Exposures are identical at the same iso on either camera using say my sigma 24mm f1 4 on each.
Sigma 18 35 full frame.
Not exactly more useful than a fixed lens.
The sigma 24 f1 4 does not become an f2 lens because it is mounted on an apsc camera.
Sigma 18 35 1 8 art on canon 5d mark ii ff full frame low light in door s 1 30 f 1 8 iso 1250.
This sigma 18 35mm f 1 8 is an optically superb lens but it s also much bigger and heavier than similar fixed lenses like the superb nikon 35mm f 1 8 dx the 18 35mm zoom range only works out to be equivalent to about 28 55mm on full frame.
If you decide to go.
The sigma 18 35 is essentially three prime lenses in one you get a full frame 24mm 35mm and 50mm look when paired with a speedbooster.
All my camera gear.
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I have recently started using a sigma 18 35 f1 8 lens on my apsc canon 80d but i also use other sigma art lenses on my full frame canon 5d4.
That early peak in sharpness is very reminiscent of some zeiss glass i m a habitual near wide open shooter for most everything so it works well for me and the sharpness decline from 5 6 11ish is not overly noticeable either still much better in that range than some other.
P 1 7 p 1 7 did anyone tried the sigma 18 35 1 8 on full frame.