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01-11-2010, 03:01 PM   #1
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K-7 LV metering with manual lenses

What I noticed is that while using manual lenses (all three are M42 mount) with Live View, every time I get exactly 1 stop longer exposure then without LV. So, I'm wondering how the Lv does the metering, in fact?

01-11-2010, 03:23 PM   #2
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QuoteOriginally posted by Jadran Quote
What I noticed is that while using manual lenses (all three are M42 mount) with Live View, every time I get exactly 1 stop longer exposure then without LV. So, I'm wondering how the Lv does the metering, in fact?
live view may be using an exposure calculation on the light actually hitting the sensor where as the normal metering takes light off the focusing screen.

I have not used M42 lenses on the K7 Yet but on the K10 and my *istD they need exposure compensation to genter the histogram
01-11-2010, 03:47 PM   #3
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QuoteOriginally posted by Lowell Goudge Quote
live view may be using an exposure calculation on the light actually hitting the sensor where as the normal metering takes light off the focusing screen.
This sounds like reasonable explanation. But, on AF lenses exposure in Lv and without it is pretty much the same, with same smaller deviations.

QuoteOriginally posted by Lowell Goudge Quote
have not used M42 lenses on the K7 Yet but on the K10 and my *istD they need exposure compensation to genter the histogram
M42 lenses on K-7 are off meter, that's true, but not near as much as on K10d that I also have. I just couldn't explain that exact difference of 1 stop with Live View
01-11-2010, 04:05 PM   #4
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QuoteOriginally posted by Jadran Quote
This sounds like reasonable explanation. But, on AF lenses exposure in Lv and without it is pretty much the same, with same smaller deviations.
yes but if they correct for the fiewfinder with the knowledge of maximum aperture then the exposure is pretty close because it is already corrected
QuoteQuote:


M42 lenses on K-7 are off meter, that's true, but not near as much as on K10d that I also have. I just couldn't explain that exact difference of 1 stop with Live View
true the K 7 metering is better than K10 but I find this is really only at large apertures (below F4, not the smaller apertures

01-11-2010, 05:01 PM   #5
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QuoteOriginally posted by Lowell Goudge Quote
yes but if they correct for the fiewfinder with the knowledge of maximum aperture then the exposure is pretty close because it is already corrected
Probably you are right. I'll compare AF exposure with M42 to find out which is "proper" exposure. It could also mean that M42 lenses constantly underexpose.

QuoteOriginally posted by Lowell Goudge Quote
true the K 7 metering is better than K10 but I find this is really only at large apertures (below F4, not the smaller apertures
Yes, You re right on that one.
01-11-2010, 05:08 PM   #6
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QuoteOriginally posted by Jadran Quote
Probably you are right. I'll compare AF exposure with M42 to find out which is "proper" exposure. It could also mean that M42 lenses constantly underexpose.



Yes, You re right on that one.
It's all about checking all your lenses and cameras to see how they perform. for exposure I use a block wall or paved road and then plot greyscale of the central 10% for all apertures

As for the M42 lenses under exposing, all of mine do, why should yours be different

here is the metering between K7, K10 with *istD screen, and origonal screen plus *istD


Last edited by Lowell Goudge; 01-11-2010 at 05:19 PM.
01-12-2010, 12:57 PM   #7
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OK, I did same exposure tests with M42 lens, AF lens and my trustworthy Minolta Dynax 7. Same focal lenght, same apertures, spot metering on uniform light wall. Conclusion is this: M42 lenses underexpose apx. 1 stop at all apertures, and LV metering with M42 lenses, which shows 1 stop longer exposure, is pretty near proper exposure.

Good to know.

Lowell Goudge, thanks for your suggestions.
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