Why why why won't my Hexar RF focus properly?!?

[sockeyed]

I picked up a Hexar RF about two months back and have had nothing but grief trying to get the focus right on it. When I first got it, I had a local tech - a guy really good with Leicas - to adjust the RF. When I got it back, it was set so it focused perfectly on infinity as it should. When I used it, however, I found that it was focusing short of where it should be. When the RF told me that a subject was 1.7 meters away, the focus would actually be about 1.5 meters away.

So I searched the web looking for answers. I found a thread on the Leica Users Group that mentioned some brass washers behind the lens mount that could be removed to remedy the situation. Doing so would effectively move the lens about 0.2mm closer to the film plane, I believe I read. So I did so. I then calibrated the RF by focusing on a subject using ground glass, then twiddling the horizontal adjustment so that the RF lined up with what the lens was focusing on.

Things seem to have improved, but I'm still finding focus errors which seem to vary with how far away the subject is. The closer it is, the more out the focus seems to be.

Can anyone suggest anything? Alternatively, can anyone suggest a technician who might be able to tackle this? Paying to have it done is better than having a camera that I can't use with lenses wide-open.

Thanks!
Ben

ps. returning the camera is not an option.

 

[sockeyed]

Oh yes, here's an illustration. Both images were shot with the same lens (CV 75/2.5) wide open. In both cases, the subjects appeared to be in focus in the rangefinder. The beer box in the first shot is obviously sharp, and the beer bottle in the second is obviously not (and no, I hadn't drunk the other five bottles first). I had adjusted the RF for the first shot using the ground glass on the film plane technique.

These were shot with the brass washers behind the lens mount in.

 

[Chaser]

There is supposed to be a konica repair man in California and for the life of me i cannot remember the link...hopefull someone will chime in but if not i will do some searching...
the Hexar is a great camera and it will be worth it in the end when it is all adjusted...

 

[pvdhaar]

Ben (sockeyed), don't loose hope! The solution is just around the corner!

When I first adjusted the Hexar RF, I ran into exactly the same problem. I got the RF patch to match at infinity, and then at anything closer than 3 meters, there would be gross focussing errors.

I soon found out that I needed to adjust the RF to match at a closer distance. In my case I used an object placed alongside a ruler at exactly 1 meter, and the lens distance set to exactly 1 meter as well. With this setting I tweaked the adjustment screw.

Imagine my surprise when after adjusting, I found that when aligned for 1 meter, the setting at infinity was still spot on. In hindsight I attribute that to the very small viewfinder magnification of the Hexar (0.6x). It's really difficult to tell whether the RF patch is really exactly lined up at infinity. At 1 meter or so, you can tell much better..

I described this under 'adjusting the horizontal alignment' in post #5 of
http://www.rangefinderforum.com/forums/showthread.php?t=1937

Oh, and you need to remove all the shims that you put in, as the lens travel doesn't correspond anymore with the RF travel..

Hope this helps..

 

[laptoprob]

As I reccommended before, Ben. Like Peter states I also correct any rangefinder - when needed - at around 3m. That works fine for me. Maybe for maximum accuracy you should set it ar 1m if needed. Infinity focus is never needed wide open, at least I don't.
Infinity shots are mostly landscape-like shots and greater depth of field is not a bad thing then. So infinity will always be infinity with a rangefinder set at 3m.

Removing the small rings should get focus towards a slightly greater distance, but the rangefinder cam and pickup moves too.... As an opposite extension rings are used for macro work.

Very sorry to hear about all this.

 

[jmtok]

Doesn't seem to be any mechanical engineers around here.

The problem is with non-linearity. Adjust it at infiity, and it will be out at close range. Adjust it at close range and it will be out at infinity.

When adjusting non-linear assemblies, it's customary to use the iterative approach to reach the best compromise.

Lightmeter curves are non-linear too. Adjusting them requires the same iterative approach. If you'll do a search on photo.net for "Calibrating lightmeter of Leica CL" you'll learn of it.

 

[bobomoon]

There is supposed to be a konica repair man in California and for the life of me i cannot remember the link...hopefull someone will chime in but if not i will do some searching...
the Hexar is a great camera and it will be worth it in the end when it is all adjusted...

Ken Ruth of Photography on Bald Mountain? Recommended by Wade Heninger at the yahoo konicarf group.

 

[furcafe]

Although Ken Ruth of Bald Mountain (www.baldmtn.com) can do the work, you may also be thinking of Greg Weber (www.webercamera.com), who is reputed to be the top independent Konica repair guy.

There is supposed to be a konica repair man in California and for the life of me i cannot remember the link...hopefull someone will chime in but if not i will do some searching...
the Hexar is a great camera and it will be worth it in the end when it is all adjusted...

 

[sockeyed]

Thanks for all of your input.

I followed Rob's suggestion prior to taking the pictures I included in post #2 above. The camera was exactly as I received it - with the shims behind the focus mount.

I set the camera on a tripod and focused the lens, using ground glass and a lupe (sp?) on the beer box, about 2m away. I then adjusted the RF so that it was in alignment with the beer box as well.

I loaded it up with film and took the first image, which is clearly sharp. I then focused on the second image (just using the rangefinder) which isn't sharp at all on film.

Can anyone see the benefit of removing the shims? The article I found describing this issue is:
http://www.nemeng.com/leica/010ba.shtml

 

[Chaser]

Although Ken Ruth of Bald Mountain (www.baldmtn.com) can do the work, you may also be thinking of Greg Weber (www.webercamera.com), who is reputed to be the top independent Konica repair guy.

Greg Weber that's the one..

 

[KoNickon]

Ben -- it does seem as though removing the shims might work, based on the Jack Flesher explanation. At this point it's certainly worth a try!

I've used a number of lenses on my Hexar -- Konica, Voigtlander and Leica -- and not had a problem. I've also not really pushed the limits of potential incompatibility, I will admit.

Greg Weber is absolutely great as a Konica repairman, though I don't know how much he's done with this infamous issue. But he's worth talking to. Ken Ruth also would be highly qualified to look this over.

A question for you -- what's the serial number of the camera? I think the serial numbers for the camera begin with 1400001, though I have never seen that confirmed.

 

[sockeyed]

My serial number is 1400614, I believe, which means that it came fairly early in the production run.

I've emailed both of the recommended technicians. I'll let you know what I hear back!

 

[KoNickon]

Ben, it may be that having a low production number as yours does means it was one that wasn't "right" coming out of the factory. I have never seen anything confirming or disproving that the cameras that had the focusing problems were early production samples, but it's a distinct possibility.

Good luck -- I think those guys will be able to help you out. Let us know what happens, because for a topic with as much conflicting information as this one has generated, any additional data (or well-informed opinions) will be helpful.

 

[ghost]

have you adjusted for infinity and 1m?

i wouldn't use a ground glass to check focus. film bows out. stick to the lens and rangefinder, then test with film.

 

[Paul T.]

Good luck. greg Weber has had my Hexar for about a year now, waiting for rangefinder parts. I believe there are others in the same predicament.

 

[sockeyed]

With the shims out, I set the camera up on a tripod exactly 1m from a target. I set the lens on 1m (a ZM 28/2.8) and adjusted the RF to line up with the target. It didn't work - the lens was not in focus and it didn't go to infinity. I will reinstall the shims tonight and try the same.

I heard from Greg Weber. This is his response:

Hi Ben;


I will be able to help you out when I get the parts promised from Konica but with them closing down I'm not sure about time frame maybe a month or two, just drop me a line then.
Thanks
Greg Weber Phone: (402)-721-3873
Weber Camera Fax: (402)-721-3838
2022 E. 7th Street Toll Free: (877)-721-3873
Fremont, NE 68025


web site: www.webercamera.com

 

[ghost]

try again with the shims in place. how did you test focus? with the groundglass?

 

[sychan]

Ken Ruth adjusted the RF on my hexar, apparently without recourse to new parts.

 

[sockeyed]

Here are the results of tonight's experimentation on the Hexar.

I've concluded that the brass shims behind the lens mount belong there. With the camera at 5m from a target, the lens reads properly at 5m with the shims in place. Without them, the lens reads about 3.25m.

So, with the shims in, I set the lens at 5m and the camera on a tripod 5m from the target, then I adjusted the RF to align on the target. Following this, I did some tests at different distances, first focusing with the rangefinder, then checking the results in-camera with my ground glass and loupe. Things looked good...mostly.

My conclusion? The camera focuses properly at all distances from 2m to infinity. Below 2m, focusing errors occur and the RF and the actual focus part ways. Something non-linear is going on which suggests something inside the RF mechanism is buggered. I think that it's beyond my capacity to fix it. It's time to send it to the pros.

Either that or, as a friend suggested, I now have the most advanced and most expensive Bessa L ever.

 

[ghost]

why adjust the lens for 5m instead of 1m?