Brightening The Yellow Patch

R

ruben

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Just in tone with the consumerist ever growing wave, eating some of my savings and much of my brains, I too feel that unstoppable impulse to open my window and cheer to the crowds with some new package from the mail.

Unfortunately, due to my exhausted resources, it will not be a really heavy package with some piece of German engineering, but a rather modest envelope with a set of LEE FILTERS, bought at us$ 20 something, before shipment. And yet I am aware of the potential danger I have paid an abusive price.

What the LEE FILTERS set is, and how we may benefit from, on behalf of our elusive yellow patches, may be of the highest importance for those newbies like me, still battling for a cause many will agree is totally lost.

Imagine for instance what a Canonet QL..., or an Olympus RC, or a Yashica from the Lynx lineage, or any of those glamorous gladiators of the past could be with a contrasty yellow patch jumping to our eyes, enabling us to accurately focus in fractions of second. A bit out of its context, I would like to bring here a sentence from one of our most eloquent street photographers (yes, I mean him), in a brief PM exchange: "For us, the viewfinder is everything"

So I have cleaned the camera viewfinder with some success, and it only made me even more anxious to achieve the goal than I was before. Then I applied the Rick Oleson very original idea, with many possible variations, but I realize that it really works FOR ME with the oversized patch in my Iskra. Then I go as far as actually buying a new 2x2 inch piece of new beamsplitter from Edmunds Scientific, only to end with the need of knowing how to cut it and a lot of small pieces, yet fewer than their still ongoing spamming, after due courteous request to stop.

Did I stop here ? Of course not, don't forget that it is not about the end result but the battle itself. So I decided to risk ruining a whole camera by wet cleaning all parts of the viewfinder, beamsplitter included. Surprisingly it didn't peel off, and another appreciated bit of improvement achieved, but far far from the goal. About the last disaster I prefer to keep quiet, our great G man already taking care for.

Denied permission to enter by the proper door I tryied by the window: Instead of brightening the yellow patch - Darkening the viewing window of the viewfinder. It did work to an interesting extent: The idea came quite naturally from my Kievs, with which you can easily focus in spite of the dark viewfinder. No doubt that having a clear viewing window with a highly contrasty and dark patch is better, but "a Contax is a Contax", not? Kappa went with them to real war.

The issue was the material to use. With simple kitchen tryial it became obvious that a Neutral Density filter of low intensity was nothing but perfection itself. Again, how to cut the glass...

Here comes the Lee set, with some dozen different very thin square leafs, very easy to cut with a simple cutter and a metal rule. Among the dozen, there are 3 labeled as ND. What a treasure. A single leaf may be more than enough for a dozen rangefinders. Each leaf is carefully packaged within a separate envelope.

Now, how good these filters are in preventing image degradation vis a vis a glass ND filter? I don't think they can match the almost perfection of glass. But I am almost certain about two things. They are MUCH better than an Ilford darkroom set of filters, none of which is ND but coloured, and thicker. The second is that with those 20 something bucks invested I will be at the other side of river.

Why I will be? Not because of the battling issue but because right now I am fiddling with the Electros, which as almost all of the dwellers here know, joycefully don't need any further yellow patch improvement.

Cheers,
Ruben

PS:
a) Darkening the viewing window may work best for cameras with relatively bright viewing, instead of cameras with relatively dark viewing window. (But on the other hand, without a decent yellow patch you have no rangefinder camera).

b) The ND cut is to be inserted within the camera, next and parallel to the outer glass.

c) Further follow up is to be expected.

d and very important) The Lee Filter set was not my own idea, nor I know what they were actually designed for, and for the matter it doesn't matter, but raised by several friends at another thread, special mention to BrianShaw:

http://www.rangefinderforum.com/forums/showthread.php?t=34519

e) The writer has no university degree, nor even a driving license, and it will be fair to state quite a small knowledge in fixing cameras, much of it due to our master Kiev how to, Russ Pinchbeck, with his celebrated Kiev Survival Site.
 
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A few moments ago I have finished to insert a cut of the Lee Filters ND6 into one of my Canonets QL GIII: IT WORKS - WOW !

Now to some fine grain details. I have two Canonets, one with a relatively good yellow patch, the other with a quite bad one. Obviously I fixed the bad yellow patch one, although I am tempted to do the same with the good one.

I could have chosen a lower intensity ND3 filter, also included, but went to the ND6 because I intend to use this camera for bright light outdoors, ISO 100~200. The other one, with the good patch, for ISO 800.

How close the transparency of the Lee filters matches the one of a ND glass, once installed on the proper place ? Surprise for me: almost equal or equal !

How dark the whole new viewfinder has turn, after using the ND6 filter? Relatively to the Canonet viewfinder before, a lot. Relatively to a standard Yashica Electro, a very tiny bit darker. Yet take into account that I could have chosen the filter ND3, also included in the package and I didn't since this camera is intended for bright outdoors.

How contrasty is the yellow patch now, compared to a standard Yashica Electro ? A tiny bit better.

Cheers,
Ruben
 
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Can it work for Oly 35sp? It has very bright finder and moderately bright patch. Though I don't know whether it's worth to improve something that is already good enough.
 
Great news for you, and good info to know too. But I fell like I was reading a Dr. Seuss book reading your succes story. No dis-respect intended.
 
It happens again! Things in this world are strangely interconnected - just yesterday I had read to my doughter Dr. Seuss "The Cat In The Hat" in Hebrew translation (with great success). It's kind of deja vu, it already happened to me when once I prepared to answer on RFF some question on exposure (with "perfect exposure" by Roger Hicks in mind) and suddenly saw Roger Hicks himself answering.
 
Ruben - well done. Using gels is a great way to improve VF contrast. I found that the gel stays in place and does not scratch easily if treated well. I wonder if a yellow gel over the RF window might also improve things.
 
Ruben, thanks for taking the trouble to post your description. I bought the same beamsplitter stock from Edmund's and used it to improve the RF on my Leica IIIf. Like the IIIf's original beamsplitter, however, the Edmund's stock is neutral in color.

It would be better if the patch (reflected by the beamsplitter) and the background (transmitted by the beamsplitter) were different colors. While using a filter to alter one or the other cuts the total amount of light in the rangefinder, a beamsplitter that reflects a particular range of colors should be more "efficient." A few sources:

Anchor Optics (www.anchoroptics.com) sells reasonably-priced "experimental grade" beamsplitters that reflect blue and gold (or, alternatively, blue and violet) more than other colors. I haven't bought any so I'm not sure if the blue-gold reflective ones would be similar in practice to the gold-reflective splitters found in many cameras.

Of course you could salvage the beamsplitter from an otherwise non-working camera. I am holding onto an entire rangefinder mechanism with this in mind, though I still have thoughts of making an entire self-contained rangefinder out of it some day.

Finally, the old Kodak disc cameras contain a very nice beamsplitter that reflects most strongly in the gold part of the spectrum, just like the ones on some RF cameras. It's almost exactly the size needed for a Leica or a clone. I used one to replace the beamsplitter in a Zorki with very good results. I trimmed it to size by grinding the sides against a whetstone... Tomosi recommends doing this under running water, but I just dampened the stone a little and cleaned up carefully later. He's probably right; I wonder how much "glass dust" is still on the floor...

Good luck with the experiments... Michael
 
Igor.Burshteyn said:
Can it work for Oly 35sp? It has very bright finder and moderately bright patch. Though I don't know whether it's worth to improve something that is already good enough.
Click to expand...


I will tell you what I have done with my bright viewfinder and good yellow patch Canonet, it may be a controversial approach so you will have to decide for yourself.

Yesterday when I was walking home at night I metered the light of a relatively well lightened road, based on an Iso 800. I noticed that with my maximum ISO speed I still don't have enough light for taking a handheld shot at 1/30 and f1.7.

But while looking through the viewfinder, I noticed that I can see a lot, far beyond what the camera is able to photograph handheld. Conclusion: I have a lot of meat to cut there, meaning that I can darken the viewfinder, although I would do it with and ND3 instead of the darker ND6, bringing the viewing closer to what the camera is able to photograph. Or in other words, after inserting the filter and darkening the window, what the viewfinder will not be able to detail will tell me I have not enough light to photograph. And what the camera is able to photograph, I will have a better yellow patch to focus.

BTW, at night, with a lot of cars and shop lights around and in front, a yellow patch as I have in that Canonet before inserting the cut of ND3, goes sometimes lost and hard to identify - another reason to use the filter and increase contrast.

Nevertheless, if with your SP you intend to do long night exposures, all the abovementioned is of no practical value for you.

Cheers,
Ruben
 
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mjflory said:
Ruben, thanks for taking the trouble to post your description. I bought the same beamsplitter stock from Edmund's and used it to improve the RF on my Leica IIIf..............
..........Of course you could salvage the beamsplitter from an otherwise non-working camera. .............

Good luck with the experiments... Michael
Click to expand...

Hi Michael,

a) Would you like to detail, to the extension of your will, how did you cut the Edmund's crystal beamsplitter ?

b) I tryied to transfer a beamsplitter from one camera to another. But as soon as I inserted the new one, I found that you will have to glue it in a very accurate vertical 90 degrees angle and diagonally too. At this point, I backed off with humbliness. I do understand that you can further calibrate the right position using the camera screws, but it seems to me that you must start from a very good neutral point otherwise you may find yoursef with the screws out of range. How do you solve this issue ?

Cheers,
Ruben

BTW, just perhaps, the colored Lee filters may be of help to your Edmundized Leica, as their translucence is amazing. By translucence or transparency I mean their non degradation of the image.
 
zuikologist said:
Ruben - well done. Using gels is a great way to improve VF contrast. I found that the gel stays in place and does not scratch easily if treated well. I wonder if a yellow gel over the RF window might also improve things.
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Hi Zuikologist,
I take for granted that you meant to use the gel inside the camera, just a small linguistic confusing understanding by me, as you said "over the RF window".

As for the yellow color, and as far as my memory goes when using the Ilford darkroom filters for improving the patch, it seems to me the yellow one confuses rather than helps. Nevertheless your targeted camera may at it viewing window some light color tone, to which a yellow gel may not confuse the patch borders.

But in any case, beyond the issue of the extraordinary translucence of the Lee filters (and I am not conouscieur at all in the area of gel filters), having an overall color toned image may not be a satisfactory solution, despite the patch having been improved.

I don't know if the original Lee filters are rather hard to find or not, but after knowing what their ND ones can do to my rangefinders, I would easily paid ten times more than what I actually paid. With the set, you are kind of "insured for life" with any old rf you own or intend to buy in the future.

Cheers,
Ruben
 
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Slightly OT, but when I cleaned the VF of my Tower 51, I was hesitant to touch the beamsplitter with alcohol or another cleaning fluid. But as the camera was a very inexpensive purchase, and essentially a non-essential camera, I braved it. Not only did the silvering remain, but wow, what a difference! The VF is still dim by Leica, Bessa and even 35SP standards, but it is quite useable. Even in dim light the contrast makes for fairly easy focusing.

Now I'll have to try the ND filter/film trick. One could use b&w film developed to different densities for this ...
 
ruben said:
Hi Michael,

a) Would you like to detail, to the extension of your will, how did you cut the Edmund's crystal beamsplitter ?

b) I tryied to transfer a beamsplitter from one camera to another. But as soon as I inserted the new one, I found that you will have to glue it in a very accurate vertical 90 degrees angle and diagonally too. At this point, I backed off with humbliness. I do understand that you can further calibrate the right position using the camera screws, but it seems to me that you must start from a very good neutral point otherwise you may find yoursef with the screws out of range. How do you solve this issue ?

Cheers,
Ruben

BTW, just perhaps, the colored Lee filters may be of help to your Edmundized Leica, as their translucence is amazing. By translucence or transparency I mean their non degradation of the image.
Click to expand...

Hi Ruben,

If I were to explain in a word how I cut the beamsplitter, I'd have to say, "clumsily." After a fruitless hunt for the glass-cutter I bought only a few weeks ago, I decided to try to scratch a line on the plain-glass side with the edge of a small file (using it more as a scribe than a file, that is, just scratching with the corner of the file). Then I used a couple of tiny scraps of wood to hold the glass, with an edge of the wood aligned with the scratch I'd made, and carefully snapped the glass at the line I'd made. Of course I wound up with an ugly, ragged edge, not at all like the neat line a competent glass-cutter would make. Then I found a little piece of rubber and held the glass with it while I ground down the ragged edge against the whetstone. I wound up with a less-ragged piece of mirror, roughly the right size, with little bits of the silver worn off on the edges. But it worked well enough.

I think I have an equivalent to your Lee filters. Somewhere, long ago, I bought a set of Kodak color-correction filters. I think they're made of some very thin optical-quality plastic, but I would have to dig them out to check. I've thought now and again about using one to darken the rangefinder, and you've convinced me that it might be worth a try.

I know what you mean about the importance of getting the mirror truly vertical... When I was working on the rangefinder of a Seagull folding medium-format camera I removed the mirror and a couple of little metal pieces tumbled out. Well, whichever way I put them back in, the mirror seemed just a little too far from being vertical to allow proper alignment. Eventually I just "kludged" it -- improvised an ugly solution that worked -- by shimming the mirror with a couple of additional thin scraps of metal, experimenting to see what number of them worked best. Eventually I got good vertical alignment as well as reasonable agreement between the rangefinder, the lens scale, and the true distance to objects, at least for objects neither too far nor too close. I'm still waiting for my test roll to come back, so I don't know how well I really did.

Every time I try to fix a rangefinder I swear I'll never do it again... for a while!

Best,

Michael
 
i have the replacement beam splitter glass for my canonet ready. i have a friend who can cut it for me. i have cement to glue it in. but i am unsure how to losen the cement on the foggy piece that's in there now. any suggestions?
 
Most of the few times I tried, I ended unintentionally breaking it.
 
I allways used a cutter knife and started to "colimate" the glue, in one case until the edges softened and in the other case until I lost my patience. :)

I assume the reason you want to carefully dismount your bad beamsplitter, instead of just breaking it right away, is that you want to hold it as a back up in case something in the further steps go wrong.

If this is your fear, I strongly recommend you to try the Lee filters. Several weeks after I started with them I am still admiring the wonderful results.

Oh, and I read you are trying to improve the patch of a Canonet. Perfect for the Lee, with three viable options of gradation in the case of a Canonet. "A la carte".

Cheers,
Ruiben
 
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