REQUEST: Speedbooster on FF DSLR camera

macgregor

macgregor

Veteran
Hello everyone, lets see if someone could please help me here.
I'm curious to see what happens when you use a focal reducer adapter in a full frame mirrorless such as the a7rII or the a7s.
Yes I know focal reducers are meant for APSC cameras, but that´s exactly what I want to see. Does the adapter itself create vignetting? If someone could grab a couple pics with a few different lenses that'd be great.
I'm asking all this because my intention is to use a PC-E / TS-E lens, which has a much bigger image circle than the average FF lens, with a speedbooster onto a Full frame sense on the a7RII. So before buying it'd be great to know if this works. Makes sense?
 
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How much of the sensor was covered would probably depend on the particular booster you were using. I would think you would get a heavy porthole-type effect, where the edge of the projected image is seen. And even though you might end up "seeing" a larger image than you would with a plain adapter, or with that lens on its native FF DSLR, who knows if that extra image area is even worth having- it may be distorted, blurry, or a mess of CA or other image defects.

I think what you would need to do ideally is use one of the medium format-to-FE boosters that were announced a couple months ago, and find a way to adapt your desired lens to those (if even possible, I think most MF lens mount systems have a much longer flange distance than any 35mm mount system). Since these boosters are designed for a larger-than-35mm image circle it should in theory give you what you're looking for.
 
You are correct aldolega, but those tilt-shift lenses also cover essentially medium format sensor sizes, so what I'd like to see is if the speedbooster does or does not portholes as you mention. Worth the try!
 
I remember putting a Metabones Ultra on a Sony A7 series and whacking different lenses. It seemed clear to me that there was a pothole effect from the Speedbooster itself.
 
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