Daily life with some old EF glass and a new M6 Mark II

davecheng wrote:

Yeah, it's hard to justify the Metabones at three times the cost of the Viltrox. The few available online comparisons seem to indicate they are comparable in terms of centre sharpness. That said, I've had my Metabones now for a couple days, and it's a keeper for me.

The Metabones has better off-centre sharpness. It appears to colour the resulting image a lot less than the Viltrox — both in terms of a colour cast, and what it does to the bokeh. The Vilrtrox introduces a slight swirly quality to the out of focus areas.

I feel the Metabones is more faithful to what the lens would actually look like on a FF camera. But most importantly, the Metabones works with my f/1.2 primes, whereas I couldn't get the Viltrox to work at all.

Interesting. I've had the Viltrox 0.71 EF - EOS M2 speed booster for a couple weeks, and managed to cleanly and reliably hack it to work with 4 vintage Minolta Rokkor MC lenses from 28 to 200mm I've bought for the M6 Mark II (see photos below -- even was able to adjust infinity focus for the Rokkors). I've posted this info on other forums as well.

I included a time exposure of the highway showing 'car trails', 2 second exposure at ISO 100 with the Minolta Rokkor MC 28mm f2.8 lens at f11 with the Viltrox 0.71x speed booster.

With their smaller vintage size and quality build the Rokkors are a great match for the M6/M6 Mark II. They make lovely, slightly warm, sharp images and are so much fun to use! They bring back happy days from decades ago using film cameras (although I was a Canon man even back then with F-1, T-70 and a full set of FD lenses). The Rokkors are noticeably sharper and render more detail and texture than the Canon EF-M 15-45mm lens, all day long, and are as sharp as the Canon EF 50mm f1.8 II and the three Canon EF-S zooms I have (10-18, 55-250, 18-135 IS STMs).

I can confirm what you say about the corner sharpness being an issue with the Viltrox, but also found this applies more to focal lengths of wide to standard, and can mostly be worked around by stopping down to a smaller aperture. I found with 28mm you must stop down to at least 8 (even further is better), at 50mm f5.6, at 135mm f 4, and at 200mm 3.5 is sharp across the frame.

A good way to test is to take photos of a constellation (stars) like Orion from a dark sky at all your f-stops with and without the speed booster. The pin point colored stars are an excellent test. Away from the center at wider apertures with wider lenses, coma and chromatic aberration, and lack of sharpness are noticeable, and with the 28mm the stars close the corners just plain look out of focus, even though the center stars are OK. Stopping down enough makes the performance acceptable, but then what is a 'speed booster' partly for? LOL

I found that the contemporary Canon EF and EF-S lenses, and the vintage Minolta lenses, behaved in very much the same fashion with the speed booster. Of course the EF-S lenses did vignette a bit, more so at the wider ends of the zooms, as they were designed for crop sensors.