Re: Working with older shutter speeds shooting E6
Can't vouch for using an actual microphone to time my shutter, but after reading numerous web how-to's on making an shutter tester using a phototransistor connected to the the microphone port of a computer sound card (then recording & reading out shutter speeds with a freeware sound editor like Audacity), I spent all of an afternoon and less than $20 to build one.
The difference of the old-increment shutter speeds versus new is a mere squidget compared to the nearly a whole stop sluggishness I was seeing at speeds longer than 1/25, until I gave the old Rapax shutter several Ronsonol soaks and a re-lube. At the speeds care about, it's now within 1/6 of a stop, consistently.
Easily earned back the cost of the tester in 4x5 film savings with the first round of testing.
Re: Working with older shutter speeds shooting E6
Might also mention that the increments on old shutters actually make more sense if shooting modern transparency film. Most films these days come in ISOs that are divisible by 50, not 30. (Exceptions would be what--Ektachrome 64T? They still making that?)
"Sunny 16" rule states that the reciprocal of the film speed at f/16 in typical bright sun will yield the correct exposure... e.g. 1/50 @f/16 for Velvia 50. But shooting 1/60 would be a 1/5 stop underexposure with Velvia rated at a straight 50. Back in the day when it first came out, original Velvia 50 was most often recommended to be rated at an ISO of 40 (not pulled but processed normally), so 1/60 at a f/16 would really represent a 1/2 stop underexposure from that, which proves significant.
(And here's where slightly slow shutter might be an advantage.)
Of course, this is just an example; we all know by now that Velvia 50 sucks at high noon but Sunny 16 +1 stop is Thin Clouds 16 +1 stop is P. Cloudy 16-- you get the idea.
Re: Working with older shutter speeds shooting E6
Keep in mind that you can set the aperture of a large format lens to anything you want. There is nothing stopping you from adjusting your aperture by a fraction of a stop to compensate for the difference between a shutter's discrete speeds and those given by your meter.
My bigger concern with an old shutter would be the accuracy of the shutter speeds themselves (i.e. when the dial says 1/10sec is that really how long the shutter is staying open?). I purchased a relatively inexpensive shutter testing unit from Calumet some years ago and have never once regretted that purchase. These testers pop-up for sale regularly or you can do like Ivan and build your own (if you google "shutter tester" there are instructions available online). I am often amazed at the inaccuracy of modern shutters. I've tested all my shutters and taped a strip with the measured shutter speeds to the lens boards of some of the worst offenders - I make adjustments to the aperture as required based on these actual speeds when I am setting up for a shot.
Re: Working with older shutter speeds shooting E6
The photo-transistor shutter tester is also sold by a guy on ebay in the $40 range. I bought one and tested it on two shutters that I had just had professionally timed. The slower shutter speeds (up to about 1/100) tested very accurately. Above 1/125, the homebuilt got increasingly divergent from the professional times ... at 1/500 it was way off. So, I trust it only on the lower speeds ... I still test the higher speeds with it and kind of interpolate (i.e. guess) considering the variance of the slower speeds from their original number.
The tester just plugs into your mike jack on the sound card. It comes with instructions and the program on a CD (you can download it for free from the web also.) Turn on the computer program, turn on a light, hold the shutter up to the light, hold the tester behind the shutter and click. Works very easy.
One thing invaluable that I learned using it is how much the shutter speed increases after 10-15 dry fires. Now when I go into the field, I run off about 10 clicks before shooting my first shot of the session.
Re: Working with older shutter speeds shooting E6
My lighting conditions are rarely exactly on the EI point zero. So it doesn't matter what kind of shutter I use, with a little adjustment of the aperture i can always make it match (especially if I know the real shutter speeds as opposed to thenominal speeds.
One of my folding plate cameras has a three-speed shutter (1/10, 1/25, 1/75). even with that it's easy to get correct exposures!
Re: Working with older shutter speeds shooting E6
Quote:
Originally Posted by
AFSmithphoto
Are we talking METRIC nudges and smidges or US Standard? I prefer skoshes, they are standardized across all measuring systems.
Well, us folks in the construction business use terms that transend any internation measuring standard but the women folk here might be a bit offended:eek:
Re: Working with older shutter speeds shooting E6
How about using Velvia 50 and a higher fstop.
Most of the time (with the 50's reciprocity issues) you will be using the bulb setting and counting out the seconds on your own(assuming your shutter has a working bulb setting).
Re: Working with older shutter speeds shooting E6
I have placed on the link below a bar-chart showing the correspondence between old-compur-style speeds and modern speeds, rounded to one-third of f-stop.
http://farm1.static.flickr.com/128/4...f77071_b_d.jpg
The difference between an old engraving and the nearest modern standard value never exceeds 1/3 f-stop.