Flash Sync Speed on IIIc

[ricklb55]

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Serial number 430451.  Mine has a PC sync cord connection just to the right of the viewfinder and it does fire a flash.  There is no additional plate under the speed dial like I have seen on other IIIc cameras with a PC added.  Anybody know what is the fastest shutter speed that will synchronize with electronic flash?

 

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[earleygallery]

That looks like a Leica pc socket so probably a factory 'upgrade' at some point. 

 

The secondary dial was for different types of bulb. I expect the lllc will work ok at 1/60 or 1/30. I'm sure someone will confirm but it might be a case of shooting a few test frames to be sure. 

 

But who uses flash with one of these anyway! 

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[Doug A]

Unless there is a flash delay control somewhere not visible in the photo the delay is fixed. That means the camera will only work with one type of flash - electronic flash or just one type of bulb. The fastest any screw mount Leica will sync for electronic flash is 1/50 and that is only for the IIIf RD and the IIIg (and the corresponding I and II models). The only other screw mount Leica with factory flash sync is the IIIf BD (and If and IIf) and it only syncs at 1/20 or 1/30.

 

At first I thought the shutter speed dial was the same as my 1941 IIIc with the lowest speeds on the high speed dial being 20-40-60. But the more I look at the photo I think I'm seeing 30-40-60. My 1941 IIIc has a factory flash conversion with the additional plate under the high speed dial and it will only sync with electronic flash at 1/20.

Edited September 25, 2017 by Doug A

[jerzy]

PC socket is from Leica, but I think that the conversion was not done by Leitz. Leitz was always adding contacts under the top cover, plate and replacing speed dial for a bigger one. Looking inside under top cover (or bottom plate with the instruction how to load the film) would probably give an answer. However, as mentioned above shall work properly with electronic bulb. Flash shall be ignited when the frame is fully opened and for this camera model it is at 1/30

[pico]

1/30^th of a second will cover both electronic flash and any bulb flash. In the rare circumstance one might use a flashbulb, depending upon which, a higher speed is possible.

[wlaidlaw]

I had flash sync added to my father's IIIa in 1965 by Wallace Heaton in London. From memory it was done for bulb and I had to specify that it was for PF5 "normal" type flash bulbs rather than FP type bulbs, which have a slower burn rate and were designed for focal plane shutters. This was because he was already using PF5 bulbs in a Bilora flash, with his Zeiss Super Ikonta, which he used for B&W and did not want to have to carry around two different sorts of bulbs. The sync speed was 1/30th sec and somewhat to my surprise, I found this also worked with the Mecablitz 110 electronic flash I was using on the Mamiyaflex SLR I had at the time. 

 

Wilson

[ricklb55]

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I ran some film tests on my camera. When used with an electronic flash I found that 1/40 and 1/60 resulted in incomplete exposure of the frame. I don’t know why I didn’t test at 1/30. I also found that at 1/200 and faster there are also incomplete exposures of the frame, which seemed certain to be improper shutter curtain closure. Funny thing is, the shutter curtains look brand new. Maybe whoever replaced the curtains did not check that the curtains were working correctly. In any case I have shipped the camera off to Youxin Ye for a CLA and I am getting the rangefinder replaced while in his good hands. Rick

[pico]

1/30^th or 1/25^th of a second works with any flash bulb and any electronic flash. If we were to dive into the F bulbs we could use faster speeds, but I don't think anyone does.

.

Edited September 28, 2017 by pico

[wlaidlaw]

1/30^th or 1/25^th of a second works with any flash bulb and any electronic flash. If we were to dive into the F bulbs we could use faster speeds, but I don't think anyone does.

.

 

Jac, 

 

I use F bulbs very occasionally when I am trying to light up a big area. I use an old 3 cell Graflite which takes large Edison screw type bulbs. I bought a box of 24 FP45 old Philips bulbs second hand on Fleabay. I also have a few new Irish Megaflash PF300 slow peak bulbs which are a bit like a nuclear explosion going off but they are very expensive.

 

Wilson 

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[jerzy]

a bit of theory and how it combines with practice

electronic flash generates light of very short duration, is in a range fo 1/10 000 sec. In order to illuminate the whole frame both curtains must be fully opened. For IIIc it is 1/30, for later models where curtains travel faster this time is shorter. Light is generated without any significant delay after the contacts are closed.

The order is: first curtain fully opened - flash contacts closed - second curtain starts closing (and flashlight is over).

Bulb flash has a different characteristics. Magnesium which is inside needs few microseconds after ignition to reach full brightness and the duration of the light (although not in constant intensivity) is much longer than for electronic flash. So for bulbs the contacts need to close a bit earlier before the first curtain fully opens. Depending on type of bulb this time was different and this is the reason for the plate and adjustable contacts. Due to longer duration it may happen that the frame will be fully exposed at shorter speeds (1/40, 1/60) but only "may". Leica has fully mechanical shutter, factory specs say that the tolerancies up to 20% are acceptable. Therefore only when frame is fully opened and ingnition happens a bit earlier as specified by bulb producers you will get repeatable results.

But as pico and others wrote - who is using now bulbs nowadays....

[jerzy]

our posting crossed, picture from Wilson perfectly complements my explanation about bulb flash......

[gyoung]

Jac,

 

I use F bulbs very occasionally when I am trying to light up a big area. I use an old 3 cell Graflite which takes large Edison screw type bulbs. I bought a box of 24 FP45 old Philips bulbs second hand on Fleabay. I also have a few new Irish Megaflash PF300 slow peak bulbs which are a bit like a nuclear explosion going off but they are very expensive.

 

Wilson

I have a recollection from when I was using quite a lot of bulb flash with large format, that the PF100s burnt for longer than PF60s, so you could use them with some focal plane shutters, although probably not with such slow moving shutters as the LTM Leicas.

 

Gerry

[pico]

Jac, 

 

I use F bulbs very occasionally when I am trying to light up a big area. I use an old 3 cell Graflite which takes large Edison screw type bulbs. I bought a box of 24 FP45 old Philips bulbs second hand on Fleabay. I also have a few new Irish Megaflash PF300 slow peak bulbs which are a bit like a nuclear explosion going off but they are very expensive.

 

Wilson 

 

I have a case of PF-330 bulbs. Not much brighter than yours, but they burn for 1.7 seconds with ~180 ms time-to-rise. Also have some Mazda 75 bulbs. I'm afraid to set them off.

[giordano]

It's easy to check for yourself whether it's synced for electronic flash and at what speed.
Take out the film, remove the lens and slip a bit of white card where the film goes. Then connect the flash.

 

First, wind the camera and set the shutter to B. You should see white card in the entire area of the film gate with nothing

of the shutter curtains visible. If you see part or all of a shutter curtain, it means the synchronisation is set for the sort of

flashbulb that takes milliseconds to build up its light output and therefore needs to be fired shortly before the shutter

actually begins to open. 

 

Assuming the whole film area is illuminated by the electronic flash at B, try 1/20, 1/30, 1/40, 1/50 - whatever speeds are

on the fast shutter speed dial. As you pick successively faster speeds, eventually you'll find that the second shutter

curtain is moving across the white card at the instant the flash fires. That means you're past the safe sync speed;

slow down by one step (or two to be on the safe side).