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Saturday, 30 December 2017

Cleaning rubber covers

Not really applicable to the 139 but from the 159 onwards rubber covers were used on all the Contax SLRs. These often look past their best and, unlike the leatherette covers on earlier models, can't be easily replaced. I've experimented with methods of cleaning them and think I finally have a reasonable solution.

If the rubber is just showing signs of turning light grey or white from age, cleaning with a cloth and some isopropyl alcohol (IPA) will normally bring back the original colour. A toothbrush is useful to get into corners.

If cleaning with IPA doesn't work, or if the surface has become shiny from handling, then I've found scraping the surface is the answer. I use the back edge of a knife - the sort where you break off the blade as it becomes used. While scraping, the surface will become even more white, or maybe brown if there's a lot of dirt as well. This is then cleaned off with IPA. It might need scraping more than once to get the cover completely clean. I've found it's usually easier to remove the cover from the camera first. This allows the edges to be done without risk of scratching the camera.

Here's the front rubber from a 159 being done. I've done half of it to show the effect of scraping.

Below is the rear of the same camera after being fully cleaned. The back previously had a lot of shiny areas from handling.




A caution: Some models had a different type of rubber covering. The only one I'm sure about is the rear door of the Aria. It has a very thin layer of rubber that is not removable and is often worn through so shiny areas are actually the plastic underneath. Don't try this technique on such covers.

Tuesday, 19 December 2017

Contax Flash Compatibility

I've always known not all Contax flashes work on all Contax bodies but I've never been sure which combinations work and which don't. I decided to do a little research and some tests. Here's the results.

I think the best way to understand the combinations is to split the various cameras and flashes into three groups thus:

Group 1: Early models
This includes the 139, 137 (MA and MD) and RTSII bodies (see note 1) and TLA20, TLA30 and RTF540 flashes (see note 2).

Group 2: Later models
This includes all SLR bodies from the 159 onwards and TLA280, TLA360 and TLA480 flashes.

Group 3: G models
This includes the G1 and G2 bodies and TLA140 and TLA200 flashes.

Group 1 used two additional contacts on the hot shoe. One was for the flash to indicate to the camera it was ready (Ready signal) and the other was for the camera to stop the flash when sufficient exposure had been given (TTL Control signal).

Group 2 also used two additional contacts but now the Ready and TTL Control signals were combined onto one contact while the second contact was used as an Auxilliary Sync contact for flashes that could support second curtain sync. The Auxilliary Sync contact also retained the function of TTL Control so retaining backward compatibility with older flash units.

Group 3 is essentially the same as group 2 except neither of the flashes have second curtain sync capability so only have one additional contact. The cameras do have second curtain sync capability so have two.

So to summarise: Groups 2 and 3 cameras are compatible with all TLA flashes (see note 5). Group 1 cameras are only compatible with Group 1 flashes. In theory, Group 1 cameras can use Groups 2 and 3 flashes but only in manual mode, however, when trying it myself, the flash made a rather disconcerting noise after each flash suggesting some connection between the additional contacts was not ideal. I wouldn't recommend this.

Notes:
1. The original RTS had no built-in flash control so is not included.

2. There was an earlier version of the RTF540 which did not have TLA capability.

3. I found the TLA280 would not physically fit onto a 139 body due to the additional contacts catching the edge of the hot shoe. If the contacts were manually depressed, it could be made to fit. Maybe this was a deliberate design choice to stop them being used together.

4. The Aria, RX, RX2 and AX bodies have 2 more additional contacts, so 5 contacts in total. The 2 extra contacts are clock and data signals to pass extra information to the flash. As far as I know, only the TLA360 has this capability.

5. I don't have examples of every camera and flash so this is based on a combination of information I've read such as camera operator manuals, tests on the combination of bodies and flashes I do have and some assumptions.

Saturday, 29 April 2017

Phenix variants

NOTE: Since writing this I have completely changed my view on who made these FX-3 variants. They were, I'm now sure, made by Phenix in China and not Cosina. In fact, there is no evidence, that I've ever seen, to support the theory that Cosina made FX-3 cameras at any time. There is plenty of evidence that Phenix did though.

I've been doing a bit of research into what other cameras, made by Cosina Phenix, were based on the same chassis as the FX-3 and, therefore, may share other parts and be useful as donors. Or perhaps may be alternatives to buy and use. What I have found is there were a number of similar cameras and quite a few were made with the Pentax K mount - the previously mentioned Centon K100 being one and others sold under the brands of Vivitar, Braun, Hikari, Promaster, Kenko, Phenix and probably a few more. (Note: not all cameras sold under these brand names were based on the same chassis). Some of these were also available with Nikon or Minolta MD lens mounts. Most are mechanical cameras using the same Copal shutter as the Yashica FX-3 or FX-3 Super 2000 though a few, including the Centon K100, seem to use an electronic Seiko shutter.

I recently acquired a Vivitar V3000 and a V3800N which are all but identical to a Yashica Super 2000 except they have a PK mount. The V3800N was given a face lift and uses a rear door straight off the Centon K100 complete with the rubber covers.

So there are many models that came from Cosina Phenix that share parts and features. All are quite basic and mostly very usable. With a choice of lens mounts available these are cheap ways of maybe trying out a lens without committing to a full system.

As a, sort of, proof of the compatibility of these cameras, I took three cameras I had, all of which had issues and none of which were really worth repairing in their own right, and built one camera from the three. Most of the operational parts (shutter, metering system and viewfinder) came from a Yashica FX-3 Super 2000 but the chassis of the camera was in poor condition with a lot of paint loss so I used a chassis from an original FX-3 and transferred the parts to that. I kept the original FX-3 film advance mechanism in the chassis. I then fitted top and bottom plates, rear door and rubber covers from a Centon K100. Here's the result fitted with a Contax 45mm f/2.8 pancake lens and custom made hood.


I removed the Centon name and model from the top plate as that's not what the camera is. 

I'm now thinking of doing a similar thing with a PK mount body as there's a few Pentax SMC lenses I've wanted to try.


Sunday, 15 January 2017

Focus screens

As I mentioned in the previous post, the S2 screen needed replacing because it was scratched. Replacement S2 screens can be found but are usually expensive. I did buy a used one from a well known UK dealer but, when I got it, it was also scratched so it went back. They can be found on ebay, usually from Far East sellers, but can be anything up to £60 or more.

The same screen type is used in the Contax 167 and the Aria so finding a broken 167 or Aria might get you a good screen but the cost is likely to be no better.

I investigated a number of other screen types to see if they would fit and, believe it or not, the 139 screen is perfect. Because the 139 screen isn't user replaceable, there's no tab on it so fitting it is a bit more difficult but the size is the same.

One good thing about the S2 is the screen is aligned by its top surface which is the surface which the image is formed on so any slight differences in screen thickness won't affect the focus. Other cameras align the screen using the bottom surface so the thickness has to be correct to get the top surface at the correct distance from the lens.

So if anyone want's a replacement S2 screen, a 139 screen may be the cheapest answer.

S2 fixed

Finally got the S2 shutter sorted and the camera rebuilt. Besides the shutter issues, the mirror had slipped and required removing and refitting, the focus screen was scratched and needed replacing, someone had glued an eyepiece to the camera that had to be removed and the glue cleaned off, the meter was dead and the seals needed replacing. All now done so I just need to load a film and start using it.