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View Full Version : When Was Last Time You Checked Your Shutter Accuracy?



Michael Kadillak
14-Nov-2009, 21:58
Came back from a day of making photographs and was perplexed by what appeared from the eye as different densities from negatives of similar light from different shutters. It got me to think that it had to be something to do with the shutters because I had complete control of all of the other variables involved. As a result I pulled out my shutter tester that had been sitting idle in my drawer and went to work. The results set me back more than a bit but reminded me of a couple of things that I had forgotten.

First thing I needed to be reminded of is that the Ilex #5 is a piece of crap. Unfortunately, there are no other options in certain situations and we need to make the best out of the situation. Measurement of actual shutter timing proved this to be the case at the low end of the shutter scale (1 second and 1/2 second). The data shows me that I need to add 1/4 to 1/2 of an f stop to compensate for the inaccuracy of a couple of lenses including the one I used to make the photograph . Two Acme #4 shutters that I had not used in a while and assumed were functioning correctly were getting hung up at 1 second and are going back to have a CLA on them.

For the most part the more modern Copal #1 and #3 were within "industry" acceptable accuracy but the statistical range of the actual shutter times checking in groups of three test firings were all over the board. One speed would be high and the next speed up the scale the same percentage to the low side. A few shutters were consistently off by the same amount across the scale but that was the exception rather than the rule.

My feeling is that if you have more older shutters than new ones particularly Ilex #5's, it may be worth your while to do some evaluation of these with a shutter tester and allow yourself to compensate for this condition and monitor this situation so things do not get further out of whack. I am reminded of the age of axiom - the accuracy of the answer is only as accurate as the least accurate input.

In the back of my mind I kept thinking of the accuracy of my hand on the bulb of a Packard shutter and how well I could time a one second or longer exposure.

Food for thought...

Eric Woodbury
14-Nov-2009, 23:49
I test all mine on a MetroLux II about once a year and log the info in a Google Document so I can track them.

RichardRitter
15-Nov-2009, 06:09
I have a few Ilex #5 shutters and try to use then on "b" or "T" settings. If I have to use then on any speed I fire then a few times before the exposure. Each shutter has been label to their speed at a given placement on the dial.

neil poulsen
15-Nov-2009, 07:05
Years ago I purchased the Calumet shutter tester, which I used on a lens just a couple of days ago. I also constructed a jig with a light source to make it easy to take consistent measurements. I make a table that gives me nominal shutter speeds (stated on dial), and I add an f-stop correction factors for each to adjust for inaccuracy.

I take about six measurements of each speed and calculate standard deviations to determine consistency. While in my experience no shutter is accurate on all speeds (or any speed?), the newer Copal and Compur shutters tend to be quite consistent. The range (max-min) is usually less than a 10th of a stop and sometimes less than a 20th or a stop.

Daniel_Buck
15-Nov-2009, 09:52
I've never checked any of mine. Ones that sound really off wack get send out for CLA

BrianShaw
15-Nov-2009, 10:12
Before shooting I sometimes release the shutters at 1 sec and 1/2 sec. If they sound OK I'll shoot without concern. Every time I shoot, though, I look at the negs and if an exposure looks unexpectedly different than "correct" I'll check the shutter more carefully, but never with a shutter tester since I don't have one.

I agree with Michael's statement that it is the old shutters that are the greatest concern.

Michael Kadillak
15-Nov-2009, 10:53
Richard's comment about using the Ilex #5 at B or T is a good one. I now dry fire them a few times just to get them warmed up and will add a piece of masking tape to add the compensation should I ever be in the "danger zone". My 250mm Wide Field Ektar and the 14" Commercial Ektar are really nice lenses to use in the field so I do not want to avoid using them to stay away from the weak link in the equation.

The point here is to not to assume anything as I honestly believe that the extra time and effort to check these older shutters out will make a difference in the final results. When we are pulling the dark slide on film that can cost $4 to $10 a sheet I hate like hell to get in the darkroom and get even modestly surprised at the results.

Eric. I forgot that this is one of the features of this unit. I was using a Calumet tester.

eddie
15-Nov-2009, 11:05
i test mine. i found that once my ilex 5 had been CLAd it ran nicely for teh next few years i owed it. the newer (black ones) copal shutters seems to run pretty well too.

always a good idea to check the shutters

Glenn Thoreson
15-Nov-2009, 12:36
I check the one I'm going to use before going out. All shutters that aren't within 1/3 of a stop have tape on the lens board with tested speeds listed. I test them anyway if it's something important. Ilex 5 shutters are not usually accurate, to say the least. The parts are heavy and the main spring is weak. A hint to testing and using them, though - they give intermediate speeds between the ones marked. If you hunt around the dial a bit, you can usually come up with some usable speeds and mark the dial as appropriate. I use filters to add a couple more effective speds. I don't think there are any new replacement parts left for these. That's a shame, as the usually have such amazing lenses in them. The 14" Commercial Ektar is a good example.

Robert A. Zeichner
15-Nov-2009, 14:26
I usually run tests of all the shutters I have before I make a trip. It's time consuming, but has saved me a lot of disappointment. I test each shutter at each speed for three firings. The consistency is more important than accuracy. No mechanical shutters are ever perfect. Ones that are inconsistent get shipped out for CLA. I make a speed table for each shutter by averaging the three readings and rubber cement to the lensboard.

Ilex shutters, while they give the impression of being a bit crude, are really ingenious in design. It takes a lot of engineering to design a simple mechanical device that can be made of stamped parts and work as well as the Ilex. The problem is they were designed to work practically dry and over time, they get gummed up and can be very unpredictable. I've had a number of them apart and have found that after cleaning, most work again pretty well. Some are beyond my repair capability and I send them out. Kodak, when they were a company that made fine lenses like the Commercial Ektars put them all in Acme, Universal or Ilex shutters. I've had a few and they were all fine performers. I still have an 8-1/4 Ektar in a #4 and after a CLA by Carol, it's a good performing combination.

Ivan J. Eberle
15-Nov-2009, 17:16
It doesn't take but a few minutes to confirm timing on a shutter using a "sound-card" photocell tester. I recently did this very thing in a motel room in about 1/2 hour start to finish on a roadtrip with a new lens I'd just bought on my way out of town. Thankfully it was a Copal #0 that was right on the money on all but the highest speed, and extremely consistent.

What I keep meaning to do is test all of my shutters after putting them in the freezer for an hour (inside a ziplock, with any luck I won't have to take them out of the bag at room temperature/condensing humidity).

Perhaps some of the problem with older shutter designs like the Acme is that they came into being when "close enough" was quite good enough. If it sync'd with a flash unit, that was about all the accuracy many studio shutters really ever required.
Likely what changed was in the late 70's and early 80's that 4-color-press printing became cheap and ubiquitous enough so that commercial stock photography came into being, and LF landscape photographers started shooting transparency film with the Commercial Ektars in available light 24/7, that the deficiencies of such shutters became glaring.