Posted by Dennis Lee on January 16, 2001 at 18:26:33:
In Reply to: Re: Polariod back for Century Graphic (6x9) posted by Dongyun Hao on January 15, 2001 at 17:48:31:: : Oh how I hate to hear your comments about there being a
difference in the GG and film plane with the Horseman back. I've
been having so many problems with sharpness it's unbelievable. My
current theory is a poor lens. See the comments about the Xenar 4.5
below in this forum.
:
: Well, inter-brand usage does somethines cause problem. I have not
yet tested the sharpness as you did, since I have only one usable
lens, a Trioptar 103mm self-cocking lens, which I do not trust at
all. I have used all modern lens such as Fujinon, Nikkor,
Rodenstock etc. But I need to make the lensboard for them which are
rarely available at my part of the world. Forgive me if the
question hurts you, did you use a slow aperture (less than f16) to
test your Xenar? did you shoot distance or close-up subject for
testing?
DL:All apertures were tested at closed and far. The close test
was very consistent showing a sharp center consistently throughout
the test.
The distance test however was very inconsistent. Sometimes the
center was sharp sometimes not. Very unusual. The shutter speeds
were not that slow and I used a cable release so that movement
should not have been a consideration. Also, movement blur has a
different appearance than simple soft focus. The distance test was
very inconsistent in background sharpness, especially out on the
edges. This was all done with the RH8 back. This is when I decided
to purchase the Horseman back.
: : Here's where I'm at: I purchased a Horseman back after much
frustration with a Graflex RH8.
:
: Lucky me, I had Horseman back already before having the lovely
Century. One point we are the same: if mordern back is available
and compatible, one has no reason to use the old back which sells
not much cheaper...
:
DL: exactly
: I found that the back fits but extremely tightly. If I make
sure the back is centered properly on the camera, groove to groove
that is, I press in on the back a little bit and with fingers from
both hands push in on both ends of the locking bar. I do the top
and then the bottom. I had a few problems at first but now it is
starting to fit quite nicely.
:
: If I had had forced it in the same way as you did, I might have
had it worked. But, did you see any scratches on your film
back?
:
DL: Absolutely not. The fit is tight not forced. I didn't use
excessive force. It was more a matter of lateral fit (side to side
shifting) that seemed to allow it to fit nice and snug. The locking
bar slides in very smoothly once positioned properly. And as I
said, even better once I've used it a few times.
: I have a Black Century Graphic by the way.
:
: I have the same one...The only un-improvable promblem to the
Century is the small sized lensboard, too small to housing any lens
with bigger shutter...I am doing a project on it, trying to let it
accept #1 shutter and long lens up to 300mm, the Nikkor M
300mm.
:
DL:Are you changing the bellows extension also? I don't think you
have enough unless the lens is a tele.?
: I do remember that alignment was very critical the first several
times that I put the back on. It was also difficult to keep from
moving the camera because of the tightness of the fit. After a few
rolls now, and a lot of on and off, it's mounting much
easier.
:
: I guess there must be more or less de-shape occurred to either
your back or Grafloc, or both...
:
DL: I don't think so, doesn't seem likely.
I don't have a caliper of any quality, it's plastic, but it did
measure a match on my camera.
: : Not trusting this I removed the GG from its holder and shuttled
it between the two film plane surfaces and got a perfect match. IE:
I focused on the ground glass in its normal position and then
placed the ground glass against the film plane in the Horseman
back. I checked the focus several times using my Leica 50 as the
loupe and the match came up excellent each time.
:
: I doubt you can manage to do this as precise as to 0.2mm...
:
DL:True, yet sharp is sharp, and without moving anything through
this process and still getting a sharp image I have to imaginge
that the test was pretty accurate.
: In testing the back with film I noticed a definate improvement
over the RH8, same lens position, just switching the back, using
Fuji Velvia. The Horseman was definately sharper but overall
quality is still borderline unacceptable for what this negative
size should produce. As mentioned earlier, I think I have a poor
lens.
:
: This is reasonable, since Horseman is a modern design...
:
DL: Yes, unfortunately I haven't done the same accuracy tests with
this Horseman back as I had with the other. I shot one roll after
purchase
comparing it with the RH8. I mentioned these results before. After
that I shot another test roll, tripod mounted, cable
released,...results were good, not great. I've been shooting with
it a little, handheld with rangefinder, but haven't processed film
yet.
: The one problem I do have with the Horseman back is that the
actual film window is being vignetted by the metal edge of the rear
bellow frame in the camera. This makes one of the vertical edges
soft on the frame. Not good for printing full frame.
:
: If we say Horseman has a rather 6X8 than 6X9 back, 56mmX82mm, the
Century has an even smaller frame. My measurement shows
55.6mmX79.6mm, a truth 6X8 format. But I think I can make a little
modification to overcome this.
:
: : Obviously I'm using the 6x9 back. I should also note the the
exposed film is considerably wider on the Horseman than the
RH8.
:
: Yes, it should be about 2.4mm wider...
:
: : A little filing will take care of the soft edge, but I'm not
going to try it until I test another lens and start getting some
sharp pictures.
:
: I agree.
:
: : I should mention that I did consider adding a washer like you
did, but when I discovered the locking bars would slide up with a
little more finger pressure I stuck to original. I think the
Horseman has a little more lip than the Graflex backs. I'm
surprised you can't get yours to fit.
:
: : You know, reflecting back a moment here, I did try an older
Horseman back and it didn't fit on my Century. That led me to try a
new back which did fit, albeit tightly, which is the one that I
bought. The old Horseman I tried was a knob wind.
:
: I have no/never used the old Horseman holder, hence no comment
here.
:
: : I for one can't believe how frustrating this beautiful little
camera has been.
:
: Don't be sad. We should be able to work out soon or later. It is
a nice camera and we can get nothing with that sum of money we paid
for a camera like that. Sorry for the delayed follow up. I think
the topic has already been off the original John's Q. So, let's
talk about it off line, if interested...I am in Japan, I may need
your info to get some parts for the Graflex.
: Thanks!
:
: Dongyun
DL: Just start a new thread up top in this Q&A forum. I'll
keep and eye out for your byline.
These guys have a lot of good resources for parts, I'm sure more
than I do. Have you checked ebay? I'm in New York City. There are a
couple shops here I can help you out with if you need them.
I'll be watching for your name!
DL