Question about metering colour slides

Discussion in 'Color: Film, Paper, and Chemistry' started by ITD, Mar 1, 2012.

  1. ITD

    ITD Subscriber

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    Hi, I've been experiementing with colour slides so that I can at least get some reasonable shots during a visit to India later in the year (great time to start given the Kodak news today :unsure: )

    I started using incident metering of random subjects and bracketing - just got the test shots back from the lab and it looks like box speed with incident metering gives pretty good basic results for daytime use, both in good sun and slightly overcast conditions. I did note however that in some cases, underexposing some daylight shots by about a stop gives a nice evening-like 'golden hour' effect, and that got me wondering about corrections I need to think about.

    If the light was actually like that at the time, I figure that the incident meter value would ensure that the resultant picture was overexposed, am I right? Would I need to compensate for the meter's lack of discrimination to ensure the shot looked as I wanted it in this way?

    I'm trying to think of how I would calculate what sort of correction to use in all sorts of circumstances and not getting it quite yet. Hope you can help.

    Thanks
    Paul
     
  2. fotch

    fotch Member

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    The meter reports what the exposure should be for a normal shot. You can adjust your camera as needed to render the look you want. Others may have a better way or better explanation. HTH
     
  3. ITD

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    OK, I take it that means my premise was correct - that using the incident reading in the early evening with the lovely golden light would make it look 'normal', i.e. overexposed compared to what I can see.

    Can anyone give me any help in terms of learning what corrections I'd need to make to get this right under various conditions? Does anyone have rules of thumb that can be applied here?
     
  4. Araakii

    Araakii Member

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    The best way is to memorize the exposures for each situation. You will still use your light meter then, but you will have enough judgment to tell if you need to make any manual adjustments.
     
  5. ITD

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    That's a shame - I've got a terrible memory! OK, so I've got one scenario pretty much in the bag then - underexpose one stop for golden early evening light.

    Are there any others that people already use?
     
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  6. benjiboy

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  7. ITD

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    Thanks benjiboy, that explains the situation for 'normal' light, but if the light falling on the subject is lower and you wish to show that lower light in the picture then some form of underexposure is required, unless I've got that wrong. What I'm looking for is any corrections that I can use to get me started. I'll obviously do my own testing for as many situations as I can fit in, but the effectiveness of that approach is often hampered by time available, prevailing weather conditions, etc.

    Maybe I just need to stick to spot metering, but I have trouble with that unless there are extremes in the scene (such as stuff I'd want to place on Zone VIII) and testing that suffers from the same time / weather problems as above.
     
  8. benjiboy

    benjiboy Subscriber

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    I understand, but in order to do that but what a lot of people who shoot slide film don't appreciate is because it's reversal film the exposure corrections are in reverse if you want a darker slide reduce exposure by a third to half a stop, and increase by the same amounts for a lighter result, from my experience trying to apply The Zone System to colour reversal film because of it's small latitude is all but impossible because a correction of a third of a stop can make a hell of difference in the slides density if you start using Zones which are in one stop increments you're in deep trouble.
     
  9. markbarendt

    markbarendt Subscriber

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    Duplexing with an incident meter is a good way to find the basic reference point.

    Retract the dome, so your meter is flat faced,Meter with the meter pointed directly at the main light and then pointed at the camera, average the two readings.

    Past your reference point it's all pretty subjective, all about what you want. (That's actually true for any metering method.)
     
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  10. jeffreyg

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    Although I rarely use transparency film I recall that as mentioned it requires accurate metering. The daylight films are balanced for approximately 5000-5500 degrees Kelvin. The color temperature will vary especially in the morning and late afternoon when the light is more "red" as well as the latitude of the location and weather conditions. Correcting for the color temperature requires a special meter and filters which in most cases would be over-kill. Slight under exposure will give more saturated colors and the opposite for over exposure. I think the easiest approach especially when traveling would be as suggested to take an incident reading and bracket. A one stop difference is half or double the exposure and that may be too much depending on the latitude of the film.

    Take some practice rolls before you go and record what you do so you can compare your results. Also, have the film processed by a good lab. One that doesn't do much may be using old worn out chemicals or other less than desirable techniques.

    http://www.jeffreyglasser.com/
     
  11. benjiboy

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    I agree with Mark entirely, I've been using this method for more than thirty years it's great, and don't worry too much if you don't have a flat plane incidental light receptor it isn't absolutely necessary it still works very well with a normal incidental light dome.
     
  12. Hatchetman

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    I've never used an incident meter so can't comment on that, but I would bring some filters. A UV, warming, and cooling filter. This makes a big difference for Velvia IMO.
     
  13. markbarendt

    markbarendt Subscriber

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    There was a point where I had never heard of duplexing, now I use it for almost everything important other than flash & studio work. It's that good.
     
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  15. ITD

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    I'll have to give it a try. I can emulate a flat plane on my meter by retracting the dome. What does it give you that a straight incident reading with the dome pointed at the camera won't do?
     
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  16. Aristophanes

    Aristophanes Member

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    India. Travel. Slide film. Exposure.

    If you have the time, incident meter as others suggest. But if you're looking for more opportunistic shots, then your camera is going to make a difference. A modern SLR with matrix metering and spot option would be ideal especially if you can afford to bracket. Add in a warming filter or 2 81a, b). That's what the pros did with equipment designed for that purpose. Just a thought.
     
  17. ITD

    ITD Subscriber

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    Yes, it would probably be the best quality option however my F90X is a bit heavy and bulky for this trip - it'll be a fair amount of travelling around and living out of a rucksack, so I prefer the rangefinders. Thanks for the idea though, I might drag it out for some stuff nearer to home.


    Is this a form of tagging?
     
  18. Aristophanes

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    I was just using the nouns as you ordered your ideas. Sometimes these technical threads forget that the subject matter make a big difference in the capture technique. When I think of India I think of people and places photos. The latter can be incident, but the former....you may not have that much time for incident metering.
     
  19. markbarendt

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    Yes, retracted dome is a near perfect emulation of flat.

    Well now that you've asked.

    Duplexing is actually the direct predecessor of domed metering and setting exposure is always a compromise based on what's important in the composition.

    For "front lit subjects" flat duplexed results and single reading extended dome readings will normally agree.

    For "back lit subjects" duplexing provides a very reliable way to balance the competing subject brightness levels.

    As you know all our subjects aren't just directly front lit or directly back lit. As the main light source starts to get behind your subject a single reading extended dome reading becomes much less reliable at creating a good compromise and the background can go quickly into over exposure and be lost.

    Duplexing provides a workable compromise regardless of where the main light is.

    I use both methods but whenever I have any doubts I fall back to duplexed readings.
     
  20. benjiboy

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    By retracting the dome you are using a flat plane and restricting the acceptance angle of the meter so it can only "see" what you are pointing it at without being effected by the surroundings with my meter a Sekonic L-358 with the dome retracted I point it from the subject to the camera and take a meter reading then press the memory button next I point the meter at the light source take another meter reading and press the memory button again, then all you do is press the average button and set that reading on your camera, this method is also good to use in the studio with studio strobes to calculate the contrast ratio between each flash head on the subject.
     
  21. Araakii

    Araakii Member

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    Suppose there's late afternoon night illuminating your subject. What I first look for is if he/she is wearing anything that would reflect strong light. If not, then you can simply shoot at the exposure recommended by the incident meter and then if you want to tone it down a little bit, you can do it at the printing/scanning step.
     
  22. markbarendt

    markbarendt Subscriber

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    Great minds think alike! :D

    We even use the same meter.
     
  23. markbarendt

    markbarendt Subscriber

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    With E-6 missing the "best" exposure for any given shot means losing forever details that may be very important. For example being one stop over exposed can well mean having no definition in the clouds, it simply won't be there to fix regardless of the tools in use.

    Also if the intent is projection, it's either right or it's not.
     
  24. benjiboy

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    Thanks Mark, unfortunately my mind's not as great as it once was with advancing age, but I still appreciate a good light meter, and I'm really into digital ones, I also have a Gossen Digipro and a Kenko KFM 2100 :smile:.
     
  25. benjiboy

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    My personal rule with transparency film and incidental light metering is with an exceptionally light subject against a light background I reduce the exposure by half a stop, and with a dark subject and background increase it by the same amount, but none of this is written in stone the best way to learn about how to correctly expose slides is to do it make mistakes and learn by them, there aren't any painless ways without wasting film and effort that you are going to learn on internet forums.
     
  26. EASmithV

    EASmithV Member

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    Reading this really enlightens me with how bad I am with metering... I usually just roll with whatever my meter gives me, or take 3 readings in the dark/mid/light zones of the image area and average them.

    I'm not quite sure I understand the advantages of duplexing... I set up a test subject and using the method discussed earlier to meter, my readings agree with what my matrix meter in camera is telling me to use anyway.
     
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