Robertl594 Loc: Bloomfield Hills, Michigan and Nantucket

Amazon is great. When I was building my focus stacking rig, I would sit and ponder all of the little attachments and Knick knacks that would enhance its functionality and adaptability, Amazon was my go to site for most of those parts.
You can find so much there.

DirtFarmer Loc: Escaped from the NYC area, back to MA

I looked at the photo of your disk and the edges of the line are sharper than I expected so you should be able to get an approximation of the edge position. But they're still fuzzy and also since the line is spread out, the contrast is reduced, so there will be some error in actually defining the position of the edge. I would expect that you would get slightly different numbers from the same image if you made several attempts to measure the angle. How precisely are you trying to measure the shutter speed? It might be worth doing the measurement several times and finding a distribution of results, from which you can find the uncertainty in the number derived.

Contrast increased using Photoshop levels adjustment layer

BebuLamar

I measured shutter speeds of many different cameras and I found if the shutter speed is within 10% at high speed you're lucky. Mechanical shutters are not very accurate at the higher speed. At low speed they are much more accurate.
This is only for digital camera. For film camera I have much better way.

alexol

[deleted]

DirtFarmer Loc: Escaped from the NYC area, back to MA

Interesting. Would you consider writing up your results and posting a PDF? I would expect there would be UHH interest and maybe beyond (although it's possible I'm just projecting my nerdness)

PS: a user page is also an option and has the advantage that it can be edited (by the producer) at any time, e.g. to add or modify results.

BebuLamar

I don't want to post my finding. I am posting this thread because I need help. Not because I am selfish and don't want to share but if I post the things that I will get many not so nice responses on the UHH. Even in this thread someone said that I should simply trust the camera to be correct. At one time I posted that my the meter of my Nikon Df changed after I sent it in for service and our CHG_CANON said that Nikon sold me a defective camera otherwise the meter should be identical before and after service. But the fact is that while the reading changed both the before and after are within tolerance. Tolerances in photography are really large and even though they don't affect the end results much that doesn't mean I should not want to find out where my equipment stand. I enjoy doing that.

DirtFarmer Loc: Escaped from the NYC area, back to MA

Although I have no say in the matter, I support your decision not to publish. It's your work and you have the right to do whatever you want with it.

Another thought occurred to me. Could you use a cylinder rather than a disk attached to the motor? You could draw several lines on the cylinder (on the side) and photograph the side of the cylinder while it's rotating. That would give you a line moving across your field of view. You would measure the width of the line rather than an angle. Having several lines on the cylinder would allow you to choose the one moving across your field of view and you wouldn't have to worry about your line being on the back of the cylinder. Otherwise your analysis would probably be very similar. You might have to do some geometry to correct for a line that has a motion component toward or away from the camera, but that would be a pretty simple geometric correction.

A cylinder might be a little more construction than a disk (which could be paper or plastic). It could be wood (painted white on the side).

There is a little more geometry involved in this method as the width of the line has to be adjusted for the distance from the camera to determine the speed while the angle measurement does not.

home brewer Loc: Fort Wayne, Indiana

With McMaster-carr there is shipping cost that is not cheap; but it will like arrive the next day. Check the return policy. I use them when i can not find the product locally. I have never gotten junk from them.

Robertl594 Loc: Bloomfield Hills, Michigan and Nantucket

I have used them. Very pleased with their product selection and shipping.
RL

dustie Loc: Nose to the grindstone

That looks like a great method.

Do you have a good location near you with a good selection of fastening hardware?
If you could walk into a store and see if they sell tee-nuts, with large enough flanges, in smaller diameters maybe you would be able to purchase something for a few cents without having to pay shipping that is a few times more than the cost of your hardware, then deal with potential delivery problems.

In the shaft bore of the tee-nut, there will be threads you don't need for your application, but will it serve the purpose, anyway?

BebuLamar

No! I have Home Depot and Lowe's, Tractor Supply and Habor Freight. Not much. I missed the old days before E-Commerce killed all the local stores. Yes I want to buy a couple of things from Amazon like. For that item which is about $8 I have to pay $7 for shipping.

StanMac Loc: Tennessee

If no force is applied to the disk, use a 90 degree triangle to get the disk square to the shaft and use Super glue (cyanoacylate)

Stan

dustie Loc: Nose to the grindstone

Ok. If it works out for you with the total order that you don't have to pay unreasonably more than the price of your item, that's good.

If you didn't already know, Lowes can usually be a source of a varied selection of fasteners, including tee-nuts.
In many of their locations, there are drawers of a wide variety of fasteners, bushings, collars, furniture hardware, etc, etc, in the fasteners area. Maybe that's not true of all locations, I don't know. It's handy when just one or a few of something is needed, when they have what can do the job.

Not sure about Tractor Supply local stocks. They may have variations between what they keep in stock from one region to another.

DVZ Loc: Littleton CO

You might look through McMaster Carr or MSC Direct website they have a large variety couplings and collars.

BebuLamar

I use this at work but it's kind of expensive to buy for my own.
https://www.amazon.com/Fenner-Drives-TTQM0516-Trantorque-Mini/dp/B01BG8C9MG