I'll try to answer some of your questions .
Valiant wrote in post #3668375
Tokina 10-17mm Fisheye-zoom vs. Sigma 15mm Fisheye + Sigma 8mm Fisheye for the full frame 24x36mm sensor camera (Canon 5D).
Now I have a lens Sigma 8mm f/3.5 Fisheye (new, not a f/4) and I have borrowed Sigma 15mm f/2.8 Fisheye at comrade. But I think, that Tokina 10-17 (with shaved sun-shade
) is very interesting lens too.
I have some questions about Tokina 10-17mm Fisheye-zoom:
1. Is contrast in conter-light shoot strongly falls?
If you mean, is contrast less with contra-light, the answer is no, provided you expose correctly. I find the results actually quite amazing.
2. Was it easy to correct CA and suppress blooming?
So far I never had the need to do so. Some people say it has lots of (T)CA at the edges, I haven't noticed any to any large degree at all. As to blooming, I guess the kind that is supposed to be generated by LCAs with specular type of highlights, again, I haven't been able to get it to do this. Certainly nothing in any high contrast shots I have made so far. And just to assure you, it is easy to get LCAs with my Canon EF 85 F/1.8 at full aperture .
3. What diagonal angle of view is usable at 10-12-14mm focal length?
If you mean on a 5D, I can't really help you here, except that Michel Toby reckons with a shaved lens hood, which could be shaved even more when you're even braver than he is, it is 194 degrees, diagonally, but it vignettes in the corners, similarly to 8 mm on APS-C. Just check the links further down. At 15 mm it is approximately 180 degrees diagonally, on FF anyway, and beyond that it doesn't increase very rapidly, as you are close to the maximum AoV of the lens already. I would think it'll start vignetting rather rapidly after that.
4. Is flare effect pronounced?
No. You get a start shaped pattern, like you'd get with any lens, caused by the iris diaphragm, plus a few, small diaphragm spots, which are not very conspicuous. Contrast is still very good.
5. Is nodal point "floating"?
I don't know, I don't normally do panoramics, and I don't have a 5D, so I couldn't tell you. I'll include a few links to the relevant pages on Michel Toby's site.
Tokina vs Nikkor vs Canon: http://michel.thoby.free.fr …_Tokina_Nikkor_Canon.html
Panography (example): http://michel.thoby.free.fr …Intricate_Panography.html
Shaving the hood: http://michel.thoby.free.fr …_the_hood/Wim_method.html
Location of nodal point: http://michel.thoby.free.fr/Locate%20point%20nodal.html
Something on CAs and fisheyes: http://michel.thoby.free.fr …length_impact_on_TCA.html
and: http://michel.thoby.free.fr …sion_and_reality_TCA.html
HTH, kind regards, Wim