Yashica Dental Eye I

I've yet to find any online copies of the manual for the DE-1 except for a for-pay manual at $13 for 9 total pages. I'll pass at that price for the content of probably 1 paragraph.
After no suggestions, I started a few deep dives in Google - with the aid of it's translator - and I think I've scoured every post on every foreign language blog that had a hint of info. 

For anyone looking for similar info, here's what I've found...

Original release: 1985
Optional accessories:
 Data back panel (connect by cable via accessory shoe)
- Conversion lens "Yashica Dental-Eye 2x Lens" (for scale 2: 1)
- Oral cavity mirror.

• Lens: Yashica ML macro 1:4/55mm, four lenses in three groups, image angle 43°
  
• Aperture range f/4-10.
• Shutter: vertical metal closure, mechanically controlled.
• Shutter speed: Constant, at 1/60 second (equivalent to it's flash sync speed).
• Film speed: ISO 64 to 1000. (64, 100, 200, 400, 800, 1000)
• Distance setting: 58.1mm to 7.9cm for an equivalent magnification from 1:10 to 1:1.
• Imaging formats: 240 x 360 mm (1:10) to 24 x 36 mm (1: 1).
• Prism viewfinder; Viewfinder information: Green LED as flash readiness indicator for ring flash.
• Focusing aid: A ring flash integrated, switch controlled 6 V pilot lamp
• Flash strength is automatic depending on selected magnification.
• Flash output: approx. 7.3 Ws (ISO 64) Guide number: approx. 3.8 (ISO 64), with flash cycle time of approximately 2.5 seconds (alkaline manganese batteries) or 2 seconds (NC batteries).
• Power source: 4 x 1.5 V AA batteries or 4 x NC batteries
  

The only default adjustment possible from the user side, is to vary the ISO dial to one of the six available film speeds to adjust exposure. Every other setting is either 'locked' at one value (shutter speed) or calculated internally (aperture and flash power level). Something similar was also mentioned in the DE-III manual. There is no metering of any kind, and the semi-permanently attached motor drive box has no motor in it at all. It houses the flash's circuit board and the 4 batteries used to power both the ring flash and the (somewhat dim) modelling light. It's screwed on, but removable with patience - and a JIS cross-point screwdriver.

The ring flash can be deactivated by a rear-mounted switch, or by not having batteries installed - but - you are still at the mercy of the camera's intentional limitations. Knowing that the shutter is always going to be 1/60th of a second leaves the challenge of how to manipulate exposures by the choice of film speed that's loaded, and then marginally manipulating the ISO dial like it's a +/- EV dial.

The top-mounted flash shoe will fire an external flash, but its intended purpose is only to power the optional data back so it can light-pulse the date/time data onto the film stock's outer edge. It might be possible to use a bounce-able auto thyristor type of flash to use it as fill, but that's only a guess. I'm planning on tossing in some 200 Kentmere B&W and testing both DE's, and thinking it might be worth a shot to try some push/pull with the speed to see if I can get better exposure control.

After some basic testing I found that one of the 4 battery box springs was missing, and the flash would fail to fire on occasion. I got a couple of old Contax 139 winders at KEH, and replaced the spring to get the DE back to 100% firing. The 2nd 'as-is' donor winder just needed a cleaned contact to get back to full working order, and is now attached to my 139 Quartz. Now it's off to get a new cover and then go for a spin once the weather gets better.

I know it's been some time since my first posting, but at least I can provide some updates and pics.

The person I'd originally contacted about creating a new set of leatherettes ended up not doing them. It certainly can't be blamed on him, as I decided against sending the gear to him in an un-assembled state. It would have been necessary in order to get all the various pieces positioned and anchored under the right-hand grip from the modified winder base that houses the battery and flash electronics. These camera's were obviously hand assembled at the factory, and there are no connectors used when the base and body are connected. There's a soldered 'wire loom' affair that would require desoldering to separate the base from the main body in order to reassemble them into separate pieces for shipping. I'll pass on that for just doing new skins.

The only way to have access to the skinable parts is to unscrew the base via the multiple attachment points - then let things dangle by it's wiring during both transport and re-covering. I suppose I could have asked him to do the disassembly to, but I thought that was pushing the expectations of what work would be done on a previously agreed-to $35 re-skinning job. Since I needed to find a part and reattach one of the battery springs, I located a dead 139 winder at KEH for under $2 and ejected a spring to do the repair.

I also wasn't thrilled about having to go through multiple times of dismantling and rebuilding, so I decided to just do the leatherette replacement myself. I found someone who had a stack of OEM Yashica FX-3 leatherette pieces that were already backed with peel-n-stick adhesives, so I bought 4 pieces. The original Dental Eye used various versions of FX-3 series parts anyway, so there wasn't any need to cut fresh from replacement skinning sheets... I just needed to split and trim a bit for the body, and do some extra trimming to do the base. The only 'gotcha' was the age of the adhesive, and it not wanting to stick at the sharply folded corners. Extra strips of double sided carpet tape was enough to keep them in place. I have some Pliobond too, in case they don't want to behave over time.

Here's a link to the results with the new replacement skin... lumiworx.com/tags/dental+eye/

It's been a very odd start to outdoor shooting time this year, with some fairly extreme swings in weather, so it will be a while longer before I can do a proper film test. I did get some Kentmere 200 into the fridge, so it's just finding the time on a few good days before testing.

The Dental Eye III is next up for rubber work on the lens grip. It's a little oxidized and needs some TLC. I have some Rubber Renue which seems to work fairly well on some test pieces of grip material. In the mean time, I took a quick pic to compare it to a standard 100mm f/3.5 Yashica ML Macro. Quite a difference in size (not counting the ring flash), and the f/3.5 has no problem doing infinity focus if needed.




BTW... The hood on the 100mm f/3.5 is actually a Konica clamp-on for an AR mount 35mm f/2.8. Visually, at least, it seems really close to the original rectangular hoods that were specifically sold for the !00 Macro lenses. I've only seen photos and never seen one in person - or for sale - so at least this one seems to fit and work just fine. I should qualify that to say... at least on an APS-C sensor it works well. I've yet to put it to use on a film body, but hopefully soon I'll know. I'm ready to start using a new (to me) Contax RX, and this will be on it for macros.

I have an original DE-1 manual. I can make a copy for $5 to cover copy and postage costs if you’re interested...