Good Canon L lens + Speed Booster performance on a6300

[rweissman]

I have acquired a Canon EF to Sony mount  Metabones Speed Booster (latest version) and tried it with the A6300, on my two standard "smaller" Canon lenses, the Canon 24-70 L IS f4 and the 70-200 L IS f4. Overall, the combination performed superbly and focused only slightly slower than my normal Metabones Canon to Sony adapter Mark IV.  Key findings:

 

1) Most of the time (90%+) focus was obtained quickly without hunting. Fast enough--though I did not check continuous focus with fast moving objects as I rarely need that mode for the work I do (events, portraits, theatrical productions). I'm not a sports shooter so can't judge how well this combo performs here.

2) Occasionally, particularly when first turning on the camera, a bit of hunting occurred but subsequent shots (even at very different distances) were generally quick.

3) In good light, including indoors, or lower light at ISO 6400 (which still looks great!) focusing was quick--not a lightening fast as using a Metabones IV--but certainly fast enough. Not much hunting at all, except in low light. Even then, many shots involved no hunting.

4) In Lightroom (latest version released  this week with native support for A6300 raw), metadata mis-identifies Canon lenses as their Sony equivalents, but manually selecting Canon lenses applied lens corrections reliably. 

5) These f4.0 lightweight Canon lenses (compared to F2.8 versions) did become effectively 2.8 lenses; this is particularly nice with the 70-200 L f4, as the native 2.8 is a beast. 

6) If I want 'normal' focal lengths, I can use the Speed Booster. For extra reach, I can use the standard Metabones adapter. This is terrific flexibility.

7) As you'd expect, there's no comparison between the Canon 24-70F4 with any of Sony's APS-C standard lenses for the A6300. The Canon is simply superb.  And the Canon 70-200 feels lighter and operates more smoothly than the Sony 70-200 f4 (which I also use), and, of course, on the Speed Booster, keeps its normal range AND becomes an effective f2.8.

 

I could not be more delighted with these results. The Canon 24-70 L IS f4 will become my standard lens when using the A6300. While large, it is not overly large nor overly heavy.  A great combo. Frankly, I was pleasantly surprised, given reports of slow focusing on the 6000.

[molan]

What do you mean it becomes an effective f/2.8, you mean as an f/2.8 lens would exposure wise or DoF wise, on your ASP-C?

[rweissman]

Both. The design goal is to provide a one stop or near one stop improvement in dof reduction and improved light gathering. See metabones' white paper. Numerous analysts have confirmed these claims. For me, the biggest value is using a full frame lens and reducing the crop factor from 1.5x to 1.07x. A 35mm full frame lens on a 6300 crop sensor is usually rendered as a 52mm lens. Using a speed booster It is becomes approximately a 35mm lens (actually a 37mm lens) --much closer to the original full frame intent.

[rweissman]

Just tried the sigma art 35 and canon l 100 macro IS. the 35 was quite fast, the 100 macro was fussier and a bit less fast but still quite useable.

[molan]

What do you mean it becomes an effective f/2.8, you mean as an f/2.8 lens would exposure wise or DoF wise, on your ASP-C?

 

Speed booster is a crop factor negator, meaning FOV and DoF is made almost like the original lens would on it natural sensor size (usually FF). IT's also works be focusing the total light onto the smaller sensor, intensifying the light meaning you gather almost the same amount of light so you ISO will be lowered and SNR will be almost equalised.

 

Speed booster is not magic, you will not gain a stop compared to FF but you will negated the crop factor (almost). It's basically a reversed teleconverter, getting a wider FOV instead of a small, gaining light intensity instead of loosing it.