"Old School" methods of shuter speed testing...

Kino · Aug 6, 2019

I have been looking for a physical copy of one of these for a while, just for fun.

However, the principals for this and using a CRT based TV for shutter testing is outlined here by Andrew Davidhazy of RIT;
https://people.rit.edu/andpph/text-calibrating-shutters.html

BAC1967 · Aug 6, 2019

Should be simple to make your own disk, just make sure your turntable is accurate. I've been meaning to try this as well, I'll probably just put some white tape on an old record. Is there a reference for the angle or distance the mark moves if the turntable is running at 33rpm?

Kino · Aug 6, 2019

BAC1967 said:
Should be simple to make your own disk, just make sure your turntable is accurate. I've been meaning to try this as well, I'll probably just put some white tape on an old record. Is there a reference for the angle or distance the mark moves if the turntable is running at 33rpm?

I found this shortly after posting the above:

https://books.google.com/books?id=g...-AKHfzGCt0Q6AEwAHoECAYQAQ#v=onepage&q&f=false

Luckless · Aug 6, 2019

An important lesson to remember based on a friend's attempt to test one of their old cameras this way:

Remember to use continuous lighting, and to not spend a roll accidentally confirming that the camera's flash is working fine...

Also helps if you're using a turntable that is actually reliable and steady speed. Doesn't take much flutter to muddy the results.

thuggins · Aug 8, 2019

It wouldn't be much use on a 33 rpm turntable. 33 rpm = .55 rev/sec. 1/125 sec equates to 1.58 degrees of rotation. It becomes a bit more practical at 78 rpm, but is still pretty much limited to 1/125 sec.

shutterfinger · Aug 8, 2019

Come on, get with it!
https://lommen9.home.xs4all.nl/technical page/start.html 1908 Shutter Speed Tester

Jim Jones · Aug 8, 2019

Oscilloscopes have been around for maybe 80 years, which should be old school enough. They remain a very informative way to check a shutter, especially between-the-lens shutters at high speed where shutter efficiency and lens aperture affects the results.

Bill Burk · Aug 9, 2019

I did this once. It's one of the better ways to judge the fairly slow speeds.

Jim Jones · Aug 9, 2019

It is susceptible to instrumental errors with focal plane shutters when the line on the turntable is traveling with or against the movement of the camera shutter.

Agulliver · Aug 12, 2019

There are smartphone apps for checking turntable speed. As far as I can tell they work well. You place your phone on the turntable platter and the app uses data from the phone's accelerometers to calculate RPM. Then use the special disk to check your shutter speeds!

I assume an app could be written using the phone's camera to detect how long a shutter is open.

Personally I use an old CRO storage oscilloscope and a fast LDR.

Chan Tran · Aug 12, 2019

Kino said:
View attachment 228340

I have been looking for a physical copy of one of these for a while, just for fun.

However, the principals for this and using a CRT based TV for shutter testing is outlined here by Andrew Davidhazy of RIT;
https://people.rit.edu/andpph/text-calibrating-shutters.html

This method is more applicable with today's digital cameras than our old film cameras. You can't put photoelectric sensor in the back of the digital cameras like we did on the film camera to measure the shutter speed. Also you have the result immediately rather than having to wait to process the film.

AgX · Aug 12, 2019

The formula for using the tv as means is based on the US (NTSC) tv-system. With other systems one must do resp. calculation.

Alan Edward Klein · Aug 12, 2019

USing slide film , what if you shot a daytime view after using a meter. Then shot a picture of the same view at each shutter speed changing the aperture stops to match. Then compare the final slides to each other to see if they all look alike in exposure and color?

M Carter · Aug 13, 2019

My DIY method for checking old shutters for up to 1/60th - 1/125th: my mirrorless camera shoots video at 120fps; I shoot several shutter actuations and then count the frames in my editing software. Give me a very accurate idea.

jim10219 · Aug 13, 2019

Take a picture of a falling object against a ruler! Objects fall at a constant acceleration of g=9.8m/(s^2). The time is calculated as t=sqrt(2d/g). You can see the distance the object has traveled in the exposure. As long as the object hasn't reached terminal velocity, and you're relatively close to sea level, it should produce an accurate enough answer for a photographer's needs. Just make sure to zoom in enough to get an accurate measurement.

Bill Burk · Aug 13, 2019

I actually use three different modes of testing... One I call D18 (density of the 18% grayscale expected vs actual). It’s best for the fast speeds as it tells you what you’re really getting. (I include sensitometry on same roll and determine deviation graphically).

One that’s electronic (obvious. It’s great for the slow speeds).

The turntable was the other way and it’s limited practically (at 78.26 rpm) to a range from 1/25 to 1/5 second.

Ces1um · Aug 13, 2019

According to the link below it is possible to check shutter speeds up to 1/1000 sec based on a 78 rpm record. It also shows the math and how it's accomplished.

https://books.google.ca/books?id=g9...phonograph-disk shutter speed checker&f=false

reddesert · Aug 13, 2019

jim10219 said:
Take a picture of a falling object against a ruler! Objects fall at a constant acceleration of g=9.8m/(s^2). The time is calculated as t=sqrt(2d/g). You can see the distance the object has traveled in the exposure. As long as the object hasn't reached terminal velocity, and you're relatively close to sea level, it should produce an accurate enough answer for a photographer's needs. Just make sure to zoom in enough to get an accurate measurement.

Try this in practice. There are two problems: first the equation you give is only correct if the object starts from zero velocity, so you need to time the object release much more precisely than the shutter. Second, the distance goes as t^2, which means it is very sensitive to time differences but only works over a small range of times, for ex in 1 second a dropped object falls 4.9 meters, but in 1/60 second it falls 1.4 mm, which would be hard to measure accurately.

With the phonograph record the angular velocity is constant, which makes the method have a hope of working. Many turntables have a stroboscopic pattern printed around the outside, so you can adjust the speed precisely using the flicker of a lamp at the 50 or 60 Hz AC frequency.

Bill Burk · Aug 14, 2019

I scanned the negatives and used Photoshop to measure the angle.

Above 1/25th second the angle was just too hard to measure so I considered it unreliable as an indication of speed.

That looks a lot like the article I followed.

Bill Burk · Aug 14, 2019

From 1/5 second to a second I took my readings from the electronic timer. The turntable would still be good for a quarter or half second but the electronic timer is fine in that range.

mshchem · Aug 14, 2019

I listen to the shutter, and look at my negatives. When in doubt I have a tune up. Even when a person knows true shutter speed you still need to bracket with reversal film.
I have a couple Metrolux II timers, they have a built-in sensor to determine shutter speed, I've never used this feature.
Maybe I should, then buy some 8x10 Fujichrome

mshchem · Aug 14, 2019

Bill Burk said:
I did this once. It's one of the better ways to judge the fairly slow speeds.

That's cool!

"Old School" methods of shuter speed testing...

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