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10-23-2011, 07:18 AM   #1
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M mode meter actuation

I have 3 non A prime lenses [full manual ones].
I know that without the A feature the lenses if used in any mode other than manual will work at fully open apertures [f2,8/f.28/f1.4] and the body will select the speed and ISO [ if set to auto]

In manual mode however the meter is only triggered by the green button and not the shutter button. correct? . is there a way round this so the shutter button operates the meter in manual so a aperture change is compensated for without the green button having to be pressed?

If I have manual lens that is at it's sharpest at F4 how can I fix the lens at this aperture and get metering via the shutter button other than the manual/green button route?

Disable the shutter arm on the back of the lens? that would darken the viewfinder a bit but would then in A mode give me F4 with the speed/iso selected to suite by the shutter button, is that not correct?

hope this makes sense to someone

10-23-2011, 08:15 AM   #2
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You cannot activate the metering full time only on demand because the lens needs to be stopped down to meter. This has been a long debated topic and at one time it was suggested to have an option of stopped down metering in Av mode by having a default setting on the aperture activation lever for stopped down as opposed to open.

Some users put a second locking pin hole in the lens mount about 3/8 of an inch away from correct lock to use the lenses like M42 lenses in stopped down mode

You can also activate the meter in DoF preview, the difference here is the meter is activated showing exposure as opposed to setting the shutter speed. In some ways I wish the green button could show metered value with no change to shutter speeed as an option
10-23-2011, 08:25 AM   #3
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Fully manual lenses should operate in both Manual (M), Bulb (B) and Aperture Priority (Av) modes - I have a K20. Obviously, you need to set the aperture by hand via the aperture ring. The camera body also defaults to f2.4 for any of the items that requires an aperture (there is no way to alter this). A while ago, I posted a question when comparing the 31 ltd with a 25 year old Contax Carl Zeiss 28/f2.8, that I changed the mounts on. Actually, I was not too careful in ensuring that I used the green button each frame (or each series of bracketing sets), however the images always turned out wonderful - as expected in the evening setting. What I was questioning was the large difference I was seeing in terms of the camera body determined exposure (or shutter) time.In the end, since I was getting the images I wanted, I really did not care what the exposure time was recorded in the images EXIF meta data was.

So, my answer - which may be terribly wrong, is - I do not think that it matters. I was using a tripod and a wired shutter release. When engaged, the camera will take a image (or image set when bracketing), even if the camera is turned off. So, that infers that, yes the camera body will meter regardless, on the shutter release.

hope that helps...

10-23-2011, 08:33 AM   #4
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Interested observer, while I do not disagree with what you would like, I think there are limitations or assumptions as to a fully manual lens metering in Av mode

- you want to retain, I assume the same shutter response, therefore you cannot stop down first, then meter, then flip the mirror to expose, too much time is lost to make these things all happen in sequence, stopping down at present is a parallel function to flipping the mirror
- as I said, assuming the is no power issue, and on later bodies I don't think so, otherwise video would not be possible, it may take power to hold the aperture activation lever in the stopped down mode then an option would be perminantly stopped down in Av mode, but then you need to turn the ring to focus
In manual mode there are two ways to meter, that is fine, but I wish that the cameras retained TTL support for manual aperture lenses like my *istD

10-23-2011, 11:22 AM   #5
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Morning Lowell,

Like I said, I might be terribly wrong, and probably am. Still learning the camera, even after almost 3 years of using it. Thanks for the explanations. In thinking about it again, there are a couple more things I want to try out - as its not that I need to develop any film.

I just might wander back up to the cul-de-sac this evening on the hillside that I use for my photography "lab" and try some more ideas out.


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