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Old Dec 16, 2003, 2:58 PM   #1
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Default Digital Rebel image depth perception?

I just purchased the Digital Rebel for family shots and when I take group pictures (fully automatic mode) of my kids or soccer team, the person standing closest to the camera has a head the size of a pumpkin, while the child to the back of the pack has a head that looks like a shrinky-dink (well that may be a slight exageration - but there is a hug difference in head size and the children are only 2 feet or so staggered in depth). I am using their standard bundled lens 18-55. Is this "normal" depth perception and what mode would be a better choice for such photos (indoor and outdoor) :?:

Thanks for your help
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Old Dec 16, 2003, 3:15 PM   #2
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This is neither a function of the DRebel or being in fully automatic mode, but rather a function of normal lens geometry.

Both camera position and focal length of the lens have significant factors on the perspective of the subject. When you shoot with a wide angle lens, objects that are closer to the lens will get magnified to a greater degree than those objects further away, while a telephoto lens magnifies near and far images equally, compressing the depth of view.

Your choice of focal length and the position of your camera with respect to the subject will have a lot to do with the sense of space and depth in your image.

Having said all that, with the 18-55 lens you will need to have your subjects on a flatter plane in respect to the camera lens to prevent such distortion. Photos such as you're describing would be better shot with a longer lens. There is also a post development trick with Photoshop to correct this, but it's MUCH easier to correct it with your lens choice.
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Old Dec 16, 2003, 3:52 PM   #3
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Default perspective

While ohenry said it correctly, you can prove it to yourself by shooting a group at 18mm and then move back to where you get the same group at 55mm. The wide angle group should show full shrinky-dink mode while the 55mm shot should be much better. Certainly the shooting distance may be limited in some cases but we usually would be happier with the 'normal' perspective of shots (the way the eye sees it) if we shot with something in the 30-35mm range. Longer than that compresses (good for some shots, bad for others) while shorter stretches it adding perspective distortions. The kit lens was created to allow those who own just one lens to do portraits at the long setting and wide angles at the other. Canon did all they can, the selection of which to use for which shot is up to us.
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Old Dec 17, 2003, 7:53 AM   #4
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Default Thanks alot for replies!

I was unaware that the that the perspective was altered that much with focal length - I have a large learning curve ahead...
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Old Dec 17, 2003, 9:25 AM   #5
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I would add that if you set the lens to about 33mm (you'll see a white dot on the lens where the zoom lengths are), you'll get the equivalent of a 50mm lens on a standard 35mm camera. That is, your focal distance is the same size as your sensor (measured diagonally) and your distortions based on depth of view should be none.
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Old Dec 19, 2003, 3:50 AM   #6
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Default Re: Thanks alot for replies!

Quote:
Originally Posted by Hoegenauer
I was unaware that the that the perspective was altered that much with focal length - I have a large learning curve ahead...
An unfortunate side effect of zoom lenses is that people pick out a spot to stand, and then zoom until the picture is framed as they want it. Much better to choose a focal length that suits your image, then walk forward, or backward, to frame the shot.

There's a lot to learn, but it's fun... :lol:

-jb
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Old Dec 25, 2012, 10:50 AM   #7
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Default referring to an old post about wide-angle lens perspective distortion

Hello OHenry:

This goes back to a very old posting:
Quote:
Originally Posted by ohenry View Post
This is neither a function of the DRebel or being in fully automatic mode, but rather a function of normal lens geometry. .......... Photos such as you're describing would be better shot with a longer lens. There is also a post development trick with Photoshop to correct this, but it's MUCH easier to correct it with your lens choice.
I agree with and understand everything you said, but am curious about the Photoshop trick you mentioned. I do quite a lot of interior architecture photography, and as you know, the use of really wide angle lenses is often unavoidable. I do as much correcting as I can with the Lens Correction function in Adobe Camera RAW, and use the Photoshop lens correction filter as well, but am still dismayed at times by the distortion of elements in the photograph, especially those close to the edges of the frame where the distortion is most obvious.

If you know a trick that I don't, I'd love to try your technique. I don't mean to ask you to write a long step-by-step description, but if you could give a brief synopsis, or point me to an on-line resource, I'd be grateful.

Thank you.
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