Are the higher shutter speeds on large format lenses always off?

[GoodOldNorm]

I have four lenses that I have tested with a shutter speed tester. Most of the shutter speeds are as they should be apart from the 1/250 and Higher speeds. Is it common for the higher speeds to be slow by 1/2- 1 stop?

[Oslolens]

Only one of my shutter where acurate, a Fujinon-W 210mm, sold to a man in need. Else both small and big where not up to the task of giving 1 stop shorter than the next.

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[Kevin Crisp]

I find 1/125th and above are generally optimistic. Age of the shutter doesn’t seem to matter.

[Bob Salomon]

Shutter speeds are,within manufacturer’s specification if they are +\- 30% of their marked speeds.

[Rayt]

So at which range will a shutter be most accurate aside from B and T

[Oslolens]

So at which range will a shutter be most accurate aside from B and T

On a non-worn shutter, every speed except the fastest and the second fastest is my experience. I prefer to sell those I don't trust, and aim to write the actual shutter speeds on the lens board, as that seem the best place to keep them.

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[Rayt]

Normally I never have a need to shoot above 1/60 but I always shoot my Cooke PS945 (Copal 3) at the fastest speed which is 1/125. I’ll take the +/- 30% error because I have not seen anything amiss yet.

[Dan Fromm]

Hmm. Shutter efficiency? Remember, shutter speed testers measure the time that the shutter is open at all. At higher speeds, leaf shutters are only partially open for most of the time they're open. Jes' sayin'.

[Jim Jones]

Dan is right. Checking between-the-lens shutter speeds is best done with an oscilloscope. This can also be used for checking sync timing and shutter bounce.

[Alan9940]

Not to be flippant, but after 40 years of LF photography I've never used a speed above 1/60. I would highly doubt that the faster speeds are accurate. The only one I'm sure that's not accurate at the higher speeds is my Ilex #4; it was serviced by Carol Flutot a well back and she provides a test list of all the actual speeds.