Making 8x10 zone system testing a little cheaper?

[Don Wallace]

I want to do some zone system calibration for my 8x10 camera and I am getting discouraged by the cost, were I to take the same route I did with my 4x5. All I really need is enough film area to use the densitomer. Would it really make any discernable difference? Any other suggestions?

OK, so I'm cheap.

[Tim Curry]

Seems to me you should be able to use the results from your 4x5 and just apply them to your 8x10. I think it would be better to calibrate your 8x10 equipment (shutters etc.) to a known standard of performance. This way your test results for one format of sheet film should match another.

Has any of your 4x5 equipment been checked against a known standard? If so, your film tests are already done.

[Don Wallace]

Tim, the problem is that I calibrated my 4x5 for rotary processor development. I will be using trays for 8x10. Sorry, I should have mentioned that.

[Edward (Halifax,NS)]

You could just recalibrate your 4X5 for trays. That would save you some money.

[j.e.simmons]

Fred Picker used to tape film into a larger film holder - for instance two 4x5 sheets into one 8x10 holder - for testing purposes. He did it so he could be sure he had two identical exposures.

That said, I don't see why you couldn't tape 4x5 film into an 8x10 holder, even one sheet to a side, for your tests.

I'm assuming. of course, that you're using the same film in both sizes.

[Andrew O'Neill]

You could test your 4x5 in a tray instead of 8x10 but then you would probably have to adjust the time when you do develop 8x10 sheets. Or you could make the "zone board" as outlined in Gordon Hutchings' book, The Book of Pyro. You can record all zones from 0 to X on one sheet of film. You only use 5 sheets of film to get a family of curves. Plenty of room for reading with your densitometre.

[Donal Taylor]

I'm still not entirely clear why you need to "do some zone system calibration for my 8x10 camera"

Why not just to everything with your 4x5? The camera shouldn't make any difference?

[David A. Goldfarb]

I can understand wanting to calibrate for different cameras. The camera is not the issue so much as the processing method, the difference in contrast of the lenses (many people might use more modern lenses for 4x5" than for larger formats), and possible differences in shutter speeds.

A neat method that I've seen for the film speed test, but haven't set up for myself yet, is to take a darkslide and drill 6 or 8 large holes in it with a keyhole saw, each one covered with a mask, and use this darkslide to make 8 exposures on one sheet. The only problem I could see would be with wide lenses, where illumination might fall off toward the corners, so be careful to use a normal or long lens, where this isn't a problem.

[KenM]

You could also use a step wedge in-camera. Sandwich a piece of film and the step wedge together, and insert it into the film holder. You may have to try a few film holders to find one 'loose enough' to make the fit not-to-tight.

Find a bright surface, set your film speed to the manufacturers speed, and expose the surface on zone X while focused at infinity. Since the step wedge acts as a neutral density filter, you'll get a full range of zone exposures on one sheet of film. With a 21-step wedge, each step is 1/2 zone, a 31-step wedge will have 1/3 zone steps.

The only problem with this method is that the step wedge is pretty expensive - $78 from Stouffer for an uncalibrated step wedge...

[Jorge Gasteazoro]

I know this is not what you want to hear, but if you did the BTZS testing method all you would need would be 5 8x10 sheets processed the way you want. On that vein, why not let the View Camera Store do the testing for you. Give them a call and ask them about their procedure. I have heard people who have used them have been very pleased with their results. From what I understand you expose a step wedge on 5 sheets of film, develop it and send the develop sheets to them, they do all the analysis and send you the results back.

Good luck.