| View previous topic :: View next topic |
| Author |
Message |
disemjg
Joined: 10 Jan 2002
Posts: 474
Location: Washington, DC
|
 Posted: Tue Jan 25, 2005 12:18 am Post subject: |
 |
|
| A recent acquisition is a Schneider 90 Angulon in Compur (sticking). After a Ronsinal bath the stick is gone and everything seems to work OK. However, I notice that if I hold the shutter up to a light I can see the star pattern of the blades on the higher shutter speeds. I'm guessing that the blades are bouncing open after the closing cycle. If so, is there anything I can do to correct this? What else could it be? |
|
| Back to top |
|
 |
Dan Fromm
Joined: 14 May 2001
Posts: 2144
Location: New Jersey
|
| Posted: Tue Jan 25, 2005 1:23 am Post subject: |
|
|
| Quote: |
On 2005-01-24 16:18, disemjg wrote:
A recent acquisition is a Schneider 90 Angulon in Compur (sticking). After a Ronsinal bath the stick is gone and everything seems to work OK. However, I notice that if I hold the shutter up to a light I can see the star pattern of the blades on the higher shutter speeds. I'm guessing that the blades are bouncing open after the closing cycle. If so, is there anything I can do to correct this? What else could it be?
|
Incandescent light or fluorescent? If fluorescent, they turn on and off 120 times per second and act as strobes. |
|
| Back to top |
|
|
disemjg
Joined: 10 Jan 2002
Posts: 474
Location: Washington, DC
|
| Posted: Tue Jan 25, 2005 11:46 pm Post subject: |
|
|
The star pattern is visible regardless of the type of light. Also, the size of the star seen increases as the shutter speed shortens; a bigger star at 1/400th than at 1/200th. No star at 1/50th or below, and intermittent star at 1/100th. My guess is that the higher shutter speeds translate into more closing speed/force for the blades, hence higher bounce. Whatever braking or control mechanism the shutter has is not functioning correctly.
The pulse seen in a flourescent light would not cause the star pattern, but would appear as a black band visible in the flourescent tube if the shutter speed was high enough to stop it. I have to admit that I have not tried to see this phenomenon with a leaf shutter, but have always observed it with FP shutters. The shutter type should not matter, although the FP shutters have higher speeds and would be able to stop the band more readily. The highest shutter speeds may show multiple bands. |
|
| Back to top |
|
|
Rangemaster
Joined: 06 Jul 2001
Posts: 412
Location: Montana, Glacier National Park
|
| Posted: Wed Jan 26, 2005 12:34 am Post subject: |
|
|
Have you taken any exposures with it since cleaning it to see if the exposure is working correctly?
Just wondering.
Dave
_________________
Focus on the Picture, Not on the Glass.
Satin Snow(TM) Ground Glass |
|
| Back to top |
|
|
disemjg
Joined: 10 Jan 2002
Posts: 474
Location: Washington, DC
|
| Posted: Wed Jan 26, 2005 12:58 am Post subject: |
|
|
No, I have not taken any pictures with it yet (I only got it yesterday). I think the shutter times OK, judging by the sounds and amount of light passing at different speeds. For B&W work I suspect that the star effect at 1/100th would be tolerable, but the higher speeds would overexpose the center by enough to be a problem. The star is quite visible.
I think its going to wind up on a view camera, shooting at f16~22 where the lack of effective high shutter speeds will not be a serious issue. |
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
