M9 - Viso III - yet another problem - inaccurate framing

[sblutter]

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I've got everything focusing perfectly, that's complete.

 

The problem now is registration - what I see and what I get are shifted in the vertical.

 

The image on the ground glass compared to what is captured in the camera is shifted down about 1.5mm from the lens side edge.

 

To clarify: assuming a horizontal image, the upper edge is obscured and the lower edge gets too much image. I taped the bottom 'real' edge as a guide to help.

 

This is causing me to either test back and forth or back up to capture a larger area - which lowers resolution due to the need for final cropping.

 

This is identical on both Viso III copies I have.

 

Other than machining well past my abilities and inclinations, I can't find any adjustments available.

 

Any ideas or experiences with the same problem?

 

How was registration with film bodies? (Just curious.)

 

Am shooting 3" to 10" tall items, Viso, bellows, 65 or 90mm lenses.

 

This is annoying and quite un-Leica. I may have to live with it...

 

Thanks

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[pico]

Is the mirror resting fully at bottom when down?

[k-hawinkler]

I've got everything focusing perfectly, that's complete.

 

The problem now is registration - what I see and what I get are shifted in the vertical.

 

The image on the ground glass compared to what is captured in the camera is shifted down about 1.5mm from the lens side edge.

 

To clarify: assuming a horizontal image, the upper edge is obscured and the lower edge gets too much image. I taped the bottom 'real' edge as a guide to help.

 

This is causing me to either test back and forth or back up to capture a larger area - which lowers resolution due to the need for final cropping.

 

This is identical on both Viso III copies I have.

 

Other than machining well past my abilities and inclinations, I can't find any adjustments available.

 

Any ideas or experiences with the same problem?

 

How was registration with film bodies? (Just curious.)

 

Am shooting 3" to 10" tall items, Viso, bellows, 65 or 90mm lenses.

 

This is annoying and quite un-Leica. I may have to live with it...

 

Thanks

 

Or you could ask one of the top technicians if they can adjust that specific alignment for you. As Jaap pointed out there are 5 adjustment points - if I remember correctly.

 

K-H.

[sblutter]

Is the mirror resting fully at bottom when down?

 

Sure seems to be

[sblutter]

Ah ha!!

 

The mirror is resting too low. Now we're getting somewhere.

 

I'll jury-rig something to prop it up until I find out how to do it properly.

 

You guys are great - Thanks!!!

[pico]

Ah ha!!

 

The mirror is resting too low. Now we're getting somewhere.

 

I'll jury-rig something to prop it up until I find out how to do it properly.

 

You guys are great - Thanks!!!

 

 

Mirror up. I've an earlier Viso and the mirror in the down position rests upon a bare allen-head stud which is adjustable for height

Perhaps yours is missing.

 

Sorry for the crude picture.

[Washington]

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The mirror was my first thought too ..... as I learned in the mechanical trades,

folks have a tendency to head for the complicated, or worst case "solution" first.

Hell. I still find myself doing it. Do the simple things first .... sometime it takes a bit

of pondering on the possible simple solutions before you get out the serious disassembly tools! Good gong, buddy!!!! Cheers.

Oh, I forgot to say that the mirror return is only by gravity... so, you have to turn the rig upright at times to get a full return.

[jaapv]

There are three adjustment points in the Visoflex., and the mirror axis alignment too. I think this is the moment to have an experienced repairperson do it, and maybe he will show you how as well. It is not really difficult, but all adjustments are interrelated, so the order in which you make them is of importance.

[k-hawinkler]

There are three adjustment points in the Visoflex., and the mirror axis alignment too. I think this is the moment to have an experienced repairperson do it, and maybe he will show you how as well. It is not really difficult, but all adjustments are interrelated, so the order in which you make them is of importance.

 

Jaap,

 

Thanks. Quoting from:

 

http://www.l-camera-forum.com/leica-forum/1314845-post28.html

 

"An interesting thread, so I checked with my technical deep throat.

The Visoflex has all five inaccuracy points of an SLR and three adjustment points:

Screen location through shims, an adjustable mirror axis and an adjustable mirror rebound point.

Adjustment is easy and many Visoflexes need adjusting on the M8/9.

__________________

Jaap"

 

 

Sorry, I confused 5 inaccuracy points with 3 adjustment points.

 

Best, K-H.

[sblutter]

Got it!

 

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[sblutter]

The above picture is the right side post of the 2 that catch the mirror.

 

It is an off centered post mounted on a freely rotating nut - thereby making it a cam. Rotate until image matches output with needle nose pliers.

 

In other words, excellent design - the essence of simplicity!! I had a hunch from Pico's pic of his V II there would be an adjustment somewhere - examining with a strong lupe revealed it.

 

What's interesting is once perfectly centered, the output in M9 is a hair larger all around than what's on the ground glass - Leitz philosophy at its finest.

 

Note how focus held (straight away!) - image is just a 95kb jpg at low rez. (viso III, bellows, 90 at f:16, 640 ISO).

 

PS: The post is slightly slimmer on my other example and again off center - therefore the same cam action.

 

With the earlier shimming of the ground glass, I now have a perfectly calibrated Viso III - sweet! It was all very easy with no disassembly required at all.

 

I hope this journey helps you guys - it was fun to share.

 

Now you all have to come to my next show here in Chicago this November

[Washington]

Lordy, that adjusting screw & lock-nut look pretty ugly though. Like someone was

in there with Vice-Grips or worse. However, it's not how it looks but where it holds

the mirror.... as you are finding out. Again: good luck! cheers.

[tobey bilek]

Now that you mucked with the mirror, the focus is off.

[sblutter]

Tough crowd!

 

To naked eye the nut looks brand new and is very black. The pic is adjusted much lighter to illuminate and educate about the cam feature - aesthetics were not a consideration. I taped the pliers, all facets remain crisp and it probably wont need further adjustment in my lifetime.

 

The nut had probably not been touched since initial assembly decades ago - that it moved at all was a surprise and luckily I got it right on the 2nd go. It was about a 1/3rd counterclockwise rotation.

 

As for focus, that result is excellent. The bellows was racked way out, the pic above is only 25% of the captured area and I had to down rez to be able to upload here. That's about the resolving limit of that lens. The nut is only 3mm (1/16") across. The smallest thing I shoot is 3" - huge by comparison. The original dng is perfectly acceptable.

 

At any rate, the main point is we've uncovered a built in adjustment that all Viso III shooters can use to enhance their accuracy.

 

It was a very satisfying experience and result.

[tobey bilek]

If you moved the mirror stop, you changed the focus because the distance from mirror to focus screen changed. Check with a diagonal target such as as a ruler. If it is right now, it was wrong before.

 

The correct order would be mirror axis for left right, rebound point for top bottom accuracy, then focus using shims. You can fix focus with mirror stop, but then you screw up top bottom framing.

 

The reason the focus is off is the same reason film and digitals are different. Film is not flat and the film channel has debth. Film Leicas were not calibrated to the pressure plate, but to some space inside the channel to allow for film curvature. With digi, no compensation is required.

[sblutter]

Tobey,

 

Just did a torture test wide open - you're right, it is now very slightly back focusing in the middle of the frame - about 2mm in my normal shooting set up.

 

I'll just re-shim - in an earlier thread I described an easy method.

 

Since I'm back focusing, will need ever so slightly thicker paper - or the addition of very thin, like ordinary copier paper. I have many different papers here - that's only a 5 - 10 minute job and already know how.

 

Getting the framing perfect was important for compositional purposes - that was way off leading to utter guess work.

 

Thanks for enforcing high standards!

[k-hawinkler]

Hi sblutter, Congratulations and thanks for sharing your experience. Best, K-H.

[sblutter]

Re-shimmed - case closed

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Hallo,

Look here: Leica M

[tobey bilek]

Now you got it.

 

None of the viso lens head have a really flat field so you can not get center to corner sharpness. If you like a 65, find a black one. It is a significanly better lens with less distortion and flatter field than the chrome. 90 2.8 is better than average. 135 4.0 is close to APO.

200 4.0 and 280 4.8 work great as teles. 400/ 560 6.8 are nice tele and close lenses, work well with the intermediate tube between head and focus mount. They have bad field curvature, but focus on the subject and it matters little. With the viso glass screen, you can focus anywhere.

 

No lenses are as good as 100 2.8 APO R. No idea how to put it on a viso though. Works a treat on Nikon though.

 

For others who may read this, the old silver mylar slide binding tape is a very fine shim, .0002. Better than paper by a mile. Cut it on a glass sheet with razor blade and use what you need. Aluminum foil good also but thicker, around .002 if I remember correctly.

[k-hawinkler]

Now you got it.

 

None of the viso lens head have a really flat field so you can not get center to corner sharpness. If you like a 65, find a black one. It is a significanly better lens with less distortion and flatter field than the chrome. 90 2.8 is better than average. 135 4.0 is close to APO.

200 4.0 and 280 4.8 work great as teles. 400/ 560 6.8 are nice tele and close lenses, work well with the intermediate tube between head and focus mount. They have bad field curvature, but focus on the subject and it matters little. With the viso glass screen, you can focus anywhere.

 

No lenses are as good as 100 2.8 APO R. No idea how to put it on a viso though. Works a treat on Nikon though.

 

For others who may read this, the old silver mylar slide binding tape is a very fine shim, .0002. Better than paper by a mile. Cut it on a glass sheet with razor blade and use what you need. Aluminum foil good also but thicker, around .002 if I remember correctly.

 

You meant, of course, Tele-Elmar 135/4.