>>" Maybe Dan can create the Tripod-Vibration study."
>
>By far the best head would be the Wimberly
Ok, That's nice. But I'm less interested in antidotal evidence
than actual science.
What Gary had created with his lens tests was a scientific study
of comparing lens resolutions in a viable manner. The study
wasn't flawless and was applicable to a fixed reproduction size,
but it created a "reference point" to work from. His tests
were, perhaps, the most important contribution to the OM
community that has come from members of this list.
I'd like us to scientifically approach this and develop a study
in which we all can contribute to. If we all follow exactly the
same procedure and use exactly the same resolution chart and
film, then this is a possibility. I would absolutely
participate!
My recommendation is Ilford XP-2, which is easily processed by
any one-hour C41 lab and *could* be anylized by the individual
doing the test. Otherwise, if mailed to me, I'll examine the
processed roll (no prints necessary) and compile the results
into an HTML page that can be posted on whoever's website. XP-2
is a wide-latitude film that is exceptionally sharp and capable
of exceeding the requirements of the test. I would also process
any roll of Pan-F+ sent to me for this test too. (a voluntary
contribution to cover chemistry costs would be acceptable).
We need to define the scope of the study.
We need to define the desired results of the study.
We need to define the procedures of the study.
(It's been awhile since I've commissioned scientific
studies--what else do we need in the planning stage?)
I have a resolution chart that can be emailed and printed out on
glossy paper in high-res mode by anybody wishing to participate
in the study.
Before getting everybody going on this, I will prototype this
study on my own equipment to make sure that a common setup is
viable and what it would look like. Off hand, here is what a
test roll *could* look like:
Frame 01, Tripod Full Height, Lens 01, Orientation-H, Flash
Frame 02, Tripod Full Height, Lens 01, Orientation-H, 1 Sec
Frame 03, Tripod Full Height, Lens 01, Orientation-H, 1/2 Sec
Frame 04, Tripod Full Height, Lens 01, Orientation-H, 1/4 Sec
Frame 05, Tripod Full Height, Lens 01, Orientation-H, 1/8 Sec
Frame 06, Tripod Full Height, Lens 01, Orientation-H, 1/15 Sec
Frame 07, Tripod Full Height, Lens 01, Orientation-H, 1/30 Sec
Frame 08, Tripod Full Height, Lens 01, Orientation-H, 1/60 Sec
Frame 09, Tripod Full Height, Lens 01, Orientation-H, 1/125 Sec
Frame 10, Tripod Full Height, Lens 01, Orientation-V, 1 Sec
Frame 11, Tripod Full Height, Lens 01, Orientation-V, 1/2 Sec
Frame 12, Tripod Full Height, Lens 01, Orientation-V, 1/4 Sec
Frame 13, Tripod Full Height, Lens 01, Orientation-V, 1/8 Sec
Frame 14, Tripod Full Height, Lens 01, Orientation-V, 1/15 Sec
Frame 15, Tripod Full Height, Lens 01, Orientation-V, 1/30 Sec
Frame 16, Tripod Full Height, Lens 01, Orientation-V, 1/60 Sec
Frame 17, Tripod Full Height, Lens 01, Orientation-V, 1/125 Sec
Frame 18, Tripod Half Height, Lens 01, Orientation-H, Flash
Frame 19, Tripod Half Height, Lens 01, Orientation-H, 1 Sec
Frame 20, Tripod Half Height, Lens 01, Orientation-H, 1/2 Sec
Frame 21, Tripod Half Height, Lens 01, Orientation-H, 1/4 Sec
Frame 22, Tripod Half Height, Lens 01, Orientation-H, 1/8 Sec
Frame 23, Tripod Half Height, Lens 01, Orientation-H, 1/15 Sec
Frame 24, Tripod Half Height, Lens 01, Orientation-H, 1/30 Sec
Frame 25, Tripod Half Height, Lens 01, Orientation-H, 1/60 Sec
Frame 26, Tripod Half Height, Lens 01, Orientation-H, 1/125 Sec
Frame 27, Tripod Half Height, Lens 01, Orientation-V, 1 Sec
Frame 28, Tripod Half Height, Lens 01, Orientation-V, 1/2 Sec
Frame 29, Tripod Half Height, Lens 01, Orientation-V, 1/4 Sec
Frame 30, Tripod Half Height, Lens 01, Orientation-V, 1/8 Sec
Frame 31, Tripod Half Height, Lens 01, Orientation-V, 1/15 Sec
Frame 32, Tripod Half Height, Lens 01, Orientation-V, 1/30 Sec
Frame 33, Tripod Half Height, Lens 01, Orientation-V, 1/60 Sec
Frame 34, Tripod Half Height, Lens 01, Orientation-V, 1/125 Sec
Notice the "reference" frames using a flash. This would be
necessary to accomodate the variations in lens sharpnesses.
When using lenses of lesser resolution, some eyeball estimating
will be necessary. Not sure quite how to deal with the exposure
variances. I was thinking that direct sunlight or open shade
would be a good choice, however, that would require varying the
aperture which could alter the accuracy of the test (see Gary's
lens test website). Maybe the resolution chart could be
modified with multiple target areas using tinted backgrounds to
lower the apparant exposure values. I'll fiddle with this and
if anybody has any thoughts, I'm listening.
My desire is to show that the sympathetic vibrations vary
according to tripod selection, height, camera body, lens and
camera orientation. The sympathetic vibrations occur at
specific frequencies that would affect certain shutter speeds
which vary with these changing variables. I'm assuming that we
need to test at all common shutter speeds from 1 second to 1/125
as a specific setup my be problematic at 1/30, but not at 1/60
or 1/15. A simplified test could be done at maybe three test
speeds, but may miss valuable results.
If, during the prototype test, it is determined that no
appreciable difference occurs between Vertical and Horizontal
orientations, or between several shutter speeds, we may lessen
the number of "test points". Fewer test points mean more
participation and a wider range of tested equipment. More test
points mean greater detail, but possible skewed results due to
variations in manufacturing and wear.
Off-hand, I'm thinking that 1/4, 1/15, 1/60 and reference flash
might be sufficient or 1/2, 1/8, 1/30 and flash. Horizontal
only.
Thoughts?
AG-Schnozz
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