Bronica S2: replacement of mirror and focus foam adjustement pads

Discussion in 'Medium Format' started by antoniobravo, May 31, 2020.

  1. so I bought a Bronica S2 that had no been used the last ten years. Being well aware from tons of comments on the net that it uses foam to position the mirror and the focusing screen, the first thing I did yesterday before going use it, was to check that. It's very easy, yet a couple screws were tricky to put back.
    The fix is explained at many places, and for the mirror the more detailed seems to be there:
    Bronica Z, D. S, C, S2, S2A, EC, EC-TL, and EC-TLll


    besides a couple good screwdriver, I used ethanol, cocktail sticks, swabs and paper for cleansing, a bit light cardboard and masking tape for prophylactic protection inside the body, glue to hold non-magnetized screws, a mobile phone screen suction cup, and self-adhesive 3mm open cell foam.

    as I take shots for my own archival, I think it may of interest to others. So, if you get an old S2, don't hesitate, it's easy. See:

    remove the viewfinder, and there are four screws holding a frame over the focusing screen. The two screws near the focal plane do also hold the bracket for the viewfinder. These four screws have same size, and are non-ferrous,as I couldn't hold them on the magnetized tip of the screwdriver, but it's no problem.

    IMG_1307_800.jpg


    under the bracket, a brass spacer and a tiny shim under:

    IMG_1308_800.jpg


    this is how the foam under the frame had turned over the years:

    IMG_1311_800.jpg

    IMG_1313_800.jpg

    IMG_1309_800.jpg



    I dipped the frame first into a dilution of soap, and rubbed away some of the stickery gum, but rinsed and dipped it for a while into ethanol

    IMG_1325_800.jpg

    removed the sticky gum by the edges on the top of the matte glass with a piece of cleaning paper with a bit of ethanol, and washed the matte side under tap water without touching it:

    IMG_1315_800.jpg

    the fresnel under the matte was clean.

    the edges on the body required some ethanol and gentle scrapping stick and swab;

    IMG_1322_800.jpg

    Put focusing matte, fresnel and retaining frame aside, and now the mirror.


    I position the body upside down at an angle, so the mirror is horizontal:

    IMG_1347_800.jpg


    put a piece of thick paper for protection on the mirror:

    IMG_1324_800.jpg

    four screws hold the mirror frame.
    The two upper ones are shorter and non-ferrous as I can't hold them with the magnetized screwdriver tip:

    IMG_1332_800_mod.jpg


    remove the mirror frame and then the mirror:

    IMG_1333_800.jpg

    IMG_1337_800.jpg

    so the mirror plate with the three foam pads:

    IMG_1339_800.jpg


    they left a mark on the back of the mirror:

    IMG_1338_800.jpg


    by just touching with the finger, the foam crumbles:


    IMG_1342_800.jpg


    I use light glue painter masking tape to protect the opening where we see the ribbon in the top middle and the gap between mirror plate and body, so to avoid foam rests get inside:

    IMG_1343_800.jpg

    IMG_1344_800.jpg


    I had to use to ethanol and rub gently with a screwdriver tip and a cocktail stick:

    IMG_1345_800.jpg


    cleansed:

    IMG_1349_800.jpg


    foam. I have some kit with different kind and size. Under the mirror I think 1mm could be enough. But open cell foam with be pressed well even if thicker (reasonably). I opted for a 3mm open cell foam with an adhesive side. Used it under the mirror and under the frame of the focusing screen:

    IMG_1371_800.jpg

    IMG_1372_800.jpg

    new foam pads:




    IMG_1353_800.jpg



    next step could be a bit tricky even if the foam is only 1mm. This new foam pushes the mirror up, and the lower edge of the mirror frame is rounded and catches under the mirror plate. So I start with the two lower screws, put loose only, they will keep the frame on place but allow for sliding the mirror into correct position:

    IMG_1356_800_mod.jpg


    the two lower screws are easy, longer and can be hold on magnetized tip of screwdriver.

    But I found the two upper ones finicky to manage, they screw under the mirror frane, not on the plate, but on a tiny support that rotates around an axe:

    IMG_1360_800_mod.jpg

    at the same time, the mirror under the frame must be slided down into the lower edge.
    The small rotating piece for the upper screws must be aligned and nor move when putting the screw back. Here I used a nail for positining:

    IMG_1363_800.jpg

    in fact when that small rotating part is correctly aligned under the mirror frame, by pressing the frame, there was a slight "click", so holding pressure on the frame with a finger, I could screw back. But the damn screw isn't hold magnetically on the screwdriver tip. Used a drop of liquid paper glue, which is very light but enough for the purpose, to hold these screws:

    IMG_1362_800.jpg

    Of course the mirror, which is pushed up by the new foam, must be correctly slided down, for the frame to set in place. But that's easy, I just used a small suction cup for mobilphone screens:


    IMG_1361_800.jpg

    mirror back in position:

    IMG_1365_800.jpg



    then the frame of the focusing screen with new (3mm) foam:

    IMG_1366_800.jpg



    that's it.
     
  2. instead of setting back the native Bronica ground glass with central focusing circle, I wanted to use an old Salyut-S glass with a small split screen, that i had around, It's an older kind not the newer that was used on Kiev-88.

    IMG_1368_800.jpg


    so I load a roll of Delta 100 and went for some shots, developed in D76, scanned with Epson V700 @3200dpi, and no fine hand tweaking in software for inversion, but instead quickly applied a set of PS procedures ("actions") from this guy:
    CNMY film inversion

    results on the hi-res tifs seem okay. But will keep testing a couple rolls, in color


    Nikkor 135mm:

    raw0002_800.jpg


    raw0003_800.jpg

    raw0006_800.jpg

    raw0009_800.jpg


    raw0010_800.jpg


    Nikkor 75mm:

    raw0012_1024.jpg
     
  3. Excellent work!

    I know that the mirror and screen foam is a problematic spot on all of these camera. I wish I'd taken the initiative to replace it on mine when I still had it, and after seeing your post I'd probably have my cameras apart this afternoon if I still had them!

    I wish I could like this more than once.
     
    antoniobravo and cameragary like this.
  4. Great job, antoniobravo!

    Many thanks for documenting these essential tasks so completely here in a p-net thread: similar info and pics are available elsewhere, but not in one place, not always in English language, and on sites vulnerable to disappearing. At least with p-net, someone who needs help with these common Bronica S2 repairs should be able to find this thread on their first Google search.

    FWIW, its recently come to my attention Frank Marshman aka Camera Wiz is still in business: other than Jimmy Koh who retired years ago, Frank is about the only tech in North America with legit experience and skills servicing the now-obscure Bronica S2 system. If you should encounter any serious problems requiring a deep dive S2 repair, consider contacting Frank via whatever current phone # turns up in a web search (located in Harrisonburg, VA). I gather he closed his shop a couple years ago and works from home now, a transition many top techs have made as they reach a certain age.

    Its ironic (actually terrifying) to realize the more popular vintage film cameras become, the more our resources to keep them operational are vanishing. So many of the good techs are already well past retirement age, a few of the best have passed away, and there is no new crop of eager apprentice techs to replace them. Not a problem for most popular 35mm gear, because millions and millions of those were made (Nikkormat, Spotmatic, SRT broke down? toss it and buy another for $40). Medium format is something else again: not nearly as many fully functional spares floating around, prices creeping ever higher, and their complicated mechanisms defy simple youTube repair tutorials (looks reasonable until you actually try DIY fixing the sluggish diaphragm in a Hasselblad Compur lens, or replace the foam pads hidden between the 500cm mirror and its plate, or the lens drive in an RB67, or the film advance in a Pentax 67, or...).
     
    antoniobravo and cameragary like this.
  5. I will point out that the mirror foam can be replaced by just removing the bottom 2 screws on the frame, the upper 2 screw are attached to a pivot, and the entire frame will hinge up allowing you to remove the mirror and replace the foam.
     
    antoniobravo and cameragary like this.
  6. thanks all.

    which I learned after I removed completely the mirror frame :) as illustrated in the middle of the post, these two small screws were a bit challenging to put back. Yet without removing the frame, it will stay inside the body, and the removal of the two upper pads there and cleaning may be tricky as I see it. I was wondering what procedure Bronica repairmen have there.
    When I will do it again (which will happen as soon I buy an extra body....) I think I 'll do the same way, removing the whole frame. But it will be much faster.

    and now that I am into this old camera, I bought online a reprint of the service manual:

    Bronica-S2-repair_manual.jpg


    ----

    as follow up regarding test of focus after the foam replacement AND the Salyut split screen, I went to shoot a roll of Lomography-100 yesterday evening. Developed in Fuji X-Press, scanned this morning.
    It seems ok.


    here with the Nikkor 105mm f3.5 leaf shutter,

    f3.5 , on the church/infinity:

    raw0002_1024.jpg


    f3.5 on the foreground tombstone:

    raw0003_1024.jpg

    f3.5 :

    raw0009_1024.jpg


    f11:

    raw0012_1024.jpg
     
    cameragary and orsetto like this.
  7. Nice to see your test shots! When you get around to using the Nikkor 50mm f/2.8, hope you'll update this thread with a few pics from it. I had the older slower f/3.5 and didn't love it, could never find the superior 2.8 for less than $450, so would be very interested what you think of the faster 50.

    Glad you seem to have got the focus accuracy dialed it without excessive effort. When I did this for my S2A and backup Bronica C body, getting the focus calibrated to new screens was slow tedious torture. Shortly after that, both cameras developed sluggish auto-stopdown issues, and I soured on the whole system. Its lotsa fun when it works, but I didn't want to lay out serious coin for overhauls (the lenses are good, but not enough to drop hundreds of dollars on body repairs).The skeletal lens heads also got on my nerves after awhile: they're clumsy if you change lenses often. Sharing a single body-mounted helical was a great cost saving idea back in the '60s-'70s when a starving photographer could buy a new Bronica wide or portrait lens head for under half what Hasselblad was asking for traditional lenses, but today dealing with exposed guts and fussy rare "dixie cup" rear caps is a PITA.

    I still have a sentimental attachment to the S2 system, but realistically never used it after picking up a Mamiya TLR kit and a Hasselblad setup. Occasionally I'm tempted by the fabulous, years ahead of its time final Bronica EC/TL variant, but then I see the thread posts on whats required to keep those going and consider switching from photography to cave drawings.:rolleyes:
     
    antoniobravo and peter_fowler like this.
  8. Gee, quite a bit of work. Have Bronica never heard of black fibreboard? It's only holding the screen down for goodness sake.

    For future reference: I think you'll find that black foam goo responds better to cleaning with White Spirit (decorator's turpentine substitute) than with ethanol. White spirit is probably safer to use on more plastics than ethanol too.

    Also, a tiny blob of Blu-tack on the tip of a screwdriver is an easy way to temporarily hold non-magnetic screws in place.
     
  9. That's my experience too. Something completely non-polar is usually the ticket for getting foam and the glue holding it in place off.

    In the US, that takes a lot of forms. Ronsonal Lighter fluid is a favorite of camera repairers, but stuff like VM&P Naptha is in the same category. Even good quality white kerosene will do in a pinch, although I'd want to follow up with something more volatile if using that.

    I wish we had more information about what types of plastics were used for specific applications. In general, I agree that alcohols(and especially ketones) are best avoided around clear plastics, which can craze badly even with the smallest amount. There are some plastics that will vanish in the blink of an eye with non-polar solvents, though.
     
  10. Common solvents don't always work the way one expects. Awhile back when I thought I might replace the peeling leather on a beater Mamiya C330 that I wanted to sell (bought only to get the attached lens), many web posts recommended methylated spirits (denatured fuel alcohol). To my surprise, this proved more adept at removing the fingerprints from the tips of my fingers than loosening the old leather adhesive: plain ordinary 91% isopropyl from the drugstore was way more effective. Same deal with naptha (Ronsonol): sometimes its a wonder fluid, sometimes it doesn't do squat. More often than not, I end up using the 91% isopropyl: thats what finally cleared the tarry gunk out of my Bronica S2A screen fittings.

    Next challenge will be to pry the front plate off my Mamiya Press Universal to clear some fungus trails off the protective viewfinder glass. From what I've read, the (easily bent out of shape) plate is held on with a combination of shellac and loctite that has to be slowly loosed over time with repeated drops of solvent. Don't know what I'll use for that: I'm worried about anything dripping or splashing on the plastic RF windows.
     
  11. It was great following along with your procedure. I'm sure this will help another tinkerer in the future. My son and I both have an S2 so I will keep this thread in mind when the time comes to do this procedure on them. Thanks, and great work!
     
    antoniobravo and cameragary like this.
  12. actually i had a can of old ( i mean old) liquid electrical tape that had dried up mostly .what remained in the can was quite sticky but clean.it left no trails.after it took me 2 days to find one of the mirror frame screws i tried dabbing the head of the screw driver in it put the screw on it and it held very good,i could actually move it around the frame without falling off.that was the toughest part of the whole job.i used an olsen screen and everything appears to be in focus.it was a tough job for me but i would tackle it again if needed.( hopefully this will be the only time before i pass on ).
    gary
     
    antoniobravo and Bill C like this.
  13. A couple of old tricks from the watchmaker's bench that can help you with this sort of stuff.

    First of all, you need a GOOD pair of tweezers for handling screws. If in doubt, you can't go wrong with Dumont brand tweezers. I like the #2 pattern, but this is also somewhat dependent on the size of your hands and on the intended use. For me, a #2 is an ideal size, but I also keep a #3C(fine tipped), #5(extremely fine tip) and #7(curved tip) close at hand where needed, and have smaller and larger ones nearby. You have a dizzying choice of alloys-I like old fashioned carbon steel for its strength and how well it holds a tip, but it can be a constant fight to keep it from getting magnetized(which can be a pesky issue). Dumoxel is a good all-purpose mostly non-magnetic alloy that holds its tip reasonably well, and is cost effective. I avoid the more exotic alloys-all of mine are either carbon steel or dumoxel.

    Once you have tweezers, practice, practice, and practice some more with picking up small screws. Initially, many people will grab too hard and send small parts flying. It takes a very light touch. With practice, a good pair of tweezers will become like an extension to your hands, and you can pick up and place small parts anywhere. Once you can do that, this stuff gets a lot easier.

    Sometimes, though, screws can be resistant to getting into place or putting them in place with tweezers. Your screwdrivers need to fit properly, and this is a good general rule. Proper watchmaker's screwdrivers(whether Bergeon, Horotec, or others) have replaceable tips. They are sharpened regularly, and are also sharpened to correctly fit specific screw heads. A proper fitting driver will "hold" a screw reasonably well. If you need to stick it to the driver, though, a drop of oil or grease on the screw head can give you just enough to get it there.
     
  14. I loaded a roll of Ektar and used it this evening. By now we are in the very long days and the weather has been incredibly sunny. Evening sun from 60°N and up has very strong luminance and some glittering. I put a collapsible rubber lens hood:

    gummi_blender_67mm_640.jpg



    developed in the kitchen as usual, in Fuji X-press, scanned with Epson V700 @3200, batch converted in software the whole roll without paying much attention to detail. Colours are sometimes wonky, need attention, but that was not the goal.



    TIFF files are in the ~270mb/frame, here 1024x jpg, so strongly degraded, from unsharpened scans.


    I took first a couple shots home, on tripod.

    f8 1s: the Nikkor-50 was some 25/30cms from the Kiev-6s:

    raw0003-positive_1024.jpg


    100% crop of the tiff, converted to jpg. I don't know how sharp that lens can be, so unsure if it's the best. Also sometimes I focus better on ground glass, but there it was on small split circle.

    raw0003-positive_del.tif.jpg



    f5.6 1s :

    raw0004-positive_1024.jpg

    f11 1/60


    raw0006-positive_1024.jpg


    f2.8 1/500:

    raw0010-positive_1024.jpg


    trying to find the spiders with 100% crop:

    raw0010-positive_del.tif.jpg

    f2.8 1/250:

    raw0011-positive_1024.jpg


    f8 1/125:

    raw0012-positive_1024.jpg
     
    peter_fowler, orsetto and cameragary like this.
  15. Very nice: thanks for that! :) I never expected you to do it all so quickly.

    I can already tell even from these web examples that the rep of the 50mm f/2.8 Nikkor being significantly better than the older f/3.5 is warranted. Don't get me wrong, the old f/3.5 is certainly OK (esp if your expectations stay within what was typical for budget 6x6 SLR wides at the time). But your f/2.8 examples have a whole different look: much less veiling, much more "3D pop" (not far off from the comparable-era Hasselblad 50mm f/4 Distagon actually). The older slower 50mm f/3.5 Nikkor tends toward a blah, sort of non-descript rendering (more documentary, less cinematic).

    Too bad the 50mm f/2.8 (and its sister 40mm Nikkor) are scarce and quasi-collectible: if they were available at a price more suited to what the body sells for, the S2 system could be a lot more entertaining. As it stands, spending hundreds of dollars for a lens limited to only an archaic camera is impractical for most of us: above a certain dollar amount, alternatives from Mamiya or modern Bronica make for better daily drivers. You were very fortunate to hit on this sweet package deal: they don't come up very often anymore (I think the last I saw was when I sold my own four lens S2A kit at a loss five years ago).

    Since you acquired basically an entire S2 system in one gulp, all you need now is a back up Bronica C body to go with it and complete your vintage Zenza experience. The C was an S2 with fixed, non-removable film back: the lack of back seams makes it look like a prop from the old Lost In Space tv series. The C weighs less than an S2, but this throws the handling off a bit: without all the interchange hardware in the rear, the C ends up being rather nose-heavy. They don't turn up often but are pretty cheap when they do, worth keeping an eye out for one. This was mine, bottom pic shows the Ukranian Arax Arsenal screen upgrade I installed (laboriously):

    Bronica C 75mm Kit 02a.jpg Bronica C 75mm Kit 07a.jpg
     
    antoniobravo and cameragary like this.

Share This Page