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03-11-2011, 06:02 PM   #1
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Is my metering off?

I have a Pentax ME Super, which I've been using for my b&w photography class with 400 tri-x. But a lot of my shots come out lighter and not as contrasty as everyone else's.

I just did a comparison with my Pentax k-r with a kit lens at 40mm, and my me super with an m 50mm f1.7, both set to f8. Both at 400 ISO. The k-r sets a shutter of 1/60. The me super sets a shutter of 1/4.

But if I turn the exposure compensation at 1/2, on the me super, it goes to 1/30 which sounds more...right?

Is it impossible to test metering using a new DSLR and an old slr? Are there too many variables?

03-11-2011, 07:33 PM   #2
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Make sure the thing you are metering is uniform, such as clear blue sky, a brick wall, etc, and that you are not using spot-metering on either body. The exposures should be very close.
03-11-2011, 09:23 PM   #3
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Just to add to SpecialK's comment, when the last time (or ever) that you had your camera CLAed? The first thing I do when I pickup a new camera is run cheap film through it to look for what you found. If the meters off it's cheap enough to get them adjusted.
03-11-2011, 09:36 PM   #4
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have you trying to change the battery?

if compare with dslr, it should have faster shutter speed because image circle and sensor size is larger hence allow more light to be collect..

focal length also effect the shutter speed..the longer the focal length, shutter speed might be slower..

03-11-2011, 09:47 PM   #5
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QuoteQuote:
image circle and sensor size is larger hence allow more light to be collect..

focal length also effect the shutter speed..the longer the focal length, shutter speed might be slower..
That causes no effect on exposure.
03-11-2011, 10:23 PM   #6
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QuoteOriginally posted by v3t0 Quote
have you trying to change the battery?

if compare with dslr, it should have faster shutter speed because image circle and sensor size is larger hence allow more light to be collect..

focal length also effect the shutter speed..the longer the focal length, shutter speed might be slower..
Battery is possible, but the image circle isn't related. An f-stop on a 35mm lens is the same as an f-stop on a medium format, as it is on any format. As for the focal length, you're probably confusing camera shake amplification and necessary shutter speed to compensate, but that's nothing to do with luminosity.
03-11-2011, 11:10 PM   #7
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I changed the battery as soon as I bought it which was about 3 months ago, and I've only put two rolls of film through it.

I forgot about the metering though, the k-r is on matrix, and the me super is center weighted right?

I'm not really sure about the differences in focal length and sensor size vs. FF, but I positioned the kit lens at 40mm because that looked closest to what I saw in the film slr's viewfinder. So that it would get basically the same picture.

Never got a CLA done, but I did buy it from keh.com if that makes a difference. Compared to buying on ebay or from some random person.
03-11-2011, 11:15 PM   #8
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Three things to consider regarding exposure issues:
  • The subject
  • The meter pattern
  • The shutter/aperture accuracy
On the first point, one must remember that the meter is calibrated to an 18% gray target. Shoot a white sheet of paper in Av mode and you will be 2 or more stops under-exposed. Ditto for landscape subjects dominated by sunlit snow or sand.

On the second point, your ME Super has a single meter pattern, center-weighted averaging (no, it does not have spot metering). What that means is that the meter is somewhat more sensitive in the middle and less so towards the margins of the frame. There is usually less sensitivity towards the top as well to compensate for bright skies. Always consider the meter pattern when shooting to know how much, if any, compensation to dial in. Too bad your ME Super does not have an AE lock button. If it did, I would suggest metering close on your subject, depressing the lock, and then compose/shoot.

On the third point, there is the outside chance that either your shutter or aperture mechanism is not functioning within spec. With your ME Super, the shutter is electronically timed and will generally be accurate if it is working at all. The aperture mechanism, on the other hand can become sticky with age, though usually this results in over-, rather than under-, exposure.

A fourth possibility is that your meter has fallen out of calibration. These things happen and can generally be adjusted by a good repair tech with access to the proper calibration protocol. (It generally involves balancing 3 or more "pots".) To test your meter, compare its readings to a known good hand-held meter or camera measuring against an evenly lit flat surface.


Steve

03-11-2011, 11:35 PM   #9
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Thanks guys, I'll do a few more tests, and probably just shoot a roll at 1/2 exposure compensation and check it out later. Even if it is for a class and somewhat important, I could try to fix it if it underexposes a bit when i'm printing.
03-11-2011, 11:47 PM   #10
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QuoteOriginally posted by Cinders Quote
Thanks guys, I'll do a few more tests, and probably just shoot a roll at 1/2 exposure compensation and check it out later. Even if it is for a class and somewhat important, I could try to fix it if it underexposes a bit when i'm printing.
If you have access to a second, known good camera or meter, you can at least test the meter accuracy. If you want a more complete testing, a camera repair place will often do a quick evaluation of meter, shutter, and aperture accuracy free of charge.


Steve
03-12-2011, 06:15 AM   #11
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QuoteOriginally posted by Cinders Quote
I forgot about the metering though, the k-r is on matrix, and the me super is center weighted right?
I suspect this is your problem. As someone said earlier, point both cameras at a clear blue sky and see what exposures they give you. If they match, then the problem isn't your ME Super. You might have to be more aware of exactly what you're metering with the ME Super to get things right.
03-12-2011, 07:25 AM   #12
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Of course, what you could do is simply adjust the ASA/ISO dial on your camera to a speed that works for YOU, for the type of negatives YOU want, and forget about 'perfect' metering and other such foolishness

As long as the meter registers a stop difference as a stop difference you're good to go.

Here's what I'd do as a start: point your 'good' camera at the northern sky, note the exposure. Using the same f/stop, point your ME Super the same way. Adjust the ISO dial till you get about the same shutter speed.

Then point both at a large wall or other evenly lit thing. Note if the shutter speeds are similar again. If not, you may need to find an ISO speed midway between sky and wall to mediate...

From your original description I'd assume your film is very much over exposed - adding the 1/2 compensation brought you to within 1 stop of the k-r.
03-13-2011, 01:08 AM   #13
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The difference in metering between the digital and the film camera is too great to seem accidental. One or both are likely off.

Still, from your post it's not clear that it's not an issue made worse by film development. Where do you get it done? Or do you do it yourself as part of the class?

I mention this only because if it does turn out that you can get better results at another developing outfit, you can live with the camera you've got for now rather than going to the ap.. $100 expense to have it overhauled and recalibrated.

Last edited by asaru; 03-13-2011 at 10:28 AM.
03-13-2011, 03:51 PM   #14
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I develop/print it myself as part of the class.

I'm still getting used to using the enlargers, but so are the rest of the class and they're getting better prints.

I highly doubt the K-r metering is off, it's brand new.
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