christianscott wrote:Hey guys, has anyone put together a similar list such as the old one which covered vignetting etc over various lenses when using an adapter?
I picked up a Sigma 17-50mm 2.8 to pair with my Metabones XL .64 and was surprised to see so much vignetting.
Does anyone have a recommendation for a similar lens maybe from canon etc that won’t suffer quite so badly?
Hello Christian. The Sigma 17-50 is an APS-C lenses designed for APS-C sized sensors. Your XL Speedbooster is expecting a larger image circle. You are seeing the very edges of the lens' glass.
All crop factors relative to 35mm photography "Full Frame":
1.9x - your "crop" without any focal reducer
1.6~1.3x APS-C lenses
1.35x - your "crop" with a 0.71x focal reducer
1.2x - your "crop" with a 0.64x focal reducer such as the XL
1x - Full Frame lenses
So technically you would need either a 0.71x focal reducer or larger lenses (full frame). Of course you can zoom in your lenses I suspect from 25ish and on it won't vignette. The 0.71x focal reducer will "crop" in your image anyways so it's not like you are losing anything in the wide end.
I have made a long video explaining all these things, you can check it out if you have time