OTVXO chimney finder eyepiece adjustment

[B.J.Scharp]

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Hi all,

Just got myself an OTVXO for my Visoflex III in the mail, and I was wondering about something.

The eyepiece is adjustable (has a helicoil that allows it to be screwed in and out). It seems to be a diopter correction for eyeglass wearers, but since there's nothing to see in the viewfinder, it's hard to know when it's correct. Does anyone know if the zero-position is just 'all-the-way-in', or does it adjust both ways from zero?

On the outside, there is a small hole which, in certain positions, exposes the screw/nubbin that runs in the helicoil. I assume this is for disassembly, so I'm hesistant to mess with it.

 

Thanks,

Bernard

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[UliWer]

vor 3 Stunden schrieb B.J.Scharp:

The eyepiece is adjustable (has a helicoil that allows it to be screwed in and out). It seems to be a diopter correction for eyeglass wearers, but since there's nothing to see in the viewfinder, it's hard to know when it's correct.

Well, did you attach the OTVXO to your Visoflex housing with a lens attached? You should see you object as always if the mirror of the Visoflex is in the right position and you have focussed your object with the lens - though the OTVXO has a bigger enlargement. Now you can adjust the sharpness according to your individual view (or glasses).  

Edited April 22 by UliWer

[UliWer]

Here you have the Visoflex with the usual horizontal finder OTZBO attached:

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and here the Visoflex with the vertical "chimney" finder OTVXO:

 

[B.J.Scharp]

Thank you for your reply.

Yes, I've attached and used it. That's when I noticed the adjustability.

My problem is that the only way you can check if the finder is correctly adjusted, is when the image on the ground-glass is in focus. So you have two variables: the lens-focus, and the finder-adjustment, but only one way to check correct adjustment.

I've used other finders with diopter adjustments, but those usually had some kind of marking inside the finder (like a meter-reading, or a shutter-speed display) you could use to check if the finder was correct. The Visoflex lacks this.

Since there is no way to lock the helicoil on the OTVXO, I hope that 'all-the-way-in' is the zero position (which is seems to be, comparing it with my OTXBO on a tripod), as that makes it easier to just click it in place and focus.

I'm just wondering if a) I'm correct in assuming this is a diopter adjustment, and b) there isn't a hidden feature behind the screw on the side.

[Carlos cruz]

I believe that zero diopter position should be in the middle as to accommodate both far- and nearsighted crowd. For best viewfinder focus I usually unfocus the lens and try to adjust vf  (if there are any markings on the ground glass it helps, if none just go for ground glass grain) When I am working long days I do it couple of times a day and my eyesight deteriorates from morning to afternoon. And usually comes back to usual value after resting. 

[UliWer]

vor einer Stunde schrieb B.J.Scharp:

My problem is that the only way you can check if the finder is correctly adjusted, is when the image on the ground-glass is in focus. So you have two variables: the lens-focus, and the finder-adjustment, but only one way to check correct adjustment.

Yes, the finder can only „see“ the picture on the ground glass which is delivered by the lens. Otherwise you wouldn‘t be able to achieve a photo which is in focus. The adjustment of the OTVXO’s eyepiece is not for focussing but it ensures that you can use different eyereliefs or distances between your eye and the eyepiece. The description for the Visoflex says that the adjustment of the eypiece corrects +1.5 to -2 dptr.  If you use the minimum extension your eye should have some distance from the eyepiece which is the case if you wear glasses. At maximum extension your eye should be immediately at the eyepiece. So you focus your lens until you get the maximum sharpness you can achieve and then finetune it with the eyepiece extension. 

Edited April 23 by UliWer

[B.J.Scharp]

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Understood. Thank you for clearing it up!

[Michael Geschlecht]

Hello B.J.Scharp,

Welcome to the Forum.

The way to adjust an eyepiece on a device like this is to put the chimney on the Visoflex with the mirror down so you can see thru the system & then REMOVE the lens.

Then, look thru the eyepiece attached to the Visoflex (With, or without the camera attached.).

With the front of the Visoflex opening pointed to a relatively evenly lit bright area/surface.

Adjust the diopter until the ground glass looks the sharpest & most in focus.

There may/may not be a small circle that is always in focus in the center of the screen. 

Now the diopter is set for you. There is no need to adjust it again unless it moves, or it is moved, from where it is now.

Happy photos.

Best Regards,

Michael

Edited April 29 by Michael Geschlecht