Incident or reflective....old school light meter....

[TooManyShots]

What is different about metering for negatives and metering for digital is that digital ISO is determined by a resulting JPEG that comes from the standard ISO process for digital, essentially the "final result", much as for slide film.

The resultant JPEG is a result or the sensor and the manufacturers software, hence different for every camera. A DSLR can get you a reasonable exposure setting at a given ISO but it is far from being able to mimic a negative.

ISO for negative film is keyed to the negative's density at certain points. Negatives are an intermediate medium, while there is an ISO speed point film can, for example with XP2 a 400 speed film, be shot at 50,100,200,400, or 800 and create nearly equivalent prints, the "final result".

What if you shoot RAW????

[TooManyShots]

Your samples in flickr has survied from metering through digital camera because SBR is rather very short or short. In almost all examples, except the pot have diffused light.

The flower pots shot was not shot in diffused light. It was at night. Film speed was 400, f3.5, 1/50s shutter speed. There was a home depot utility light powering a 23w CFL. The lamp distance to the pots are about 1 foot above.

[baachitraka]

The flower pots shot was not shot in diffused light. It was at night. Film speed was 400, f3.5, 1/50s shutter speed. There was a home depot utility light powering a 23w CFL. The lamp distance to the pots are about 1 foot above.

Correction: I wanted to write, expect the flower pot shot rest was shot with diffused light.

[markbarendt]

What if you shoot RAW????

This ISO standard is the ISO standard, ask the ISO if you really want to know.

[benjiboy]

OMG, this is a lot of misleading information. If it were true, why would my Minolta Spotmeter F give me identical readings as my Canon dSLR, when both are aimed at the same 18% grey card and set to the same ISO value?!?!?!

In fact, using my Minolta Autometer Vf in incident mode, its reading agrees with the two reflected light meters mentioned above, too.

And exposures are fully satisfactory if I am shooting with my medium format film color transparencies or my dSLR...I do not need to compensate one vs. the other, to deviate from the meter suggestion, which would be necessary if the digital ISO value were not the same as film ISO.

I base my information on tests done by the technical staff of Professional Photographer Magazine with a Minolta Autometer VF done in an article in the last few years, this is also why you can programme the sensitivity of Sekonic L-758 Meters to the actual individual sensor of up to four different digital cameras, because they are all have different responses to light. Watch this , and you will understand.
http://www.youtube.com/watch?v=tdyosItw3Mk

[baachitraka]

This ISO standard is the ISO standard, ask the ISO if you really want to know.

Further standardised digital camera meter do not really care about the format, it just suggests a value(shutter speed and aperture).

[Diapositivo]

http://en.wikipedia.org/wiki/Film_speed (it also talks about digital camera ISO measurements).

Measuring ISO film speed depends from method chosen and some assumptions made in the ISO method.
Measuring of digital cameras' ISO sensitivity is even more complicated and up to a certain point arbitrary.
Digital ISO sensitivity when using raw is even more arbitrary or if I get it right impossible, just like it would be impossible to define the ISO sensitivity of a film without specifying the development method. The film with a latent image does not have an ISO rating per se.

Theory aside, I don't subscribe the idea that incident light metering cannot be used for digital cameras and the other way round. At most, one can find the deviation of the two (e.g. in the exact same conditions your DSLR 200 ISO is maybe equivalent to your reflected light meter 160 ISO, a third of stop off) and work from there obtaining reasonable values from a practical point of view. Over-thinking the matter doesn't help.

The rationale of bringing a DSLR instead of a separate light meter to help exposure with a film camera is certainly questionable, but that's another matter.

Separate light meters, and incident light metering in particular, are quite in use as far as I know also with digital cameras, not just with film cameras. E.g. in portrait work incident metering is used also when working with digital cameras, if I have to believe to videos I see on TV.

Modern separate light meters can be programmed with the dynamic range of the camera or film in use so as to better help exploiting the dynamic range without burning highlights (a problem with slide film and especially a problem with digital cameras because of the "cliff effect" or "wall effect" of the highlights).

The same separate light meters are employed also in digital photography which means the the ISO value makes some sense with both technologies (small correction factor apart if the manufacturer was a bit "optimistic" regarding ISO sensitivity for marketing reasons).

The ISO value of a digital camera is infinitely less useful an information than the ISO value of a film, and the logic in exposing a digital frame can be completely different than exposing a film frame (especially negative) so it's not so much the meaning of the ISO term in the two different technologies (which at the end of all the theory is in practice more or less the same) but the general exposure logic which can be completely different when the subject brightness range is extended.

Conclusion: a DSLR can be used as a light meter with a film camera if the subject brightness range does not pose problems, small repeatable differences apart. I wouldn't use it with complex light as the matrix metering might try to salvage highlights applying some sort of strategy which wouldn't fit film photography*.

YMMV

* I wouldn't use matrix metering in any case, but that's me.

[benjiboy]

Hahahaha....that's almost like saying each DSLR unit has its own metering standard and photographers can't cross reference with one body with another. I am pretty sure if you meter with an EOS 3 with a Canon 1dmarkIII on the same scene, you get the exact same reading.

That's exactly what I'm saying, because you are obviously new to photography before you start laughing, at facts your'e "pretty sure" about, watch this video and it will explain that individual DSLR sensors give different responses to light. and how some light meters can be calibrated to each cameras individual sensor http://www.youtube.com/watch?v=tdyosItw3Mk

[TooManyShots]

That's exactly what I'm saying, because you are obviously new to photography before you start laughing, at facts your'e "pretty sure" about, watch this video and it will explain that individual DSLR sensors give different responses to light. and how some light meters can be calibrated to each cameras individual sensor http://www.youtube.com/watch?v=tdyosItw3Mk

So, how many stops of light we are talking about here? If the difference has no meaning in a real world situation, I would rather focus on shooting. You can say I am new since I didn't start shooting during the film age.

[Alan Klein]

Originally Posted by Alan KleinI think you're the only person who picked up he's shooting digital on a film forum.
I shoot both... And doing paid gigs with digital of course.

I was just trying to get a laugh. My own experience using Minolta IIIa with both features, is to use
10% spot reflective when the shot is in the distance and once in a while to use incident if I'm in the same light as the subject and fairly close. The meter allow me to average three readings. I also braket 1 stop. Of course, I only use this method when shooting film. I wouldn't want anyone in the forum from getting upset.