Okay, let me be very clear here. I am NOT saying that these are spectacular lenses (maybe with a few exceptions), nor am I saying these are better than native options etc. All I'm saying is, well, it's an option.
A couple months ago I stopped at my local camera store (that tends to be Canikon centric), I can't remember what I was there for but I usually browse their selection. I'd been thinking about a long tele for occasional wild life, but wasn't prepared to pay for any modern offerings. A Sigma APO Tele Macro 300/4 in Canon EF mount caught my eye.
"It's good, but it only shoots wide open" he said " and Sigma won't re-chip it." Well, I happened to have my Metabones with me, so figured I'd give it a go. after a few shots wide open, he mentions that it Error's out on a Canon body as soon as you stop down, so I try... you see where this is going. It works great! I can shoot at any aperture. Then he pulls out a 400mm APO Tele Macro f/5.6. I wasn't 100% of the optical quality though, so I passed on it that day and went to do some homework. As soon as I started reading reviews of this lens, I figured out when I could go back to pick it up.
Don't worry, I'm getting to samples from the lens. But in case you're thinking I got lucky with the Tele Macro's, a few weeks later I see a Sigma Aspherical 28mm f/1.8 come along, with the note that it won't stop down on Canon bodies, and a price reflecting the issue. Curious (and a sucker for a fast prime) I of course purchased it. Tossed it on the MB (It's actually a MkIII running 0.47 FW) and voila, I have a fairly loud but fast focuing fully functional 28mm f/1.8 with pretty good IQ.
Now things aren't all perfect here, and I'm still learning how to best use these lenses and their strengths and weaknesses, which I've detailed below. But if you're shooting adapted with a Metabones, and any of the below lenses are of interest to you, I'd say give it a go. You can find a list of possible lenses at the end.
Results - 28mm f/1.8 Aspherical
So how do the lenses fair? Pretty well, especially given the price.
The 28/1.8 is reasonably sharp wide open, with usable midframe results, but smeared corners. At f/11 it makes a good landscape alternative though. Vignette is somewhat high which isn't surprising, but I found it fairly pleasing in use. In looking up information, Sigma states this was the fastest wide for its time.
As mentioned before, vignette is high, distortion is lower than I would have expected for an old, fast, wide.
Bokeh isn't great in high stress environments, but I found it fairly pleasing overall, certainly decent for an older 28mm at f/1.8. Unless there are hard OOF points of light, like through trees it's pretty smooth. Wide open is busy, and it never really cleans up a whole lot. Overall I'd say f/2.5 is the smoothest, smaller apertures start to show too much shape.
CA is well controlled in the center, though it's present in the periphery. It's a one click clean up though, so not something I'd worry about. Full disclosure, this was at f/2.8, not f/1.8 but I haven't seen it be much of a problem in real world use so I'm not going to worry about it.
Handling is good. It has flaked on me one time, where the AF motor was making noise but not focusing. A quick disconnect and re-connect and I was back in business. I'm also on a MDIII with firmware 0.47, so there may be room for improvement, I'll probably get an MBIV one of these days. Focus is anything but quiet, I'd say its close to the noise from the Techart Pro AF adapter. It's sure and quick though, better than I was expecting. I'll try and get a video of the speed and noise but it's likely to take me a while. Below is a gallery of some real world shots. It's not going to win any awards, but for a very affordable fast wide, I think it's a keeper.
Results - 400mm f/5.6 APO Tele Macro (Non-HSM)
Okay, we're not getting a more in depth review like the 28mm. Just a few samples, and quick thoughts. I find this lens very sharp. AF is quick enough once it finds it's range. It's a good idea to use the focus limiter, because if it goes off on a hunt it's going to take a few seconds to get back towards infinity. The macro feature is nice, as it allows approx. 1:3 at 400mm, which is a comfortable working distance. I had some concerns about AF accuracy at first, and while I'm still testing, I think it was due more to the lower light shown in the horse photos. It didn't act like it was having trouble acquiring, but seemed to backfocus at the time. Unfortunately I already deleted the ones where it was back focusing, and so far I haven't been able to re-create the problem (not complaining!) I'll update this if there's more to learn as I go. Also planing on pairing this with a Sigma 1.4x so maybe we'll do a more through review in the future.
8mm 4 EX Circular Fisheye
15mm 2.8 EX Diagonal Fisheye
28mm 1.8 II Aspherical
50mm 2.8 EX Macro
105mm 2.8 EX Macro
300mm 4 APO Tele Macro
400mm 5.6 APO Tele Macro
500mm 4.5 APO
500mm 7.2 APO
800mm 5.6 APO
24-70mm 3.5-5.6 Aspherical UC
28-70mm 2.8-4 UC
28-80mm 3.5-5.6 Mini Zoom Macro Aspherical
28-80mm 3.5-5.6 Mini Zoom Macro Aspherical HF
28-80mm 3.5-5.6 Mini Zoom Macro II Aspherical
28-105mm 2.8-4 Aspherical
28-105mm 4-5.6 UC
28-105mm 4-5.6 UC-II
28-105mm 3.8-5.6 UC-III Aspherical IF
28-135mm 3.8-5.6 Aspherical IF Macro
28-200mm 3.8-5.6 Aspherical UC
28-200mm 3.5-5.6 DL Aspherical IF Hyperzoom Macro
28-300mm 3.5-6.3 DL Aspherical IF Hyperzoom
70-210mm 3.5-4.5 APO Macro
70-210mm 4-5.6 UC-II
70-300mm 4-5.6 APO Macro super
70-300mm 4-5.6 DL Macro super
100-300mm 4.5-6.7 DL
135-400mm 4.5-5.6 APO Aspherical RF
170-500mm 5-6.3 APO Aspherical RF