burychka Offline Upload & Sell: Off
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Metabones Speedbooster EF to EFM has arrived. Quick and dirty tests. I've not compared these lenses on a full frame body yet, but I do have some recollection of their strengths and weaknesses. As to the adapter: Came in a box from B&H with only one deflated air pillow and so was left to bounce around in the box. Fortunately it has its own protective plastic box as well and was undamaged. No manual provided, so I am at a loss as to the purpose of a small button to the left of the top. I can't detect any change when I press it. Have sent inquiry to metabones tech support. It is heavy and feels substantial. Lenses are a tight fit.
All the lenses I've tested had AF lock just as quickly as if the Speedbooster were not there. No focus issues at all on newer or older lenses.
Except for the 50/1.2 all show the modified F stops in the M50 viewfinder. That is, the 50/1.4 when wide open, reports F 1.0 in the viewfinder and in Adobe Bridge. Lens focal length and identification show differently for primes and zooms. Focal length used is reported as the actual focal length times .71 for all lenses, so the 50 shows as 35, the 24-105 zoomed wide shows as 17mm. As to lens I.D., primes show the original focal length, so the 50 shows as 50. Zooms otoh show as I.D. the zoom range modified by the .71 factor, so that 24-105 is identified as a 17-74.
I did quick tests with the camera on a tripod pointed at the brick wall in back of my house. I use that for tests because it is easy to see sharpness differences, distortion, and vignetting. I have an outdoor clock that I include to see detail and CA. Overall, all the lenses I tested were sharp in the center and softer in the corners, however not much, and I could almost say the lenses performed about like they do on a ff camera. In each case, if I stopped down to the native max aperture, I would have to say they were very close to the original FF performance.
Adobe RAW. I routinely use the lens corrections tool in Adobe RAW (CC). With the Speedbooster, the program did not auto detect the lens as it normally would. However, if I selected the lens from the drop down, the corrections--distortion, vignetting, and CA--were as they should be. With the 50/1.2, the 50/1.4, and the 28-135, a bit of manual purple fringing correction was needed. For the other lenses Adobe's built in corrections were all I needed, except for the ancient 35/2, which I guess is missing from Adobe's database. Interestingly, that lens had almost no distortion, vignetting, or CA even wide open at the Speedbooster F1.4.
Here are the lenses I've tested so far. I don't have an online site to upload, or I'd be glad to do that. For each lens, I tested it wide open, then stopped down 1, 2, and 3 full stops. I've not fully tested, but I did try a couple of wide open shots of a foreground object, and the background bokeh looked really good with both 50's, the 85, the 28-135, and the 35/2.
50/1.4 boosted to 1.0
50/1.2 boosted to 0.85
28-135 boosted to F2.5 - 4. This old lens was a pleasant surprise. The old rubber focus ring is sticky, though. Bridge sees it as a 20-95mm zoom. Effectively 32-152 F2.5-4. Interesting.
24-105 boosted to F2.8. Nothing short of spectacular. Pretty sharp in the corners, Adobe RAW fixed 100% of distortion, vignetting, and CA. Reports to Adobe as a 17-74 (times 1.6 makes it effectively a 27-118/F2.8. Now that 's a walking around lens. Imagine the size and weight of a 27-118/2.8 as an actual full frame lens.)
85/1.8 boosted to 1.2 Effectively a 96/1.2 with nice bokeh.
35/2 boosted to 1.4. Effectively a 40mm F1.4. Odd duck, eh? This was always an underrated lens with noisy AF (fast but sounds like a wasp in a matchbox!)
70-200/2.8 boosted to F2.0 with fast AF. This is an action lens, even though the M50 is marginal as an action camera. Basketball, soccer? Serious vignetting, but the Adobe RAW slider all the way over fixes it. Effectively an 80-227 F2.0 in full frame vernacular.
Tamron 150-600 F5-6.3 boosted to F3.5-4.5. FF equivalent 170-680. Everything works but this lens on a crop sensor is worth more as a 240-960 FF equivalent zoom without the extra stop of light, I think.
All in all, I think this works about as well as I had hoped. More testing is necessary, but the mid range of focal lengths, from say 24-200 are probably where I'll find the most utility in the extra stop of light. The 50/1.4 is one to look at. A FF equivalent of 57mm F1.0 makes that lens (that almost everyone owns already) a low light wonder. The 70-200/2.8 is similarly transformed, and I'll bet the value would be even more appreciated by someone with a 70-200/F4.
I haven't tried the 100-400, 300/2.8, the 24-70/2.8, 500/f4 but I will. I'm happy with this purchase, as it brings new capability to some old lenses and new ones too.
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