Metabones speedbooster ULTRA + Sigma 17-70

[bencollins]

Hey guys!

 

Just purchased a Metabones Speedbooster ULTRA.

 

Currently using a Sony A7S body (so I know I need to shoot in APS-C mode). The lens I'm trying to use is a Sigma 17-70 2.8-4 (here's a link to it on B&H: http://www.bhphotovideo.com/c/product/909806-REG/Sigma_884101_17_70mm_f_2_8_4_DC_Macro.html).

 

It seems that we get vignetting on this lens no matter what the settings are. Even in APS-C mode it seems to be a problem. Here are some images: https://www.dropbox.com/sh/wk001p8ytsszk0n/AAAjJNy4bUFlA9hqG2f1UUNGa?dl=0

 

The adapter firmware is up to date. I've tried all the different modes on the Metabones and nothing seems to help. 

 

Any ideas? Maybe the lens isn't compatible. If that's the case, is there something I can look for in a lens description prior to purchasing that would tell me whether it's going to vignette to this degree?

 

Thanks in advance for your help!

[Golem]

I have an old 35-140/3.5, shiftless aperture,

excellent macro feature, etc etc. It's one of

the truly premium 3rd party lenses of its day.

But it vignets on a LensTurbo [Zhong Yi copy

of SpeedBooster]. No other lens, and I have

more than plenty, has shown that problem.

 

Is your Sigma a film-era design ? Both lenses,

yours and mine, have remarkable zoom range

especially considering their lens speed. I'm

wondering if that might be the "red flag" you

asked about. I know for sure mine is film-era,

and I'm thinking that it was designed to barely

cover the 22.6 x 34.6mm area of film that is

actually seen, the rest of the 24 x36mm format

being hidden either by the negative carrier or

the slide mount. In digital photography there's

no "film area" hidden by negative carriers etc

so we see the formerly hidden vignetting.

 

Just my thoughts. Can't say for sure whether

the above is the real problem.

 

`

[molan]

I presume you found out in the mean time, but it was because of the "Speedbooster" it's no Magic.

 

You don't gain a stop with speed booster, all you it does is negating crop factor, but since you where trying to use it on an APS-C sensor (FF crop to APS-C) rather than on MFT then you should not have used a Speedbooster.