Firstly the Sigma 35mm f/1.4 DG HSM ART lens is a work of art. (No pun, really) It is beautifully made and feels incredibly robust. It also feels expensive, serious and like it would last for ever. Just one example. It has the best lens hood I've ever used. Its rigid and solid and locks into place very securely. These are Leica type tolerances. I'm not denying it's heavy and large, it is, but just handling the barrel and shooting pictures with it, it absolutely oozes class. This is not the Sigma of old, who made decent lenses but to a budget, but something much more upmarket. The fact that the 35mm f/1.4 is actually substantially cheaper than it's marque equivalents makes it even more remarkable. The black smooth sheen also fits with the A7r very well. This isn't retro chic, this is ultra modern state of the art optical engineering and the message you get from it is "If you can't make great images with this, it's YOUR fault.'
Secondly, paired with the LA-EA4 adapter the lens has seriously good auto focus. I read somewhere that someone else felt that a-mount lenses with this adapter focused quicker than the native lenses did. I certainly wouldn't argue with that. I was surprised by this and also by how smoothly and silently the lens focuses. Very impressive. In fact I'm so impressed I spent last evening on the internet blowing just over £200 on 4 ageing Minolta AF 35mm lenses, three zooms and a 50mm f/1.7. This includes a 35-70mm for £18!! And yes I know what I've said about Minolta lenses in the past, but some of you have convinced me that I may have got this wrong. However they are very cheap and I'll find out soon enough which of us is right without having spent a great deal. And if they work well then that's a bonus.
All this because I really enjoyed using the A7r with AF. I know I have the 28-70mm but the Sigma is a much better lens in almost every way and after my tests I anticipated great things. And as you will see later I wasn't disappointed. I don't often recommend things as you know, but I would say that if you are considering the LA-EA4 adapter and a-mount lenses, either because you have some or are planning to get some, then my experiences are 100% positive. It is bulky but actually very light, and as I indicated the AF, with the Sigma 35mm, is very good indeed. It's even pretty good in low light, though as with any AF you do need to find something with decent contrast to focus on.
So to the main course. The image quality. Well, quite simply, it's one of the best lenses I've ever used and it might just be the absolute best. It is almost flawless (Almost!) As has been well documented elsewhere it's superb wide open. The point of focus is pin sharp and there are no soft corners and with the lens profile in Adobe camera raw there's no vignetting and not very much CA or fringing. (hence almost flawless) There is a picture in the album of a half-timbered library and I took the shot at f/1.4 by mistake. I was shooting some stuff wide open while a cloud was overhead and when the sun came out for a few seconds I shot the building without changing the aperture. When I looked at the image on my screen I was stunned by just how good it is. Most lenses don't look this good at their prime apertures.
The lens has no light fall off and is wonderfully consistent across the frame and in conjunction with the lovely smooth and precise AF it was a pleasure to use. It's also spot on at f/1.4 for focusing, no micro adjustment needed here. However I would mention that I needed to keep the shutter speed up. It didn't particularly like anything lower than 1/125th. sec. though this I suspect has a lot to do with the camera and it's shutter. Sharpness? well of course it's sharp. If it wasn't I'd want my money back, but for me the real strength is the ultra-clean superbly even files. Plus there is no distortion that I can see and minimal flaring when shooting directly into the sun. To be honest I'm not used to that. It's the only lens I can remember using that doesn't need some adjusting to get results like this.
It's obvious that this is a lens made with as little compromise as possible. And no it's probably not as good as the Zeiss 55mm Otus, but then this is a much more useful focal length for me. Plus it's such a great all-round lens. If I was still shooting weddings, I'd probably use this lens for everything. It also opens up possibilities for the A7r to work in low light and unlike other fast lenses I've used, I would have no problem shooting wide open. It is easily the best lens I've ever used at it's maximum aperture and in some ways I guess it's setting a new benchmark for that.
Now I can't tell you how it compares to other 35mm f/1.4 FF lenses, because I've never used any. But if they are better than this, then they must be something very special indeed. I can't wait to use it again.
N.B. to see more on the cameras and lenses featured in this post click on the relevant labels (tags and keywords) at the bottom of this post.