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06/26/2008 05:25:53 PM · #1 |
Cropped lenses usually cannot be used on full-frame sensors for a number of reasons, the most noteworthy being that the image will not use the whole sensor causing bad vignetting. The second reason is the back of the lens is longer and will collide with the mirror.
Why has no one made a 1/4 inch or 1/2 inch adapter that would move the lens further out thereby increasing the size of the image preventing vignetting, and also preventing collisions with the mirror?
The connections would just feed through and it could be made from plastic.
The only possible reason I can figure out is because it might interfere with auto-focus since the point of focus would be shifted forward, however I think cameras already cope with this.
What is anyones thoughts on this?
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06/26/2008 05:31:45 PM · #2 |
Too technical for this hour of the morning....wait until I have had my third cup of coffee please...lol!
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06/26/2008 05:36:13 PM · #3 |
| D3 has no problem with cropped lenses, so it doesn't matter unless you'd do something stupid like switch to Canon :P |
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06/26/2008 05:40:03 PM · #4 |
Originally posted by Anti-Martyr:
D3 has no problem with cropped lenses, so it doesn't matter unless you'd do something stupid like switch to Canon :P |
HEHEHE, the only problem is it does this by automatically cropping the edges from the image resulting in a 6mp image. If successful the spacer ring would use the whole sensor giving a nice crisp image across the whole 12mp. :)
This ring is not unlike the already existing telephoto rings with 1.4x magnification, they do this very trick, however I am unsure if they will allow fitting a cropped lens on a FF camera. |
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06/26/2008 05:40:14 PM · #5 |
Originally posted by togtog:
Cropped lenses usually cannot be used on full-frame sensors for a number of reasons, the most noteworthy being that the image will not use the whole sensor causing bad vignetting. The second reason is the back of the lens is longer and will collide with the mirror.
Why has no one made a 1/4 inch or 1/2 inch adapter that would move the lens further out thereby increasing the size of the image preventing vignetting, and also preventing collisions with the mirror?
The connections would just feed through and it could be made from plastic.
The only possible reason I can figure out is because it might interfere with auto-focus since the point of focus would be shifted forward, however I think cameras already cope with this.
What is anyones thoughts on this? |
Where the heck did you read this?!
Originally posted by Anti-Martyr:
D3 has no problem with cropped lenses, so it doesn't matter unless you'd do something stupid like switch to Canon :P |
Yeah, true.
Originally posted by togtog:
Originally posted by Anti-Martyr:
D3 has no problem with cropped lenses, so it doesn't matter unless you'd do something stupid like switch to Canon :P |
HEHEHE, the only problem is it does this by automatically cropping the edges from the image resulting in a 6mp image. If successful the spacer ring would use the whole sensor giving a nice crisp image across the whole 12mp. :)
This ring is not unlike the already existing telephoto rings with 1.4x magnification, they do this very trick, however I am unsure if they will allow fitting a cropped lens on a FF camera. |
You can turn that off. Full frame with a DX lens (yield: vignetting)
Message edited by author 2008-06-26 17:43:32. |
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06/26/2008 05:42:16 PM · #6 |
well, i dunno about focus issues and the like, but that adapter thingy sounds like a good idea to me...
what i do know about are a few "hacks" that convert a cropped lens into a full frame compatible lens:
Nikon 10.5 fisheye on a D3 by cutting off the lens hood
Canon 10-22 on full frame
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06/26/2008 06:50:57 PM · #7 |
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06/26/2008 07:14:54 PM · #8 |
Originally posted by togtog:
Why has no one made a 1/4 inch or 1/2 inch adapter that would move the lens further out thereby increasing the size of the image preventing vignetting, and also preventing collisions with the mirror? |
For this, correct me if Im wrong but if thats all you are looking for wouldnt a simple extension tube work? ;) |
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06/26/2008 07:26:28 PM · #9 |
Originally posted by dknourek:
Originally posted by togtog:
Why has no one made a 1/4 inch or 1/2 inch adapter that would move the lens further out thereby increasing the size of the image preventing vignetting, and also preventing collisions with the mirror? |
For this, correct me if Im wrong but if thats all you are looking for wouldnt a simple extension tube work? ;) |
Those are close, the problem is, they come in either full-full or cropped-cropped, no one seems to make a cropped-full ring. |
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06/26/2008 07:45:11 PM · #10 |
| I only thought of the extension tubes as theres usually nothing inside them... never took a close look at them myself. I got a somken deal on a Tamron 2x teleconverter but they are different from the extension tubes or so I thought... |
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06/26/2008 07:45:43 PM · #11 |
| Moving the lens further from the focal plane will have the effect of enabling it to focus closer, but you will lose the ability to focus to infinity. Not a real flexible solution, unless you're after macro only. |
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06/26/2008 07:54:20 PM · #12 |
| Ahhhhh, thank you kirbic, that would explain why no one has done it yet. :) |
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06/27/2008 05:16:53 PM · #13 |
Originally posted by togtog:
Those are close, the problem is, they come in either full-full or cropped-cropped, no one seems to make a cropped-full ring. |
Thought the new ones let you do this. See //www.bhphotovideo.com/c/product/300601-REG/Canon_9198A001_Extension_Tube_EF_12.html
Also, you can use some cropped lenses on FF if you're sure the mirror won't hit the end. I've tried an 18-200 Sigma on a 5D and it works. However, you don't use the whole sensor, and the edges of the image circle leave much to be desired. |
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