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.
Old LF shutters, even when properly adjusted, can drift with temperature, exercise, and other factors. If you're shooting color transparency with old shutters, testing around the time of making the exposure wouldn't be a bad idea.
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'd still be curious how accurate the actual machine is compared to a know source. I've made several DIY testers and found some introduce noise, appear off but in reality it's how you read the wave forms, or the speed of the photo diode or transistor to react are slow or has memory, the light source is not positioned properly or is not bright enough or varied. I'd like to see repeatability specs.
This is a very good idea. People who sell second-hand items on eBay can check shutter accuracy and give a table with the real shutter times. This can be important for buyers working with slides, like me.
I'll buy one of those sooner rather than later.
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).
Benjiboy, I understand what you mean, but the problem with shutters is that their mistake is not linear. You can have most speeds quite exact and then one single shutter speed too slow, or you might have fast times OK and slow times too slow. This would show as "random" small divergences between expected and actual result. That, in turn, might lead to changes in development time, agitation patterns etc. or adopting a different Exposure Index, and the random problem would go on showing from time to time. I would like to have the comfort of knowing that my shutters are fine, or that only certain speeds on certain cameras require a little compensation.
Last time I brought a camera (Canon Canonet QL19 III) to a laboratory they asked me €30 just to check if the shutter was good enough, and they did not give me a table with actual times. With a device like this, I can routinely check the shutters of all cameras, and bring to maintenance only those that I know are a bit too off.
I have 5 SLR and 2 RF and I know I will recover the costs quite easily.
Good idea, good initiative.
Benjiboy if you are shooting B&W film then a shutter that if off by 1/3 or less either way is said to be in good working order. At least this is what I have read over the years and have experienced with my own tested lenses.
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.
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.
People should chose an option that is comfortable for them.
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.
If you have any more questions, don't hesitate to ask.