Archived posting to the Leica Users Group, 2000/01/05

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Subject: [Leica] Technical Pan Sharpneness & Camera Vibration
From: Frank Dernie <FrankDernie@compuserve.com>
Date: Wed, 5 Jan 2000 10:30:34 -0500

Paul Roark asked about the effect of vibration on the resolution available
from tech pan film on a 35mm camera. 

I have never shot a test chart so I do not know resolution numbers but I am
pleased to share some observations and measurements FWIW.

1) I am sure that the vibration you hav e noticed is due to mirror
movements not the shutter. A Hasselblad is useless for the type of
photography I do due to vibration, and it has a leaf shutter. The mirror
and darkslide etc vibration OTOH is like a grenade going off in the hand.

2) I did measurements about 20 years ago of vibration on an Olympus OM1,
Nikon F2 and Leica IIIf. This was what i owned at the time. I still have
all but the Leica which was stolen. The vibration level was at its lowest
on the Leica with the Olympus surprisingly good and Nikon some way behind.
What was particularly interesting was the time over which the vibration
contiued. It was sufficiently short for the effect to be important at
shutter speeds of 1/60 to 1/2 second but for slower speeds to be
negligible.
At the risk  of over simplifying for the sake of clarity this is analogous
to very long exposures where people, cars etc move through a scene and are
effectively unrecorded. If the vibration effectively lasts 1/30 secs the
camera is vibrating for the entire time the shutter is open at 1/60th but
only a fifteenth of the time that the shutter is open during a 1/2 sec
exposure. The effect of the vibration will then be negligible.
3) the combination of tripod mass, rigidity and position of the camera on
it and the camera mass etc has a large influence on measurements. The best
camera can be made worst by mounting it on an unsuitable (for it) tripod.
4) I have done no measurements since but for back packing a Leica M system
IMHO is unbeatable. With a 35 aspherical summilux or 24mm Elmarit I get
results which for me exceed that which I get with a Mamiya 7 and are way
better than my Hasselblad efforts, I reeally should sell that camera.
Very complicated
cheers Frank