Fujifilm X-T3 vs Canon 5D Mark IV, bokeh @ 50mm, f/1.4 (equiv.)

hchris wrote:

Interesting, thanks a lot.

You're welcome, thank you for the interest

It’s difficult to compare the shots regarding brightness, as the ISO values are always different. In order to judge properly between these setups, I think you should fix that as well.

Unless I'm missing something, I'll have to disagree - that second image pair is exactly about comparing brightness (even though I said "exposure", which arguably may not be the most correct term, but let's leave that for another topic).

Ideally, Mitakon, being ~1 stop faster (brighter, f/0.95 vs f/1.4), should deliver same image brightness for ~1 stop slower ISO speed (or ~1 stop faster shutter speed), and that is what that second test is about.

Of course, as lens light transmission is not ideal (T-stop not the same as f-stop), Fuji / Mitakon pair image ended up darker, which could (should?[1]) mean Mitakon is less than ~1 stop faster than Sigma in regards to light transmission - in other words (and more importantly), it is not allowing full stop ISO (or full stop shutter speed) advantage in comparison to Canon / Sigma.

But it may be interesting to see brightness difference for the same shutter speed / ISO with both wide open, where Mitakon is expected to be brighter, I agree. Also, maybe a comparison with different ISO and brightness to match, loosely measuring light transmission advantage.

Thanks for your thoughts.

[1] I'm questioning this as camera manufacturers might opt to brighten certain lenses in-camera, as I've read somewhere for Fuji doing with (some of) its own lenses, so lens light transmission couldn't really be compared purely by end image brightness (for otherwise same setup).