Using digital flash system with a film SLR - Proper metering?

[ddeerreekk]

Hey everybody! A bit of a general question. My goal is to trigger some speedlights with my SLR to take portraits with my lights, on 35mm. I have all the equipment that I think I'd need to trigger the flashes, my main question is how I would get a proper exposure.

I'm a young photographer and am new to film, so some areas are a bit foreign to me. With my regular photo setup (shooting on a Canon 7D), I'd simply set up the flashes, plug in some good manual settings, shoot some photos and adjust the camera / flash outputs as neccessary from looking at the LCD. Obviously film doesn't have this ability. How can I measure the light well enough to shoot this way and get a good ballpark exposure?

I figure the two options will be to either get some sort of light meter ($$$ - hopefully not), or shoot the photos first with my DSLR to get the look I want, and then transfer those settings over to the SLR. Would that work? Are the two formats similar enough to compare? Ie. if I'm shooting f/4, 1/250th at ISO 100 on my SLR, does that mean that I could get a similar exposure on my film if I shot f/4, 1/250th on 100ISO filmstock? If the digital ISO don't correllate that well with film, is there some sort of conversion chart I could use?

Anyway, I'll stop talking now, I'm sure you get the point of what I'm after, but don't hestitate to ask for clarification.

SPECS:
Canon 7D DSLR
Minolta X-700 SLR
Paul C. Buff Cybersyncs (similar to pocket wizards)
Lumopro Speedlights

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[Corto]

Your X700 has TTL Flash, I never used a X700 but it was a fairly advanced camera.
The Rokkor Files - The Minolta X-700

Shoot a 12 exp test roll, And Bracket your shots?

[compur]

If you're not using a flash setup that is compatible with your X700 TTL feature then a separate flash meter will tell you the correct aperture (or you can use the guess-and-bracket-and-burn-film method).

[kgeranzani]

If you're not using a flash setup that is compatible with your X700 TTL feature then a separate flash meter will tell you the correct aperture (or you can use the guess-and-bracket-and-burn-film method). - Very True

[ddeerreekk]

Thanks, everybody.

If you're not using a flash setup that is compatible with your X700 TTL feature then a separate flash meter will tell you the correct aperture (or you can use the guess-and-bracket-and-burn-film method).

Is there a way to do this without buying a flash meter? Can a DSLR act as a flash meter (similar to my original question).

[c.cloudwalker]

You need a flashmeter.

Even with your 7D it would be a good thing. More precise, easier setups in less time.

With film, flashmeter and a Polaroid back was the way a lot of people did it.

[Rephargotohp]

You could calculate using Guide Numbers in the back of your flash manual

[Mike_E]

You could calculate using Guide Numbers in the back of your flash manual

Strobist: Guide Number: Your Free Flash Meter

Flash Photography - Understanding Guide Numbers

If you are using more than one flash then they become additive (and I don't know why This is trying to link this sentence) so a flash meter is easier but in a static environment you don't really need one.

[Derrel]

Yes, use the 7D to determine the correct exposure. With color negative film, you ought to be close enough to use the same settings on the Minolta as on the 7D. See how it goes. If your film photos are consistently a bit too dark, then use a wider f/stop on the Minolta than on the 7D. COlor negative film is best exposed by reading the light hitting the SHADOWED side of the face, and setting the exposure based on the SHADOW side of a person; digital is more like color transparency film, where an incident light exposure meter reading is set to favor the highlight side of a person's face or of a scene, so I'd expect that your exposure settings that look the absolute best on the Canon 7D digital might tend to be a little bit "under" for color negative film shot in the Minolta.

A digital SLR is like a Polaroid camera--only better and faster and cheaper as far as determining exposure! I think the Canon 7D's ISO ratings are pretty close to the stated values. They cannot be "too far off". Real-world tests should give you a pretty good fell for how this method works.