Originally posted by elliott Interesting thought, it would be terrible for so many reasons though. Most of all it would introduce annoying shutter lag. Also, with stop down metering you get center weighted metering, so if you want to meter off something that isn't in the center, you're out of luck. How would I disable this feature easily so I'm not metering before every single shot when light conditions aren't changing, yet still be able to quickly meter when the light does change?
If you think using the green button is unnecessarily hard, then maybe you should not bother with manual lenses to begin with. It is by far the simplest solution without adding hardware cost, it isn't like the button is inconveniently placed either, you can easily press it without taking your eye away from the viewfinder and it is so close to the rear dial that I can hit it without even taking my thumb away from that either. It becomes a reflex, you don't even think about it after a while.
Well, if they made this a menu option, then we could both be satisfied.
But now you got me thinking about how far they could really carry this capability ....
The stopdown metering need not introduce any additional delay. All the body needs to do is change the order of what it already does today in one shutter release operation. Just stop the lens down, then meter, flip the mirror, and trip shutter. Instead of: meter, then stop the lens down, flip mirror, and trip shutter. Maybe I got a couple things crossed up here, maybe stopping the lens down and flipping the mirror are probably done simultaneously today to save time, but anyhow, the action doesn't need to be two discrete steps, even if it introduces a little additional delay because the stop-down and mirror flip are handled sequentially. I doubt there are any other mechanical gears used to control the sequence of these operations, and if they are all timed electronically, then doing this would not add any manufacturing costs whatsoever to the camera!
Also, they could make this feature "timeout", so that if you pressed the green button within the last 10 seconds (or whatever you programmed in there), then pressing the shutter release button could fire the shutter without re-metering. But if you (or should I say "I") haven't pressed the green button in at least 10 seconds, then stop down meter before firing the rest of the sequence.
They could even make the half-press work like metering and AF does today (which is already customizable!). Stop down meter on a half press, but lock in that metering (whether it keeps the lens stopped down to minimize shutter delay or unstops the lens to make it easier to recompose) while the button is kept half-pressed.
None of these rely on mechanical couplings or add to production cost. I don't hate the green button, perhaps the same way that a prisoner doesn't necessarily hate the prison guards.
Rather, why not integrate stop down metering better, if mechanical coupling is so inconsistent and expensive.
I can't imagine that Pentax engineers have not already considered ideas like these.