I hear from lots of people that arenâ€™t happy with the 8-15 f/4L fisheye. They wish Canon would update the full frame fisheye 2.8 prime.
Who are these people? I have no experience with this lens, but every review I've read online is glowing. They all say it's sharp, contrasty, and has excellent build quality. Heck, even the Nikon users are extremely jealous about this lens.
I think the people who are complaining are the ones that don't own the new lens. I have to admit - I was a complainer at first. I wanted f/2.8 and as a full frame shooter - couldn't care less about the zoom. Then I read the review on The Digital Picture (.com) and realised that f/2.8 on the original is pretty blurry and for me that makes it a useless aperture. I think it's probably impossible based on physics of light to make f/2.8 sharp on a 15mm fisheye. Since a soft aperture is unacceptable for a L-designated lens, I'd say this is a contributing factor in making the widest f/4 - that and it being a zoom where f/4 is standard.
Anyway I went out and got one and did a two week road trip pulling out the fisheye regularly (new toy). It has all the "C's" in spades - color, clarity, contrast - all fantastic. Unfortunately also cost - not cheap. It's a little bit punchier in the colors that my 17-40mm f/4L. I really can't fault the IQ at all except corner sharpness until you stop down but that's to be expected for a fisheye.
What a lot of people don't realise is that you can use it on a full frame down to just below 14mm. The difference between 15mm and 14mm is quite large, and I'm really glad I've got that extra mm over the original one.
Besides cost, the only other thing that annoys me is the outer lens cover comes off really easily with the slightest push of the release button. The built in 'hood' stays on pretty well as that twists off.
If you are a full frame shooter then if you want f/2.8 then you can go out and buy the old one, but expect pretty ordinary soft results and if you are a pixel peeper, you just won't use it. As an owner of the new lens, I really don't think anyone should shed a tear with the news of the old lens being discontinued.