Which lens should I get - Focal Length Comparison


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CS TAN

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Sep 3, 2007
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A lot of threads in CS is about which lens to get for landscape, portraiture, wild life, etc...

I think the question has a lot to do with people not understanding the focal length and what they would be getting within the frame when using a particular focal length lens.

I found this on the web which I feel is quite useful myself so just want to share with others here:

http://www.juzaphoto.com/eng/articles/focal_length_comparisons.htm
 

Thks for sharing
 

Nice site!
Thanks for sharing
 

however I should hasten to mention that such a way of comparison only works for close-by focal lengths (eg comparing 300mm against 400mm). it is not valid if you compare say 50mm to 200mm as the perspective changes with the focal length. a short lens shows you a lot of background, whereas a long lens gives you a "barrel" effect.
 

however I should hasten to mention that such a way of comparison only works for close-by focal lengths (eg comparing 300mm against 400mm). it is not valid if you compare say 50mm to 200mm as the perspective changes with the focal length. a short lens shows you a lot of background, whereas a long lens gives you a "barrel" effect.

:nono: No that's not true.

Besides, Juza's article seems to be talking about focal lengths on APS format only, and yet he mentions FF here and there - which isn't exactly helpful. For example, he says
17-55, 17-85 and similar zooms, created for APS-C cameras, offers a pretty wider angle of view than standard zooms for FF cameras, as the Canon 24-105 L IS.
Well. It doesn't matter if 24-105 is a FF lens or not, it's simply 24 vs 17 compared on the same format.
 

:nono: No that's not true.

Besides, Juza's article seems to be talking about focal lengths on APS format only, and yet he mentions FF here and there - which isn't exactly helpful. For example, he says

Well. It doesn't matter if 24-105 is a FF lens or not, it's simply 24 vs 17 compared on the same format.

what do you mean its not true? cropping a 300mm lens image down will not give you the same picture as one that is produced by, say, 100mm.

a 24mm FF lens on an FF sensor will not produce the same image as a 15mm FF lens on APS-C sensor, for the same reason. it could be close but not the same.
 

I believe the website is best use for focal length comparison between two close focal length lenses. e.g. how much wider is 16mm as compare to 17mm. How much area will I be missing if I go for 24mm instead of 17mm. The website give you a visual aid to "see" so as to help you decide.
 

a 24mm FF lens on an FF sensor will not produce the same image as a 15mm FF lens on APS-C sensor, for the same reason. it could be close but not the same.

:bsmilie: Tell me how it won't.
 

The compressed/exageration effect would be different. Imagine you have a huge a55 sensor that you can mount a 135mm lens and it will give you the same view as a 24mm on a full frame.
With the 24mm full frame you will get that impact, whilst the larger sensor will have more compressed picture.
 

It will be the same if you maintain the same subject magnification ratio.
 

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