I have a small shutter tester. I checked the speeds of several
Packard shutters and found they were pretty uniform but varied with the
size of the shutter. There is a small range of speeds depending on how
hard you squeeze the air bulb. Long ago a couple of air regulators were
sold to go in the air hose between the bulb and shutter. I never found
one so don't know how well they worked.
Many standard shutters, both leaf type and focal plane are not very
consistent. For instance, Ilex recommends you trip the shutter a couple
of times before making an exposure. This is especially true of the
self-setting shutters. Graflex recommended that its focal plane shutters
be "packed" at the highest speeds by winding and tripping several times.
My measurements show this does make a difference.
A properly cleaned and lubricated leaf shutter can be reasonably
consistent. By that I mean each exposure is the same although the
absolute accuracy may not be good. So, if the shutter is marked 1/10th
second but is actually 1/7th its less important than that it be 1/7th
ever time.
Accuracy is not very good with most types of shutters. For one
thing the calibration of leaf (between the lenses) shutters is for the
iris wide open. The speed marked is the _effective_ speed at maximum
aperture. Since the shutter has a finite opening and closing time this
is less than the total open time measured at the center of the aperture.
The effective speed becomes slower as the lens is stopped down. The
ratio between maximum aperture and small apertures for a medium size
Compur shutter is about 1.5 times (I am going by memory here) so
exposures made at small stops will be effectively greater than those
made with the iris wide open. This is really a measure of efficiency
which increases as the iris is stopped down.
There are other effects in focal plane shutters. The efficiency of
the shutter depends on the ratio of the slit width and its distance from
the film plane plus the angle of light from the lens. The greater the
distance of the slit from the film the longer the effective exposure due
to diffraction at the edges of the slit. Also, the focal length of the
lens and the f/stop, especially with wide angle lenses, affects the
efficiency. The smaller the angle the greater the efficiency. There are
formulas for this in old books on optics. Because the shutters in 35mm
cameras are generally closer to the film than in a press camera the
error caused by the shutter is less.
The 1/1000th speed on a Speed Graphic or Graflex camera is true only
where the lens is stopped down, can be half that under some circumstances.
All this makes use of the latitude of the film. One can measure the
actual application time at the focal plane for any kind of shutter. If
genuinely accurate exposures are desired this is really the only method.
On 4/8/2017 2:14 PM, Eddy Willems wrote:
20 years ago I went with a lot of camera's from my studens to an Hasselblad technician who had a shuttertester,
with most of the camera's there where problems, in ten test on the same shutterspeed we saw an e fluctuation that could not bet tolerated.
I had also a packard shutter with mee and he was everytime just 1/25 of a second
he had 5 people asked to push the shutter and the shutter gave with everybody 1/25
it was that day the most accurate shutter
Op 8/04/17 om 21:07 schreef `Richard Knoppow:
The Copal would expand the use of the lens considerably.
Packard shutters are very simple. They are worked with a toggle that is activated by either an air cylinder or an electro-magnet. There are two types, one is "Bulb" only, the other also has an "instantaneous" setting with a pin coming out the front to choose. The bulb type stays open until closed by sucking the air out of the cylinder. The syringe used must have a fitting on the top for your thumb and not an automatic valve. The "instantaneous" setting is by means of the toggle, the blades are pushed open and then pushed shut again by a steady pressure on the air bulb. The speed depends on how hard you squeeze and the size of the shutter but is on the order of 1/20th second for the smallest shutters to about 1/15th for the larger ones. The Packard shutters I have with a flash contact have a simple leaf contact that is touched by the end of the blade toggle at wide open. It can be used with strobe or with flashbulbs as "open flash". I don't know how they would arrange a variation for bulbs or strobe. I have a couple of shutters with micro-switches mounted on them, evidently they were originally non-flash shutters later modified.
The usual arrangement is to mount some sort of plug on the lens board to connect between the shutter contacts and the outside world. I would not just run wires though the lens board because of the light leak. On my Packard shutters I use a short pig-tail with a small two prong AC connector on it.
The virtue of the Packard is that it can be used with any lens, the disadvantage is that there is little control of shutter speed. For strobe you must have relative darkness because the shutter stays open so long. For instance, you can't really use flash fill in daylight.
I also have a large Ilex shutter modified to take small lensboards on its front. Its used as a behind the lens shutter, like the Packard, but has some speed range and flash synch.
I also have a Apo Artar, I think, without looking at it, that its also a 390mm, f/9. Mine is a "Red Dot" which is coated. I also have a 12" Apo Artar, a much older one, in a Compur shutter. It is an astonishingly sharp lens.
On 4/8/2017 9:44 AM, Tim Daneliuk wrote:
I have that same lens. I had Grimes reshutter it in a modern Copal. Never regretted doing so.
On April 8, 2017 11:21:27 AM Richard Lahrson <gtripspud@xxxxxxxxx> wrote:
Hi!
Another problem is the 360mm/9 Apo Artar lens w/packard shutter on
a board. The shutter is mounted inside the camera and the sycronization
contacts need to be drilled to the outside of the board where
the supplied wire ends in two raw leads. These leads have
to be then wired to a 1/4" plug of the Balcar powerpack. Plus there
are three contacts off the Packard shutter, so one is for bulbs
and the other electronic flash.
Since the 360mm lens simply unscrews from the Packard shutter
I think I'll send the board to SK Grimes and let them do it right.
I need this lens with the flash.
Rich
On Fri, Apr 7, 2017 at 7:31 AM, Redacted sender msampson45 for DMARC <dmarc-noreply@xxxxxxxxxxxxx <mailto:dmarc-noreply@xxxxxxxxxxxxx>> wrote:
Just about any of the flash meters made by the 'big 3'
manufacturers will work. I would avoid the Sekonic L-328 (if
any are left) because they suffer a circuit board failure that
can not be repaired. I now use a Minolta IV...
There are lots of flash meters out there cheap now because in
current professional practice, you just check the screen on the
back of your dSLR.
Mark Sampson
-----Original Message-----
From: Kurt Griffin <kjg@xxxxxxxxx>
To: pure-silver <pure-silver@xxxxxxxxxxxxx
<mailto:pure-silver@xxxxxxxxxxxxx>>
Sent: Fri, Apr 7, 2017 9:19 am
Subject: [pure-silver] Re: Balcar Flash
About a decade ago, I was looking for a spot meter and got a
great deal on a Sekonic unit that also measures flash. It’s
worked well for me in all the modes I’ve had occasion to try.
—Kurt
On 6 Apr 2017, at 22:34 , Eric Nelson (Redacted sender
"emanmb" for DMARC) <dmarc-noreply@xxxxxxxxxxxxx
<mailto:dmarc-noreply@xxxxxxxxxxxxx>> wrote:
I use the minolta III although presently having trouble
finding the batteries ( you need three CR 1/3n) here in
BKK. I don't believe the CR 1/3n are the original
intended batteries but that's what you use now.
I just so happened to have looked at ebay for Minolta III's
yesterday and they are under $100. Minolta IV might give
you a longer life as they're newer.
On Thursday, April 6, 2017 10:08 AM, Richard Lahrson
<gtripspud@xxxxxxxxx <mailto:gtripspud@xxxxxxxxx>> wrote:
I just got a Balcar A2400 w/5 heads for a bit
more than a box 10 exposures of new Polaroid
film which I intend to use. With color the
flash should be the right color balance.
Can anyone recommend a separate flash
meter? Thanks! Rich
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
WB6KBL
