Flash sync for Compur Rapid/Seikosha Rpid shutters

[johnnyrod]

I am still trying to get a straight answer as to whether Compur Rapid and Seikosha Rapid shutters, without M/X switch, are going to be X or M sync, anyone know for sure? It would seem that around WWII and after, many shutters were made X sync for ease, and flash with a bulb meant using slower speeds so as not to miss the flash light. Out of the ones I have though, they either have no flash connector or are a bit newer and have an MX switch anyway (Synchro Compur), but some I am looking at don't have the switch.

Usual apologies if this has already been covered but I can't find it.

 

[Roger Hicks]

Has to be X. Reason: M won't work with X flash, but (as you say) a longer shutter speed takes care of M. Then there's FP...

On the other hand, X flash barely existed during WW2, so I suppose it's possible that some shutters are M-synch only. Not Compur Rapids and Seikosha Rapids, though, I suspect.

Cheers,

R.

 

[Sarcophilus Harrisii]

It's easy enough to work out for the ones with connections. Hook up an electronic flash. Set the fastest shutter speed. Hold flash behind shutter. Look at shutter. Fire shutter. If it's X sync you'll have a blinding revelation. If not, it's M sync. Roger explained the possibilities well, above. Don't try this if you have epilepsy, though.
Cheers,
Brett

 

[sevo]

Single sync Compur and Prontor shutters could be ordered with sync to the camera makers specs - and some shutters were not used in equipment we'd commonly associate with photography, sometimes with very odd specs. X sync however is simplest (needing no advance or delay escapement), and you will usually encounter that where nothing specific is stated, but you can sometimes run into odd shutters...

 

[johnnyrod]

SH - I usually do that with the flash and camera pointing at a wall, you still see a bright reflection if it's X, through the lens. I don't have a Compur/Seikosha Rapid with a PC port though; I'm trying to find out as some cameras I look at to buy do have them, e.g. Super Ikonta, Mamiya Six.

Roger - you could well be right. I checked the manuals of a couple of cameras from the early 1950s and they mention electronic flashes.

Sevo - thanks.

 

[oftheherd]

You have probably already looked, but below are links that you may find interesting it not always as informative as you might like.


http://www.skgrimes.com/library/used-obsolete-discontinued-shutters/compur

http://pheugo.com/cameras/index.php?page=compur

http://camera-wiki.org/wiki/Compur

http://benoit.suaudeau.perso.neuf.fr/manuels_rep/obturateurs/compur_rapid_shutter_repair(2).pdf

http://olympus.dementix.org/Hardware/PDFs/CompurShutter.pdf

http://camerapedia.wikia.com/wiki/Seikosha-Rapid

http://camera-wiki.org/wiki/Seikosha-Rapid - showing flash actuator, X or M unknown - I have a non-working Mamiya S which has a shutter with flash sync. Based on the connector and when it was manufactured, I am assuming M sync, but I don't know. Electronic flash was not common then as has been mentioned. As I recall, that was because they were fairly expensive, more so than bulb flash. The flash sync is the spring just above the shutter cocking knob and going towards the red circle (behind which was the connector).

http://camerapedia.wikia.com/wiki/Zenobia

 

[charjohncarter]

I have one camera Balda Hapo 66e that has no settings. It is set for M (flash blubs), I use my electronic flash (X) with it and has some vignetting. But I still get a nice image.

 

[Roger Hicks]

I have one camera Balda Hapo 66e that has no settings. It is set for M (flash blubs), I use my electronic flash (X) with it and has some vignetting. But I still get a nice image.

It shouldn't vignette. A partially open shutter should have the same effect as a smaller aperture, i.e. reduced exposure but not vignetting. Have you tried it with the back open?

Cheers,

R.

 

[charjohncarter]

It shouldn't vignette. A partially open shutter should have the same effect as a smaller aperture, i.e. reduced exposure but not vignetting. Have you tried it with the back open?

Cheers,

R.

Not with the Balda:


TriX HC-110h by John Carter, on Flickr

And yes I've tried with the back open; lots of light, too much to tell anything. But then maybe it is 'X.'

 

[johnnyrod]

Looks like X sync to me! As Sarco says above, the test is easy, and the results are distinctive - I have tried on M and X with a Synchro Compur. On M there is no light, so this picture would not have come out if it were M sync with a strobe flash.

 

[Bill Clark]

Info on wiki:

https://en.m.wikipedia.org/wiki/Flash_synchronization

 

[charjohncarter]

Looks like X sync to me! As Sarco says above, the test is easy, and the results are distinctive - I have tried on M and X with a Synchro Compur. On M there is no light, so this picture would not have come out if it were M sync with a strobe flash.

My Ansco Speedex II (same as an Agfa Isolette II) gives tons of light through on 'M' with Prontar SV shutter. My Agfa Isolette II with a Pronto shutter give plenty of light, no choice of settings. Seikosha shutter on my Super 23 give no light on 'M.' The Balda Hapo 66e definitely has vignetting when the flash is used; completely different from a normal Balda image without flash. So my conclusion is some 'M' settings allow flash; but maybe not complete coverage: i.e. vignetting.

 

[sevo]

My Ansco Speedex II (same as an Agfa Isolette II) gives tons of light through on 'M' with Prontar SV shutter. My Agfa Isolette II with a Pronto shutter give plenty of light, no choice of settings. Seikosha shutter on my Super 23 give no light on 'M.' The Balda Hapo 66e definitely has vignetting when the flash is use; completely different from a normal Balda image without flash. So my conclusion is some 'M' settings allow flash; but maybe not complete coverage: i.e. vignetting.

But the shutter usually is in the same plane as the aperture (give or take a few mm) - so there should be no vignetting from the shutter if there is none from the aperture.

 

[Roger Hicks]

But the shutter usually is in the same plane as the aperture (give or take a few mm) - so there should be no vignetting from the shutter if there is none from the aperture.

Quite. This puzzles me too.

Cheers,

R.

 

[johnnyrod]

Does the Balda have a three-blade shutter? If so it won't form the same shape of aperture when part-open, it'll be more of a three-pointed star shape.

 

[charjohncarter]

You saw the picture? No star just vignette. And my shutter has 5 leafs. I have other photos taken this way. I feel like I'm being fact checked after a debate. How many flash photos have you guys taken with an 'M' (if it is 'M') setting and electronic flash. Here again the flash PC doesn't say either 'X' or 'M' on the Balda.

Besides it is my camera, and I like the vignette effect; lets leave it at that and get back to the OPs question.

 

[johnnyrod]

It's not meant to be the Spanish Inquisition (sorry), just trying to make sense of it all - seems odd that on M you get any flash as it's normally 20ms or so pre-fire (though were some 5ms?) vs. electronic flash of less than 1ms. I've never taken a pic on M as I doubted it'd work TBH, though I now have 35mm cameras with X/M which is a cheaper experiment than 120 at £2 a picture! I did wonder if your M isn't firing early enough so is actually closer to X, or the shutter takes longer than 20ms to open (if it is even possible for these two mechanisms to run independently) - hence the pondering about the part-open shutter and the vignetting. I'm working on a 3-leaf shutter just now; I don't know the Hapo so I looked it up but I still wasn't sure if it was 3 or 5.

Anyway back to it!

 

[sevo]

or the shutter takes longer than 20ms to open (if it is even possible for these two mechanisms to run independently) - hence the pondering about the part-open shutter and the vignetting.

If the shutter takes longer, the pre-fired flash would come even earlier (relative to the shutter), and miss even more of the shutter-open time. Besides, a part open shutter should not vignette, as the shutter blades are very close to the aperture plane. Is the vignetting really different from the vignetting you get (perhaps at some apertures only) without flash?

The only explanation that I have is that the vignetting might come from the flash head itself rather than the lens or shutter - in that the flash arc changes geometry over the duration of the discharge. There might be significant changes in illumination between the full electrode-to-electrode discharge and an afterglow that is limited to some smaller region, perhaps only the very centre of the tube.

 

[charjohncarter]

It's not meant to be the Spanish Inquisition (sorry), just trying to make sense of it all - seems odd that on M you get any flash as it's normally 20ms or so pre-fire (though were some 5ms?) vs. electronic flash of less than 1ms. I've never taken a pic on M as I doubted it'd work TBH, though I now have 35mm cameras with X/M which is a cheaper experiment than 120 at £2 a picture! I did wonder if your M isn't firing early enough so is actually closer to X, or the shutter takes longer than 20ms to open (if it is even possible for these two mechanisms to run independently) - hence the pondering about the part-open shutter and the vignetting. I'm working on a 3-leaf shutter just now; I don't know the Hapo so I looked it up but I still wasn't sure if it was 3 or 5.

Anyway back to it!

I have two Prontor-SV shutters both allow light on 'M' and two Pronto with no markings that allow light. Like I said the Seikosha (two) both do not allow light on 'M.' I haven't checked my Rolleiflex T but I will. Someone here said that you could order a German camera and specify your choice 'X' or 'M' but maybe the low end of the shutter scale the Pronto was maybe to cheat so either 'X' or 'M' could be used. Of course, that doesn't explain the Prontor-SV allowing light on 'M.'

Also, I found this on Flickr. This Pronto shutter is newer than both of mine.

https://www.flickr.com/photos/s-demir/4554055284/in/pool-camerawiki/

EDIT: I just checked my Rolleiflex T, the Compur shutter; no light on 'M.' I guess I just got lucky with my Balda. And johnnyrod the Balda is five leaves. By the way the only reason I even tried to use the e-flash on my Balda was because I did the flash test to see if light came through.