DPChallenge: A Digital Photography Contest You are not logged in. (log in or register) 
 

DPChallenge Forums >> Tips, Tricks, and Q&A >> What are the Results of ...
Pages:  
Showing posts 1 - 8 of 8, (reverse)
AuthorThread
 03/03/2004 03:16:16 PM · #1
... putting a circular fish eye lens on a DSLR with a crop factor? I'm thinking that some of the circular image is cropped off, correct? Anyone has some examples if you have tried this before?

Thanks!
 03/03/2004 05:04:51 PM · #2
I don't know that I can authoritatively answer your question, but I would think that since you are only imaging the middle of the projected image, the fisheye effect would be reduced compared to a full-frame sensor (or 35mm film). This site has some comparison shots of the Sigma 12-24mm f/4.5-5.6 Zoom and Sigma 15mm f/2.8 Fisheye Lens taken with a 10D. You can even click on the reduced-sized versions to see the full-size JPEGs so you can better evaluate the lenses.
 03/03/2004 05:24:04 PM · #3
Originally posted by EddyG:
I don't know that I can authoritatively answer your question, but I would think that since you are only imaging the middle of the projected image, the fisheye effect would be reduced compared to a full-frame sensor (or 35mm film). This site has some comparison shots of the Sigma 12-24mm f/4.5-5.6 Zoom and Sigma 15mm f/2.8 Fisheye Lens taken with a 10D. You can even click on the reduced-sized versions to see the full-size JPEGs so you can better evaluate the lenses.


This is a great read but a circular fish eye with 35mm film would give you a print with a circle in the center and black borders for the remainder of the print like this.

I'm assuming with the crop factor you would loose some of the circle image. I was trying to see if anyone has experemented with a lens like this on their digital.

Thanks, EddyG!this
 03/03/2004 05:32:22 PM · #4
Ah, didn't know you were wanting to go all the way down to 8mm! Have a look at this site which indeed shows the circular image being "cropped" as expected.
 03/03/2004 05:47:41 PM · #5
Originally posted by EddyG:
Ah, didn't know you were wanting to go all the way down to 8mm! Have a look at this site which indeed shows the circular image being "cropped" as expected.


Ah-ha! Thanks for finding that. I was wondering. Doesn't look as appealing now.

Thanks again!
 03/03/2004 05:47:56 PM · #6
Yup, you crop out a more or less rectangular center section. Actually means you can use somewhat dubious quality WA lenses and get good results, because most of the CA and distortion is at the edges and not even seen on a 1.6x crop DLSR.
 03/03/2004 06:02:48 PM · #7
The Peleng 8mm fisheye produces similar results to those in the link posted by EddyG (from the Sigma 8mm). The image circle for the Peleng is a bit bigger, so there is a bit more crop.
I'd post an un-defished image, but I'm halfway 'round the world from my archives.
I've found that a "partial de-fish", just enough to get rid of the black corners, combined with framing technique, yields a very nice result. Full de-fish results in alot of stretching, and thus resolution loss, at the corners.
For the record, the Peleng 8mm fisheye is definitely a lens I will not give up. It will be even better, someday, on a full-frame DSLR!
 03/03/2004 06:22:02 PM · #8
Forgot I had an image here in SG:

Here is the original un-defished image, and here is the partially defished one.

Mebbe not the best example, but at least illustrative of the results.
Pages:  
Current Server Time: 08/31/2025 03:45:50 PM

Please log in or register to post to the forums.


Home - Challenges - Community - League - Photos - Cameras - Lenses - Learn - Help - Terms of Use - Privacy - Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 08/31/2025 03:45:50 PM EDT.