Concept for a Shutter Tester

[jarl33]

Difficult if you don't have access to a scoop or pulse counter. The most generic idea I have is to use a turntable. You know, the thing they used to listen to those big flat carriers they called LP's.

You could make a heavy paper disk that overhangs the platter and make slits in it. Depending on your rpm selected and the size of the opening you can calculate what you should get. If you have a direct drive one, that should do great. Haven't tested this so no idea how precise it would be. But it would be at least a means to know if you are measuring something sensible or not.

Another idea would be to use a camera with a good electronic shutter control. Something like a later film EOS or equivalent from another brand would do fine.

Alas...I tested an EOS Rebel Ti and the timing seemed to be really close to the theoretical values (at least up to ~1/500th or so). Meaning my older cameras are indeed slower than they should be :/
I'll have to live with it for a while, I guess.
Anyway: the Adafruit circuit with the custom code seems to be good enough for now.

Cheers!

[Havoc]

Another type of test I tought of in the mean time would be a drop shutter. If carefully build these only depend on gravity and the size of the slit for obtaining an exposure time.

[Tin Can]

Yes, I bought one from Lucas direct several years ago.

Have you all seen this:
http://www.catlabs.info/product/photoplug

[Paul Ron]

very cool. it doesnt get any easier than that.

[michael_wi]

In hobby electronics magazines from the 70s thru the 90s had at least one shutter tester/timer every couple of years. Hands On, Popular Electronics, Radio-Electronics, et al for the US. Practical Electronics, Electronics Today (International, Australia, Canada) and others for those across the pond from the US.

Now I know what you are saying, lot of good that does me now. Well head on over to AmericanRadioHistory.com and start looking around. Use the search function for each magazine archive. Try shutter, darkroom, strobe, and flash. Then go back and look at some of the radio construction articles from the 20s. There were some nice looking receivers. In the beginning of radio it was mostly DIY.

If you like analog meters - Practical Electronics August 1977 p640. Uses a jelly bean 741 op amp as an integrator. Sounds fancy but its just an IC hooked up a certain way. It can be calibrated with a stop watch.
if you want a digital readout - Electronics Today (UK) May 1994 p34. This is a complex project for beginners, basically a pulse counter. Lots of CMOS logic.

[jarl33]

Hello Michael,

Somehow I missed your link to the American Radio History website, and only today -when closing browser windows- did I see it. GREAT site The circuits on the two articles you pointed out may be overkill today (considering most things can be done in software), but the articles themselves explain very well the difficulties in putting together a decent tester.
As a correction to future readers, the "Practical Electronics August 1977 p640" is in practice "Practical Electronics August 1972 p640". There's another (digital) shutter timer on the March 1989 edition of the same magazine (page 12), that curiously is written by the same guy as the article on "Electronics Today" (May 1994)
I'll be lurking over there some more...

[Paul Ron]

popular electronics or maybe it was radio electronics that had a project back in the 70s to capture n hold a wave form on an ociliscope. i built n used that for many years as my shutter tester hooked to my techtronics duel channel that is as large as a egg crate... it also served as a room heater. electronics has come a long way.

[Tin Can]

How many here can listen and watch a shutter open/close and be fairly sure the lower speeds work well?

We also are told to regularly exercise shutters and to warm them up prior to a critical shot.

Many LF exposures are done for seconds that LF few shutters can do without a human.

I can easily observe 1 second to 1/10th and can accurately count seconds silently from 2 to 60 seconds.

Don't forget to read what our sponsor Quang-Tuan Luong has shared. An intensive document right on this website.

https://www.largeformatphotography.info/shutters.html

Now if I could find my shutter timer...

[Paul Ron]

listening to a shutter comes from many years of working with them. BUT don't just listen, you have to actually see the light.

just as an example.... Mamiya RB67 shutters have a common problem, the shutter doesn't open when fired, but it times perfectly by ear. A tiny spring either breaks or slips its post is usually the cause.

[Tin Can]

I was commenting on LF only and I wrote to watch the shutter in my first sentence.

All Mamiya RB lenses I have, I bought NOS in the box from Japan 9 years ago when they were dumping them.

Really nice shutters and glass.

I spent 50 years listening to a Pentax 35mm shutter which has never missed a beat and never been repaired.

listening to a shutter comes from many years of working with them. BUT don't just listen, you have to actually see the light.

just as an example.... Mamiya RB67 shutters have a common problem, the shutter doesn't open when fired, but it times perfectly by ear. A tiny spring either breaks or slips its post is usually the cause.