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picker77
10-Mar-2011, 20:52
Curiosity about the real-world speed accuracy of the shutters on my various cameras and lenses finally overwhelmed me, and being too lazy to hunt down the parts and build my own, I ordered a $14 (plus $17 shipping and three week's transit time) phototransistor-based tester from a Romanian gentlemen named Vasily Florin (shuttertester@gmail.com) who sells on the auction place under the name "vfmoto".

After playing with this thing for a few days, I have to say it works like Bob's your uncle. Ridiculously easy to set up and use. Just download Audacity (an excellent little free audio editor from Sourceforge.net), plug the tester into a PC or laptop's mic input, turn on any small, bright single-source light (a cheap little single-LED flashlight is perfect) and go to town with it. It's extremely accurate (to five decimal places or more if you want), and if you've never seriously tested your shutters you might be in for some eye-opening results. I was. Most of my shutters (even the old ones) are surprisingly accurate (and very repeatable) from one second down to around 1/125, but only a few can hack it at 1/250 and only one or two came anywhere near 1/400. Most accurate was a Nikkor-W 210/5.6 in a Copal #1, which was nearly dead on at all speeds. I was shocked to see that some of my worst (on high speeds anyway, med/slow were great) were the Seiko leaf shutters on my RB67 lenses. That was pretty disappointing!

But at least now I know where and how much I need to compensate for better exposures, so it was a valuable exercise.

I have zero financial connection to this person's business, I am just a happy customer. If you want to mess with testing your shutters, I can heartily recommend Vasily's tester, which appears to be carefully built, works fine, and came with a seriously long cord (nearly 10').

Peter De Smidt
10-Mar-2011, 21:08
Thanks for the review.

Roger Cole
10-Mar-2011, 21:09
Thanks for the information; that's very good to know. I may buy one. I had my LF lenses CLAed back in the late 90s when I started LF and the guy who did it provided a printed graph of shutter accuracy (with lines for accepted tolerance) at each speed for each of them. What you report was true then on my just-CLAed shutters too. Fine up to 1/125 or so, progressively running slower at higher speeds, but for LF I almost never shoot shorter than 1/125 and rarely that short.

It would be a cheap way now to test 'em out again and be sure they're still good.

Revolucion Artistico
10-Mar-2011, 22:09
I just bought one off him last week, but am still waiting to get it, so it's good to know it works well and is easy to use. Thanks for the review

Vladik
10-Mar-2011, 22:41
I have to fully agree with picker's review :)

Another satisfied customer.

Vasily also has a great customer support and is ready to answer any questions.

picker77
11-Mar-2011, 07:27
I looked at many "instant digital readout" testers, usually in the $100 and up (way up) range. But they all still need the same basic setup as this one to use and have more parts that can fail. All this one requires is one more step in the process--you have to use your mouse and a cursor to mark and measure the start/stop pulses on your pc, then read off the number displayed. Because you can zoom the view of the pulse, this is easy. With only a little practice I became consistent and accurate in measuring the pulses. Kind of fascinating, too, to watch the actual shutter opening and closing via the pulse shape. Once you see what the opening or closing pulse shape of a correctly working shutter looks like, you can even tell if shutter blades or curtains are hesitating or hanging up during the actual opening or closing action. I also tested a favorite old mint FED 3b that had been CLA'd by Yuri at FEDKA in New York a couple of years ago. It was pretty accurate overall, but most interestingly it was also reasonably good at the higher speeds, where nearly all my "modern" leaf shutters seemed to struggle. More kudos to Mr. Oskar Barnack and his brilliant design!

rdenney
11-Mar-2011, 08:13
We've had extensive discussions about these testers at quite a technical level, and to summarize, these testers work well in the range where they work well.

I found them to be accurate up to about 1/125 shutter speed. Beyond that, and the response time of the photo-transistor, the DC filtering on the sound card, and the uncalibrated light source, all greatly affect the waveform you see with Audacity. Choosing the correct part of the spike is easy when the shape of the spikes are tiny compared to the distance between the on and off spike, but with higher shutter speeds, those spikes get quite close and then interpreting where to make measurements introduces a lot of potential error.

I have tested the photo-transistor testers, one of my own design based on the online sources and one bought from a trusted ebay seller (both ended up being nearly identical), using an oscilloscope which is both fast and is not subject to the DC and high-frequency transient filtering on the input of a sound card. The resulting spikes therefore represented the actual output of the circuit. I found that the amount of light reaching the transistor could cause it to saturate early in its exposure, or later in its exposure, given different waveforms and making interpretation even more difficult. Again, this is all down in the noise at 1/125 and slower. With this setup I was able to get results I was comfortable with up to maybe 1/500.

The Calumet tester, when used as instructed (requiring one to adjust the light source to fall within a certain threshold), measures accurately to 1/1000 at least. Wally's design seems to be similar, and he has explicitly corrected the issues we have discussed with the transistor tester.

So, it works fine within a certain range, and if one only has Copal 3 and Ilex 4 or 5 shutters, there is no issue. Be careful with higher shutter speeds, though.

Rick "who rarely uses those high shutter speeds with large format in any case" Denney

cyrus
11-Mar-2011, 08:36
Indeed I made one of these using the online instructions and discovered a shutter bounce on one of my lenses!

picker77
11-Mar-2011, 10:14
Well stated, Rick. Vasily claims these can work well up to 1/1000 but my experience with this one at around 1/400 seems to bear out what you said. I have a good electronics bench and a Tek scope, so could have tried that too, but the choke point of an unknown (and maybe variable) response time of the sensor used would still remain, not to mention the probably much larger delay variables built into the audio chain of the sound card/chipset itself. Like you, I have high confidence in measurements taken with one of these up to maybe 1/250, after that I dunno. Since I rarely shoot chromes and rarely use anything faster than 250 anyway, none of this is a major problem for me, just interesting knowledge.

Just for fun, I'm going to put this thing on my F100 and my RF645 today if I can figure out how to make them fire with the backs open.

It's still a marvel to me that camera and shutter makers in the 30's and 40's could come up with precise timing mechanisms that were small enough to fit in a camera or shutter and yet be consistently repeatable through many thousands of cycles.

GPS
11-Mar-2011, 10:31
...

It's still a marvel to me that camera and shutter makers in the 30's and 40's could come up with precise timing mechanisms that were small enough to fit in a camera or shutter and yet be consistently repeatable through many thousands of cycles.

To let you marvel even more think of the fact that in the 30's and 40's precise shutters were already well established in photography. It was after 1912 (Compur) that they became available to photographers.

Jim Graves
11-Mar-2011, 10:48
I agree with Rick ... I compared two different testers of this style using shutters that had been professionally tested. Both testers were accurate at slower speeds but both started to go astray at 1/125 and got farther and farther off as the speed increased. I would not trust them above 1/125.

Ivan J. Eberle
11-Mar-2011, 13:13
Speeds that most LF photogs care about are the speeds at 1/125th to 1 second. With 4x5 or larger format, speeds faster than this are most often used to exclude the ambient light contribution for daytime flash, for which timing will not be so critical. Someone is sure to chime in with an exception ;-) or start talking about integrated exposures, but for typical situations when stopping down to taking aperture with leaf shutter lenses this can be safely ignored.

However one can quite easily make a very simple shutter tester like this using a much better phototransistor (faster-rise and fall times, a bit more expensive but still under $15). I did and it's sufficiently accurate at these faster speeds. Main issue then becomes setting the right sampling resolution in Audacity, not saturating the sensor by adjusting the light source or aperture, and choosing where to split the rise/fall curves, and interpreting the results.

Michael Clark
11-Mar-2011, 16:09
Does anyone know the accuracy of the Metrolux II 's shutter timer?

lecarp
11-Mar-2011, 16:34
I notice there are a couple versions of Audacity. Is a particular version required?

picker77
11-Mar-2011, 17:07
I notice there are a couple versions of Audacity. Is a particular version required?
I don't think so.. I just downloaded the latest version from the sourceforge.net Audacity website and used that. It worked fine.

picker77
12-Mar-2011, 09:14
FWIW, here are the results of this exercise. Each speed was measured three times, averaged, and then approximated into a fraction. Clearly I need to either spend some $ on CLA's or lay off using higher speeds on most of these.

I guess the old saying is true: Don't bet the farm on shutter speeds above 1/125 with older shutters. :)

onnect17
12-Mar-2011, 19:27
Few years back I purchased a used Universal Counter in the auction site (HP5315A)
for $35 and made a simple interface circuit (it's not that difficult). I use a pocket laser as a light source because it allows me to measure the opening/closing, necessary to get a real speed number.
And of course, depending on the shutter design and the F selected, the effective speed is not a unique number.

My suggestion is not to assume as a fact you shutter is slow based on some dongle you connected to the mic port. That device only will give you an idea all the way to 1/30s the most.

The field is a different story. If after filters correction I still using anything faster that 1/30s for landscape it means I'm using the wrong emulsion/ISO.

picker77
12-Mar-2011, 21:11
My suggestion is not to assume as a fact you shutter is slow based on some dongle you connected to the mic port. That device only will give you an idea all the way to 1/30s the most.


I'm curious why you seem to imply that measuring shutter speed using a phototransistor is more accurate with a laser than with a single-point LED light source--in either case you're measuring the length of time between semiconductor turn-on and turn-off by a point light source as seen through a shutter. And in each case you're measuring opening and closing. It's true there is some unknown pulse delay built into the audio chain in a sound card, but that delay is the same for both the start and stop pulses, so the actual time/distance between the pulses (as measured on a video display timeline) still remains the same. Any delay or distortion involved might be a factor in obtaining a reliably consistent turn on/off, but if the light level from the source isn't overdriving the semiconductor (thereby causing major pulse distortion) then the actual time duration between pulses is not difficult to measure.

It's very easy with any good audio editing program to visually measure portions of a second down to at least four decimal places (five is not all that hard, either), more than what's needed here. The limiting factor is mostly related to human difficulties in consistently placing the editing program's timeline cursor on the correct points in the rise and fall "curves" of the light-on/light-off pulses. Because of that, there is an increasing amount of human error introduced at much over 1/250. However, that error only becomes really difficult to manage above 1/500 or so, because that's when the pulse on/off time you're trying to capture is beginning to approach the maximum switching speed of the semiconductor device--in other words, the start pulse and stop pulse get so close together (or at least so close the response of the audio chain becomes a major factor) at very high shutter speeds that they begin to merge, making it very difficult to measure where one stops and the other one starts. The ideal thing to look at and easiest to measure would of course be a perfectly square start & stop pulse, but that's impossible because shutters don't physically open and close instantaneously. That's where "shutter efficiency" factor is important for higher shutter speeds, and also where the aperture used becomes more of a factor.

For simple measurements such as I did, though, I used wide open apertures and ignored efficiency, because it isn't much of a factor at slow and medium speeds. Being able to see on screen the actual opening and closing curve of the shutter's blades is, in my eyes, actually one of the benefits of using the "dongle", as you put it. Hesitating or inconsistent shutter blades are easy to spot, and once you get some practice in consistently placing the cursor on the proper spot on the curve, very consistent and repeatable measurements to four decimal places becomes pretty easy. And four decimal places is a lot better than 1/30 second. :)

Frequency counters have much the same problem as human eyeballs in interpreting wide pulses, though. Feed a counter a pair of wide pulses with very little time separation between them (ie, a very high shutter speed), and serious errors will result, so pulse shape and repetition rate are important limiting factors, just as they are with a "dongle", a sound card, and the human eye. You have my curiosity going, though, so I think I'll fire up my HP counter and TEK scope and see what I can see.

Shutter testing is an interesting subject, makes me wonder exactly what procedure Nikon and others measure 1/8000 sec and more in some of their shutters. I guess that's where the $5K+ shutter testers come in, as opposed to the $14 deluxe model I used.

onnect17
13-Mar-2011, 16:25
The only advantage of the laser is to position the beam in any part of the opening area in the shutter, most common in the center and in the border. The difference divided by two will you a number near to the open / close time.
With the HP Counter ( used as time lapse ) I can set the levels in the comparators (going up and going down) and the only cutoff is the capacitance of the cable entering the counter.
I set the limit for that simple circuit to 1/30s because of the precision. 25% or 1/4 stop is significant for trasparency film. In fact, for those interested in using the phototransistor method, the circuit is redundant. The input in the PC is a pull-up resistor to +5v followed by a highpass capacitor, so all you should need is to connect the phototransistor (or photodiode) directly to the input.

Now, if you suspect sticky blades in the shutter, the Casio ex-fc100 has a mode to record 1000 fps in a very small resolution (and noisy too) but good enough to find any
troubles.

Brian C. Miller
13-Mar-2011, 18:54
I just went looking for shutter testers, and I found S.K. Grime's Leica shutter tester (http://www.skgrimes.com/idcc/index.htm). This version was not made by Leica, but the concept is so revealing! A drum with slits, running at a constant speed! (slaps forehead)

So of course the question really is, how did they accurately measure speeds before electronic dohickeys were available? Of course, by tripping the shutter against a bright intermittent light source. Like the slit drum.

Jim Jones
13-Mar-2011, 19:41
One simple method was to use an audio signal generator to fire a neon lamp, and a photo detector and counter to count the light pulses while the shutter is open. If the shutter speed encompasses only a few pulses, looking through the shutter and tilting the camera at right angles to shutter movement spreads the flashes out for a rough visual count. Observing a TV screen through the shutter is adequately accurate for speeds from about 1/30 second up. Photographing a rotating disc with radial lines has long been used.

rdenney
14-Mar-2011, 05:58
When we had NTSC television and CRT displays for watching it, we could measure shutter speeds of focal-plane shutters with reasonable accuracy. Analog NTSC video scanned the odd rows of phosphors on the screen, followed by the even rows, every 1/30 second. Each odd or even set included about 260 rows (depending on overscan). A photograph of the screen showing a bright band that included about eight rows was 1/1000 of a second of exposure.

I'm sure it can still be done with HDTV, but there is more thinking required, including knowing which HD mode is being displayed by the monitor. I don't know if persistence with these high-speed modes makes it more difficult to see the bright bands, and I suspect it's not as easy at it used to be. Obviously, I haven't tried it.

It's almost worth keeping an old TV around plugged into a composite video source. Any stable image will work, even a white screen, if it's exposed so that the bright band is in the middle of the exposure latitude.

The old devices with slits in them still required a sensor that would count the resulting pulses, as I recall. That isn't hard. And, as has been pointed out, it's easy to build a circuit that can produce any arbitrary pulse frequency. An LED hooked to an audio output would work as well as a neon tube, if the LED is fast-acting enough.

Even a digital camera could be used. Just sweep it across the field of view as the shutter is opening and closing to reveal the pulsations. A quick enough sweep will separate the pulses in the exposure. I used that trick to measure the frequency of an LED light source being used for a freeway dynamic message sign I was testing. I didn't have the proper test equipment, and want to check whether the manufacturer met a 100-Hz minimum requirement for pulse frequency. I set the camera on 1/4-second exposure and swept it across a single illuminated LED. I could count the pulses right on the DSLR's preview screen. 25 pulses / 0.25 second = 100 Hz. I had to assume the camera's shutter speeds were accurate, but that's not much of an assumption using slower speeds on a quartz-controlled timing circuit.

Rick "thinking even a low-power laser will saturate any photo-sensitive device making it hard to interpret" Denney

Roger Cole
14-Mar-2011, 08:41
CRT TVs are still common and any DVD player or old VCR will output a composite NTSC signal.

Ivan J. Eberle
14-Mar-2011, 11:04
Jeez, some of you fellers could doubtless screw up a wet dream. The $14 testers work very well indeed for most of what LF photograpers care about, and an even better but elegantly simple solution is within reach of even beginning electronic hobbyists for trifling dollars more. It's right here in this thread, for anybody who can read past all this noise...

vfmoto
17-May-2011, 11:02
Hello,

I hope my post will not be regarded as spam. I accidentally found this thread now.

First of all I would like to thank the people that said all the nice things about me.

The Audacity shutter testers (all of them) are a bit tricky if you don't follow some steps. These steps vary from a photocell type to another and from a tester type to another. I can only speak about my testers. Other testers (made with other parts) are different, not bad, different. Maybe they are better than mine, who knows.

That means that what I am about to say may not apply to other Audacity testers.

My testers won't work well with a laser. The 1000 and 2000 speeds are done with an electronically controlled focal plane shutter. Human error is a big factor. Light source is the biggest factor of all.


I found them to be accurate up to about 1/125 shutter speed. Beyond that, and the response time of the photo-transistor [...]

This might happen either because the shutters are indeed off or because the test is not done right. Picker77 and the others that bought a tester could tell you that a bad spike can have an error of more than 30% for fast speeds of 1000. I hope they read their emails and the manual. I am surprised by the fact that a lot of people don't. The faster the speed, the bigger the error.

The rise and fall time of the photocell is negligible. Some have a rise and fall time of the order of microseconds. A microsecond is 1000 times faster than a millisecond (1/1000th of a second).

So a microsecond is about 1/1000000 in camera speed.


I agree with Rick ... I compared two different testers of this style using shutters that had been professionally tested. Both testers were accurate at slower speeds but both started to go astray at 1/125 and got farther and farther off as the speed increased. I would not trust them above 1/125.

This is exactly what I mean. If you are not doing the tests right, the faster the speed, the bigger the error. There are good spikes and there are bad spikes.


I notice there are a couple versions of Audacity. Is a particular version required?

The newer ones that are required by Windows 7 are a pain in the butt to use. You don't get the time difference in the bottom of the screen. You should get Audacity 1.2.6 if your operating system can support it.

rdenney
17-May-2011, 11:16
[in responding to something I said] This might happen either because the shutters are indeed off or because the test is not done right. Picker77 and the others that bought a tester could tell you that a bad spike can have an error of more than 30% for fast speeds of 1000. I hope they read their emails and the manual. I am surprised by the fact that a lot of people don't. The faster the speed, the bigger the error.

The rise and fall time of the photocell is negligible. Some have a rise and fall time of the order of microseconds. A microsecond is 1000 times faster than a millisecond (1/1000th of a second).

So a microsecond is about 1/1000000 in camera speed.

If you will search the many threads where we have discussed this topic, you'll note compelling arguments why the circuitry surrounding the sensor device (be it phototransistor or photodiode) must be carefully done to achieve anything like the rated response characteristics of the sensor. The simple sound-card testers usually don't have that necessary circuitry, resulting in unpredictable saturation and a range of other issues.

A bigger problem is that the microphone input of a sound car is filtered for DC. That means the battery's direct current, as switched by the sensor, will be fed through a capacity to eliminate the DC--or really any AC below a certain frequency. If that lower frequency is rolled off at, say, 20 Hz, it will start rolling off the switched output of the sensor within 1/20 second. That's why the waveform shows a spike when the shutter opens and an opposite spike when it closes. The wafeform is also affected by the frequency response of the sound card. You get a much different picture when looking at the sensor output on an oscilloscope instead of as input to recorded sound. I've done so.

The shape of those spikes is rounded off by that filtration, and if the light source is too bright it will cause the sensor to saturate and clip. The corner of the waveform where it clips might appear significant, but really it's quite arbitrary. I always adjust the light source to prevent clipping, but then I get a very rounded spike that is hard to interpret.

When the round shape of the spike is small compared to the shutter open time, it does not impose much potential error. When it is large, it does. At fast speeds, the two shapes collided, making the interpretation that much more difficult.

I don't know how one could overcome the filtering on the sound card input by any amount of modification of the sensor circuitry. The sound cards impose limitations and fortunately those don't affect large-format shutter testing much. But I could not get readings of the faster speeds on my Speed Graphic using a sound card that were consistent with what I measured using an oscilloscope.

The device is inexpensive and works well for slower speeds, but it is what it is.

Rick "not idly speculating" Denney

BetterSense
17-May-2011, 11:28
Lets not forget that an accurately adjusted 1/500th of a second shutter may be open for 1/250th of a second AND BE PROPERLY adjusted at the same time, due to the opening time of the shutter leafs.

If you measure a fast shutter speed and find that it's actually open for a longer time, that doesn't mean it's adjusted wrong, unless you value exact shutter open time over exact exposure (and I doubt that is the case in LF very often).

vfmoto
17-May-2011, 11:38
If you will search the many threads where we have discussed this topic, you'll note compelling arguments why the circuitry surrounding the sensor device (be it phototransistor or photodiode) must be carefully done to achieve anything like the rated response characteristics of the sensor. The simple sound-card testers usually don't have that necessary circuitry, resulting in unpredictable saturation and a range of other issues.

A bigger problem is that the microphone input of a sound car is filtered for DC. That means the battery's direct current, as switched by the sensor, will be fed through a capacity to eliminate the DC--or really any AC below a certain frequency. If that lower frequency is rolled off at, say, 20 Hz, it will start rolling off the switched output of the sensor within 1/20 second. That's why the waveform shows a spike when the shutter opens and an opposite spike when it closes. The wafeform is also affected by the frequency response of the sound card. You get a much different picture when looking at the sensor output on an oscilloscope instead of as input to recorded sound. I've done so.

The shape of those spikes is rounded off by that filtration, and if the light source is too bright it will cause the sensor to saturate and clip. The corner of the waveform where it clips might appear significant, but really it's quite arbitrary. I always adjust the light source to prevent clipping, but then I get a very rounded spike that is hard to interpret.

When the round shape of the spike is small compared to the shutter open time, it does not impose much potential error. When it is large, it does. At fast speeds, the two shapes collided, making the interpretation that much more difficult.

I don't know how one could overcome the filtering on the sound card input by any amount of modification of the sensor circuitry. The sound cards impose limitations and fortunately those don't affect large-format shutter testing much. But I could not get readings of the faster speeds on my Speed Graphic using a sound card that were consistent with what I measured using an oscilloscope.

The device is inexpensive and works well for slower speeds, but it is what it is.

Rick "not idly speculating" Denney

You make very valid points but as I said, it all depends on the tester. I can't speak for other designs because they are different. For example, that battery you talk about does not exist in my tester.

I did not come here to promote my tester or to argue with anybody. This kind of quest for something simpler and better made me make the tester after I tried the internet thing. I don't know if I made it better. I like to think I did.

I don't have any large format cameras so I can't really say I belong here. Anyway, keep on keeping, everybody!

Florin "not really idly speculating either" Vasile

rdenney
17-May-2011, 12:16
You make very valid points but as I said, it all depends on the tester. I can't speak for other designs because they are different. For example, that battery you talk about does not exist in my tester.

I did not come here to promote my tester or to argue with anybody. This kind of quest for something simpler and better made me make the tester after I tried the internet thing. I don't know if I made it better. I like to think I did.

I don't have any large format cameras so I can't really say I belong here. Anyway, keep on keeping, everybody!

Florin "not really idly speculating either" Vasile (emphasis added)

Vasile, I believe I have misinterpreted your online description. It includes two batteries, which I assumed were required to power the sensor circuitry as well as the light source. And the sensor appears to be in a standard clear photodiode package. A battery-powered circuit will use the sensor as a switch, and that sensor is subject to all the issues I raised. All of them that we have seen sold at low prices on ebay, and that have used sound-card inputs, have been phototransistor or photodiode switching circuits. I bought one on ebay that was precisely that.

If there is no battery, you must be using a photo-voltaic cell, like a silicon crystal cell, I'm assuming. Something has to generate some voltage for a microphone input to see.

How do you overcome the DC filtering on the sound card? Perhaps you have a particular means of interpreting the waveform made possible by the calibrated light source. Getting the light source right is critical with all the different circuit approaches.

I did not intend to sound argumentative. This has been a topic that has been discussed in quite a bit of depth on this forum, and the understanding of what is available is so saturated with the simple battery-photodiode-sound card design that it might require some particular emphasis on your part to overcome that expectation, assuming you are doing something different.

Rick "hoping to hear more" Denney

vfmoto
17-May-2011, 14:28
(emphasis added)

Vasile, I believe I have misinterpreted your online description. It includes two batteries, which I assumed were required to power the sensor circuitry as well as the light source. And the sensor appears to be in a standard clear photodiode package. A battery-powered circuit will use the sensor as a switch, and that sensor is subject to all the issues I raised. All of them that we have seen sold at low prices on ebay, and that have used sound-card inputs, have been phototransistor or photodiode switching circuits. I bought one on ebay that was precisely that.

If there is no battery, you must be using a photo-voltaic cell, like a silicon crystal cell, I'm assuming. Something has to generate some voltage for a microphone input to see.

How do you overcome the DC filtering on the sound card? Perhaps you have a particular means of interpreting the waveform made possible by the calibrated light source. Getting the light source right is critical with all the different circuit approaches.

I did not intend to sound argumentative. This has been a topic that has been discussed in quite a bit of depth on this forum, and the understanding of what is available is so saturated with the simple battery-photodiode-sound card design that it might require some particular emphasis on your part to overcome that expectation, assuming you are doing something different.

Rick "hoping to hear more" Denney

Hello,

I sell 4 different types of testers. The thread did not mention the type but it mentioned the price. The testers priced at $15 don't have a battery. These were the testers mentioned in the thread (at least that is what I understood). They use the phantom power from the sound card. Yes, there are big differences between supplying power with either batteries or phantom power. They are so big that you don't need an oscilloscope. You can see it with the naked eye in Audacity (on my testers, at least). These differences are reduced if you do the tests right and very big if you do them wrong but it does not really matter because the tests were already done wrong.

These little testers had a single little inconvenience. Steve Jobs and his Apple computes. For reasons I don't know, Steve decided that his computers don't need phantom power and I got a lot of "Mine doesn't work!" emails until I figured it out (the fact that I never owned an Apple computer did not help).

That is why I made the 1/2000th tester and decided to shoot 2 birds with one stone. Put a light source that I know how it will work with the photocell and make it adjustable, power the light source from the batteries and also power the photocell from the batteries to make it Apple compatible. For some time I would ask my customers what computers they use and wire it accordingly.

Now your next comment might be "But you said there are differences between the 2 types of power supply."

Yes there are and you managed to give the answer in the reply. I have my own way of interpreting the wave form and it works accurately with my testers only. For other designs and photocells my instructions will not give accurate readings. I see people with comments like "Plug it in, light it up and shoot!". This is wronger than wrong. To give you an idea on what it takes just to try and explain how the Audacity tester works, I send a 12 page PDF manual with general screenshots and instructions an Audacity test done with the unit that the customer bought, screenshots from that test of good spikes and bad spikes and some extra info in the email.

The Audacity test is done at the fastest claimed speed. This also serves as proof that the tester is capable of the advertised speeds. I do the tests with an electronically controlled focal plane shutter.

The people that bought a tester from me can confirm this.

So I know my patterns with phantom power and batteries and I give the instructions accordingly, some of the tips being custom for that tester only.

How did you come up with these patterns, you may ask. Well, if people don't believe me my testers can measure those speeds they won't believe my claims that I have made literally THOUSANDS of tests.

Why? Because it started as an internet curiosity and ended up being a very fun challenge.

Now, let's get to the thing that really messes up the readings. The operator. People would send me screenshots and I was a bit shocked to see that most of them don't follow the instructions so their results are not that accurate. The patterns can give you all the info you need and a thing that might look like noise to some and go unseen to others could be the marker for your start point. Another thing that might look like noise to some and go unseen to others could be the marker for your exit point. To really get accurate results you have to be able to see them. For me, they are obvious because I've done so many tests. To others they are invisible and they get very confused when I explain it to them making it more difficult to understand. This is why I don't even mention these fine details unless I see that my customers are trying to measure the fast speeds and are really anal about their times.

The thing is this:

It does not matter one bit if your real shutter speed is 962 for a theoretical speed of 1000 and your tester shows a speed of 975. It won't affect your exposure that much and even if you would like to compensate, I don't really see how you could adjust your camera settings for a minor difference like this one. I don't know about you, but If my mechanical shutter is within 4% of the theoretical speed, it's spot on!

And here is another thing. Let's say you do a test with Audacity and you have a measured speed of 950. Now let's say the real speed is 985. You have a hunch that your measured speed does not exactly match the real speed so you fire up the old flux capacitor and do a test making sure you don't get hit by the intergalactic death ray. SCORE! Your measured speed now matches the real speed of 985. Now what? How many people have the tools and knowledge to do fine a shutter adjustment from 985 to 1000? How many are willing to take it to a shop that has the right tools and knowledge to fix it but will do it for a modest fee of a few hundred dollars?

P.S. You've made some very valid points and if all the things you said would be solved you still would not get your measured speed to match that accurate speed on 957.23 or whatever it is because there is even more to it than this.

The patterns are the key to get to get good enough results (let's say within 5% of the real speed) but there is no easy way of learning them.

There would be more to write about this but the thing is that I don't have all the answers. There's a reason the mega expensive shutter testers are mega expensive.

I'm going to bed now. Bye!

Florin "even if some of you don't believe my testers are any good, at least I confirmed the good communication part" Vasile

vfmoto
17-May-2011, 15:01
I forgot to mention on thing.

You kept saying you bought a tester from a reputable eBay member and the results were bad. If that member is who I think it is, I can say that the truth was bent quite a bit in that listing and that member threw a few dirty punches at me. From what I saw, that was a stock internet design.


Florin "doesn't really want to look like a bitter seller in the eBay wars and won't mention this again" Vasile

rdenney
17-May-2011, 22:26
I forgot to mention on thing.

You kept saying you bought a tester from a reputable eBay member and the results were bad. If that member is who I think it is, I can say that the truth was bent quite a bit in that listing and that member threw a few dirty punches at me. From what I saw, that was a stock internet design.


Florin "doesn't really want to look like a bitter seller in the eBay wars and won't mention this again" Vasile

I made no such claim. I said I bought a typical photo-transistor tester of the type one can find schematics for on the Internet. The seller sent me what I paid for, and said nothing about you.

I tested his (plus a couple of my own design) against a Speed Graphic shutter that has a curtain that moves mostly at one speed, and uses different sized slits for different speeds. When a test records a narrow slit as having the same shutter time as a wide slit from the same curtain, one starts to dig deeper. That's not a precision issue--it's an accuracy issue. We had a whole lengthy thread digging into that one.

We decided that the photo-transistor models were accurate enough for use with large-format lenses, which are rarely used at speeds faster than 1/125. Up to that speed, they don't require the experience you describe to get a reasonable measurement (and my standard of reasonableness is easier than yours--+/- 20%). Faster than that, and the light source must be carefully adjusted and the waveforms carefully interpreted. I tested several of those up to 1/1000 (using my electronically control Pentax shutter as a control), but the two curves collided to such an extent that I had to use an oscilloscope to get around that blasted DC filter.

Wally's design, which is pricier than yours, provides a counter, similar in usage to the Calumet tester. Even that requires careful adjustment of the light source, and the instructions with the Calumet tester were explicit on the matter. But I've tested up to 1/1000 with those testers with reasonable accuracy (verified with the Pentax shutter and validated by photo tests with Velvia). Again, reasonable accuracy is within a quarter stop.

If you've documented how to interpret those waveforms accurately, then your book is worth as much as your hardware.

Rick "who also experimented with slits and nose baffles on the sensor" Denney

vfmoto
17-May-2011, 23:29
This is a 1/1000th spike from my tester. I can't speak for other designs but I found it easy to select the desired area in Audacity at this speed. It was done with a focal plane shutter. As I've said before, I don't own a large format camera.

+90% of my tests done at 1000 are in the 980 - 1025 range for that shutter. Call me biased but I doubt this is a coincidence.

http://i1198.photobucket.com/albums/aa442/iwantanortonmanx/1000cab.jpg

Florin "at the end of the day, it's best that people choose a method/tester type/design they are comfortable with." Vasile

msk2193
4-Jun-2011, 12:24
After reading the OP and first few responses, I ordered a meter from Vasile, and it was here faster than most first class mail gets across the country! That signature required delivery took two hours in line at the lovely post office, but that is for another thread!

Only had a few minutes to play with the kit, but I must say it is extremely easy to follow the instructions and set-up. On a just CLA'd shutter the reading was right on the money. One other shutter (images were more than a bit udner-exposed) shows it needs servicing! There goes June's disposable income. ;)

Tim Meisburger
4-Jun-2011, 14:41
I should chime in. I bought a tester from Vasily and promised to give feedback on ebay after trying it out, but got caught in the middle of a move and by the time I got around to it, it was too late.

I found the tester a bit complicated at first, as I am not used to reading waveforms, but within an hour or so I was able to get the hang of it and test all my lenses. I had a few emails back and forth with Vasily to confirm I was interpreting everything correctly, and he was very helpful.

For those with some sort of technical expertise, perhaps this is not what they want, but for anyone who just wants to test their shutters, I think this is great! So, I guess this means five stars (Vasily, hope this makes up for never leaving feedback. Also, start shooting LF; you'll never look back...).

Best, Tim

vfmoto
6-Jun-2011, 05:54
After reading the OP and first few responses, I ordered a meter from Vasile, and it was here faster than most first class mail gets across the country! That signature required delivery took two hours in line at the lovely post office, but that is for another thread!

Only had a few minutes to play with the kit, but I must say it is extremely easy to follow the instructions and set-up. On a just CLA'd shutter the reading was right on the money. One other shutter (images were more than a bit udner-exposed) shows it needs servicing! There goes June's disposable income. ;)

Hello,

I do not ask for signature at delivery. I don't know how USPS does things but I am sorry you had to wait in line for 2 hours.

I am happy you like the tester. :)


I should chime in. I bought a tester from Vasily and promised to give feedback on ebay after trying it out, but got caught in the middle of a move and by the time I got around to it, it was too late.

I found the tester a bit complicated at first, as I am not used to reading waveforms, but within an hour or so I was able to get the hang of it and test all my lenses. I had a few emails back and forth with Vasily to confirm I was interpreting everything correctly, and he was very helpful.

For those with some sort of technical expertise, perhaps this is not what they want, but for anyone who just wants to test their shutters, I think this is great! So, I guess this means five stars (Vasily, hope this makes up for never leaving feedback. Also, start shooting LF; you'll never look back...).

Best, Tim

Tim, you were the first person that bought a tester from me. I am glad to hear you still like it.

Shooting LF is not possible for me at the moment. My small apartment has no room left for a dark room. Maybe some day.

Cheers,
Florin

renes
6-Jun-2011, 08:04
I bought Vasily tester too, easy and fast to use, all my shutters are now tested, even these from Sputnik Stereo.