Let me help. <evil grin>
Croubie - you beat me to the punch! I was writing this when you posted. Great minds think alike. Then again, so do insane ones.
The problem tends to be what your metering when using any form of reflected light meter.
different meters can all give you results that vary by a stop or more - and every one is possibly correct - or every one is potentially off. What you REALLY want to know, is how much light is falling on the subject, and that is done with an incident meter , or metering off a grey card. They should all be fairly close if you use a grey card - if not then one or more of them need calibration. Reflected, you have to engage brain and adjust for where you want to place the value you just metered. ( if spot metering ) or know the charactaristics of how it "sees" the scene. Is it center weighted, averaging, Matrix, etc.
But the meter is only the beginning of your woes.
You have metered, and now you have some numbers to work with, say, f8 @ 250th. But is that f8 REALLY f8? How do you know? And what about the shutter speed. Been calibrated lately, and do you know the true speed? And how about how leaf shutters change relative speed and exposure depending on aperture and shutter speed.
Its enough to drive you bonkers. - So - forget all that, and do the next best thing. TEST. It will save your sanity - or failing that, will give a crazy person some pretty good exposures.
See - the numbers are just funny shaped marks that out brains read as f8, or 1/250th. They are an approximation of what it should be. If the errors on a meter lean slightly to the underexposure side, and the ones on the camera ( shutter actually 1/187th or some such ) tends to give a bit of overexposure - and don't forget that the f stop could be a another 1/3 or more from the actual transmission value. The focal ratio is based on the size of the hole relative to the focal length, not on how much light actually gets through the maze of haze inside the 14 element poorly coated cheap zoom lens, vs. how much gets through your 4 element late coated perfect zeiss tessar - both can be set to f16, but the tessar could pass 2-3X the light to the film.
So if meter tends to underexpose and equipment tends to over expose about the same amount, things cancel each other out and you may have near perfect. Or, they could add up and really screw you up with very underexposed or overexposed results.
Well... at least we now have a LATENT image. Then your development process can have almost as much fun... Thermometer calibration, ph of water used to mix developer, age, oxidation or contamination of developer, etc. Oh, how about your timer, and agitation style. ( Lost all hope yet? )
Fortunate for use, there is a bit of latitude in most films. Amazing we get anything with this madness.
The only really useful answer is test. Bracket and test some more. Of course you could get your shutters all calibrated and adjusted and such. Or just test each lens that has a built in shutter - against a standard negative. Helps to have a densitometer. You know, yet another meter that needs to be calibrated against a known standard... Look! Here come the men in the white suits with the big net.
Now that I have put your mind at ease as to which meter to use, Sleep well.
ps. Don't forget that the batteries we use tend to vary in voltage over time, which can also affect results.
You also need to check a different light level as non linearity can be a problem, cell, battery, meter
Levels brighter and darker than you normally use.
Then you need a silver shot to confirm.
With LF Id build the shutter speed tester and confirm actual shutter times allowing for efficiency.
On a cold soak day the shutter is the biggest 'variable' in your error budget.
I use Westons and do a similar check Weston to Weston.
I find similar differences between my metered RB and my Nikons.
I trust my Sekonic L-358 in incident mode, it's my benchmark. It gives me a way to objectively judge what I'm seeing.
What I do from there is meter with a certain camera/lens/meter-mode combo until I figure out what it takes to match the incident meter. This typically teaches me how I and my camera meter see and how we are getting misled by the reflective system.
My intent with this process is simply to understand what the camera/lens/meter-mode combo is telling me.
Mark Barendt, Ignacio, CO
"We do not see things the way they are. We see things the way we are." Anaïs Nin
Thed d70 is going to underexpose by design. It's bad to overexpose digtial; blown highlights and all. The others could be a difference between metering modes.
this still doesn't get you to the right place -- like i said, it is entirely possible the meters won't agree completely but so what? A meter reading is only a starting point. From there you ponder skin color, overall brightness, is the light diffuse or contrasty, are you feeling high key or low key, does this particular 50-year-old camera's shutter tend to run a titch slow?
Originally Posted by RedSun
And so on.
I can get different readings -- usually very close -- even from the meters in two separate Leicas, and you know those are built to pretty exacting, and similar, standards. From there, it's all in your brain.
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A man with one watch knows what time it is, if he has several, he's not sure, you can bet your boots that if you made an exposure with all these cameras at the given meter reading the exposure wouldn't be far off.
Originally Posted by benjiboy
A man with a shortwave radio tuned to WWV knows what time it is, except for other government time signals (CHU from Canada, for instance) there's no other trustworthy standard.
But on topic, if there is a UV filter on the lens, this can affect readings slightly. For that matter the lenses could have differing transmission factors - best to get one good meter and take very good care of it.
The situation is that, I'd like to take out Sinar and use it. I have a Goosen and a Sekonic meter, but neither is spot meter. So I plan to use a in-camera spot meter to help me get started.
I have the two Bronicas with the AE III meter. But I've not used the spot meter much. The average metering gives me very good results.
Both the Nikon F100 and N80 gave me good results, though I've rarely used the spot meter.
I can't really commend on the two old DSLRs. They are for fun and I'm not really serious about them.
When I did my testing, I set to Aperture mode (aperture 8). Focus the camera to the yellow card and read the shutter speed. All the lenses are close to standard and the camera is held at the same distance.
I understand that this is not ideal test situation. The indoor light is dimmer.
I think at this point, I'm going to bring my D200 with me. Do a few shots to see what its meter can do. Nothing is perfect and I can still compensate the exposure in darkroom or PP.
you can trust sunny 16.I calibrate or verify my meters with it.
Originally Posted by RedSun
You can discount any meter reading you get from digital cameras from your experiments because the light meters in digital cameras are calibrated to the particular camera model's sensor not to the sensitivity of film, ie. 100 I.S.O. in a digital S.L.R. can produce a different exposure to the same I.S.O. on film