Shutter speed testers (Page 4): Not knowing the investment amount OP considers too high, I offer the following link: A mobile phone with an RCA type jack (or an adapter is required)...

waltnetto Loc: LaVerne, CA

Not knowing the investment amount OP considers too high, I offer the following link:
A mobile phone with an RCA type jack (or an adapter is required) along with a non-LED light source.

https://www.catlabs.info/product/photoplug-optical-shutter-speed-tester

Catlabs is a very interesting site to visit and their customer service is damn good.

scoundrel Loc: Wytheville VA

BebuLamar wrote:

Some cameras have a large shot to shot variation. That is why although I don't worry about rolling shutter problem I really want to get rid of the mechanical shutter as it's a very inaccurate device.

I have had cameras where the shutter stuck open sometimes but never a shutter with erratic timing.

scoundrel Loc: Wytheville VA

DirtFarmer wrote:

Well, first of all, I would expect you would have ... (show quote)

Most of your objections are valid and have been foreseen. Televisions with CRTs, especially black and white ones, have been obsolete for quite some time. A working one indeed most likely will be hard to find. I also hadn't run a test similar to the one you did with your TV. I don't know whether yours was a plasma or an LED TV, but the fact that it had a continuous image was no surprise to me. I don't know if all flat screen TVs are like that, but I suspect that a significant fraction are.

You are also right that a long enough phosphor decay time would bias the shutter speed readings to slower than they are, but a long decay time would also cause specular highlights to leave noticeable trails and degrade the image. The idea of using a TV set to check actual shutter speed is not original with me; I got it from an issue of Camera 35 from the late '60s or early '70s and successfully tried it. On both the TV sets the article's author and I used, the phosphor decay time was very short. (For what it's worth, the technique also works with focal plane shutters if the curtain travels horizontally, but the bands are curved and more or less diagonal instead of horizontal.)

Your idea of using a light sensor connected to an oscilloscope near the film plane and a diffuse light source in front of the lens, but with some caveats. I have also used that technique myself on another camera. The scope must have several features that your typical hobbyist's scope does not have: this is a one-shot waveform, not a repetitive one. This means that the scope's sweep must be triggered and must have a camera mounted to capture the trace or must be able to store the waveform. I had a suitable storage scope available in the electronics lab at college, but your average hobbyist is not likely to have such a scope. The scope must also have a grid on its display and the time base of the sweep must be calibrated.

The necessary light sensor circuit would be easy enough to rig up for someone familiar with tinkering with electronic breadboards. The circuitry required is simple, but my guess is that the OP is unfamiliar with electronics and would not have enough of a continuing need for such an oscilloscope to buy one. I made my own photosensor by grinding the top off a generic transistor in a metal TO-18 case, mounting it to a circuit board with a resistor and a 9-volt battery clip for a power supply. I may even have that circuit lying around among my electronic bits and pieces, but I don't guarantee that the modified transistor still works after fifty years exposed to dust and uncontrolled room air. By the way, the circuit also picked up the 120 Hz out variation in the fluorescent lights used to illuminate the paper target in front of the camera's lens., but that didn't affect the measurements.

scoundrel Loc: Wytheville VA

I did some shopping for scopes and was blown away by some of the offerings available these days from brands like FNIRSI Technology, Siglent Technologies, Quimat, and Rigol. Best scope for the money appears to be the Siglent SDS1202X-E, which gets little but rave reviews. This model, which is more than good enough to handle the requirements for the current application, can be had for something in the neighborhood of US$300 new. (Probes extra cost).

BebuLamar

scoundrel wrote:

I did some shopping for scopes and was blown away by some of the offerings available these days from brands like FNIRSI Technology, Siglent Technologies, Quimat, and Rigol. Best scope for the money appears to be the Siglent SDS1202X-E, which gets little but rave reviews. This model, which is more than good enough to handle the requirements for the current application, can be had for something in the neighborhood of US$300 new. (Probes extra cost).

I have some USB based scopes from Picotech. They are only 10MHz which is as low as they can go but more than sufficient for shutter testing. About $150 each.

scoundrel Loc: Wytheville VA

I take it you mean the Picoscope 2204A? The OP will need to use that one with a portable computer as a controller/display, but he may already have one of those. If he does, it might suit his needs. I haven't heard from him in a while.

BebuLamar

scoundrel wrote:

I take it you mean the Picoscope 2204A? The OP will need to use that one with a portable computer as a controller/display, but he may already have one of those. If he does, it might suit his needs. I haven't heard from him in a while.

I have 4 of those 2204A I bought for a project. The OP certainly has a computer because he posted on the UHH. Either Mac or PC would work and doesn't have to be a portable either. I use mine on the desktop.

scoundrel Loc: Wytheville VA

The OP has some computing device that can communicate with the net, but it might be a cell phone or something so loaded down with external peripherals (like mine) that it might as well be regarded as a piece of furniture, so the question is still worth asking. There is also the possibility that a rude reply on one of his other threads has chased him away.

mtbear

When I used to go to camera shows there was always someone there that had a machine and often tested for free.

a6k Loc: Detroit & Sanibel

scoundrel wrote:

I don't know whether this technique still works with more modern technologies, but in the days of old-fashioned picture tubes, each half-frame me was scanned 60 times a second, 263 odd-numbered scan lines for the first half-frame, 262 even-numbered lines for the second half, for a total of 525 lines for each frame, each line representing 1/15,750th of a second. For Europeans, that would be 50 half-frames a second at 625 lines for each full frame, giving 15,625 lines per second.

Turn the screen's contrast down to its minimum setting. Then shoot a picture of the screen for each shutter speed to be tested. Shoot at least three shots for each shutter speed to minimize the possibility of being unable to count the lines because part of the lines were uncountable because the shutter opened or closed while the beam was outside the visible picture area.

For shutter speeds faster than a nominal 1/50 or 1/60 second, it is just a matter of counting the visible lines and dividing by 15,750 or 15,625, as the case may be, to get how long, in seconds, the shutter was actually open. This will be easier to do with old-fashioned black-and-white sets than color ones, but I think it can be done with color sets too. For a nominal 1/400-second leaf shutter, which is about as fast as you can expect a leaf shutter to go, you can expect a nominal 39 to 40 scan lines to be visible.

For a nominal 1/25 or 1/30 seconds, you can expect the majority of the screen to be scanned twice, with a strip to be scanned either once or thrice, depending on whether the shutter is faster or slower than the full-frame rate. It is then a matter of counting the number of dim or bright lines to find out how fast or slow your shutter is, compared to the television's full-frame rate. The same idea applies to 1/50 or 1/60 second shutters, except it is difficult to count scan lines that aren't there if the actual shutter speed is faster than the half-frame rate. You can get close enough by measuring the gap in the picture with a pair of drafting dividers and transferring the measurement to an adjacent part of the picture that has the necessary lines. This won't be perfect, but it should be close enough.

I don't know whether this technique still works wi... (show quote)

I haven't tried this in many years but be aware that fluorescent tubes flicker at 60 hz. As for the other speeds, if that one is OK you can measure the density changes from there to other speeds. How? with a light meter and a white target on your monitor or some similar concept. There are light meter apps for smart phones. You camera has a light meter. You may even have or be able to borrow a real light meter.

If you are near a general aviation airport and can find a cooperative pilot, one whose panel is "glass" rather than old style, then have him/her run the prop at 1800 rpm. "You do the math". The prop should appear to stop at a multiple of your shutter interval.

scoundrel Loc: Wytheville VA

a6k wrote:

I haven't tried this in many years but be aware th... (show quote)

Nope. The power waveform goes through zero twice each cycle, during which the output goes out or more likely dims because the phosphors coating the inside of the tube continue to glow for a short time while the UV from the fluorescent light is absent. This also causes a noticeable color shift cycle in the tube each half-cycle if the total output doesn't actually go dark each half-cycle.

Incandescent lights also dim and brighten twice each cycle, but brightness variation is not as noticeable because the filament's cooling rate is too slow to notice readily. Nevertheless, this variation can be detected with a photodiode circuit and an oscilloscope. You may have to switch your scope to AC to get rid of the large DC component to spot this variation though.

Have you actually tried this idea of having the airplane rev at 1800 rpm (30 revs per second)? You must take into account the number of blades each propeller assembly has as well, because if your particular airplane has three blades, you can have the pilot rev at a more modest 1200 rpm to get 60 blades per second. With an assembly with two blades, you can drop down to 900 rpm to get 30 blades per second. A prop with only one blade would make for a very unbalanced assembly. (Of course, it is possible to make a two-bladed prop with a single piece of metal. In fact, I would expect most two-bladed prop assemblies to be constructed in this way.)

a6k Loc: Detroit & Sanibel

scoundrel wrote:

Nope. The power waveform goes through zero twice e... (show quote)

Correct about 2 blades vs 3 blades. Yes it works as shown with video. One blade vs two is equal in this case. Use to check old tachs but pointless with electronic ones.

Here is an easy one. The iPhone always shoots at the same aperture but varies shutter speed with precision. Compare with same target at same time and maybe evaluate the exposures.

scoundrel Loc: Wytheville VA

Very similar results despite 5-1/2 stops (46x) of exposure/ISO difference.

It also occurred to me that you could do the same thing with an unloaded induction motor that rotates at a nominal 1800 RPM. in practice, the actual rotation speed would be about 1725 RPM because of what electricians and engineers call "slip" in an induction motor. The propeller would be replaced with a black disk of cardboard with a single white radial stripe painted on it. The error caused by the slip will be a negligible 0.06 stop, but if even that much is too much, it can be roughly compensated for.

a6k Loc: Detroit & Sanibel

The similar results really aren’t. I just wanted two examples of how the iPhone measures shutter speed. It’s not likely any more accurate in practical terms than the light meter app but it is very precise. That is the point. My guess is that it measures time very exactly since it has so many related time functions.

scoundrel Loc: Wytheville VA

a6k wrote:

A reasonably accurate way to check exposure, in my... (show quote)

I have never seen a 12% reflectance gray card, but I have a 18% reflectance one from Kodak. As far as I can tell, most sources use 18% reflectance as the standard for "medium" gray, which is what is typically used as a standard for measuring exposure with a reflectance meter that does not require exposure compensation. The 92% reflectance of typical white copy paper or the 90% reflectance white side of my gray card reflects 2-1/3 stops more light than the gray card and the exposure should be compensated accordingly.

As far as exposure tolerance goes, an exposure error of 1/3 stop (low by 20% or high by 25%) should probably be considered noticeable and should therefore be compensated for. This includes shutter speed errors.