Shutter Test Log Sheet
I recently invested the grand sum of $15 and assembled one of those nifty sound card shutter testers. I'm amazed at how accurate and useful this little device is.
I made up a log sheet for when I test shutters that has all of the 1/3 stop and 1/6 stop +/- speeds listed. It is a handy chart that you can record the results of your tests on. I've attached a PDF file and please feel free to use it.
If you are interested in this cheap and accurate tester - the following website was my inspiration:
Wonderful! It's Mac friendly and I have most of the parts in my junque drawer!
Advice on using shutter tester
A couple pointers regarding this cool little device. I used a toggle on/off swithch, 1 AA battery, 4.7ohm resistor, and a photo transistor in my unit. I also have a 5mm LED holder (concave) for the photo eye to peek through. I don't know electronics much, so I had a friend do the soldering. I don'
t feel much need for testing my focal plane shutter camera as it's never been an issue in the 25 years that I've loved owning a Contax 139Q. My Nikon D200 (I think it's sinful to admit owing such a beast on APUG!) isn't an issue. My Rollei 35S and my ETRSi Bronica will get a workout though - along with the Alphaxes and Copals in my life.
When you test, put your aperture at f16 or smaller (on a lens that stops down to f45). The walls of the curve on the graph will be much straighter. My little unit works well even in reduced room light. I put a big lenswrap like a tent from the lensboard back to cover the shutter. I have a small right angle clamping vise (for picture frame making) that I secure the lensboard with. I have a Bombay Company 3 tier fountain pen stand that is perfect for holding the small maglite that I shine through the lens. Some people use laser pointers. I haven't tried that yet. I do about 5 to 10 exercise shutter pops before recording and then record 5 pops on the sound software. I go with the average of 5 readings these unless there's a real change from the first exposure from the others.
You'll find that it's easier to immediately edit the flatlines between your recorded waves by highlighting them and deleting them. Then when you make the window of Audacity (or other program) bigger, you have your 5 waves right there for measuring.
Good luck with it!
PS - I have an old Red Kodak 626 camera that I now know has an extremely accurate and repeatable 1/30th of a second shutter speed. I'm thinking ASA 10 to 25 film in those days so the fixed aperture must be f11 or f16. I never would have known this if not for my little tester and now I just might respool some 120 Rollei 25asa on the camera and wait for a sunny day..
Hey, I'm in Vancouver - great clouds, the Sun... not so much as Borat would say.
Some Photos of Thorney's Tester
Words don't do it justice!
Here are a few shots of my desktop setup. If you're wondering what that is that the tester is perched atop, it's a genuine dinosaur bone - a vertabra.
In this setup you can see the flashlight, my trusty old 80 year old Dagor that is sooo sharp and its Alphax shutter.
A couple of shots included for scale. The tester by two different types of Rollies!
Then there are some screenshots showing what the raw sound file looks like. There is then a screenshot showing how I prepare the file for easier testing.
The last screenshots show the enlarged curves and two samples both were 0.047528 and the next three were 0.047891 for an average of 0.047567 seconds. This is 1/21 of a second. The shutter speed tested was 1/20th and when I had this lens tested by a technician six weeks ago he reported 1/20th. Not bad for a vintage shutter! What amazes me is how consistent most shutters are that I've tested. This shutter only varied in the ten-thousandth of a second decimal place.
I encourage you to make one and try it out.
Must be the Rizla effect (worse than Callier!)...
The Alphax shutter speed was 1/25th that was tested. So it's consistent but a slow about 1/3 of a stop.
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You may also wonder how I know the battery is off. I chose to put the audio out wire at the 'on' side of the switch. The wire is my indicator. Works well actually.
I also recommend use of a caliper so the holes you drill for the switch, wire, and light sensor are nice and snug. I purposely made the audio out wire hole very tight so that I don't need any kind of collar. It's very secure and makes the unit look more like the sleek beast she is!
One more thing I just noticed. I'm newish to APUG so the posting process is a bit of a learning curve especially attachments.
I indicated above that two identical reads were showing in the measurements. Actually there was a rogue 0.048254 in there that I mistook for a '528' - yes these are millions of a second here! The adjusted average is more like 1/20.8 seconds. I like comparing the shape of the waves. Different shutters have much different curves. Different speeds on the same shutter can have different curves, I think this I should expect between the higher two speeds and the others. Separate springs perhaps?
Thanks for the excellent detail description and pics of your rig Thorney... I built one today and am now in the process of mastering Audacity sufficiently such that i can get consistant and repeatable results... almost there. I've gotta say this little device is a real cracker - cost me less than $AU10 to put together.