Adjusting Compur/Copal shutter speeds

[paul_c5x4]

Testing the shutter speeds on my (small) collection of shutters, I find the speeds faster than 1/100 sec are way out. For example, Copal:

1/125 measured at 1/83
1/250 measured at 1/166
1/400 measured at 1/166

Syncro-Compur

1/100 measured at 1/86
1/250 measured at 1/123
1/500 measured at 1/117

Compur-Rapid

1/10 measured at 1/15
....
1/100 measured at 1/80
1/200 measured at 1/107
1/400 measured at 114

Most of the other speeds were within 10%, and a few, spot on. Apart from the fastest speed on each shutter, I'd kinda hoped for reasonably accurate timings - Not wanting to send the mechanisms away for a CLA, is there anything that I could do to improve the speeds ?

[ic-racer]

The Compur is fully adjustable. The manuals are out there, here is one http://cgi.ebay.com.my/Rolleiflex-TL...mZ120362946347 If I had the PDF I'd sent it to you.

[jon koss]

Sometimes bad results implicate the test and not the subject. Are you certain that your test method is reliable?

Best,
J

[paul_c5x4]

Sometimes bad results implicate the test and not the subject. Are you certain that your test method is reliable?

Repeated the tests again this morning, and the results are within 2% or so.

The Compur is fully adjustable. The manuals are out there

Seems there are quite a few places selling the Rollie manuals. Reluctant to shell out $35+$13 without knowing if the required information is included. Looks like ebay #360153020687 would cover two of the shutters in question.

Googling with a better search parameter, I found http://www.suaudeau.eu/memo/rep/Comp...ir-manual.html.

I would imagine Copal shutters would be similar in terms of cleaning and adjusting.

[jfdupuis]

When you measure high speed leaf shutter opening time, you need to think about the effective opening time. For that, I think you need to integrate the amount of light that pass through and not just looking at the opening and closing time.

When calibrating my shutter using a phototransitor and my sound card, I realized that the highest speed are off quite a bit. About 0.20 stop at 125, 0.5 stop at 250 and about a full stop at 500. The other speeds are within 0.10 of a stop. Since I'm not able for now to get the DC component of the signal, I can't validate my assumption. As soon as I can get my hands on a DAQ card, I will check if integrating the signal make a more sense.