expensive lenses will out resolve cameras. With compact cameras this is also the case, so when shopping for any cameras look at the lens. Normally lenses are marked with f-stops. The lower the f stops the more light it can pass through indicating a better lens. With zoom lenses one normally see two f stop markings i.e. f3.5 – f5.6 this means that at the widest setting it opens up to f3.5, but as you extend the zoom it drops to f5.6.

Lenses are marked in mm and this refers to the focal length on the old 35mm film format. Our newer digital cameras have slightly smaller sensors effectively cropping the image. On many Canon SLR cameras we can use a 1.6 crop factor. This means if someone recommends the use of a 80mm lens you actually need an 80/1.6=50mm lens to get the same effect.

The next problem I see is people mostly want to get longer telephoto lenses to give them more reach. Obviously a good telephoto lens is invaluable for sport and wildlife photography. This is where I draw a distinction between serious amateur photographers and family photography. I find it immensely boring to look at a selection of wildlife photos shot by someone that went to a game park. Remember wildlife photographers may take 1000’s of photos and only display their 10 best. I see lots of telephoto lenses being used once or twice and then gathering dust. Any telephoto lens longer than 200mm normally needs a tripod, which is an added hassle. Rather walk closer or reframe to get the shot.

This brings me to some lens recommendations. The kit zoom lenses sold with cameras give reasonable results but you can improve by spending money on quality glass.

  1. The first lens to consider is the 50mm fixed lens. It has no zoom but has a low f stop number and normally very good quality. On most SLR cameras with the slightly smaller sensor, the focal length can be multiplied by 1.6. So 50mm x 1.6 = 80mm which is a good lens for portrait work. You will be able to create some lovely head and shoulder shots with nice broken (out of focus) background.
  2. Let’s be honest - most of our photos include groups of people or scenery where a wide angle lens is great. I bet this will be your most used lens -  try it! A short zoom such as the Canon 17 – 40 mm L is great value. On a Canon 600D, 60D or 7D this lens becomes a 28mm – 64mm due to the 1.6 crop factor. For a really wide lens with some artistic perspective try the Canon 10mm - 22 mm lens. See photo left of baber 5D and 17mm-40mm lens set at 17mm makes the fish   appear larger than it really is.

Lens quality in compact cameras is just as important but remember that the sensors on these cameras are smaller, so you will see lenses with focal lengths of less than 10mm. In compacts look at the f stop as an indicator of the amount of light the lens will let through - this will give you an indication of the lens quality.

Read 933 times Last modified on Wednesday, 22 May 2013 10:30

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