Consider too that with Nikon DSLRs also using RGB metering these might be seen as a metering, capture and instant-proofing system, prior to committing that image to a big and expensive sheet of film. (It's been working well for me in 4x5 the past year. Doubt I'll be buying an incidence meter after this thread, myself.)
Ivan, very interesting, what DSLR Nikon models have the RGB metering?
Interesting Rob......well, maybe this might be a smarter buy than a Sekonic Color meter... if you put a diffuser over the lens, it may serve as the ultimate incident meter.... It seems the new soon to be released D400 would be a nice offering, as it appears to be a direct competitor to the Canon 50d, so maybe $1k and one hell of a camera
or for $400, it appears the D60 has the same color RGB exposure metering system? hmmmm....
My D200 actually works better for this transparency metering and proofing task than my D300. It's easier to use with a base ISO of 100 and also a low setting of ISO 50 (Astia, Velvia) and also has about the same dynamic range. The D300 exceeds the DR of E6, has a base ISO of 200 (though it's got a much better CMOS sensor for high ISO work).
Meters in certain MF cameras like my Pentax 645N also being so good as to rarely blow highlights on a transparency (Matrix-like 6 cell Multi-segment, and spot) coupled with the reality that very big prints can be made from 645 via hybrid processes... has recently got me to thinking I'll stick with it in MF, but soon abandon transparencies in LF to go with Portra NC and NPS160. Figure I'll not miss the fussy metering in fast-changing light too much.
All you have to do is to look at the published spectral sensitivity graphs for various
color films to realize that not only do these films differ from one another, but that
none of them has a perfect color response. Digital receptors aren't perfect either.
That's just one reason why it's impossible to build a "perfect" light meter. You'd have
to design a different one for every type of color film, with linearity matched to every sensitize layer and idiosyncracy involved. Something which did this would
probably be the size of a Volkswagon. Any of us who have worked much with
tricolor meters, spectrophotometers, or tricolor printing understand that this
is a very complex problem. Even if you could design something portable and reliable
enough, would anyone build and market it? Or would you get any higher percentage
of usable exposures than with a meter design of thirty or forty years vintage?
Probably not, because when most of us botch an exposure, it's due to something
other than the meter!
Perfectly predicting the correct exposure value may never be 100% reliable-- but at something like $10/pop for a sheet of 8x10 color transparency film nowadays, it doesn't take a lot of wasted film to motivate one to improve upon a meter or metering regime if it can be improved.
Could somebody market it? Perhaps it's closer to hand than we think if we're stuck in some mindset of "tradition".
Killer app for an iTouch, iPhone (or my Blackberry Storm) for a LF photographer: a $9.99 download that matches the camera phone's spectral and DR response to various film types, and displays a histogram. (I'd pay more-- a lot more!)
I doubt this will affect any of your disucssion but I saw some data in the IHS Engineering Database that indicates that industrial light meters are calibrated at a color temp about 3800 deg. (I'm writing this from recent memory... but I still might be off a few degrees.)Originally Posted by bglick
The relationship between lux/footcandles and LV/EV is often provided in the light meter manuals... as you already know. It is amazing that so few people understand that there is even a relationship between the engineering values of light measurement and exposure recommendation -- almost to the point of thinking a photographic light meter is a magic wand of some sort.
Re: the last 10% (of this and almost any other topic... it is hardly worth sweating over most of the time. I, too, can attest to that!
You'd need to develop three parallel spectro programs fed off a beamsplitter, then
come way to calibrate each channel. Last time I talked to an engineering co capable
of this they thought it would have to market in the $6000 range. But the real problem is that you'd have to sell thousands of the things to offset the cost of
miniaturizing the components. Probably the closest thing you'll ever see is going to
happen in the world of DLSR's, which some of you have already noted as alternative
to light meters. R&D goes after money, not what's hypothetically possible. When my
wife worked in Biotech she operated a trade secret spectrophotometer which filled
a small room. It cost six million bucks, mostly I suppose for the proprietary software development. The science is there, just not the incentive or potential market. Tricolor meters like are being described on this thread are stone age by comparison to what's now technologically feasible.
Ivan, thanks for being the voice of reason here. You are soo right, the goal is, to improve our chances of success in tricky lighting conditions when shooting expensive sheet film. While Drew is right about matching each meters spectral response with each films spectral response to really hone in on success.... in the end, this comes down to a question of degree. IOW, if this Nikon metering method reduces errors in tricky lighting from 1.5 stops down to .3 stop errors, I think most of us would consider it a total success. Thanks for the tips on the Nikon D200. With a diffuser filter over the lens, I think it would make a great incident meter also....
Also, I too have adapted your concept of using Neg film when I am not forced to shoot trannies. For a lot of LF newbs who are just starting out, and who desire to shoot color trannies, I always suggest to them, jump up one format size (4x5 to 5x7, or 5x7 to 8x10) and shoot Neg film, your life will be so much easier. This assumes the film will be scanned before going to its end use. The jump up in the format size will compensate for Neg films larger grain and lower resoution vs. trannie film. It's pretty hard to improperly expose Neg film.
In my case, often I shoot trannie, 35mm and 120, 4x5, 8x10 and the film is processed and goes directly in stereo viewers, I have to get it right....when viewing the film, that 1/2 stop of under / over exposures is very frustrating....
Ivan, it seems the D60 has a new RGB metering system vs. the D200, sort of next generation.... would you recommend the D60 ?
Also, do you think the D200's sensors responds the same as trannie film? Seems like a great tool...?
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