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03-02-2009, 01:00 AM   #1
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M Lens autometering, but why?


I own a Pentax M-50mm 1,7f Lens.

When I got it They told me that I had to press the "Green button" to meter.

But of some reson it's metering automatic om AV (aperture priority)

I thought I had to manage it always in M-mode and with green button press metering, but i was wrong

Maybe not an important thread but I just wanted to say this so other people don't belive the same thing as I did. Auto-metering works with M-lenses.

Thanks for reading


03-02-2009, 01:17 AM   #2
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i believe that this only meters for wide open aperture
03-02-2009, 01:18 AM   #3
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QuoteOriginally posted by losecontrol Quote
....Auto-metering works with M-lenses....
Yes it works, but:

1. It works on film bodies
2. It works also on DSLR, but you have to mount the lens in a specific way (not fully mounted), so the body doesn't grab the aperture lever and open the lens wide. But in this case, you'll have trouble focusing at small apertures, as the lens is acting like M42.
03-02-2009, 01:24 AM   #4
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I believe two posts above are correct...

03-02-2009, 01:33 AM   #5
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yes I got excited when found Av worked with M lens then got disappointed with the wide open aspect

03-02-2009, 03:33 AM   #6
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That's why I personally steer clear of M series lenses.
As much as they are optically good,
only being able to use them in Manual mode is too much
of a handicap for me as I like to shoot quickly,
hence the relative low prices for them.
03-02-2009, 07:28 AM   #7
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QuoteOriginally posted by losecontrol Quote
... Auto-metering works with M-lenses....
Auto-metering also works with no lens at all.

Auto-exposure with a manual lens is more or less accurate depending on the lens, if it is stopped down, and electrical contact between the camera and lens.

It is safest to use the M mode & press the appropriate button.

03-02-2009, 03:34 PM   #8
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QuoteOriginally posted by creampuff Quote
only being able to use them in Manual mode is too much
of a handicap for me as I like to shoot quickly,
FWIW, I used to find that M mode slowed me down, until I started using "M" mode all the time. Once I got used to it, I realized that what had been slowing me down was having to *think* about the process every time I switched modes. By using "M" all the time, I stopped needing to think about it. Hit green button every so often when I notice the light change, but mostly, just leave things alone and shoot. I'm now as fast as I was when shooting Av or even P.


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