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10-03-2008, 07:17 AM   #1
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k10D metering with M lenses in M mode - K200D doing a better job w/ Green button

First off, I'm a rank amateur, so please take my comments in that vain. I've reviewed the 5 or so threads on this subject and have come away with the impression there's really no easy way to "green button" exposure as a proper exposure starting point with the K10D when using M lenses in M mode. Quite disappointing, actually. Here's my issue:

I recently picked up a used K10D. I am a K200D user. Using my Pentax 50mm 1.7 M lens with the K200d in M mode with the menu setting "use aperture ring", the exposure is spot on with the press of the green button across the apertures. In other words, to me, the shots seem to be exposed properly. I recently acquired a 28mm f/2.8 M lens and the K200D also gives the correct exposure with the press of the green button across all apertures.

Now on to the same set up with the K10D and same procedure. The K10D is 2 stops deficient underexposed when wide open or up to about f/5.6 on setting the exposure with the green button. Above f/5.6 stopped down, the metering is all over the place: good in some instances, overexposed in others and not consistent.

In one of the threads addressing this, it was said that one guy's M lenses metered better in the F8-11 range (maybe not exactly what he said, but close). I'm not finding this to be true with my K10D and my Pentax 50mm M f/1.7 lens. I'm having to adjust the shutter at a minimum two full stops slower to achieve a proper exposure and sometimes three stops when wide open.

I guess I'm not understanding why my K200D would meter spot on across the apertures, but the K10D won't. My other menu settings on the K10D are set at default. If there is a menu setting or other setting that would correct this, I'd sure appreciate knowing, but I've fiddled with the program line, noise reduction, "green button in TAv & M modes". Of course I have it set to "use aperture ring", all to no avail. Thanks in advance.

10-03-2008, 08:42 AM   #2
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This has been reviewed in detail.

While you may be a rank amature by your own definition, you are spot in with respect to the K10D's metering.

I have attached a link to a past post, where this was hotly debated, until I posted the results comparing 3 "cameras". Cameras is in quotes, because I only have 2 bodies, a K10D and an *istD, but the 3rd camera I actually made by putting the *istD focusing screen into the K10D. the results were very clear.

https://www.pentaxforums.com/forums/241716-post69.html

At some point, If I ever purchase another body, (CBA is calling me towards a K20D) I plan to convert the K10D to a manual focus body only, and go for a split image, which is reported to be better on metering than the K10D screen.
10-03-2008, 08:45 AM   #3
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Is the K20's metering any better in this regard?
10-03-2008, 08:54 AM   #4
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QuoteOriginally posted by mrpackerguy Quote
Is the K20's metering any better in this regard?
great question, I don't think so, because someone else in the same discussion thread commented that the K10D and K20D screens were identical, hence one could expect the same problem. This is, however, only speculation, someone would need to verify it

10-03-2008, 09:18 AM   #5
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Not to de-rail my own thread, but how do you get the histogram off the LCD display after shooting a picture?
10-03-2008, 09:35 AM   #6
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QuoteOriginally posted by mrpackerguy Quote
Not to de-rail my own thread, but how do you get the histogram off the LCD display after shooting a picture?
I have made my own process for checking exposure accuracy not only of the bodies but lenses. (again it is described earlier in the thread but I will repeat it here for simplicity)

I select a uniformly lit and colored surface. Usually this is a paved road, sidewalk or concrete wall.

I then shoot a shot at every apature click on the lens, metering with the green button, to set shutter speed. I use 1/2 stop increments for shutter speed because this is what the detents on a manual apature lens are.

once I have taken the series of shots, I put them into PSP X2 (any photo editor will do) and measure the greyscale value for the center 10% of the frame.

It is that value that I plotted against Apature, with apature on a log scale, so that each stop is an equal distance.

I have done similar tests keeping shutter constant and changing apature both sides of the middle stop to check the dynamic range of the sensor and camera also. this is how I know that with neutral contrast, in the middle of the range each stop is 45 greyscale. (max contrast each stop is 50, min contrast each stop is 40)
10-03-2008, 09:53 AM   #7
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Thanks for that. What I meant, was how do I remove the histogram display from the LCD after each shot?
10-03-2008, 11:26 AM   #8
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QuoteOriginally posted by mrpackerguy Quote
Thanks for that. What I meant, was how do I remove the histogram display from the LCD after each shot?
You mean when you review a shot?

there are 4 different modes of review, when you go back and look at a shot pressing the preview button (bottom left)

Picture preview
Picture plus info overlaid on top (shutter apature picture number etc)
Picture plus histogram (you can get greyscale plus all colors with the 4 way controller)
small picture plus camera settings.

You cycle through them by repetitively pressing Info button

or do you mean on the instant review?

In the menu, second page, under instant review there is a check box for histogram.

10-03-2008, 11:53 AM   #9
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QuoteOriginally posted by Lowell Goudge Quote
You mean when you review a shot?

there are 4 different modes of review, when you go back and look at a shot pressing the preview button (bottom left)

Picture preview
Picture plus info overlaid on top (shutter apature picture number etc)
Picture plus histogram (you can get greyscale plus all colors with the 4 way controller)
small picture plus camera settings.

You cycle through them by repetitively pressing Info button

or do you mean on the instant review?

In the menu, second page, under instant review there is a check box for histogram.
Yes, on the instant review right after a shot is taken.
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