Nikon DP-20 finder for the F4

Recently, as part of a beautiful, practically unused, late model Nikon F4s which (ahem) came my way, I immediately noticed a problem with the DP-20 finder. There was quite a heavy infestation of fungus on at least one of the internal eyepiece surfaces which was so bad it made viewing the lower meter readout difficult, blurring the LCD. I’d already knocked the seller down quite a bit (without knowing about this issue, of course) and so my initial reaction was not to demand a refund. I’ve fixed this kind of thing before – in lenses and more simple finder pieces – so how difficult would it be to eliminate the fungus from this otherwise pristine DP-20 and restore it to minty condition?

Well, as it turns out, quite difficult. But feasible, given care and patience.

This project required some careful planning, given the condition and obvious complexity of the finder. I got hold of the service manual for this finder which, unfortunately, is an x-generation photocopy scanned by an ancient scanner (probably) and so the image quality gives rise to a fair amount of guesswork. I was so determined to get this right that I bought a well-used finder for a cheap price, so that I could practice and note any caveats before working on the “real thing”. At worst, I’d spam it up completely and learn something in the process; at best I’d have a working spare finder that I could use for parts if need be. The practice run went very well in the end; a very grubby, fungus-infested DP-20 (though not nearly as badly affected as the minty one) with decomposing foam seals is now very clean, fungus-free, re-sealed and functioning perfectly, with just a few external scratch marks. I’m keeping it as a spare.

Now much more confident that I could do this, I set to work on the minty one. I’ll describe the steps I took in case this is of use to anyone else who wants to have a go at restoring their own finder. Note that this doesn’t require a complete disassembly but it’s worth mentioning that the finder optics and areas around are quite complex and fragile. With care there should be no need to de-solder any wires, but some patience is required.

The finder optics comprise three separate lenses in front of the prism (not including the screw-in eyepiece on the outside of the casing). The first lens is held in place by two small screws, whereas the second, which is able to travel forwards and backwards, is held in only at the top by the dioptre adjustment mechanism. The third and final lens, before we reach the viewing edge of the prism, is attached to the meter cell unit and is the most difficult to work on. The worst possible area for an infestation of fungus, if we were to try to remove it, would be the back-side of the third lens. Guess where it was in my finder.

Step one, a challenge in itself, is to remove the centre parts of the dioptre dial and meter selector dial without causing too much damage. These plastic discs cover the screws that need to be removed in order to remove the dials. They are held in with glue and are, frankly, a pig to remove because it’s likely that there will be some degree of marking to the outer parts of the dials during removal. To minimise this I covered the outer dials with insulation tape and then gently levered the covers out using a very small screwdriver. Once the screws are exposed both dials can be removed. Take care with the two washers for the meter selector dial: the white plastic one goes against the inside of the dial and the black foam one goes against the case.

After removing the four black screws of the outer case, the top can be lifted away from the body. A little bit of wiggling may be required here. The wires attaching the flash shoe to the main body are quite long and I didn’t need to detach them at all. With the main cover off the first lens can be seen directly, with the two screws holding it in place. 

Take the first lens off and inspect both surfaces; with luck any fungus will be here (this is where it was, mostly, in the “scruffy” finder with a tiny bit also on the front surface of the second lens). If there’s some on the back surface of the second lens then this can be taken out by first loosening the dioptre adjustment unit which sits on top. Notice the two small screws holding this part down (not the larger one; that can stay in place) and loosen them a a bit. Be careful here as the two mercury switches are held by this unit and they are glued to the unit underneath, yet there’s some play to take advantage of. The top adjustment unit may be lifted just enough to wiggle out the second lens, which is held there by the pin of the swinging arm. Again, inspect both surfaces.

If there’s fungus on the front surface of the third lens, it can be treated in-situ. If it’s on the back side, though, then the meter cell housing needs to be taken out. There are two screws holding this in place – a small one and a larger one, but this unit is the most difficult to get out so take extra care here. Remove both screws. Facing the lens, first lift the left side and then lift the right side a little. It may not appear to want to move much but persevere here, gently lifting either side and twisting slightly, firstly at the top, outwards, and then push up, swinging out at the base. Watch for wires snagging and gently lift them out of the way so that the lens/cell unit can swing outwards. Don’t pull it too far out. To clean the back side of this lens it will be best to turn the whole lot upside-down and move the unit out far enough to get at the surface, but no more. 

DP-20 insides
Lens no. 3 of the eyepiece group – clean and clear. Nearly half of the inside surface was covered in fungus.
DP-20 eyepiece lens group holder- side view
Side view. Notice one of the mercury switches and wires going into one of the meter cells in the lower left of the picture.

Once clean, re-assemble everything in reverse and look for any wires that may have become detached. I had just one such casualty – the black wire of one of the mercury switches – which was a simple fix with a soldering iron.

Neither the fungus in scruffy nor that in minty had etched the glass coatings at all and so I was able to remove it completely, using my usual method. There’s no secret to this, although people tend to have their preferences as to which tools and compounds to use. I have cleaned fungus from photographic optics for a few years and I’ve never had any return, using simple, easily obtainable isopropanol, cotton buds, cocktail sticks and certain brands of optical cleaning wipes which are, specifically, impregnated with alcohol. It’s the cocktail stick wrapped in an optical wipe which really does the trick, with gentle rubbing over the affected area. If necessary, the area can be finished off with an optical-grade microfibre cloth. Perhaps stronger chemicals, such as hydrogen peroxide, may be required for very well-established fungus but I’ve yet to encounter any.

Pentax ME 

Not the ME Super, but perhaps the ME Better!

Pentax ME

I think I struck lucky with this one. Found, by chance, when searching for a Pentax-M 50mm lens, the description of this item detailed the lens only and was priced at about the same as the lens alone would go for. But all the pics showed the camera too, so I asked the seller to confirm what was included in the sale. The answer: everything! I snapped it up even though I wasn’t sure I’d need the lens (see previous post) because the camera looked so clean. No knowing whether or not it would work, though, so it was another cheap punt.

This is the camera that led to the later, and much more popular, ME Super. The latter has many refinements but, as I have discovered, also involved some cost and weight reduction by replacing some of the metals with plastics. One of the reasons I prefer the look of the plain ME is the metal top cover with the ASAHI stamp; the Super has a top cover which is mostly plastic but plated with a metallic outer and, as such, has a slightly different appearance. There are no buttons near the shutter dial on the ME because it’s not possible to set manual shutter speeds on this model; it’s aperture priority only apart from a purely mechanical speed of 1/100s (x-synch for flash) and B. The shutter dial itself is more robust on the ME, compared with the all-plastic affair of the Super, and I prefer it even though it results in a more fiddly process to remove the top cover. Most of the remaining differences between the ME and the Super are inside.

So, upon arrival, the lens seemed fine apart from the fact that it was very dusty inside. No fungus (unlike the one that had arrived just prior to this) and mechanics were fine. This was a simple, half-hour job to dis-assemble, separate the main groups either side of the aperture blades and blow out the vast majority of the dust that had settled onto the two surfaces there.

I noticed immediately that the camera’s wind-on lever was loose when near the end of its travel and it didn’t click closed. The shutter, though, seemed fine as did the electronics and meter display. I knew what this meant: the “click spring” had broken off inside. The purpose of this spring is to secure the wind-on lever close to the camera body to, firstly, switch off the meter and, secondly, prevent accidental partial wind-on. Easily overlooked but should not be; the broken-off bit of metal can travel down into the workings or even shutter and seriously jam or permanently break something. I decided to resist the temptation to check shutter speeds any further and see if I could fish out the broken spring. Luckily, after removing the camera base plate, a few short shakes resulted in the piece in this picture falling out.

Broken click spring
Broken-off click spring. Better out than in!

Safe now to carry on testing, I figured all seemed well apart from the usual need to replace the mirror buffer and light traps.

I ended up harvesting a click spring from a parts-only ME Super (the springs are identical) and installed it into the ME. The Super has a refinement, though, where a second, coiled spring is used to strengthen the main click spring and presumably make it less likely to break off. The coiled spring is held around a post and is sprung against a second post, neither of which are present in the ME. I discovered that both posts are direct replacements for plain screws in the ME and so I gave the ME the Super’s full click spring refinement job! Perfect.

With the top cover still off, all that was left was to remove and replace some crumbling old foam which was meant to cover the open area where the meter LEDs go, leading straight into the area between prism and top surface of the screen. This was a very fiddly job and resulted in more cruddy bits than I wanted to see when looking through the viewfinder, so when all was sealed again I removed the prism and cleaned the underside, the viewfinder side, the back of the viewfinder lens and the top surface of the screen. The prism itself is held in by two tiny screws – one on each side – and removal requires the electronic boards to be carefully lifted away from the top surfaces first of all. After loosening the two prism screws the entire prism will then lift out. It’s the same situation in the ME Super and it’s the only way to remove debris that has found its way into the space between prism and screen, since screens are not user-removable in these cameras. The eventual replacement for the ME Super – the Super A (Super Program in the U.S.A.) – does have user-changeable screens which, if nothing else, makes cleaning much easier.

I have renewed the mirror buffer now and will soon replace the light traps in and around the rear door so that I can run some film through. I love the mirror/shutter sound and feel of this camera; there’s something very reassuringly 1970s about it and that’s only meant in a good way. It’s ever so slightly less dampened in movement compared with the Super but it’s certainly no Spotmatic in terms of noise or vibration. And that’s not to say that the Spotmatics are bad, either – far from it.

Something worth mentioning is that I get the distinct impression that the ME suffers much less from the very common shutter and wind-on issues that many Supers will suffer from now, if not serviced. Perhaps because it’s slightly less refined internally, with fewer plastic parts. My Super had the wind-on issue (film winds but shutter won’t charge), which I appear to have fixed without the need for a full service, and my (much more shabby) parts body has the same issue which can’t be fixed in the same, relatively simple, way.

So, is the ME better than the ME Super? Purely in terms of functionality, not really, and yet I prefer it. If you’re on the lookout for a fully working ME Super and don’t care much about manual shutter speeds, give the ME a go.

Hassy

How did this happen?

I blame it partly on my discovery of Vivian Maier a year or two ago but, if I’m to be honest, medium format has been in the back of my mind for many years. I’ve seen the odd Hasselblad when scouring various camera shops over time but admiration was really as far as it went. The desire to try a larger format than 35mm never went away and it seems the Maier effect must have accelerated the inevitable. Drawn more to 6×6 than any other (645 too much like 35mm, 6×7 too bulky) I purchased a TLR* quite cheaply, restored it and love the results on film. Square format it would be, then, so a Hassy was bound to happen eventually.

This is a 501CM which was made in 1997 and came as a boxed kit with A12 film back, 80mm Zeiss Planar T* “new-C” f/2.8 lens, Acute-Matte-D crosshair screen and waist-level finder. It was less expensive than expected, partly due to the lens and partly the external condition. The lens is essentially a CF with the F bit removed (to distinguish from the original C-type), introduced to cut costs at the expense of a feature that not many would apparently need. Both body and lens were coated in a layer of grime which, thankfully, I was able to remove thanks to my OCD-fuelled cleaning but, unfortunately, years of filth has caused some pitting in the chrome. There’s nothing much I can do about that but I’m satisfied that both body and lens are now clean (the lens looks almost new now).

Of course, no auction-site purchase would be complete without an issue or two (OK, perhaps I exaggerate) and the first of these was immediately apparent: the screen was distractingly grubby and no attempt at cleaning would make it good. After some research I discovered that the shockingly-expensive AM-D screens are made of two layers, and it became clear that the dirt was in between. “Don’t ever take the screens apart or you’ll ruin them” was the message I was reading over and over, so I took it apart and very gently but thoroughly cleaned both layers. Whatever it was has actually permanently etched the top glass layer, sadly, although I was able to drastically improve things. I can only imagine that the screen had become wet at some point and some glass-etching fungus had grown in-between, where it had stayed damp for some time. Anyway, re-assembly was much more difficult; it can be done as long as swearing is permitted.

Issue #2 was more tricky because I was still getting a feel for how the camera operated as a unit. I put the occasional wind-on jam and A12 winder looseness down to my inexperience but more research indicated that there could be problems with sticky old grease in the back’s mechanics. Off came the cover (with this latest A12 the dark slide holder needs to be removed first: four screws hold it on to the rear of the magazine casing) to reveal no sticky grease but one gear wheel with two missing teeth! Said teeth were floating around inside but hadn’t caused any mischief themselves; the problems were down to the gap in the gear, resulting in it sometimes catching and sometimes another cog free-wheeling inside the gap. No idea how two teeth were sheared off without causing damage to another cog as well, but that was the situation and I can understand why the seller had missed it. I actually managed to glue the teeth back on – talk about intricate – and everything worked perfectly, but it didn’t last, of course. And, because I’d taken the back apart to check and fix what was meant to be a common issue, I couldn’t return the kit even if I’d felt inclined to. I couldn’t find any A12 parts here and the alternative seemed to be to pay for a full service and repair.

Whilst away on holiday I managed to find a service manual, the cog part number and a nice chap in the U.S. who happened to have one new. The part was waiting for me when we returned home a few days ago. I used SPG to lubricate the teeth of the new wheel, because the description is similar to that of the grease specified in the service manual (and I already have SPG!) and spent an hour or so fitting it and making sure all the bits were working properly. Success!

I’ve fixed the light trap (temporarily: it needs a new foil part but don’t have that yet, so I trimmed a small breakage to stop it catching on the dark slide) and I’ve adjusted the film progress indicator because its rotation was slightly off. This indicator should be red when no film is in, white when it’s freshly loaded, and should gradually turn to red as the film is used up; mine was slightly off and fixing it was more difficult than it sounds. Not essential, but since it’s there I want it working properly.

One last thing has been done prior to the imminent film test. I bought an extra screen (pre- Acute-Matte as I’m not made of money!) with a split prism. This confirmed my suspicion, when using the AM-D screen, that infinity focus (and, therefore, everything else) was ever so slightly off. At the lens infinity stop a distant image was still not quite aligned. I’ve corrected for this with a tiny adjustment of the mirror stop (right side whilst facing front of body).  I’m aware of the factors which can contribute to focus alignment in Hasselblads and have confirmed that focus is correct across the whole screen, so I’m quite confident. Aside from impact damage (no sign of that) the mirror stop is the most likely factor following hundreds or thousands of shots and there are, thankfully, no foam pads to deteriorate under the gliding mirror of this model. Testing will confirm. If something such as body length needs adjustment, I’ll send it to a specialist. If it’s instead the lens, I’ll soon find out. Optimistically, though, I think this mechanical marvel is all good to go now.

*TLR = Twin Lens Reflex. Eg., Vivian’s Rolleiflex or, in my case, a Yashica Mat.