X-Synch on the Graflex RB Super D

I was puzzled that the internets seems to have no information on the Super D’s flash synch. I posted on Graflex.org looking for some insight, but ended up – eventually – investigating the system myself.

The result? Yes, you can use electronic flash on your Graflex RB Super D! How? well, simple. Using what some folk call “drop curtain”: what this meant was obscure to me too, but I worked it out. The shutter on the Super D gives you speeds from 1/30 to 1/1000, however there are two other speeds which you can obtain: if you lock your mirror down, and roll the shutter curtain to “O”, when you release the shutter, the mirror flips up exposing your film, then the shutter closes. At the lower spring tension you get approximately 1/5, and at high spring tension you can obtain 1/10. This is brilliant, isn’t it? Yes, but even more so when you consider that these two speeds can also be used with electronic flash, as the flash contacts close when the mirror completely clears the film gate!

Disassembly:

Once I had figured all of this out, I was disappointed to find that I was unable to trigger my flash, so I had to check the flash contacts and see what was up. To get at the mechanism, you need to remove the shutter plate (where you set the curtain aperture and flip the mirror). Before taking off the plate, I would suggest removing the back (remember there are a few hidden screws that you can only access with the back partly rotated), so that you can use a (white) pencil to mark the position of the upper lip of the shutter curtain on “O”. To remove the shutter plate only four screws need to be removed, but you also need to extract the pin that is on the mirror shaft. This took me a couple of weeks, and I ended up using a microjet torch (the variety that takes a butane lighter inside, and burns up to 1300c with a tiny sharp flame) to heat up the metal locally, just enough to be able to tap the pin out. The concentrated heat seems to not cause any problems, and with a few seconds was just enough to loosen its grip. Be careful and gentle – don’t force anything. Then remove the four screws (one may be flat-headed), and the shutter will close. Don’t panic.

Repair:

What you will find is that the actual mechanism of the Super D’s shutter is remarkably compact and simple, and that the flash contacts themselves are little platinum tips like what one would expect inside a motorbike engine’s distributor. Give everything a wee clean. The leather will probably have a bit of greenish waxy oxide on it, and some dust. The flash contacts are very easy to adjust, but I would start by spraying some contact-cleaner or switch-cleaner into them, and maybe fiddling a bit of paper over the platinum points. The reason why my flash was not triggering is that the “thumb” at the bottom-right of the shutter mechanism. The thumb is the spring-loaded part which is meant to close the contacts when the mirror hits home. Said this, it also appears to be held in place with a tin-plated screw which has oxidised over the past 65 years, and hence become a bit stiff. So unscrew that, use a dry brush to clear off the oxide, then I added some PTFE lubricant and reassembled the thumb. Check that all of the other moving parts are free. I added some PTFE to a couple of the other pivots, and cleaned the dry grease from the upper curtain roller bush. Make sure you did not get any lubricant on the flash contacts (or clean them again), and check that the gap is good: connect an ohmmeter to the contact prongs, and rotate the mechanism to make sure that the thumb is closing the circuit, and that it is opening again. If you need to adjust it, you bend the upper contact by a hair, using a screwdriver or something (it is very malleable). It is also worthy of note that the flash timing would be adjusted by the shape of the thumb, but it should be right, so don’t bend it.

Reassembly:

Once you are satisfied that everything should work smoothly, rotate the curtain key until the “O” is centred in its window again, as you are likely to have wound the gears way past its correct positioning. Make sure it is centred, and not just visible. At the back of the camera, wind the curtain up until your pencil marks match. Try using something like masking tape on the ribbons to hold it, probably just above its marked position, so that you have enough play to mesh the gears. Place the shutter plate onto the two pivots, and wiggle it until your gears mesh, place two screws to hold it tight, then untape your curtain, and check that it holds with your pencil marks matched up. If they do, then try running the shutter at its different gaps to make sure they are all correct (as in they start with the gate closed, and end with the gate closed). Replace the other two screws, position the mirror lever and replace its pin (which may not be easy). Replace the rotating back.

If you are lucky, you may have some kind of a cable which plugs into the two-pronged flash port. I did not. So I had to make an adapter. I made the contacts out of a figure-8 connector, which i covered in heat-shrink tubing, soldered on a PC socket, and then caked the lot in Milliput® epoxy putty. I put cling-film in the socket first, so that I could get my putty out when it had cured (this works well), and then I filed and sanded it back. Some day I shall get round to painting it black too.

In conclusion, this solution makes the Super D one of the most ductile large-format portrait cameras, as you can look through the lens without the delay of then closing down the shutter to load film. Though the Super D has automatic diaphragming for its own three lenses, I only have one of these, and plan to modify the front standard to take brighter lenses like the Dallmeyer Pentac 8″ f2.9, and being able to use electronic flash with these lenses is quite an unusual privilege.

6 Responses

  1. Hi Tobias – thanks for this blog! As you say, there is very little available on the subject. I have a 5×4 RB super D, and have a new bi-post to pc lead, but the electronic flash is not triggering. At first when I touched the lead to the bi-post a flash would occur immediately, now nothing happens – no trigger on 0 setting (drop curtain). I’m considering (with trepidation!) doing your overhaul, and have a few questions. I’m trying to visualise the mirror pin you speak of: is that a pin holding the chrome mirror-lift lever in place? Looking at mine, I see what might be the two diagonally-placed heads of a dull-metal pin that goes through the chrome lever and presumably the inner shaft. It’s very small. Is this the pin – do you just tap it out from either side, and then does the mirror-lift lever just pull off the shaft? I don’t have the heating equipment you used… Secondly – when you take off the shutter wind plate – does this affect the spring tension on the shutter? Is there a danger of the spring unwinding or unravelling? I don’t fancy having to try and re-set it!! From your instructions it seems as if its just a matter of making sure the blind is at the same position and re-engaging gears. Difficult to visualise when you haven’t seen it! Thirdly – presumably the shutter winding key has to come off? I see some kind of pin there too. Lastly, does the shutter release lever (the L-shaped lever that engages with the mirror-lift) have to be unscrewed? Thanks – Russell, Bristol, England

    01/03/2012 at 20:02

    • Tobias

      Hi Russell,
      I would imagine that your issue is the same as mine. I opted not to buy the bi-post cable as I could only find them as expensive imports.

      In reverse order, the L-shaped curtain release and the curtain winding knob are actually attached to the shutter plate. The only part that needs removing is the pin that you describe, which holds the hub of the chrome mirror-lift lever (Part “H” on the image below).

      The RB Series D has similar controls on the shutter plate

      So, whether you will need to pop down to Maplin and get one of these micro-torches (cost about a fiver, and they take a standard butane lighter inside the handle) to locally heat it, or whether yours will just tap out, is a different issue. I tried to tap mine out over a long period, and I tried extracting it with a small g-clamp, to no avail. A good old-school mechanic might have an extractor small enough to do the job cold, but there is very little clearance for any tooling on the hub of the lever.

      06/03/2012 at 10:59

  2. Thanks. I got some further advice from a retired Graflex technician who recommended an auto centre punch to drive out the pin, and it worked. A good blow out with an air blower sorted out the flashing problem: there must have been some conductive material bridging the gap between the bi-post contact plates inside – nothing more! Good outcome! Incidentally – how do you get round the exposure problem with the drop curtain technique? 1/5 th sec is slow enough to get a decent exposure in most inside situations: I’m wondering whether the extra flash would be sufficient to freeze any movement in such a situation? Guess the 1/10th sec might be a bit more flexible, if 1/10th works with electronic flash? Any tips from your experience would be appreciated! Thanks again for your trouble – hopefully all this will be of benefit to others. These cameras are still terrific users…

    10/03/2012 at 17:51

    • Ah…first film has been processed, and 1/10th does the job with electric flash! Seems the trick is to set an aperture that would result, without flash, in considerable underexposure. Then the extra light from the flash is sufficient to freeze any movement/camera shake and to avoid too much ‘slow-sync’ effect. Just for the record I found that portraits taken on 100 iso film under normal interior tungsten light, exposed at f11 with open flash at 0 setting + HI-tension worked perfectly (even if focussing is a little tricky!)

      15/03/2012 at 23:35

    • Tobias

      Was that from Bert? If so, I’ve just been avoiding bothering him, as I imagine he gets a rain of affection each day. Anyhow, can you send me a picture of this punch? I had a look at quite a few extractors and punches, and found that they were all far too big.

      As for exposure, I guess this depends on what kind of strobe you are using. With my older Bowens Monolites, and the newer ones that I have used, the modelling light turns off for a fraction of a second after the flash is triggered (whilst the caps charge). Therefore, using the drop-curtain with most studio strobes should yield an accurate exposure, when the majority of the ambient light is provided by the modelling lights (which is also preferable, as light in front of the camera does not obscure your viewfinder). I guess that if you were working with mixed or fill-light, or indeed hammerhead ‘strobist’ setups, then you might need to calculate exposure differently indeed.

      Anyway, I’m glad that you got some good results with this. I need to work with it more too, but have been stuck experimenting with my New55 stuff, which is faster to just shove in a Press camera. Post a link to your results, if you fancy, as I am dead curious.

      06/04/2012 at 10:11

  3. Don Gatòn

    Hi Tobias, resuscitating an old post here, but as you say, there’s little info regarding these cameras around.

    I’ve been thinking of getting a Super D, however I use flash for nearly everything, so I’m a little concerned re. the exceedingly low synch speed. Have you since found any other way to synch flash at higher speeds?

    Also, you say that you didn’t buy a bi-post cable. This presumably means that there is more than one way in which flash can be triggered by this camera (one via bi-post, another without)?

    I used to use a Crown Graphic, triggering the flash via bi-post connection on the front lens/shutter, which had an “X” setting and allowed for pretty fast synch speeds (1/100 if I remember right). Presumably this is not an option with the Super D, as the advantage of this camera is precisely it’s reflex shutter mechanism, which it would be stupid to forgo in favor of a lens-shutter. In that case, where does one connect the bi-post cable? Also, how do you get away with not using a bi-post cable, and what do you lose/gain by doing so (other than saving money on a cable)?

    Basically I’d need to use this camera hand-held with flash at around f8, in well lit environments where a 1/10th of a second shutter speed would likely cause a “flash/blur” effect that (for my purposes) would be totally undesirable. If I cant find a way to get a faster synch speed (1/60 or faster) then I’ll probably strike the Super D off my list of options.

    Any advice would be greatly appreciated. Thanks!

    13/05/2014 at 13:24

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