Concept for a Shutter Tester

[Drew Bedo]

Proposed Shutter Tester

I can't do this. I do not have the knowledge vbase in electronics or the skill set toi even experiment with this idea. Maybe someone here can.

I understand that folks have used a sound program to capture the actual sound of a shutter functioning and derive a shutter speed from that. The idea that popped into my thoughts was to use a light detector to generate a current that would be processed into a sound signal. As the light increased the "sound" signal would get stronger, then weaker based on the amount of light falling on the detector. The sound application would then display this as a curve and measure of the duration of the shutter's action would come from that.

Dunno what components would be needed or how to put them together. I have no idea what software would be needed either. In the home workshop version, this might be the size of a shoe box and require separate light. In the refined commercial version, the whole thing would fit onto the front of a lens like a lens cap and be the size of a soda can . . .with blue tooth connection to a smart phone for the display.

A quick check of the actual shutter speed could be made in the field with the soda-casn model.



Maybe the best approach is to build it as a focal plane detector instead of at the front element.

Too much late afternoon coffee on a rainy day I guess . . .sorry.

[Luis-F-S]

Too much coffee

[Jim Jones]

A light sensitive detector and an oscilloscope have long been the basis of some shutter testers. This lets one plot light against time for a more comprehensive test than testers that integrate the light during the exposure to yield a figure that simplifies exposure calculation. Simple additions to the circuit also check flash sync delay. For focal plane shutters, the light detector should be small, and near the plane of the shutter. In this case, several readings should be made along the direction of travel of the shutter. Detector position is less important when testing between-the-lens shutters. I consider shutter testers like these far more useful than those that rely on sound.

[LabRat]

A bit of a different frequency on the scale of wavelength... :-)

Steve K

[Will Frostmill]

There's some diy schematics out there that do what you ask, except you need to hook it to a computer. Basically, you use an infrared detecting LED in series with a 9v battery, a resistor, and solder it to a minijack (mini headphone jack). Plug the jack into your laptop, start the free software program Audacity, hit record, and then whatever light hits the sensor makes a nice peak in the DC voltage at audio frequencies. I built one about two or three years ago. I can't point you to the tutorial that showed me how, but there's probably enough keywords in this post to do the trick.

Now, replacing the computer with something compact? An RasberryPi mini computer should do the trick, and there's at least one youtube video of it running Audacity. Someone cleverer than me could code something on the Pi that will automatically read the audio stream and spit out the duration of the square waves you get from the sensor. And, probably pipe the output to a simple set of 8-segment LEDs. Bluetooth would be harder.

My experience was the difficult part was interpreting the "sound wave" graph correctly. It took quite a few trials to get consistent results due to operator error. A fun project, though.

[Drew Bedo]

Will F.: Thanks for validating my early AM Brain-Burp. Glad to know that it is possible. Hope this plants a seed with someone with the ability to do make it happen.

Still hoping for the Soda-Can model.

[coisasdavida]

Have you guys seen this: https://www.lomography.com/magazine/233990-shutter-speed-tester-for-your-iphone ???

[Tin Can]

Have you guys seen this: https://www.lomography.com/magazine/233990-shutter-speed-tester-for-your-iphone ???

I have used that app extensively with the adapter.

Works great.

I need to find it in my moving boxes....

[Drew Bedo]

Looks great! So it seems to work using the actual SOUND of the shutter operating?

Doesn't use the amount of light coming through the lens? And this is a DIY assemble at home project, too I gather. I don't think my phone has that plug-in though. Maybe there is a cross-over cord at Best Buy.

Looks pretty much like what I had in mind. Thanks for the info!

[adelorenzo]

The problem I had with used sound-based shutter testing apps was you need to figure out where to put the points on the sound wave. It wasn't obvious all of the time I was never sure how accurate it was.

I bought a Phocron XA shutter tester (http://www.phochronxa.com/) when they launched on Kickstarter. It's really easy to use and gets repeatable results.

[Paul Ron]

sound is not a reliable method to time shutters. the light method is the best.

a simple photo transistor such as a TIL81 or eqiv simply soldered to the wires (observing polarity) and jack plugged into your computer's mic input is all you need. btw the mic input has a pre amp so pluging into a "line in" wont work unless you add other components to the circuit.

[Tin Can]

sound is not a reliable method to time shutters. the light method is the best.

a simple photo transistor such as a TIL81 or eqiv simply soldered to the wires (observing polarity) and jack plugged into your computer's mic input is all you need. btw the mic input has a pre amp so pluging into a "line in" wont work unless you add other components to the circuit.

Here is a schematic with a different TIL. (https://www.lomography.com/magazine/233990-shutter-speed-tester-for-your-iphone) Lomo is finally good for something!

I haven't found the TIL81 yet, for less than $30 and as high as $50.

[JMO]

I believe this Phocron XA shutter tester is still available through the Internet page at the URL adelorenzo provided. I spoke to the maker on the phone and purchased one from him about a year ago, and it has worked perfectly. The Phocron also has a calibration mode feature. I created a little stand or jig to hold my lenses (which are all mounted in Linhof Technika-style lens boards) in a position aligned with the light probe of the Phocron, so I can test the shutter speeds really quickly and easily. If I recall correctly the only lenses I had to remove the front and rear glass elements from in order to test the shutter speeds were my 400mm and 600mm Fujinon-T telephoto lenses. All of my other non-tele lenses were tested in their lens boards with the lens elements intact. I was pleased to find that all but one of my lenses had shutters that were pretty accurate at all speed settings that mattered (I didn't bother testing test speeds shorter than 1/60sec.), and so only that one lens and shutter had to go out to Carol Flutot for CLA (which she returned much more accurate). Given the modest price of the Phocron unit, I wonder why you would want to make your own, unless you insist on DIY?



The problem I had with used sound-based shutter testing apps was you need to figure out where to put the points on the sound wave. It wasn't obvious all of the time I was never sure how accurate it was.

I bought a Phocron XA shutter tester (http://www.phochronxa.com/) when they launched on Kickstarter. It's really easy to use and gets repeatable results.

[Paul Ron]

Here is a schematic with a different TIL. (https://www.lomography.com/magazine/233990-shutter-speed-tester-for-your-iphone) Lomo is finally good for something!

I haven't found the TIL81 yet, for less than $30 and as high as $50.

i havent bought them in years... they were 99 cents at one time. wow. but any photo transistor or diode will work. here is a quick search of alide electronics...


https://www.alliedelec.com/view/search?keyword=photo%20transistors


.

[Paul Ron]

I believe this Phocron XA shutter tester is still available through the Internet page at the URL adelorenzo provided. I spoke to the maker on the phone and purchased one from him about a year ago, and it has worked perfectly. The Phocron also has a calibration mode feature. I created a little stand or jig to hold my lenses (which are all mounted in Linhof Technika-style lens boards) in a position aligned with the light probe of the Phocron, so I can test the shutter speeds really quickly and easily. If I recall correctly the only lenses I had to remove the front and rear glass elements from in order to test the shutter speeds were my 400mm and 600mm Fujinon-T telephoto lenses. All of my other non-tele lenses were tested in their lens boards with the lens elements intact. I was pleased to find that all but one of my lenses had shutters that were pretty accurate at all speed settings that mattered (I didn't bother testing test speeds shorter than 1/60sec.), and so only that one lens and shutter had to go out to Carol Flutot for CLA (which she returned much more accurate). Given the modest price of the Phocron unit, I wonder why you would want to make your own, unless you insist on DIY?

how much? looks nice.

[Peter Collins]

I use "Shutter Speed" on the iPhone WITHOUT the PhotoPlug. That is, I use the sound of the shutter for the test. I use in on my between-the-lens Copal shutters.

I find the output quite easy to inspect--to find the opening and closing of the shutter--at slow speeds. It provides a judgement/conclusion that the shutter is 0, 1/3, 2/3 f-stops slow or fast. It works very well at slow shutter speeds, but not, say 1/125sec or higher.

This is very useful because rarely do I use the higher speeds. I'm typically exposing and worried about wind moving the subject or the camera, i.e., at 1 sec, 1/2 sec, 1/4 sec, after application of filter factors and bellows extension corrections. I need, therefore, assurance about the slow speeds for each lens. I haven't felt the need to use the PhotoPlug or any light-path/duration detection method.

Just my $0.02 here.

[Bernard_L]

The link provided by Randy Moe is instructive. Up to that point in the thread, I was just shaking my head in skepticism. The first part of the Lomo article shows the shortcomings of the sound method. How are you to measure a time from this kind of plot? Why were the red lines placed here rather than there?
183725
The schematic with a light sensor (phototransistor) is better than similar ones seen elsewhere on the internet, because the current path is closed inside the schematic itself, not inside the (unknown) inside of the phone's or computer's soundcard. What is also good is the fairly low value of the resistor 4.7kΩ, ensuring the response is relatively fast.
183726
In case you must use a microphone or line input that is not powered, you can include the power source as follows:
183727
One drawback of soundcard inputs is they have a high-pass filtering, in practical terms, they have a series capacitor, which is why even the better Lomo schematic produces this kind of response, instead of the expected "brick" shape; nevertheless good enough for measuring times. I found that high-pass filtering sometimes more pronounced on the mic input than on the line input, presumably to prevent "proximity pop". And a Terratec external USB sound card to have more extended low-frequency response.
183728
The ideal circuit uses a photodiode operated a zero-bias, an op-amp wired as current-voltage converter (transimpedance), and a hacked soundcard with a short-circuit across the input capacitance. Or a digital scope, if you have one.

[Pere Casals]

Proposed Shutter Tester

This is $15 at ebay (search shutter tester):

183729

It's a bare photodiode with case, cable and conector.

You have two models for the connector, one to be plugged to an smartphone an the other for PC, one has to be careful with that...

As will says, Audacity can be used to record the sound signal and from that measuring the aperture time.

I bought one of these but instead I removed the conector and I use my Pro USB oscilloscope to see the signal. This is more convenient because it freezes the screen when the impulse goes in, and it has a easy way to measure interval and HZ.

But you can buy an usb oscilloscope for as low as $25 (search ebay OmniScope 2xChannels 18MSPS oscilloscope)

183730

In that case you may need the help of a teachy friend to get used to the way it works, not difficult at all for basic usage...

You have shutter testers under $100 (Tester-CAM-Lite Mini V2, also ebay)...

...but I found very interesting to see the signal from the photodiode in the screen because it shows how the shutter opens and closes, this interesting for diagnostics.

It doesn't matter much the way one measures it, but I found extremly interesting to test speeds of owned shutters, and the consistency of each speed !!! One can overcome a missmatch by adapting the exposure/aperture, but an inconsistent behaviour is a worse problem.

One has to remember that mechanical shutters were sold with +/- 30% accuracy specs, so 1/30 can be 1/20 or 1/40, 1 stop difference an still in specs!... and now we have decades old shutters, so a testing is a must, IMHO, specially for velvia

[Tin Can]

Bernard, I don't have a 'scope but have used them.

Would something like this very cheap oscilloscope work for our shutter speed application with the Lomo circuit and/or your improved powered circuit?

https://www.banggood.com/DSO188-Pocket-Digital-Ultra-small-Oscilloscope-1M-Bandwidth-5M-Sample-Rate-Handheld-Oscilloscope-Kit-p-1315186.html?gmcCountry=US&currency=USD&createTmp=1&utm_source=googleshopping&utm_medium=cpc_elc&utm_content=frank&utm_campaign=pla-mix-us-pc-0626&gclid=EAIaIQobChMIwqLVmsKm3gIVTL7ACh2kYgDvEAQYBCABEgLv_vD_BwE&cur_warehouse=CN

I found even cheaper ones on eBay, but they had no box.

Former tube radio collector.

[Bernard_L]

Bernard, I don't have a 'scope but have used them.

Would something like this very cheap oscilloscope work for our shutter speed application with the Lomo circuit and/or your improved powered circuit?

https://www.banggood.com/DSO188-Pocket-Digital-Ultra-small-Oscilloscope-1M-Bandwidth-5M-Sample-Rate-Handheld-Oscilloscope-Kit-p-1315186.html?gmcCountry=US¤cy=USD&createTmp=1&utm_source=googleshopping&utm_medium=cpc_elc&utm_content=frank&utm_campaign=pla-mix-us-pc-0626&gclid=EAIaIQobChMIwqLVmsKm3gIVTL7ACh2kYgDvEAQYBCABEgLv_vD_BwE&cur_warehouse=CN

I found even cheaper ones on eBay, but they had no box.

Former tube radio collector.

Not with the original "Lomo" circuit, because it relies on the microphone socket (on an iphone, I guess) being powered. Beyond that, I cannot vouch for the reliability Chinese USB-scope, only comment on the specs; here I'm guessing because I get an Access Denied, probably the URL you give is for US customers only, but from the URL itself I see 1MHz b/w, 5MHz sampling rate; modest values but amply adequate for shutter testing.

With that USB scope you have two marginal gains wrt using an audio input on a PC, plus Audacity software: (a) higher sampling rate, but the 44kHz (0.022millisecond) sampling of .wav file acquisition is OK for testing a 1/1000s shutter (and these are always slow anyway); (b)passing DC, showing you the true time profile of light admitted through the shutter, not just the duration.

You probably know that for a central shutter at maximum speed, the opening and closing time are a substantial fraction of the nominal exposure time; in that case, displaying the true light profile may be useful.

[Bernard_L]

Afterthoughts:
Check that the input sensitivity can be adjusted over at least say 10mV...1V
On-screen cursors: I take them for granted on a scope, if absent on a cheap one, time measurements would be less convenient.

[Tin Can]

Good advice Bernard. Thank you.

I am now shopping for a higher end oscilloscope. Maybe USB.

The Tektronix scope I used 20 years ago to check ultrasonic bolt elongation was very expensive. I see prices for ultrasonics have gone way down and include a waveform screen.


Afterthoughts:
Check that the input sensitivity can be adjusted over at least say 10mV...1V
On-screen cursors: I take them for granted on a scope, if absent on a cheap one, time measurements would be less convenient.

[Bernard_L]

The Tektronix scope I used 20 years ago to check ultrasonic bolt elongation was very expensive.
Interesting. I had to deal with screw pre-load in assemblies that were cooled to 4K (liquid Helium). Had to just torque the screws, rely on modeling and a guesstimate of the importance of friction in the pre-load.
[off-topic]:eek:

[Drew Bedo]

Umm. . . .What about using a DSLR or High-End Mirrorless camera to take a video of the shutter's open-close cycle? A high-speed video would give the needed input for shutter speeds typical of most LF shutters.

[Pere Casals]

Umm. . . .What about using a DSLR or High-End Mirrorless camera to take a video of the shutter's open-close cycle? A high-speed video would give the needed input for shutter speeds typical of most LF shutters.

It may be useful for the lower speeds, but for higher speeds it would not be accurate. With the machine vision cameras I use I can take 700 frames per second using Format 7 feature, by taking only a little crop of the sensor, and this would be suitable for 1/50 perhaps with 7% accuracy (50/700x100).

Your idea would be good for 1s to 1/4 speeds perhaps, may be 1/8.

[Pere Casals]

Let me add to that:


It may be useful for the lower speeds, but for higher speeds it would not be accurate. With the machine vision cameras I use I can take 700 frames per second using Format 7 feature, by taking only a little crop of the sensor, and this would be suitable for 1/50 perhaps with 7% accuracy (50/700x100).

Your idea would be good for 1s to 1/4 speeds perhaps, may be 1/8.


One thing you can do with a DSLR mouted in the back is exposing a DSLR shot two times, one with the DSLR shutter (with the LF lens shutter open, T position), and the next shot with the DSLR shutter open (in T position) and exposing with the LF lens shutter.

Then you can compare both digital shots, as the DSLR shutter time is very reliable you may see how much the effective LF shutter speed is close to the the marked speed, if shots are inspected in raw mode then you can compare the average pixel values (linear) of both shots to even calculate the missmatch factor.

IMHO this would be the right way to use a DSLR as a shutter tester, you would only need a lensboard with a macro extension ring bayonet to attach the dslr in the lensboard, and that lensboard would be attached to the back of a monorail, that will take the lesboard. This is interesting because it would be also useful to make calibrations for aperture scales, obtaing not the exact geometric aperture scale but effective aperture, that's good enough for most photographers.

[Paul Ron]

Let me add to that:




One thing you can do with a DSLR mouted in the back is exposing a DSLR shot two times, one with the DSLR shutter (with the LF lens shutter open, T position), and the next shot with the DSLR shutter open (in T position) and exposing with the LF lens shutter.

Then you can compare both digital shots, as the DSLR shutter time is very reliable you may see how much the effective LF shutter speed is close to the the marked speed, if shots are inspected in raw mode then you can compare the average pixel values (linear) of both shots to even calculate the missmatch factor.

IMHO this would be the right way to use a DSLR as a shutter tester, you would only need a lensboard with a macro extension ring bayonet to attach the dslr in the lensboard, and that lensboard would be attached to the back of a monorail, that will take the lesboard. This is interesting because it would be also useful to make calibrations for aperture scales, obtaing not the exact geometric aperture scale but effective aperture, that's good enough for most photographers.

excelent point!

[Drew Bedo]

The link provided by Randy Moe is instructive. Up to that point in the thread, I was just shaking my head in skepticism. The first part of the Lomo article shows the shortcomings of the sound method. How are you to measure a time from this kind of plot? Why were the red lines placed here rather than there?
183725
The schematic with a light sensor (phototransistor) is better than similar ones seen elsewhere on the internet, because the current path is closed inside the schematic itself, not inside the (unknown) inside of the phone's or computer's soundcard. What is also good is the fairly low value of the resistor 4.7kΩ, ensuring the response is relatively fast.
183726
In case you must use a microphone or line input that is not powered, you can include the power source as follows:
183727
One drawback of soundcard inputs is they have a high-pass filtering, in practical terms, they have a series capacitor, which is why even the better Lomo schematic produces this kind of response, instead of the expected "brick" shape; nevertheless good enough for measuring times. I found that high-pass filtering sometimes more pronounced on the mic input than on the line input, presumably to prevent "proximity pop". And a Terratec external USB sound card to have more extended low-frequency response.
183728
The ideal circuit uses a photodiode operated a zero-bias, an op-amp wired as current-voltage converter (transimpedance), and a hacked soundcard with a short-circuit across the input capacitance. Or a digital scope, if you have one.

To come back to this approach for a bit:

I gather that the sensor is a microphone, and what is measured is the mechanical noises nade by the moving parts of the shutter as it opens and closes.

Can the microphone be replaced by a light detecting sensor? This would generate a signal more directly associated with the duration of the light passing the shutter. It might clean up the curve displayed.

[Pere Casals]

To come back to this approach for a bit:

I gather that the sensor is a microphone, and what is measured is the mechanical noises nade by the moving parts of the shutter as it opens and closes.

Can the microphone be replaced by a light detecting sensor? This would generate a signal more directly associated with the duration of the light passing the shutter. It might clean up the curve displayed.

all those sensors are photodiodes sending electrical signals to the computer audio input, no microphone...

[Drew Bedo]

Thanks. Somehow I missed that. sounds really good.

[Pere Casals]

Thanks. Somehow I missed that. sounds really good.

Drew, to make those sensors work we should illuminate the other side of the shutter, when shutter is open the light illuminates the photodiode (or phototransistor, or photoresistor) and then that sensor allows to pass an electrical current that goes to the audio input. The audio input does not know if the signal comes from a microphone or from a photodiode... so it records just the input voltage in the way it is intended, sadly audio inputs usually have a series capacitor to filter out DC, but anyway it will be possible to see shutter action.

There was some confusion around that, as the device is connected to the audio input some sources were saying that it was a microphone, but at least the devices I see at ebay are all optical...

[Havoc]

I use for this a TORX type "optical fiber receiver", mine is an TORX193 I think (long time). These are the components used for digital audio TOSLINK. They are not that expensive and do not need more than 5V power, a small capacitor and a pull-up resistor (look the specific datasheet for your component). One advantage is that you can plug in an audio optical cable of say 1 meter. This gives you a sensitive surface of 2mm diameter that you can position where you want to measure (the loose end of the cable). Cut off the other connector with an x-acto knife if you need something really small. Just place a bright light on the other side of the shutter. I use an old FLuke scopemeter but anything measuring time is usable with some experimenting, you just get a positive pulse for the time the shutter is open.

[Tin Can]

Video of a Packard shutter (https://youtu.be/jzeLQES4XUE) when I was having hand strength problems squeezing the bulb...RA is real.

[Drew Bedo]

Havoc: Thanks for that clarification. The last time I did anything like this I was 12-13 (1961) and it was a Heathkit buzzer kit we used to learn mores code in Boy Scouts.

Seems like someone would have done up acommercially produced product before this. I know that there are dedicated shutter testers . . .but they see to be over $100 and on up. This type of item ought to be commercially available for less than $50 I would guess.

[tonyowen]

http://https://www.ebay.co.uk/itm/Camera-shutter-tester-for-shutter-speed-up-to-1-1000th-for-PCs-and-laptops/153172456357?hash=item23a9ca33a5:g:Ys0AAOSwVL1WEWxR:rk:4:pf:0 (https://www.ebay.co.uk/itm/Camera-shutter-tester-for-shutter-speed-up-to-1-1000th-for-PCs-and-laptops/153172456357?hash=item23a9ca33a5:g:Ys0AAOSwVL1WEWxR:rk:4:pf:0)

after a lot of changes to make link work - has anyone any opinions
regards
Tony

[Tin Can]

Looks like somebody got smart and copied the the original product with improvements.

I think the original inventor was Northern EU, this is Romanian.

Probably no laws broken and I have Romanian friends.

[jarl33]

Hello all,
I've been following this thread -along with some other jewels around here- for a couple of weeks, after I bought a Baby Speed Graphic from a thrift store for a whopping U$20.00
I intend to take the camera on a short trip in January, and decided I absolutely needed to test the accuracy of the shutter - even though the film and the stand development will probably take care of any deviation.

Anyway: I ended up putting together a simple device using an Arduino Uno and an "Infrared break beam sensor " from Adafruit (the sensors are made by Omron, but I can't find any part numbers. Total investment is probably under $20
I followed Adafruit's connections (https://learn.adafruit.com/ir-breakbeam-sensors?view=all) but wrote a new Arduino sketch (I can share it if anyone is interested). Things seem to work fine in that I get consistent numbers, except all the cameras I've tested (from the Graflex to a Minolta XG1, a Maximar 6x9 and a few others) seem to be way too slow, so now I'm looking for ways to test the tester... any suggestion is welcomed.

[Pere Casals]

http://https://www.ebay.co.uk/itm/Camera-shutter-tester-for-shutter-speed-up-to-1-1000th-for-PCs-and-laptops/153172456357?hash=item23a9ca33a5:g:Ys0AAOSwVL1WEWxR:rk:4:pf:0 (https://www.ebay.co.uk/itm/Camera-shutter-tester-for-shutter-speed-up-to-1-1000th-for-PCs-and-laptops/153172456357?hash=item23a9ca33a5:g:Ys0AAOSwVL1WEWxR:rk:4:pf:0)

after a lot of changes to make link work - has anyone any opinions
regards
Tony

I purchased a similar one from same manufacturer, it worked perfect, but I'm using it conected to a usb Pro oscilloscope, because of convenience.

Any way I realized that there are Sound Card Oscilloscopes (google that) that can replace Audacity to acquire the signal. This would be better because we can use the trigger feature of the "oscilloscope" to stop signal when the pulse is acquired. Also there are oscilloscope apps for android (etc) taking signal from the audio jack.




any suggestion is welcomed.

Just check (datasheet) the rise/fall times of your sensor, this may range from 1ms to tinny fractions of a microsecond.

1ms may be good to test 1/30 but not good for 1/400, and if wanting to also test a SLR at 1/8000 then better the rise time is one microsecond, because at 1/100,000s rise is some 10% of the pulse.

This summer I've been using (500Mhz) photodiodes able for optic communications while exploring laser switching times.

I used: HAMAMATSU S5972

Farnell and Amidata RS have it...

[Havoc]

Things seem to work fine in that I get consistent numbers, except all the cameras I've tested (from the Graflex to a Minolta XG1, a Maximar 6x9 and a few others) seem to be way too slow, so now I'm looking for ways to test the tester... any suggestion is welcomed.

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.

[koh303]

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

[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 (http://www.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 :D 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.

[Bill Burk]

I went out to the beach a couple weekends ago and thought I was so clever timing the shutter and setting it to precisely 1/6 second. Took a couple shots.

Then I realized I was shooting waves and needed 1/250, so I was back to the old “pick highest speed and hope it’s pretty close”

I want to know why hasn’t someone made a shutter tester from a scrapped digital camera. Seems you should be able to quantify exposure fairly accurately with an imaging sensor

[Paul Ron]

yeah digital sensors arent that easy to hook up to a sound card with 32 input/output pins, an array, used to transfer the image data to a CPU.

https://www.whatdigitalcamera.com/technical-guides/technology-guides/sensors-explained-11457

BTW LF and MF leaf shutters are the same, except for the housings they are mounted in. the cells are mounted exactly the same way, screw directly into the shutter as well. Dont be fooled by the plastic exteriors.