First of all I would like to apologize for my lack of activity in this thread. I assumed that I will receive email notifications when someone posts in my thread but I never got any. After the thread dropped to page 10 or so, I thought it was dead.

Quote Originally Posted by benjiboy View Post
I never needed a shutter speed tester, If I suspect my shutter-speeds are inaccurate I give the camera to the technician who services my equipment, and ask him check it and correct it if necessary, because if you test them yourself and find then inaccurate you're still going to have to get them corrected anyway.
If that works for you, great! Sadly it's not always black and white. The gray between the 2 can be pretty time consuming and expensive. If you know the error of your shutter you can compensate for it. Some camera repair shops are quite expensive and they charge a fee just to tell you if it works right. Not to mention the time your camera is unavailable (unless they do the tests on the spot). If you have one camera you can keep the fees at a minimum but if you have 10 or 20 a simple test will end up costing an arm and a leg.

People should chose an option that is comfortable for them.

Quote Originally Posted by Revolucion Artistico View Post
To me this would depend on how far off speeds are and if they're consistent or not. If lets say the slow speeds are consistently off and I now know by how much I would probably just compensate. BTW I just got my tester a few days ago and have been playing with it, it seems to work well and I've been getting good results. Pretty easy learning curve, the only thing I'd say is that with audacity I couldn't find the correct time measurement setting with the newer beta version so I downloaded the older version off the website and it works as described.

There is a way to measure the speed on the new versions of Audacity but I find it a bit annoying. The old versions are the best for tests. If you want to know it, I will post it. It was written by a customer.

Quote Originally Posted by ralnphot View Post
I can see the value of these for LF purposes. It is good to find out the actual speed of a shutter for precision exposure settings. I have to only hope the setting will give the desired results with my ancient lenses. This would save on expensive sheet film.
This is why I first made the tester. I needed a cheap way of saving my rolls of film.

Quote Originally Posted by paul ron View Post
I think the engineer was asking if the testers were ever compared to a known source or standard to calibrate the "machine" as accurate to a tolerance?... not asking if the shutter measurements are within tolerence, but the actual test machine itself is within a measurable tolerence.
I have often thought about this and what would be the best benchmark. I did the tester to measure my inaccurate mechanical shutters. The problem was I did not have an accurate one to see if the measurements are OK. I got an electronically controlled shutter and I started testing different light sources and photocells. The electronically controlled shutter proved to be very accurate and very consistent. After I finished the first shutter tester I took one of my old cameras with a mechanical shutter and tested the shutter speeds. They were off by a big margin so I sent the camera to a repair shop. I asked for the shutter speed values before and after the CLA. When I got it back I did the test again. I both cases (before and after) the times matched with a +2%/-2% error. I did not have access to a fancy test lab with people running around in white coats, if that's what you're asking.

Quote Originally Posted by benjiboy View Post
No, I meant how close the measured shutter speed is to the marked speed on the shutter speed dial, and what margin of error is acceptable, i.e. if the marked speed is 1/1000sec and the measured speed the unit is operating at is 1/807sec,or 1289 sec, is this acceptable or not, what is the acceptable margin of error before the the shutter is sent for re -calibration.
This depends entirely on the shutter specifications. If the manufacturer gives an operating error of +30%/-30% and your shutter is 29% off, the shutter is within the specified limits and everything is OK. Your shutter works fine. If the manufacturer gives an operating error of +3%/-3% and your shutter is 4% off, you need to have it repaired. I mention this in the manual. Try and find the shutter specifications. Last thing you want is to fix a good working shutter.

Quote Originally Posted by paul ron View Post
I'd like to see repeatability specs.
An electronically controlled shutter will give you plenty of those. For the 1/1000th tests I got a lot of 0.000998 results.

Quote Originally Posted by Diapositivo View Post
Question: is it possible to have the instruction manual? That would allow to understand better the usage of the various devices and choose among them.

Question: would it be possible for you, in the future, to have a opening tester? A device that shows the actual aperture as opposed to the theoretical aperture (the two do not always coincide. Some magazines publish tests on lenses with this kind of examination performed).
I am working on a website for the testers. I have a domain registered that I don't use. I will probably add more details and the manuals there. In the meantime if you want the manual, PM me an email address and I will send it.

Regarding the second question, I don't know when I will have the time to research and develop other testers. This is a hobby of mine. It does not pay the bills.

Quote Originally Posted by graywolf View Post
One thing that most of these types of testers don't do is measure a leaf shutter at 70% open as per the spec's. That makes it look like the shutter is running slow at higher speeds. That is where the stories about leaf shutters only doing 1/300 of a second at 1/500 come from. All of the properly CLA'd shutters (post wwii) I have tested have run within 1/6 of a stop at all speeds. If it does not, then it needs to be properly serviced.

I have one of the Calumet Shutter Speed Testers and the instructions tell you to use a dimmer on your light source to make it read that 70% open speed. I do not know it you can use that technique with the sellers testers or not.
I never tried this but the light intensity has a huge influence on the results. Changing the light intensity will affect the values so I don't see why this won't work.

If you have any more questions, don't hesitate to ask.