noflashplease: By all accounts, Nikon's 20mm F/1.8 is sharp wide open, takes standard 77mm filters and lens caps. Canon doesn't have anything comparable, of course.
noflashplease: Canon FD 20mm and EF 20mm lenses have completely different optical designs.
Jan Madsen: I purchased the previous version. A good idea, but unfortunately a completely useless system. Far too many bugs, and when I eventually got a measurement / AF correction it was often way off for large aperture lenses - where it really counts. For F/2 and smaller apertures it works ok, for f/1.2 the results fluctuates, and for the Canon 50mm f/1.0 it is almost impossible to get anything meaningful out of the system.
Now if only Reikan would offer support, and correct the numerous bugs, fine, but this company has offered the worst support I have ever encountered with a commercial product - that is none. You can create a support case, and then - nothing. No answer for months. Only way to get any kind of reply from them is to plaster their Facebook wall with notes about the poor service - that worked twice, but then silence again. Unless Reikan has made a dramatic change of attitude towards the customers I would say use other options. Sadly.
I also have the 85mm f/1.2, and like Dr_Jon has experienced the rather high level of purple fringing at f/1.2. It is really annoying on high contrast subjects. Other than that (and the weight!) it is a wonderful lens, much easier to use than the 50mm f/1.
Rishi: The 50mm f/1 has a lot of longitudinal chromatic abberation mixed with some spherical abberation, so when you look at a point source of light (at f/1 of course) and racks the focus manually from front focus to back focus the light goes from a green diffuse blob through a minimum of spherical abberation to a red blob, but where other lenses with less extreme aperture have a well defined best point of focus the 50mm f/1 has a more diffuse transition through best focus, so what is really the best focus is not that simple... Accepting a little spherical abberation gives highest sharpness (which is still not that good), but also rather low contrast, while minimizing spherical abberation gives better contrast, but even lower sharpness. Pick your poison... The lens is best for moody, low contrast subjects, it is certainly not the sharpness king, not even stepped well down (center gets pretty good, corners never).
Rishi: Reikan software gave consistent results with the 85mm f/1.2 II on a majority of the runs, but on some runs the result would be another value, clearly off. Setup the same for all runs.
The 50mm f/1 gave results totally off on all runs, and with values all over the place. Admitted, it is a difficult lens, as maximum sharpness is a rather diffuse concept with this lens (at f/1 of course): You can try to minimize spherical abberation (one value), longitudinal chromatic abberation (another value) or some compromise in between (a third value) - and it varies with focus distance... But the Reikan software should at least give consistent results. When I finally got a reply from Reikan (after 37 days) they admitted never having tried the 50mm f/1, and suggested I use another USB cable!
Shooting real world the results are consistent, even for the 50mm f/1. I have a 1Ds-II (good AF), and a 5D-II (so-so AF) so the results are within the capabilities of the camera AF systems.
I purchased the previous version. A good idea, but unfortunately a completely useless system. Far too many bugs, and when I eventually got a measurement / AF correction it was often way off for large aperture lenses - where it really counts. For F/2 and smaller apertures it works ok, for f/1.2 the results fluctuates, and for the Canon 50mm f/1.0 it is almost impossible to get anything meaningful out of the system.
mrc4nl: "According to Canon, the 11-24mm's front element is the largest ever manufactured for an SLR lens, at 87mm in diameter"
Nah, the front element of the nikon 6mm f2.8 is bigger(by a wide margin) 200mm!
Nikon 1200-1700mm f/5.6-8: 212mm.Canon 1200mm f/5.6: 214mm!
MPA1: Only f4? Who wants a lens that slow? I think the Nikon 14-24 f2.8 is still better.
You can't compare 11 and 14mm, there is a huge difference.
Presumably they mean "largest aspherical lens element", otherwise it doesn't make sense. The Nikon 13mm (to stay with the rectilinear lens type) is far bigger.
COSTISTOICA: Yesss, canon wins. canon has need 40 years to beat Nikon 13mm f/5,6 wide angle lens :" The 13mm is Nikon's greatest lens. It is Nikon's greatest lens because not only is it big and supremely expensive, it is Nikon's, and perhaps photography's, greatest lens because it lets us make photographs we can make no other way.
The Nikon 13mm is the world's widest non-distorting professional SLR lens ever made, by anyone, in any format. It allows us to get closer to our subjects, stretch distances and create images from perspectives otherwise unimaginable. "
The Sigma 12-24mm Mk. I has very low distortion, low at 12mm, almost gone at 13mm. The Mk. II is quite different, with lots of it. Will be interesting to see the distortion level of the Canon 11-24mm.
Peiasdf: Fancy. Is this the widest rectangular-wide production lens ever made?
I think you are mixing things up... Widest Nikon is the 13mm f/5.6 from 1975. The Nikon 12-24mm f/4 is a DX lens. Sigma 12-24mm was wide angle king in rectilinear 24x36mm lenses until today.
Scottelly: I wish they would just update the 50mm f1.2 AIS lens into an auto-focus G lens with nano-crystal coatings (to slightly improve the image quality) with the EXACT SAME optics in all other respects. That would be AWESOME. Of course, maybe they already considered that, and they decided not to mess with a good thing (they already have the 50mm f1.2 AIS, and it works great). This lens certainly gives people more choice, doesn't it?
Scottelly you need to view the rear pupil with the eye approximately where the sensor is - everything else doesn't make sense - photos of the rear pupil are from far away, and will show wildly varying sizes. Put your eye close to the rear of the lens, and the f/1.2 pupil will look nearly the same both for a 50mm and a 85mm. And yes, the Canon EF mount is substantially larger, so that f/1.2 is easy, and f/1 is just possible. Furthermore, the smaller Nikon F mount is further from the sensor (enough space for a Nikon->Canon converter ring), making things even worse.
To Scottely: You must distinguish between front pupil and rear pupil. The front pupil is detemined by focal length divided by aperture, so a 200mm f2 lens is 100mm (big!). Rear pupil is almost 100% dependent on aperture, not focal length. So a 200mm f2 and a 24mm f2 have rear pupils about the same size, and thus require about the same amount of mount diameter. All this is a simplification, but it is an easy way of describing things. So as aperture, not focal length, is the important parameter at the rear, there is a limit on how large an aperture can be handled by a particular mount, irrespective of focal length - limited by the mount diameter in conjunction to its distance from the sensor. Most mounts are limited to around f1.2, inlcluding the Nikon mount, but Nikons electrical contacts gets into the way for f1.2, unless you cheat by letting them cover a little of the rear lens. Canon does the same for f1.0, the contacts sits on a platform over the edge of the rear lens.
HiRez: Wow, that is one bigass 55mm lens. Why can't they make an autofocus version of their lenses though?
In reply to Petka: There is no technical obstruction for making the lens autofocus. The Canon 85mm f/1.2 moves the complete optical system (except the rearmost element) during (auto)focusing, and that is one heavy clump of glass, much heavier than a 55mm f/1.4. Same with the Canon 50mm f/1, also a heavy lens with lots of glass.
Zeiss has decided to omit AF, that is a marketing decision. Makes the system technically much simpler, and they avoid all the hazzle of reverse engineering the AF protocol/interface for each camera brand.
dansclic: High quality at moderate prices ???? I Am dead !!!! If you want quality you have to pay for, cheap stuff from sigma is not a good deal : 50 per cent is decentered, mecanical problems, un reliable autofocus.....So again a 1700 USD Lens and what ? Buy a used nikon or canon instead.
Sigma lenses so far (for Canon 1DsII and 5DII):15mm f/2.8 fisheye: Fine.12-24mm f/4.5-5.6: Fine.20mm f/1.8: Required tape on the hood to avoid ratteling.28mm f/1.8: Fine.70mm f/2.8 macro: Sharpest lens ever encountered.100-300 f/4: Fine.So except for the tape on the 20mm hood (just like the Canon 200mm f/1.8!) no problems at all for 6 lenses.
Not the worlds first 180mm f2.8 macro - Sigma made one earlier, in the 1990's, also with AF. So it is kind of a revival.
J.K.T.: I simply can't figure out what is the point of having both this and 150/2.8 OS.
Just like what's the point of having both a 24 and a 28mm in the catalog. Choice. I have the Sigma 70mm macro, the 150mm would complement it nicely, someone having a 100-105mm might find the 180mm a good second longer macro.
Not the first time Sigma had a 180mm f2.8 macro though, so it's kind of revival, with all the modern additions of course.