Working with older shutter speeds shooting E6

[rjbrine]

I am thinking of buying a second hand lens with the older shutter speeds as they are so much cheaper. I shoot mostly on Provia 100F and wondered if I am being unrealistic to think that I can achieve the necessary accurate exposure required for E6 when the light meter is displaying modern speeds.

Any advice / experiences on this matter would be gratefully received.

Thanks.

[Gordon Moat]

I have been doing this with some very old cameras. My first suggestion is to try some colour negative film, and then inspect the film to see if you are way off, or sort of close. Usually the fastest speeds are more off than the slower speeds, though sometimes 1 second can be quite a bit slower than that.

Another thing is to use your computer mic to record the shutter sound into audio software. Then view the wave shape for each shutter click, and you can measure the actual passage of time at each shutter speed. You should find at least a few of the speed settings within less than 1/3 stop off optimum marked speed. As long as you can be within 1/3 stop, then you are fine with E6 films, but then you need to stick to those few accurate shutter speed settings. If it is off more than that, then you need to remark your shutter to avoid mistakes, or ideally have it serviced.

Ciao!

Gordon Moat Photography

[Dan Fromm]

rj, are you worried that your new old lens' shutter is off speed or that you don't know how to reason from, say, f/16 at 1/30 to f/? at 1/25?

Gordon addressed the former. If you're going to test, use color reversal film. It is much more sensitive to exposure errors than the negative film that Gordon suggested. And if you want certainty, buy the shutter a CLA (for clean, lube, and adjust). There's a law of nature to the effect that all old shutters are off.

About the latter, think a little. At, say, 1/30, the shutter is effectively open for 33 ms. At 1/25, 40 ms. At 1/15, 66 ms. 40/33 = 1.21, so if the meter says f/30 @ 1/16 is it, then at 1/25, very roughly you want an aperture that's 20% smaller than f/16. That's around mid-way between f/16 and f/22.

If you find thinking hard, get a dead Weston Master V and use its calculator dial.

[Gordon Moat]

I think Dan might have meant transparency film. You could do a test with that, especially if you have a rollfilm holder (to keep costs down and simplify the test). Basically assume the aperture is precise, then devise an evenly lit test that you then repeat for each shutter speed, just changing the aperture to compensate for (assumed) proper exposure.

However, the reason I did not suggest that is due to the higher per frame cost of 4x5 transparency film. It would be an expensive test to figure out the accuracy of an old shutter, while with negative film you could at least see if it was close enough to be useful. Far cheaper is the sound test, for which Dan has nicely provided some numbers.

Ciao!

Gordon Moat Photography

[BrianShaw]

My experience has been that the difference between, say, f/16 at 1/30 to f/16 at 1/25 is negligable... even when shooting color transparency film.

[rjbrine]

Thank you all for your advice.

I think working with older speeds will be fine after a little experimentation. Very inventive suggestion to record the sounds. Following the advice I will do some test sheets for comparison in the region I normally work (1/8th - 1/30th) for piece of mind. My gut feeling is that there will not be a huge amount of difference between 1/8 and 1/10 for example but I don't want any disasters on a commercial shoot. In theory if I am careful with my metering then it should be a slight push or pull in the lab.

If I can find myself a bargain on Ebay it is probably worth learning how to work with both sets of shutter speeds. I now wish I hadn't given away my Weston V thinking I would never use it....

Thanks again for your contributions.

[C. D. Keth]

I subscribe to the nudge method. Since 1/25 is slightly more light than 1/30th, I stop down a nudge.

Photography is not an exact science. Hell, it isn't a science at all.

[BrianShaw]

Photography is not an exact science. Heck, it isn't a science at all.

Oh thank goodness! I almost asked "how much is a nudge" and "what unit of measurement is that in"?

[C. D. Keth]

Oh thank goodness! I almost asked "how much is a nudge" and "what unit of measurement is that in"?

It's more than a smidge and less than a tidbit.

[AFSmithphoto]

Are we talking METRIC nudges and smidges or US Standard? I prefer skoshes, they are standardized across all measuring systems.