backlash problem sent to epson Indiana

[wutthehack]

a few months ago i acquired a leica 90/4 and jupiter 135/3.5.....found that my r-d1s has backlash problem, so i contact Epson for repair in Toronto. They send my r-d1s to Indiana for repair. However, the repair centre say my r-d1s is problem free, the problem is my leica 90/4!!! and sending back the camera to Toronto! I am wondering if they really check in details or not...since this is happening on two lens. how can i test if the r-d1s has backlash or not?

 

[Manuel Patino]

Please excuse my ignorance, but what is backlash in a R-D1? Sorry about your problems BTW. I hope you have good luck getting them sorted out...

 

[thegman]

I have never heard of backlash in cameras, do you mean backfocus?

I'd get into a dealer and try another lens on it, maybe a 35mm or a 50mm. The R-D1 has a fairly short range finder base length, and a 135mm lens on it might be beyond what you can expect to focus with it, especially at f/3.5.

According to www.dofmaster.com, if you use the 135mm to take photo of a subject 1m away at f/3.5, then you have less than 1cm DOF, so basically, you can't really focus it at all, regardless of how accurate everything is. Even 2m away, you've only got a few cm of DOF to play with.

I'd get into a dealer and have a go of some other lenses. I would probably guess that there is nothing wrong with either the lens or the body, you're just up against the limitations of lenses and range finder cameras in general. Even with perfect auto-focus, a 135mm lens, wide open, close up, you're really going to struggle to get meaningful amounts of your subject in focus.

If you're shooting stopped down/far away, then maybe ignore what I've written, but I'd try out some shorter lenses on it.

 

[jonmanjiro]

I think the design of the Epson rangefinder mechanism makes a certain amount of backlash unavoidable. I can nail focus at large apertures pretty much every time by focusing from infinity to the point of focus, but not when I focus from minimum focus distance to the point of focus. When I sent my R-D1x to Epson Japan recently for RF and focus adjustment, they said the backlash was within tolerance.

 

[jonmanjiro]

I have never heard of backlash in cameras, do you mean backfocus?

Backlash and backfocus are different things, although backfocus can be caused by backlash. Backlash is caused by loose tolerances or slop in the RF mechanism.

 

[Rob-F]

I remember about backlash from my Air Force days. It's about the free play in mechanisms. There has to be some free play so that, for instance, a gear train won't bind up. But if the gear, or other mechanism, needs to reverse, then for the moment when the free play is being taken up, the driven gear doesn't move--not until the space between gears has been taken up. An engineer I knew called this "dead band."

Now about the 90mm Elmar. I imagine it's made like my 90 Elmarit, which has a spring-loaded sort of cam to transmit the focusing movement to the cam follower in the camera. The grease in the mechanism dries up, so that the spring can't keep this little part--it's sort of like the pushrods in a car engine--tight against the cam follower. The result is that the "pushrod" can move accurately in one direction, when it's being driven; but not on the return in the other direction. So then you focus the lens, and the camera can't follow the focus action--not when focus is being moved in that direction. I believe that's what they meant by backlash.

So when the experts get done with it, if it still doesn't work, try freeing up that pushrod with some WD-40. That's right, WD-40. It contains Naptha which will dissolve that old grease. Then lube it with a good modern grease. I use a gel grease which stays where it's put--you don't want it getting on the glass. I got it in Radio Shack.

Edit: I should mention that I unscrew the lens head from the mount before using the WD-40 and lube. That's to keep those products away from the glass.

 

[wutthehack]

Thx Rob-F for the information on 90 Elmar! Maybe i should stick with 50mm lens!

 

[Guaranteed]

I think the design of the Epson rangefinder mechanism makes a certain amount of backlash unavoidable. I can nail focus at large apertures pretty much every time by focusing from infinity to the point of focus, but not when I focus from minimum focus distance to the point of focus. When I sent my R-D1x to Epson Japan recently for RF and focus adjustment, they said the backlash was within tolerance.

Thanks for the post, I find the same style of focusing with my R-D1. I(sadly) haven't used my R-D1s enough to notice if its the same or not.

 

[aldobonnard]

I had a strong backlash on one of my R-D1x, which I sent twice to Epson (the first time, the test procedure which was given to them for reproduction of fault, was not precise enough). The second repair has fixed the issue (changed one part).
The other R-D1x and R-D1s don't show any problem of backlash, only variations in front/back focusing depending on which lens is used. Something to be learnt and noted for each lens, but it's not difficult.

I concur with Jonmanjiro, this is in some way unavoidable, and exacerbated when using lenses like 85/2, which in my view exceed the R-D1 VF accuracy, unless using a magnifier.

RCutler site presented this RF accuracy table:

Table 1. Epson R-D1: widest apertures for accurate focusing

Focal length Maximum aperture
50 mm f/1.0
75 mm f/2.2
90 mm f/3.2
135 mm f/7.2

Something to remember when using your R-D1 at the limit of its possibilities.

That said, I get a more consistent focusing accuracy with my R-D1 than with my M9, but less consistent and pleasant than with the ZM 🙂

 

[le-alain]

I have no problem focusing with my 90 f4 Elmar,
but 135mm Hektor was unusable.
75mm is OK at 2.8, but not at 1.8, to thin DOF
50mm 1.5 and lower focals are OK