Shutter Speed Testing (was Re: [LargeFormat] rest)
Clive Warren
largeformat@f32.net
Tue Jan 30 08:22:01 2001
At 09:18 30/01/01 +0000, philip Lambert wrote:
>Is there an easy way of checking the accuracy of shutter speeds? I have
>several old lenses whose shutters seem to run slower than a new shutter.
>Philip
>----- Original Message -----
>big snippety snip
Yep!
Calumet make a digital shutter tester which is relatively inexpensive and
does the job well. I have used mine for a couple of years and am very
happy with it. Having fired the shutter a couple of times, I then use a
bright light source behind the lens with the shutter tester held such that
the light sensitive cell is placed close to the centre of the rear element.
The shutter is then fired about three times and an average reading of the
shutter speed is used as the reference point for that shutter.
Writing the information down and placing the note in the bag with the lens
is a good idea for use in the field. Cold temperatures will have an effect
on an old lens, particularly if it has not had a CLA recently. A shutter
that seems to behave well in the warmth of your living room will sometimes
stick open in low temperatures!
Most of the older shutters sitting around here fire at all speeds quite
happily after a CLA, but the top speed(s) are usually about double the
stated opening durations.......
There is one Ektar in a Compur that I am very reluctant to clean up as it
seems to run at modern shutter speeds even though marked up for the older
speed range...... All down to old gummed up oil :-)
All the best,
Clive http://www.f32.net
Large Format Travel and Stock Photography