Rodenstock 75mm F4.5 coating deterioration/issues on the inner cells...repairable?

[audioexcels]

Well,

I'm having all sorts of problems as of late. I received a lens that has some interior coating issue problems. A person at a local camera shop said it can happen if water gets in or if cleaning detergents are used on the top/bottom of the cells and gets through to the inner cells. He basically told me that in spite it is only a size of 1/2 a dime or so, that fixing it would be way too much to even do. Has anyone encountered such a thing and is it repairable or no? If it is, what would it cost do have the work done. It is, as listed in the subject, the Rodenstock 75mm F4.5 Grandagon and the seller of the lens is completely uncooperative in accepting the damage in spite a photo of the rear lens shows the same "brownish" looking color that you can see when you look at the rear lens cell. It is like a brown mark on the tiny part of the cell that looks almost like the lens was burnt in that spot. Same thing on the other side (front lens cell), but it is clear and not a brown/burnt look like the rear one).

Thanks everyone!

[JW Dewdney]

Is there any optical effect on the resulting exposed film? I'll bet not. Hmm... is the mark round? I wonder if the lens was focussed on the sun or something. That might well do it (burn the coating off).

[Bob Salomon]

Nothing normal - using, cleaning, etc. will cause this.

If you send us the lens we would be happy to look at it and see what can be done. It is highly unlikely if the coating is comprimised, that it can be repaired in the USA.

[GPS]

Is there any optical effect on the resulting exposed film? I'll bet not. Hmm... is the mark round? I wonder if the lens was focussed on the sun or something. That might well do it (burn the coating off).

Exposing a lens to sun cannot burn its coating off - only what is in the focus point (i.e. out of the lens) can be burnt.

[JW Dewdney]

It can burn right through aperture blades - ! The inner surfaces aren't that far away. Think about it. Concentrating all the photons coming from the sun through the first surface of the lens through the nodal point.

[audioexcels]

Thanks everyone for your answers and help. To let you know some things, I have just realized another something...well...a few things naturally.

This is an F4.5 lens. It, for some reason, uses a Copal 1 shutter. It came from a Sinar type board (old style...mechanical and not auto type). So the lens is an older one, says nothing "Sinar" on it...yet, they had it in a Copal 1. The Copal 1 I have right now is for a Schneider 210mm Symmar which of course is an F5.6 lens. So here's what I've discovered:

1) I should have mentioned that I had only looked through the glass with my eye to see more of what kind of affect this lens may be having on the outside world because I have been on a big search for the camera that will give me the kind of needs I'm looking for and I feel I may have found it...a whole plate type. I just realized I have a lensboard that will fit the Copal 1 and I can mount it to this cheap 4X5 Calumet tomorrow.

2) Well, tonight, I mounted it to the jerry rigging full plate antiquity camera...it is darn old, but it is super flexible and it is a featherweight, having no problem taking this 75 lens back for full focusing and yet being able to extend its bellows like 25"'s!!! Getting to the point, I held the lens in place...yes...this is a story that I'm sure many diyers have gone through at some point. Had no dark cloth because a bunch of lens cells are on it;)...so I use my black jacket as a basic, but not fundamental by any means way of keeping out the light. But my holding the lens, while keeping the jacket in some decent position, while moving the camera in and out of focus and adjusting the front for more back positioning of the 75 near the ground glass, I see a very very good illumination of the ground glass. I roamed around a lot and was able to focus in on things and they look extremely sharp and clear. With this super low light visibility, I was unable to get enough light to really see all that is going on but in the least, there were no strange defects on the screen...Now I did go into even dimmer light where the lack of ground glass illumination faded off and the image circle shone quite brightly at dead center...

3) Tomorrow I will get the lens onto the older 4X5 and see how it looks in the morning light since I will be up very early, and then at broad daylight (as if that's such a thing along the Oregon coast)...yeah, call it cloudy/bright daylight. I will report back with the results I see on the screen and if there are any issues at all with the image being brighter, softer, etc. in certain areas of the frame...For now, I can say that what I saw tonight looked very uniform and again, things were very bright and sharp. I got out my wife's little digicam that has a 36mm equivalent focal point...and I must say, if only the 75 works properly AND COULD cover the full plate...gosh would I be in wide angle bliss...Looking at her through the view and then through the digi was quite something and obviously dramatically different...digicam gave me her nose to her hand. View with 75 gave me all of her including all the surroundings above her head, to her left, right, in front, behind, etc...

4) I have a land holder polaroid, but no film to get in there. I'd LOVE to get a few shots with it because I feel this is where the proof would be in the pudding. I would love to see shots under the light table, but frankly, I look at prints more than illuminated negatives....and the printed result is what I am after...not the whether I can see some defect under a loop, but whether I see a nice big print showing excellent rendition across the frame...

This is all for now folks...I hope maybe I can somehow get my hands on some Polaroid film and take a few snaps though around here, there's no such thing as Polaroid film though I think I have actually seen some for the landcameras!!! If that stuff will work in a 545 holder, I may as well go grab it...but my days with a Polaroid tell me it surely won't. Anyone want to send me over some Polaroids...maybe 5 at the most? I can shoot it at a few different apertures and in different light....etc...

Thanks all. You have all been very helpful and I REALLY appreciate it!!! (BIG CROSSING OF FINGERS THAT I HAVE A USEABLE LENS STILL!!!!)...this one really took a bite out of me and frankly ruined my day with the seller (from Ebay) of the lens not doing anything about his demolishing of it during shipping and when looking back on his auction, seeing the brown part of the lens...it's all the proof one needs, but it was a Paypal transaction, the person is overseas, and what can I do???...but pray this sucker works!!!!

[audioexcels]

Nothing normal - using, cleaning, etc. will cause this.

If you send us the lens we would be happy to look at it and see what can be done. It is highly unlikely if the coating is comprimised, that it can be repaired in the USA.

Hi Bob,

Thanks for the response. What will it cost for an pre-exam and if it can be repaired in the US, what would that likely be?

Thanks Bob and everyone else again for your help!!!

[JW Dewdney]

You could even have a fairly serious CHIP out of the glass on one of the surfaces - and it might not even make a shred of difference in the resulting images. Anything within the lens (between front and back surfaces) will rarely affect image quality (i.e. small scratches, chips, etc... something like that is best filled in with india ink however - I've never tried it - but that's what I hear).

Check out the shim also (don't mean to be insistent) -but that was the word from the Sinar-Bron repair tech I spoke to re: conversion from DB to copal.

[Bob Salomon]

Hi Bob,

Thanks for the response. What will it cost for an pre-exam and if it can be repaired in the US, what would that likely be?

Thanks Bob and everyone else again for your help!!!

It does not cost anything to look at the lens. If the lens needs repair there would be charges and it would have to go to the factory.

In order to see what the status would be we would need to see the lens. Then we can answer questions.

[GPS]

It can burn right through aperture blades - ! The inner surfaces aren't that far away. Think about it. Concentrating all the photons coming from the sun through the first surface of the lens through the nodal point.

JW, the nodal points of a lens are not points to which all rays are somehow focused to and concentrated on. Only the principle focal point (the one on the back of a lens) receives the concentrated sun rays energy. If you were burning things as a kid with a loupe you know that as soon as you put the surface out of focus, the rays energy is considerably weaker. The loupe doesn't heat more than your hand in sun does.

[JW Dewdney]

Hmmm... well maybe I've been looking at to many 'ray diagrams'... I always thought that the 'nodal point' was so called because all the rays passed through a 'node' (by definition) - which was what made that the ideal point to place an aperture - though, of course, if that were REALLY the case - then stopping down wouldn't cause a change in exposure, would it...??? okaaayyy... got it.

[GPS]

Never mind JW, there was the time I was thinking in the same way as you - until I "got it" that through the nodal point, in fact, doesn't pass any ray at all - being it just an imaginary point. Oh, the mysteries of optics, I love them!

[audioexcels]

Hehehehe. It's nice to see this thread got a little crooked and made for some interesting discussion on light rays. Well, I had the opportunity to look again with the lens and a full plate setup as I was too lazy to get the 4X5 out, and the illumination looks just fine. Just need to get some polaroid film from someone or maybe buy some to see what things are looking like on the film. I can always just do a contact if I cannot find any polaroid around here.