Originally posted by Clothears I'm not sure if I'm doing this right but a possible sequence seems to be:
1) Set aperture ring enabled
2) Set green button to DoF preview
3) Set AE-L to lock exposure (do I need this?)
4) Mount M lens
5) Turn on camera and set focal length
6) Select M mode
7) Compose picture, focus, including setting aperture as desired (using green button to check DoF), and using wheel to adjust shutter speed to get correct exposure according to the meter in the VF
8) Press shutter button
I got a picture that may be roughly correctly exposed but I've only tried it indoors and it's dark now.
But this is in M mode, and I wanted to do it in Av. However, the green button seems to do nothing in Av.
You brought up an interesting problem that I hadn't thought about. With previous Pentax cameras your basic method of using a manual exposure lens would be to:
1. Set the aperture ring to enabled
2. Set the aperture on the lens.
3. Point to what you want to shoot, push the green button which would very quickly stop down the lens and allow the camera to meter. You can see the viewfinder very briefly go dark and brighten again - not long enough to check dof, long enough just for the camera to meter.
This gets you your one button push exposure. That's how the K-S1 works for it's default settings (I've been using it that way).
Previously, if you wanted to check dof, there was a third stop on the on-off switch for dof preview, the place where the K-S1 has the movie mode.
Since the K-S1 doesn't have the optical preview where it used to be, they put it on the green button. What you did was enable the green button to stop down the lens to see dof preview. I suppose if you want, you can then change the shutter speed to match the exposure using the meter, but I didn't try that - seems too awkward to hold down the button and manipulate the wheel.
And that's the problem.
You CAN'T use the green button to set the shutter speed if you have it assigned to optical preview!!! In my opinion, that's downright dumb. A person who's shooting a manual focus/manual exposure lens is far more likely to want to see the optical dof AND be able to set the shutter speed by one button. They should have set it up that a different button for previews. I tried it just now.
I want the green button for setting shutter speed in M mode far more than I want optical preview so I've changed my camera back to the default setting for the green button. If I really want optical preview I'll change it in the menu and then change it back.