Testing shutters speeds with a dSLR

I’ve been using a method for testing shutter speeds is with a dSLR. This method only really works with really big shutters like the focal plane units in Graflex cameras. Extend the bellows (flip up the mirror if it’s an RB), take off the lens and any film back. stick your dslr on a tripod with its lens inside the bellows in the place of the lens board.

Point this assembly at something, turn off the lights and light that something and focus on it through the dSLR. Adjust your aperture on the dSLR to reflect the shutter speed that you are trying to test, and take a test shot with that speed on the dSLR. Then turn the dSLR’s shutter to 1″ and wind the Graflex’s shutter to that speed. Open shutter, fire Graflex’s shutter. Then compare.

I’ve found this method to be much easier than measuring an impulse and trying to compare microseconds to specific fractions of a second. On the dSLR you can look at a histogram approximate a percentage diffence in exposure. 10-20% is acceptable with black and white film.

Tobias Feltus:
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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!

However my bi-pole sync port was not working…

Disassembly:

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 or silver tips like what one would expect inside a motorbike engine’s distributor or a relay. 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 had to do with 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 (and the contact itself is on the small leaf-spring, bottom-centre of the picture to the right). 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/delicate). 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.

Tobias Feltus:
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New55 Project experiments (or shall we call me N55 North?)

Bob Crowley and I have been working on the New55 project for well over a year now. I forget even when it started. His blog has been visited heavily by eager fans of Polaroid Type 55, and criticised widely by some less-grateful citizens of the photographic community.

So how far have we got? Bob made the initial jump, by creating a first monobath reagent. He chose Kodak’s HC-110 as a developer base, as it has a long lifespan. He was using Ammonia and Ammonium Thiosulphate to boost pH and fix, but I got poor results from his mixture, and could not stand the smell, even with a respirator and ventilation (yes, my workshop is also the kitchen, so this mean the window and balcony door being open). So now that we knew it was possible to process a 4×5″ B&W neg in one pass, I moved on in my own direction. My first aim was to make the soup odourless, so I moved towards Sodium Thiosulphate and Sodium Hydroxide. My 8th mixture is what I started calling Reagent 4 beta 8, but now it is just R4. In under 5 minutes at 20c I was able to obtain negatives from Efke PL25, rated at 25ISO, that had a density and balance that is close to the delicacy that we like in T55. I was pleased.

The next step that Bob had been making over in Boston at the N55 “labs” at Soundwave Research were in assembling prototypes of pod-developed film to be field processed in a Polaroid 545 back. So I tried to figure out what the minimum amount of water needed to dissolve the solid chemicals in R4 was (not easy for a trial and error chemist like myself), and then added some Methylcellulose to the mixture to thicken it. I had made up about 2 35mm film canisters of reagent, and popped them in the film fridge. My first test was rather spartan, taping black paper and scraps together in a changing bag.

So what we have here is a control image developed in HC-110 dil-B as per normal, then a similar exposure (I was exposing 4 sheets at a time for tests) from my kitchen window in R4(b8), followed by a composite of my first p/n pod processed test (using fixed-out MGIV paper as a receiver), and finally the test that I did last night: the goop has been in the fridge for over a month, but my getting a heat sealer meant I could make pods, so I had to give it a shot, and it seems to work just fine. I taped things together in the changing bag, and using electrical tape as a light seal means that it has a tendency to buckle and thus break even contact between the surfaces. Oh well. But it proves the validity of my R4 even as a pod processed p/n. I can’t tell if the apparent contrast is to do with the concentrated chemicals, or just the fact that the chemicals were ‘mottled’ on the surface of the film, thus developing unevenly. The image was stable when I peeled it apart, but of course the anti-halation was still there, so i popped it in some fix to clear this, which is also less hassle than the Sodium Sulphate to clear T55 goop.

Now to order some Shanghai 4×5, get some receiver from Bob (via the 20×24 studio scraps corner), and some other bits, and I am curious to try and work with an all-raw chemicals mixture too.

Tobias Feltus:
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Graflex RB Super D: converting the back to take “standard” accessories.

Finally, after a couple of years lusting after one, I have a Super D (thanks to Bob Crowley and his find). It is in very good condition, in fact, almost new, and hardly used if at all. The only issues were need for a bit of lube in the shutter, and some minor cosmetic issues (like the leather coming loose on the lens door, due to retraction). However the Graflex standard back is not too useful today, or at least, it is not much use to me, as I want to use some Polaroid, and a Grafmatic sheet loader. The normal approach to this adaptation seems to be along the lines of what Bob did with his, involving taking a Grafloc back, cutting it down, and gluing it into the RB’s back. But I saw little point in this as Grafloc backs are expensive, to me, and also there is little need for a springback on a reflex camera.

The differences that I found in the Graflex back are:

the accessories are 6.5mm wider than the international standard

the accessories do not have a light trap lip sticking out, but rather a recess in them.

So, I had to shim the whole plane of the mount up by 1mm to create a groove to accept the light trap, and move in the tongue sliders. For most accessories they are fine the way that they come, however my Polaroid 545 back has two slots in either side, so I had to cut my sliders into the typical two-eared shape. I did this with a dremel and files.

But from the start, clean everything up, and the edge of the tray needs filing back by about 1mm so that it sits flush with the new raised level.

I then cut a piece of 1mm black styrene that I had to fit, and cut out the slot for the light trap. Then I glued this in with contact adhesive. The component has no structural value nor requirements. Then I drilled out and countersunk all of the necessary holes, including four new ones to move the lower screws that hold the slider supports in place. They had to be moved 3mm in, so I moved them diagonally to avoid weakening the frame. The slider bar supports are made of mahogany with brass inserts. To move them in the necessary 3mm I cut thin strips of 3mm plywood and glued these into the existing rebate with aliphatic resin, but any good PVA will do the trick. Then I primed and painted the brass tray with the new plastic shim, and the enhanced supports.

Re-glue the felt onto the base of the tray (cutting 4 new holes where the new screws go), and reassemble the base and rotating components. Screw the slider supports back in using the same screws, and reassemble the whole caboodle.

The last thing to do is to shim the ground glass and fresnel assembly. I just used two thin strips of the same 1mm styrene, as this was the only change in the focal distance made.

And now I have a Super D which can take all manner of film holders, including Fidelity double darkslides, as they are grooved on the side so they can be gripped by the sliders.

Tobias Feltus:
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