Originally posted by Scintilla Is there an advantage to focusing wide-open on mirrorless bodies? Without an OVF to worry about dimming, wouldn't you rather focus at the selected aperture to get accurate DoF feedback (and no focus shift issues)? Unless perhaps light was really low...
Actually, you focus wide open on a
Pentax body (with a K-mount lens), and with a stopped down lens on a mirrorless with an adapter. Assuming a lens that has no significant focus shift issues, you get much more precise focusing with a wide open lens. But yes, for me the main advantage is low light focusing. And you
do have to worry about dimming even with an LCD (I use liveview pretty much all the time for macro). There's a limit to the LCD gain which can be applied. My main use case is macro, and it's super difficult to see anything with a stopped down lens. Makes shooting reversed lens setups very difficult. So if I can, I'd much rather be shooting with a native lens that stays open until I hit the shutter than with an adapted one where it's stopped down. The only downside to focusing wide-open for macro is that sometimes at high magnifications your DoF gets so fantastically thin wide-open that it's really hard to find the subject. Even if you're pointing right at it, it can be bokeh'ed into oblivion. Still that's better than total darkness.
The theoretical ideal (for macro) would be a lens/camera combo that adapts to light conditions and when there's reasonable light stops down
a bit even prior to the shot, and then stops down fully once you hit the shutter. Alas, that doesn't exist, AFAIK...