"Focus indicator with Screw mount" option

[azemerov]

Just for curiosity - Pentax K100D has a custom setting option called "Focus

indicator with Screw mount".

I wondering - what the point to disable FI (which is default setting)? Why not

to enable FI all the time?

 

Thanks, Alexander Zemerov

[azemerov]

Same question about "Using aperture ring" option. Why not to enable shutter release ALL the time no matter what is aperture ring setting (A or manual)?

[andrewg_ny]

My theories:

 

Focus indicator - if you have it enabled, it probably won't allow the shutter to be fired unless you get focus lock. This might be a nuisance for people who might just assume avoiding AF involvement altogether when using a MF-only lens.

 

Using aperture Ring: I'm thinking accident avoidance. Lets say I switch my A-capable lenses between my film & digital bodies and sometimes mount them on the digital body with the ring still in the non-A position--this would force me to change the lens back to 'A' before shooting, probably a good thing. If all your lenses are A-capable, there is little reason to want to enable stop-down metering.

[renatoa]

I don't know if Pentax bodies works this way, but on Nikon bodies this feature is a must for the focus trap technique. I mean prefocusing on an object in the target area where your subject will pass, and then keep shutter completely pressed until your subject appear, camera is in focus and it fire.