Does the focus drift over time on an R3a?

[fbrahic]

Hi!

I have a Bessa R3a with a Nokton 40/1.4. I love the camera - a great buy if, like me, you can't afford a Leica.

I have had the standard issue of the focus being off at infinity. I (very carefully) adjusted it using the screws under the accessory mount.

Now, just a month later my focus is off again at infinity.

Do these cameras just drift out of focus over time, or is it just mine? Any fixes that will last more than a few weeks? Will a professional adjustment somehow last longer than doing it myself?

Also, when I was testing the close focus, I noticed that the camera focuses about 5mm past .7m at the closest. Is this within acceptable limits, or is this off too?

How concerned should I be about the focus being off, considering that I mostly shoot at f2 or higher, rarely at f1.4?

Thanks!

Francois

 

[pvdhaar]

First of all, make sure that the focussing problem isn't user error. Check that you have your eye centered behind the finder. If you're in the habit of looking into it, the impression may be that the double image doesn't line up while actually it does.

If you still have adjustment problems, you can use a bit of Loctite to lock the screws. There are three variants; permanent lock, strong lock and light lock. Use the latter one, so that you can change things without breaking anything. Don't use anything based on cyanoacrylate (a.k.a. super-glues), because the outgassing fumes can etch glass surfaces.

At 0.7m, a 40mm/1.4 wide open has a DOF of approximately 2.6cm. The 5mm error you mention falls within this range and shouldn't pose a problem. In fact, given that the rangefinder is coupled to 0.7m, this may be the distance where the RF coupling roller disengages from the cam in the lens, so you're working at the limits of the system anyway..

 

[fbrahic]

THanks! Any tips on how to safely apply the loctite?

THanks! Any tips on how to safely apply the loctite?

Any tips on how to safely apply the loctite?

Do I need to remove the screw to get the Loctite into the threads, or will it find its way in there somehow if I put a tiny bit on the head of the screws?

Removing the screws makes me nervous...

I wouldn't want it to go in the wrong place, and it's awefully small in there! How do you usually do it?

 

[jlw]

You definitely don't want to remove the screw. Just apply the tiniest possible drop to the screw head -- if you do it at all.

I say "if at all" because I've got exactly the same camera/lens combo, and I've never had any drift issues on mine. Even without Loctite, the adjusting screw shouldn't be loose enough to just wander out of adjustment every few weeks (unless you habitually keep the camera bolted rigidly to your F/A 18 Hornet or the rollcage of your Baja 1000 truck.) It would make me wonder if the RF's internal mechanics might not be loose...?

Anyway, the point is that if the camera is still under warranty, you should shoot it back and have this addressed, rather than trying to Band-Aid it with Loctite (to mangle two registered trademarks in the same sentence.) Even if it's no longer under warranty, it might be worth paying to have a technician fix it. I can't help suspecting that if it has a drift problem now, the passage of time is going to make it worse, not better!