This is a telephoto Canon EOS prime lens that Sigma discontinued about a decade ago and they languish on eBay for under $250 USD because they often don’t allow proper aperture control when mounted on current Canon bodies. In older bodies, the camera would issue a sync command twice before requesting lens info and since Sigma reverse engineered the EOS communications protocols, these older lenses would wait for the 2nd sync command before responding. Newer Canon bodies now only issue a single sync command so an Error 01 will result if you try to change the aperture from its maximum opening.
The lens is otherwise a very good performer, with 10 elements in 7 groups, 2 super low dispersion elements with true internal focus and a nonrotating front element. There is an integral sliding hood. In terms of size and weight it is a dead ringer for the Zuiko 300 mm f/4 PRO. When used with a m43 smart adaptor, there appears to be no issue with aperture control. I plan to use it with my Metabones Speed Booster to give a 290mm focal length at f/4, again very similar to the Zuiko 300mm f/4 PRO.
I’m currently using the Zuiko 75-300mm zoom which has acceptable image quality, but I’m always looking for the best prime lens performance. Here’s what the Zuiko 75-300 MTF curves look like at 300mm @ f/6.7
And here is what the Sigma 400mm f/5.6 looks like. Top row is Sigma 400 using Kipon smart adaptor at f/5.6 and f/7.1. Middle row is with Metabones Speed Booster S at f/4 and f/7.1. And bottom row is with Metabones Speed Booster T Ultra at f/4 and f/7.1.
The Sigma 400 with the Metabones Speed Booster outperforms the Zuiko 75-300mm at equivalent apertures as expected (f/7.1 vs f/6.7). However there was no AF with the Speed Booster T Ultra, only with the older Speed Booster S. It seems to happen only with this Sigma lens for some reason. It may be that I need to update the firmware on the T Ultra.
I took some test shots at the fine print on boxes some twenty feet away on my kitchen counter and it shows how much better image quality is with the Sigma prime. Taken with the E-M1.2 at ISO 1600 from left to right, f/4, f/5, f/6.3, f/8.
and now taken with the Zuiko 75-300 at 300mm, f/7.1 and f/8.
You can view these shots together at 100% size here: https://dl.dropboxusercontent.com/u/4852049/allcompared.jpg
Clearly the Sigma 400 with Speed Booster S wide open at f/4 is already better than the Zuiko 75-300 at f/7.1, while the Sigma 400 closed down to f/8 is incredibly sharp. AF speed on the adapted Sigma appears to be quite fast and reliably very accurate. If it wasn’t raining all weekend, I’d be outside catching some birds shots to verify the Sigma 400mm’s performance.
I caught this black grey squirrel in my yard this afternoon about 50 feet away and up a tree to challenge the focusing system. Left is the 75-300mm f/7.1 and right is Sigma 400 @ 300mm f/7.1. You can view the 100% crop here: https://dl.dropboxusercontent.com/u/4852049/squirrelcompared.jpg
In case you’re wondering what that hazy horizontal smear is below the squirrel, it’s the fishing line I strung from between the back of my house and the large silver maple. I had my son’s unicycle toy riding back and forth on it for my C-AF tracking tests in an earlier post.
Some more comparison shots. You tell me which one is which!
And here are the links for 100% sized versions: https://dl.dropboxusercontent.com/u/4852049/femalemallardcompared.jpg
And: https://dl.dropboxusercontent.com/u/4852049/mallardmalescompared.jpg
Jim Chung's Ramblings 
The right side ducks are the Sigma Ducks.
LikeLike
Does autofocus work on the Sigma lens with the adaptors?
LikeLike
Yes, the Sigma has AF with Kipon and Metabones smart adaptors
LikeLike
sorry Jim, I have kipon and has a wrong AF… slow and
imprecise… with Omd em1.2 and sigma 400 apo macro …
LikeLike
Try updating the Kipon firmware. It’s not fast but seemed to be accurate.
LikeLike
I will invite all my friends to your blog, you really got a great blog.;-~:;
LikeLike
Fascinating and informative article, Jim. Incidentally I just discovered your blog and have been slowly (and apppreciatively!) reading my way through a number of your posts and thoughts. I’m especially intrigued by this post as I’m considering going down the rabbit hole of interesting adapted telephoto lenses for my venerable (but quite fine) E-M1.
I’m also curious – do you have either any direct experiece with the Sigma 400 tele macro’s slightly smaller sibling, the Sigma APO tele macro 300mm? My supposition is that it should do very nicely as well, with the right mu-4/3 adapter. It has the additional advantage of an f/4 aperture, though not quite the reach of its larger sibling.
One last question, from my curiosity – you are using the Metabones speed booster on the 400mm. Do you have any experience with or recommendations for any other adapters? (The list would include Kipon, Viltrox, Zhongyi, etc…)
Thank you again for a thoughtful piece.
LikeLike
Thanks for the comments! I used to have an early Kipon adaptor which I found lacking so I mainly stick with the high quality Metabones adaptors. The Vitrox adaptors appear to be quite good but occasionally there are issues as you will discover in more recent articles, Metabones is the most reliable and best performing.
LikeLiked by 1 person
Thank you, Jim. I’m seriously considering finding an older Sigma APO tele macro too – preferably the 400mm, but possibly a 300mm, which has less reach but is also a stop faster. If I can find one, I’ll need an adapter – and though the Metbones seem to garner the highest amount of praise, Viltrox seems to be the consensus choice for a cheaper alternative. Some folks have opined that in their early years, Metabones adapters had more of a hit-or-miss record, but because they stuck with it and kept evolving and improving, they eventually ironed out most of the kinks. Supposedly, Viltrox is trying to do the same thing; but, obviously, they are a number of years behind Metabones. In any case, your input is helpful and most appreciated! and should I get one, I’ll let you know my results 🙂
LikeLike