niels123 said:
What are your experiences? How does it (AF-wise) compare to the other Sigma art lenses (for example 35 and 50 which I had and still have)? I think the AF-consistency of the 50 art is acceptable, but not great.
I have also (for a moment) considered the 85 1.4 art, but I already have both the 1.2 II from Canon and the 85 1.8 VC from Tamron and I like the relatively compact design and stabilisation of the Tamron. The size and weight of the 85 1.4 art is holding me back from it (and also lack of IS). In addition: from reviews I get the feeling that the 135 art has more resolution than the 85 art. What do you think?
Niels
In considering Sigma focusing issues, you need to think of it as two different issues:
1) Focus Adjustments Based on Subject Distance and Focal Length
I have found that the AF consistency with my Art lenses (I've owned 5 and currently own 3) was pretty darned good after they were painstakingly and annoyingly optimized with the dock. To give perspective, doing a "quick" dock AFMA process of 1 hour didn't result in best results, but wasting 3 hours on a lens getting it just right did the trick. This length of time was with a zoom lens (18-35), and it's 4x faster with the primes. Glad I did it though. Amazing glass, unmatched in an AF lens.
2) AF Consistency
Once you have it zeroed in with the dock, there is a potential separate issue, which is focus consistency. If you have a properly adjusted lens, this could surface as a probably small problem if it appears at all. It should be worst with the 50 Art, as it has the largest focusing element prior to the introduction of Sigma's new motor system (more on that below). This problem is when the lens knows precisely where to focus, but the motor mechanism fails to consistently get it to the right place each time. It is super easy to test. You lock a camera down and point it at a stationary target and rack the focus one way or the other and then press the AF button and see if it keeps going to precisely the same place each time. My 24mm and 50mm Art lenses consistently focus to within 10-20 percent of the focal plane, which makes me happy. I suspect some folks complaining may have higher standards than I do, or they don't have as well adjusted a copy of the lens.
The 135 Art and the 85 Art were upgraded to a larger focusing motor to both handle the movements of larger/heavier focusing lens elements, and I believe also a second motor or set of gearing that allows for a more fine final adjustment. My 135 Art is rock steady consistent at f/1.8, which is particularly impressive because no other 135 even goes down to 1.8, so it is dealing with the thinnest focal plane of the bunch.
Conclusions:
- If you compare image quality (you can see one comparison below from The Digital Picture...) the Sigma does noticeably better than the Zeiss at f/2, so you'd likely sell that lens barring any odd attraction to a specific rendering quality...
https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=924&Camera=453&Sample=0&FLI=0&API=0&LensComp=1122&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=1
- The 135 I have didn't even require any AFMA adjustments. More powerful, faster focus motor that appears super confident, where my 24, 50 and previous lenses just felt unnotable.
- The typical answer you'll get on these forums (and it's usually a good one) is to rent the lens and see for yourself with your setup. That said, few people will waste the hour it'll take to adjust the lens (if they even HAVE the dock) with a rental. I'd recommend buying from B&H with the dock and returning if the performance isn't adequate.
- Waiting for Canon is a bit of a sport, but we can expect that if a new 135 does come and has IS, it will not be the same shocking sharpness of the 35mm II, as explained by their engineers in this week's posted interview on their compromises in order to get IS into a lens of that aperture. It appears the 85 IS L is impressively sharp, but doesn't have the Blue Goo and other elements that largely eliminated various aberrations so impressively in the 35. This appears to have been a design compromise decision that seems perfectly rational. This means your choice would likely be to emphasize sharpness with the Sigma or IS with the Canon (if it comes). I'd say that we're likely to see a 50mm come out first, but then I think Canon won't do that because it's become too entertaining to watch some forum members here go apoplectic when they fail to produce one.
