Which Light Meter to Trust?

Discussion in 'Miscellaneous Equipment' started by RedSun, May 21, 2014.

  1. RedSun

    RedSun Member

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    Just of curiosity, I tested the in-camera meters of several cameras. For a certain scene, with ISO 200 and F8,

    Bronica ETR AE III spot reading 1/10 sec.
    Bronica SQ AE III spot reading 1/10 sec.
    Nikon F100 spot reading 1/15 sec.
    Nikon D200 spot reading 1/15 sec.
    Nikon D70 spot reading 1/20 sec.

    I do not have a hand-held spot meter and would like to bring a 35mm or MF camera and to use the built-in spot meter. With the above, should I trust the old Bronica meter, or the newer D200 meter? I know the difference is small, but 1/2 a stop is still very important with my LF.
     
  2. Tom1956

    Tom1956 Inactive

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    You've actually got a whole stop variance there. This should be resolved, however you have to do it. If I'm outside 1/3 stop amongst all my cameras and meters, it drives me nuts to find the dirty culprit that fouls up my averages. A whole stop to me is sure death.:whistling:
     
  3. RedSun

    RedSun Member

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    This is precisely the reason. I'll start to use my Sinar...
     
  4. summicron1

    summicron1 Subscriber

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    what sort of scene? The only way to test meters is in indentical light against an 18 percent gray card for no other reason than if you don't test them all against the same standard, you don't know.

    No card?Anything will do, but it must be the same for all. But even then you will probably find variance -- some meters are more sensitive to different colors, lenses on different cameras may transmit light differently, who knows?

    Light meters are advisory only -- you use a meter and camera together until you know both. Then your pictures come out the way you want them, not the way the camera wants.
     
  5. RedSun

    RedSun Member

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    I put on a computer yellow notepad with a few words typed. It is similar to grey card, but just pale yellow. The lenses are all near standard. I expected variances. But just wonder what caused the differences and which one I should use. Since I shoot film, I lean more toward the Bronica and F100.
     
  6. StoneNYC

    StoneNYC Subscriber

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    I have found that different in Camera spot meters 10 to react to light differently.

    For example, my Canon 1V will tend to need 1/3 to 2/3 exposure difference depending on the kind of light. Even with spot.

    A very bright sunny day, it might read 1/30 but really should be 1/60 and in dim light it would read 1/30 but might actually need 1/15

    So it's possible that you were also seeing the same situation with these various cameras, you might've tested it during the day any bright scene, and they all gave you different results, but I would suggest also testing the same theory in a completely different light environment and see if the differences change with each camera.

    Then based on those pieces of information I would suggest choosing the one that varied the least between those two lighting situations and use that one...

    I'm not sure exactly how you chose to do your spot metering, of course, but I suggest trying the meter in different lighting conditions before making the decision.

    Hope that helps.

    Also, if you really want to go crazy, you could of course go to the camera shop that does rentals, and rent one of their higher-quality spot meters like a Minolta or Sekonic 7xxDR (the X's are numbers but I can never remember what they are, the first digit and last letters will identify which if you look at the Sekonic offerings) and if you search for Minolta spot meter, there's really want in particular, I believe it was the last spot meter that they made, very famous, and still used by many photographers.

    Anyway just some food for thought.
     
  7. Poisson Du Jour

    Poisson Du Jour Member

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    Sekonic 758DR. It's an extremely rewarding way to go crazy actually. Ditto the Minolta or older Pentax spot meters. We humans can do much, much better than in-camera meters if we put our mind to it.

    Would have been handy Stone to know just where I could have hired a Sekonic before I had enough money to actually buy one, goodness knows how many moons ago, but it would have been easier in the circumstances...
     
  8. StoneNYC

    StoneNYC Subscriber

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    In your part of the woods (or should I say outback?) I wouldn't know where to get one. But I settled on it, and so glad I did. Way worth the money. Just wish it came with a leather case sometimes, or at least one with a flap over the too instead of that zipper, it's nice in theory but mine always falls out since I don't zip and unzip after every test...

    Anyway, if the OP can, try metering with different types of light (not just aiming at different types of light, change your whole environment... It's entirely possible, that even though all of these cameras are set on their spot metering options, that because light is still coming into the entire thing, that Stray light is affecting the actual spot meter, and affecting it differently with each camera
     
  9. snapguy

    snapguy Member

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    a read

    Did you read exactly the same physical area with each camera light meter? You seem to be testing cameras with different formats which would give you different areas in view.
     
  10. Dr Croubie

    Dr Croubie Member

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    There are also lesser/cheaper meters that get the job done, L508 and L608 also do spot, but also zoom 1-4 degrees, the 758 is stuck on 1-degree.
    By pure coincidence, my L608 just arrived today from fleabay. As soon as I get a battery for it, I'm going to test every one of my meters in all my cameras (outdoors in midday sun, pointed at a grey card of course).

    Just for the OP, how did you meter them? Viewfinder blind down and/or eye up to eyepiece? Stop-down or wide-open?
    I once had some rather underexposed shots from my M645AF, stop-down metered at f/8-16, on a tripod so my eye wasn't on the eyepiece. Some almost unintelligible, like 4 stops under.
    Took me wasting a nice roll of Efke 25 down the Great Ocean Road for me to learn what that viewfinder blind is for.
    (ps, don't forget that T stops and F stops are different beasts, and zooms are noticeably darker than primes as a general rule)
     
  11. blaine.minazzi

    blaine.minazzi Subscriber

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    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. :D

    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.

    :tongue:

    Blaine


    ps. Don't forget that the batteries we use tend to vary in voltage over time, which can also affect results.
     
  12. Xmas

    Xmas Member

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    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.
     
  13. markbarendt

    markbarendt Subscriber

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    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.
     
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  15. jp498

    jp498 Member

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    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.
     
  16. summicron1

    summicron1 Subscriber

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    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?

    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.
     
  17. benjiboy

    benjiboy Subscriber

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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.
     
  18. E. von Hoegh

    E. von Hoegh Member

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    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.:wink:

    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.
     
  19. RedSun

    RedSun Member

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    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.
     
  20. RalphLambrecht

    RalphLambrecht Subscriber

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    you can trust sunny 16.I calibrate or verify my meters with it.
     
  21. benjiboy

    benjiboy Subscriber

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    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
     
  22. RedSun

    RedSun Member

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    This makes sense.
     
  23. benjiboy

    benjiboy Subscriber

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    I can assure you this is true, U.K Professional Photographer Magazine did extensive tests in an issue of a few years ago and proved this I suggest your best course of action is to sell the the existing hand held meters you have and buy a modern digital meter that can do reflected incidental and 1° spot metering like the Sekonic L758, Kenko KFM 2100 or Gossen Starlite 2.
     
  24. yurisrey

    yurisrey Member

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    ^+1 to benjiboy's previous post (#20). And on the whole subject of calibration of meters: no two meters will read exactly alike. There will always be a slight difference.
     
  25. pdjr1991

    pdjr1991 Member

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    +2! Don't even get me started on people who use their camera's to meter scenes for other cameras. Too many variables (for example OP did not mention what lenses he used to meter.). If you can use a lightmeter, use it.
     
  26. markbarendt

    markbarendt Subscriber

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    Horse feathers.

    There is an ISO standard for digital just like there is for film.

    Properly set digital cameras can be reasonable meters. The wild cards are the settings and modifiers the users dial into their cameras.