Originally posted by excanonfd Well no, it doesn't behave anything like an A lens, rather it behaves exactly like like an M42 lens mounted on a Pentax DSLR - with an added thrill of playing Russian Roulette with your M lens.
Yep, that is the executive summary. In short, the only trick is finding a fool-proof way to keep the lens on the camera short of drilling a second hole in the base. There are no metering advantages and you have the headache of always having to mess with the aperture ring when refocusing. Fully manual aperture
sucks for general shooting for most cameras having TTL viewfinders*. There is a reason why auto-aperture actuation was a premium feature when it first became widely available and why almost all SLR lenses since have supported the feature. (Prominent exceptions are (all?) bellows and tilt/shift lenses.)
All that being said, many users state that they like not having to use the green button for every shot. I have never quite figured that out. I shoot quite a bit with K-mount glass lacking the A-contacts (straight K-mount) and almost never touch the green button. I simply use a flow that is essentially similar to that I use with my stop-down meter cameras. It goes like this:
Meter once...shoot freely- Camera in M mode
- Aperture ring on desired setting
- Determine appropriate shutter speed. This may be done any number of different ways, though stop-down metering using the green button is easiest. Almost as easy and somewhat more accurate with most dSLRs is to use a hand-held meter in either incident or reflected light mode.
- Do a test shot, chimp, and fine adjust the exposure settings as needed
- Frame
- Focus
- Expose
- Repeat steps 5-7 until your finger gets tired, card fills, battery dies, or the subject/light changes
As long as the light hitting the subject remains the same, there is no need to mess with the settings. Sound too simple? Perhaps, but such has been the practice with stop-down meter cameras since the mid-60s and is the universal fall-back technique regardless of available exposure system for difficult lighting.** Oh, it is also how strobists work (at least one way).
Steve
* Manual aperture comes with the package on view cameras and adding the feature would only marginally improve work flow...not worth the effort.
** This is the dirty little secret of many birds-in-flight, sports, stage, and event photographers.