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04/10/2005 07:44:07 AM · #1 |
Hello all...
Thought I'd share this with those of you new to photography:
Focal Length and Compression
This is a technique that can be used to enhance your images (as you take them of course). The above website has a very brief explanation but the illustration is excellent. I used this for my cemetary shot and am working with it for my free study.
As we all know, the camera doesn't necessarily see things the way we do. But sometimes it sees it better using the right filters or lenses.
Happy hunting!
d
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04/14/2005 05:01:55 AM · #2 |
Thanks... very nice demonstration.
Yoav.
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04/14/2005 05:20:19 AM · #3 |
As an interesting corollary to this, had he also made a shot from the 100mm position using the 35mm lens, and then CROPPED it to cover the same angle as the 100mm shot, the images would be indistinguishable from each other if it weren't for the increased graininess of the cropped-out and enlarged section.
In other words, it's not that a telephoto lens itself has some magic ability to compress things, because it doesn't. It just performs what amounts to a crop on the visible scene. Don't believe me? Try it yourself. Set up your camera with a zoom lens on a tripod, at maximum zoom, and bring it to bear on some near-distance objects that "stack" with each other. Take that shot, then zoom back as far as you can and take another. Now crop the second shot to include only what the first one sees. You can superimpose these images one ach other precisely; try it in photoshop and see.
Robt. |
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04/14/2005 05:24:04 AM · #4 |
Robert,
Does what you're talking about take into consideration the lamp post is an identical size in all the shots? |
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04/14/2005 05:30:26 AM · #5 |
Originally posted by PaulMdx:
Robert,
Does what you're talking about take into consideration the lamp post is an identical size in all the shots? |
Yes. The point here is that the changes we are seeing in the demonstration have nothing to do with the optics of lenses and everything to do with the actual, physical relationship of the objects to each other and to the camera. What a telephoto lens does (and it's ALL it does) is optically crop your field of view. It does not, and cannot, change the physical relationships of objects to each other.
In other words, you choose your shooting position to get the relationship between objects that you desire, then you choose your lens (or the amount of zoom) to frame those objects as you wish them framed. But for any given position, the ONLY difference between a telephoto shot and a normal shot cropped toinclude the same field of view as the telephoto is that the telephoto shot is "sharper" since it uses the entire sensor, not just the cropped, central portion of it.
Robt. |
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04/14/2005 05:59:12 AM · #6 |
But if you shoot with a 50mm lens, and then retreat to get the same field of view of your main subject with a 300mm lens, the background is compressed compared to the 50mm shot. Isn't that the point?
Robert's example is true, because the image plane is at the same respective distance and angle to the scene whatever lens is used.
E |
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04/14/2005 06:04:05 AM · #7 |
Originally posted by e301:
But if you shoot with a 50mm lens, and then retreat to get the same field of view of your main subject with a 300mm lens, the background is compressed compared to the 50mm shot. Isn't that the point?
Robert's example is true, because the image plane is at the same respective distance and angle to the scene whatever lens is used.
E |
Right, the "point" is to step back far enough to get image compression. No question about it. It's just that in my experince as a teacher, most people believe there's soemthign "magical" about telephoto glass, that the lens itself does the compressing, and this is not true. Let me put it this way; back in the film days when i was teaching, I'd have students complain that they 'couldn't get" this shot because they had "only" a 200mm lens and they "needed" a 300mm lens to "get the compression they wanted"... They were always stunned when I pointed out they can get the exact same shot with the 200mm and cropping.
Robt. |
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04/14/2005 07:22:38 AM · #8 |
Robert,
You are absolutely right. Not only do I take multiple images of something I like with different aperatures, I take many shots at different focal lengths and distances. You never know when that 10mm or 1 stop can make a huge difference.
I posted this link because:
1. I stumbled across it and thought it very simply illustrated a basic photographic technique and
2. I have seen images here that I thought would go from good to great with its application
Sorry if I made it sound as if the lens does all the work. I just wanted to give people the option and something to think about the next time they go out to shoot.
Thanks for the great clarification!
d
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