Zoom, tele photo lenes.

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gerbstoke

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Now I know that I'm going to come across a bit thick here but what exactly is the magnification on some these lenses?

100-400
70-300
55- 250
75-300

What exactly does this mean. What should I be looking for in a lenses so that I can shoot a bit of wild life and birds.

Thank you for your help in advance
 
The magnification is how many times the shortest focal length will divide into the longest focal length. ie. 100-400 equals 4x magnification.

For birding and wildlife, it's not the magnification that's important but the maximum focal length.

Out of the lenses you listed, the 100-400 would give the longest focal length of 400mm. The Sigma lenses do a very affordable range up to 500mm. Do a quick search on the forums and you'll find loads of posts.

HTH
 
The numbers refer to the focal length of the lens. As these are zoom lenses, they cover a range of focal lengths, the smaller number being the shortest focal length, the larger the longest focal length.

For bird photograhy, generally the longer the focal length the better.

You can't quite the compare the magnification factors of binoculars to camera lenses, but in another post, you were discussing getting a Canon EOS7D. With that camera a focal length of 28mm gives a natural angle of view, so a 400mm would appear to give an image 14 times bigger. For that camera, I think you would need a lens that reaches at least 400 or 500mm.

Birds are generallly quite small and you need that focal length to get them to fill a reasonable part of the frame.
 
Bigvin said:
The magnification is how many times the shortest focal length will divide into the longest focal length. ie. 100-400 equals 4x magnification.

HTH
Click to expand...


Not true, all you have quoted is the zoom ratio, not a magnification ratio.

By your definition, a 600mm lens has a lower magnification than a 16-35mm!
 
I would recommend a Canon 400mm f5:6 it is a great lens for birds, although it might push your budget a bit. There are some fantastic shoots from this lens in the bird forum and on Flickr. In hindsight I might have been tempted to buy a Canon camera to be able to use this lens.
 
Magnification normally refers to the a zoom lens and how it changes focal length usually the smaller the magnificent the better the quality in price range.

normal vision is said to be about 50mm, so if you divide the the focal length by 50 it will give you an idea of how different it is to normal vision. Don't forget to times the focal length by the crop factor of your camera if your not using a full frame camera. (canon is x1.6 for most camera)

I think the Canon 400mm is more like 1000, around 500 I would looking at the sigma 150-500 it is a little over. Great focal length, it not the sharpest but give great results.

Just remember for birds you need a large aperture for distant shots I look at using f11 to f22.

I hope that helps.
 
It helps very much. I wouldnt know where to start if it wast for you lot on here.
 
gerbstoke said:
It helps very much. I wouldnt know where to start if it wast for you lot on here.
Click to expand...

Well there's quite a lot of confusing information given so far ;) but the bottom line is you generally need the longest focal length (highest number) you can get for birds.

Try this, assuming you have a kit zoom, set it to 50mm and then pick a subject the same size as the bird you want to shoot, and move close so it fills the frame. Measure the distance, and let's say with a small garden bird you'll be at about 2ft.

Now if you fit a 100mm lens, you will get the same framing at 4ft; 200mm will be at 8ft; 400mm you can shoot from 16ft. With small birds you need a long lens and get as close as you can.
 
If you don't mind imports I'd have a look at www.panamoz.com as they have some great prices on lenses such as the Sigma 120-400 OS http://panamoz.com/index.php/lens/s...ns-for-sony-digital-and-film-slr-cameras.html and the Sigma 150-500 OS http://panamoz.com/index.php/lens/s...m-for-canon-digital-and-film-slr-cameras.html I have got both of these lenses and they are both fantastic lenses giving you very good IQ, the AF speed is good and the OS system is fantastic. Great for aviation, birds and sports.

They give a 5% discount for paying by bank transfer meaning the 120-400 would cost £550.05 delivered. I've just had a Canon 70-200 MkII delivered in less than 3 days and I've used them a few times before so I can highly recommend them.
 
gerbstoke said:
Now I know that I'm going to come across a bit thick here but what exactly is the magnification on some these lenses?

100-400
70-300
55- 250
75-300

What exactly does this mean. What should I be looking for in a lenses so that I can shoot a bit of wild life and birds.

Thank you for your help in advance
Click to expand...

I asked a question a while ago the answer to which may help here and that was mm in relation to magnification of binoculars.

50mm (as a 35mm equivalent) is considered roughly what we see with our own eyes so if you divide your lens focal length by that number to get your magnification value. For instance i wanted to know what lens would give me the same magnification as my 10x binoculars so we times 50mm by 10 to get a 500mm lens.

So this is a rough guide:

100-400 x2 - x8
70-300 x1ish - x6
55- 250 x1ish - x5
75-300 x1ish - x6

If you can understand and relate to binocular magnification it is easy to pick a lens that you want. Of course this is all based on a camera with a full frame sensor. If you have a crop sensor you will need to factor that in.
 
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