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View Full Version : Linhof mirror finder - adjustment required?



Uri A
24-May-2010, 13:23
Hi all,

I bought one of those Linhof mirror box viewfinder things (cant think of the correct name for it) that clips to the ground glass for focusing. It's a 2 part plastic one with an 80's looking Linhof logo on it. I'm using it on a Master Tech.

Anyhow, I am somewhat disappointed with it's performance as a focusing aid ... You can kind of tell when you're near focus, but a truly sharp image (like i get on the GG without it) eludes me... the thing is well built (obviously) and in good condition. Could the mirror be out somehow??

Anyone? Bob Salomon - HP Marketing ?? :)

Thanks!

Peter K
24-May-2010, 13:49
Sorry not Bob but another user of Linhof cameras.

Do you have a fresnel-lens? Without you cannot see the whole gg at once. But this is also the limitation of the "Right Angle Reflex Attachment", for focussing with a loupe one has to remove the attachment.

Bob Salomon
24-May-2010, 15:41
Any device that lets you see all, or amost all, of the GG at one time is really not a focusing device as it only has about 2x magnification. It is a viewing aid. The Right Angle Reflex Attachment is hinged so it can swing down to allow you to put a loupe on the gg for critical focusing. Or you can take the mirror half off and use a loop inside the base of the unit.

And, as Peter mentioned, it must be used with the Fresnel screen.

Uri A
25-May-2010, 01:59
Thank you both. Could you please explain this, Bob: "Or you can take the mirror half off and use a loop inside the base of the unit."?

Bob Salomon
25-May-2010, 02:52
Thank you both. Could you please explain this, Bob: "Or you can take the mirror half off and use a loop inside the base of the unit."?

On the version made for the past 3 or 4 decades (4x5' one and 2x3" one) the two halves come apart. If you have one that does not and it fits 45 or 23 cameras then you have an antique.

Bob Salomon
25-May-2010, 02:53
Thank you both. Could you please explain this, Bob: "Or you can take the mirror half off and use a loop inside the base of the unit."?

On the version made for the past 4 or 5 decades (4x5' one and 2x3" one) the two halves come apart. If you have one that does not and it fits 45 or 23 cameras then you have an antique.

Bob Salomon
25-May-2010, 02:54
delete

Uri A
27-May-2010, 01:13
oooh, I see: stick a loupe inside the bottom half - got it! Probably easier to swing it all outta the way though..

thanks Bob.

Bob Salomon
27-May-2010, 01:36
Uri,

There is another factor. The Right Angle Reflex Attachment uses a rather expensive front surface mirror. If someone replaced the mirror at some time with a standard mirror then it would not be focusing at the proper point. But they would have saved the cost of the correct mirror.

Sevo
27-May-2010, 04:24
A rear-surfaced mirror would have a somewhat offset ghost image from the glass surface superimposed on the main image. This will not affect focusing itself, as these mirrored ground glass viewers (other than a proper reflex finder) go after the ground glass and hence cannot affect the focal distance, but it might make it harder to see the GG image.

Uri A
27-May-2010, 04:32
hmmmm... interesting thoughts. Is it really plausible that someone hand cut a new mirror for this unit? I s'pose it could be.. or maybe I was expecting the kind of view you get with the Sinar reflex viewer and the little flip up specs (crystal clear & razor sharp)

- cue Frank Petronio with a "should've bought Sinar" comment LOL ;)

Thanks gentlemen!

Bob Salomon
27-May-2010, 05:10
hmmmm... interesting thoughts. Is it really plausible that someone hand cut a new mirror for this unit? I s'pose it could be.. or maybe I was expecting the kind of view you get with the Sinar reflex viewer and the little flip up specs (crystal clear & razor sharp)

- cue Frank Petronio with a "should've bought Sinar" comment LOL ;)

Thanks gentlemen!

Properly installed, modern gg screen and matching fresnel it is very clear and sharp. Assuming the proper mirror and everything clean.

Peter K
27-May-2010, 06:26
hmmmm... interesting thoughts. Is it really plausible that someone hand cut a new mirror for this unit? I s'pose it could be.. or maybe I was expecting the kind of view you get with the Sinar reflex viewer and the little flip up specs (crystal clear & razor sharp)
To check if it's a surface-mirror carefully put the tip of a pecil on the mirror's surface. If there is a small gap between the tip and it's mirrored image you have a rear-surfaced mirror.

Also a Sinar reflex viewer can only show you what he gets: without a fresnel-lens an unevenly illuminated groundglass.

Sevo
27-May-2010, 07:36
Replacing mirrors is trivial if you know how to handle a glass cutter - Edmunds, Surplusshed etc. have a plentitude of suitable surface mirrors.

That said, I still consider a (missing) fresnel the most likely cause, and a low-quality replacement ground glass second to that. Mirror flaws tend to make themselves obvious in more ways than just a loss of brightness...