Weird Prontor Shutter

[hsandler]

I bought a Zeiss Nettar which came with a Novar 105mm f4.5 lens set in what is labelled a Prontor-S shutter (see photo). From what I have read, the Prontor-S did not have adjustable sync. However, this shutter has two switches. At the 2:00 position with respect to the photo, there is an indicator which can point to either a red or yellow dot. An "x" appears next to these. This seems to be a flash sync selector. There is another lever with a red dot, seen at the 4:00 position, with indicators labelled "M/" and "\F", with the slash symbols engraved and filled in yellow. From what I can deduce by playing with it, when the upper switch is set to the red dot, it means X sync, and in this case, moving the lower lever to "M/" actually seems to be charging the self timer. When the upper switch is set to the yellow dot, it means flashbulb sync. Moving the lower lever to M/ in this case probably means M sync, as the lever snaps back immediately on releasing the shutter, unlike the self timer function; however, I won't know until I develop the current roll in which I took a flashbulb photo. I assume F is for another type of flash bulb.

My first question is whether the order of cocking the shutter and changing these levers matters in terms of wear of any parts. The shutter hung up on a few of the photos in my first roll, and I think it might have been when I had inadvertently applied some light pressure to the M-F lever. My second question is historical: is this actually a mislabelled Prontor-SVS shutter, or were there variants within the Prontor-S type that are not documented? The top speed of this shutter is 1/250s. I can't seem to find any shutter or camera manual online in a casual search that describes this particular shutter.

Zeiss Ikon Nettar 517/2, early version by Howard Sandler, on Flickr

 

[shutterfinger]

M standard filament flash bulbs 15~20 millisecond burn time to reach 2/3 of peak output
F gas filled flash bulbs 5 millisecond burn time to reach 2/3 of peak output.
Usable light is from 2/3 of peak output to 1/3 drop off from peak output.
Shutters underwent in production changes over their life without a name change.

F flash sync is usable with electronic flash on cameras/shutters without an X sync. The aperture may need to be opened 1/3 stop for best exposure.

 

[hsandler]

M standard filament flash bulbs 15~20 millisecond burn time to reach 2/3 of peak output
F gas filled flash bulbs 5 millisecond burn time to reach 2/3 of peak output.
Usable light is from 2/3 of peak output to 1/3 drop off from peak output.
Shutters underwent in production changes over their life without a name change.
View attachment 249945

F flash sync is usable with electronic flash on cameras/shutters without an X sync. The aperture may need to be opened 1/3 stop for best exposure.

Thanks. So I assume the order of setting switches for M sync flash is the same as for using the self timer. Does the document you reproduced mention if the self timer is to be charged before or after cocking the shutter or setting the shutter speed?

 

[shutterfinger]

Its a segment from this Prontor repair manual. https://drive.google.com/file/d/0B1sPJkp-MdghNW9TUkI4bDItUDQ/view?usp=sharing
Another repair manual you may find useful https://drive.google.com/file/d/0B1sPJkp-MdghVFNtSzhyay1lTkE/view?usp=sharing and https://drive.google.com/file/d/0B1sPJkp-Mdgha0F2YlJfNUdySms/view?usp=sharing

General rule of thumb: change shutter speeds, flash sync before cocking the shutter. In your case the levers will likely be easier to operate with the shutter released.

 

[hsandler]

Its a segment from this Prontor repair manual. https://drive.google.com/file/d/0B1sPJkp-MdghNW9TUkI4bDItUDQ/view?usp=sharing
Another repair manual you may find useful https://drive.google.com/file/d/0B1sPJkp-MdghVFNtSzhyay1lTkE/view?usp=sharing and https://drive.google.com/file/d/0B1sPJkp-Mdgha0F2YlJfNUdySms/view?usp=sharing

General rule of thumb: change shutter speeds, flash sync before cocking the shutter. In your case the levers will likely be easier to operate with the shutter released.

Thanks. The links don't seem to work for me, but your rule of thumb tells me what I needed to know--cock the shutter last.

 

[AgX]

Does the document you reproduced mention if the self timer is to be charged before or after cocking the shutter or setting the shutter speed?

A selft-timer both at leaf as at focal-plane shutters is a clock -work of its own and to my understanding in no case there is a dependancy of order of operations.
(But I can at least imagine mechanical designs where it would matter... )

 

[Dan Daniel]

A selft-timer both at leaf as at focal-plane shutters is a clock -work of its own and to my understanding in no case there is a dependancy of order of operations.
(But I can at least imagine mechanical designs where it would matter... )

Yep, I don't even need to imagine it. On the shutter for Kodak Medalists I, the self-timer can only be cocked and activated after the shutter is cocked. There is a latch on the self-timer cocking lever that is released when the shutter itself is cocked.

Leave it to the Rube Goldberg disciples at Kodak's camera design department to have made an exception to a rule.

 

[AgX]

Thank you, Dan.