focal length comparison

[palmerstoat]

Is there anywhere out there that shows the same shot from the same known distance to demonstate the different focal lenghts on a 100- 400L lens. do you know what I mean? one would need to know the distance from lens to object in each case and the size of object, ie an everyday object like a car or something. I hope you know what I mean Cheers Palmerstoat.

[Curtis N]

Go to the link below and download my Photography Calculator.
Go to the Depth of Field Calculator tab.
Choose your camera format, focal length and subject distance, and it will give you the dimensions of your field of view. Change the focal length or the distance, and the field of view will change accordingly.
http://boonecounty.info/photocalc.htm

[PacAce]

Is there anywhere out there that shows the same shot from the same known distance to demonstate the different focal lenghts on a 100- 400L lens. do you know what I mean? one would need to know the distance from lens to object in each case and the size of object, ie an everyday object like a car or something. I hope you know what I mean Cheers Palmerstoat.
Not sure if something like this is what you had in mind but it should be close:

http://consumer.usa.canon.com/app/html/EFLenses101/focal_length.html

[RTMiller]

Here's a little backyard test I did a while ago. I don't know the exact distance to the stop sign but it was easily a couple hundred yards away.
http://www.photography-on-the.net/forum/showthread.php?t=65308

[SkipD]

There's a LOT more to choosing a focal length. I'd like for you to read the following thread, as you will find it very informative - with photo examples and everything: http://photography-on-the.net/forum/showthread.php?t=94147

There's another thing to understand too. The 100-400mm lens, for example, produces different images on different camera bodies (having different film or sensor sizes). On a 20D, for example, you see less of the image that would be produced on a 35mm film camera (or "full-frame" digital body). This gives the impression that, when mounted to a 20D, the lens is 1.6 times as long as the same lens mounted on a "full-frame" camera such as the new 5D. This gets to be very confusing, and there are a number of threads on the forums here that try to de-bunk a lot of the misunderstanding about the "crop factor".