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S35 Zeiss B-Speeds work on full-frame Sony a7S III


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There are two sets of PL converted S35 Zeiss B-Speed (Super Speed Mk I) prime lenses housed in Chicago, that I know of. Both are owned by Stephen Wester, owner of Atlas Lighting G&E rentals, DP, & Gaffer. The image circles of the 25, 35, 50, & 85mm T1.4 lenses cover my full frame Sony a7S III sensor with a Metabones adapter. The 18mm does not cover and a 1.2x crop is needed, however the Standard Speed 135mm T2.1 does. Wonder how it would work on other large format cameras such as the LF, C500II, C700, FX6, FX9, or Venice.

 

https://www.atlaslightingchicago.com/

Edited by Brandon Hinsley
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Unless the Metabones adapter has some sort of extender optics incorporated (which I don't think it does)  I can't see how most of those lenses would cover a full frame sensor. From my measurements, Zeiss Super Speeds under 85mm won't cover the 43mm diagonal required for the Sony A7Siii's nearly full frame sensor, unless you're using a cropped mode or a reduced aspect ratio.

The 35mm Super Speed for example only covers about a 37mm diagonal, the 25mm even less. My records are from Mk II and III Super Speeds, but I don't think the B speeds have a larger image circle, they are essentially the same glass. Any of the longer focal length Zeiss Standard Speeds will cover a full frame no problem.

Whether those lenses cover any of the other cameras you list depends on the recording format, only the 85mm and 135mm would cover an LF in Open Gate 4.5K 3:2 mode where you need a diagonal of nearly 45mm for example, whereas all but the 18mm would cover 3.8K 16:9 which only needs about a 36mm diagonal.

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  • 2 weeks later...

This music video was shot with Super Speeds on an A7SII:

Quote

the lenses were pl mount via an adapter. We shot full frame, 4k. I don't remember any vignetting, but I did put a letterbox crop so maybe that covered any shadows in the corners. But there lenses presented no problems!

This video is not a good example because it's unevenly lit, but it seems to work okay, and I'm pretty sure the lenses only work stopped down a little.

Edited by Karim D. Ghantous
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There's definitely some vignetting on some shots there,  but it works nicely with the lighting. The cropping down to about a 2.2:1 aspect ratio reduces the required image circle diameter down to roughly 39mm, which is not much beyond what the 25mm and 35mm cover at their minimum. Their image circles will be larger at closer focus distances and wider apertures. (To give an image circle dimension you need to measure at worst case scenario, which is commonly stopped down and focussed at infinity, but a lens might cover a larger circle if you don't stop down past T.4 or focus further than 10 feet away for example.) There's no mention of what focal lengths were used, but I don't think I see any 18mm shots.

The question of whether a lens series designed for a particular format covers a larger format camera sensor is always dependent on these sorts of factors - the focal length used, the focus distance, the aperture and the final cropped aspect ratio. 

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