using extension tubes on bronica s2a

[cameragary]

recently picked up a bronica s2a with extension tube set . i have not taken any pics with this camera as i am new to mf .i have shot 35mm exclusively and have done macro work in my garden. i have always wanted to try 120 film so i took a chance on this camera.

now my question , with ext CA tube nounted with 75mm 2.8 lens can i get some guidance on how many stops i need to open up the lens.i was thinking i could use my canon A1 with my 50mm 1.4 with a 2x teleconverter plus my fd25 extension tube to get my aperature to 2.8 just like the 75mm with the ca tube.meter with my canon set up and use the meter reading for the bronica. sound doable? . i do not have a hand held meter just yet . all the camera's i've had all had light meters in them.the couple of folding camera's i have i just use sunny 16 rule of thumb for expsure.i really want to get a good understanding of how to use them with the bronica.

hope you can help

thanks for listening - gary

[AJG]

Your idea might get you close to what you need, but you should be aware that the magnification for filling the frame with 35 mm is going to be less than what it will be with your Bronica. The easiest formula that I know is M+1 squared, with M being the magnification on the film. If you put a ruler in front of your subject and then measure how big that image is on your ground glass you should be able to figure this out. So take a meter reading the way you usually would with your Canon and then change exposure according to what the magnification is and you should be fine.

[cameragary]

Thanks for getting back to me.

is there a chart of sorts that gives magnification rates of each tube?.

As far as measuring the image,you do need to remove the wlf . Correct.let's day said flower has a real size of 3 inches ,you would measure the size of the flower in viewfinder let's say 1 inch ,you would add 3+1 to come up with a factor of 4 stops ?.sound a little correct?

[orsetto]

The official Bronica exposure chart can be found on page 34 of the S2A instruction manual, available at this link:

 

https://trondbaashus.no/filer/bronica/S2A_Manual.pdf

 

I owned an S2A outfit for some years before switching to Hasselblad: lovely, quirky, fun camera, but not perfect for every situation. As you've probably already discovered, the S2 series is the LOUDEST camera ever to grace this earth: the shock and awe will clear the vicinity of any living creature that can hear it. That can be an issue with some small wildlife, birds, etc. You also may encounter vibration issues due to the complex, clanking mirror and viewfinder roller blind: if possible, try to damp the vibration by grasping the front of the camera or the extension tubes with your hand. Unfortunately the mirror cannot be locked up (actually down) in the S2 cameras, because of its coupling with the roller blind.

 

Also very important to note: the S2 cameras have significant problem of viewfinder focus accuracy drifting with age. While overall a very cleverly designed, advanced camera for its era, the method employed to mount the S2 focus screen was atrociously misconceived: so failure prone, Nikon eventually backed out of supplying lenses from fear blurry pics caused by the poor focus screen mechanics would taint the reputation of Nikkor lenses.

 

The focus screen "floats" between a leaf spring frame at the bottom and a foam frame at the top. Like all camera foam, it rots to a gluey mess after a few years, which throws focus accuracy out just enough to kill true sharpness. You can check your S2A by focusing thru the finder at a very distant infinity subject. Don't simply turn the lens to its infinity stop: focus by eye, and if the lens is not then naturally at the hard stop, your focus screen may have drifted. Shoot a test roll at various distances before your first important project: if results are consistently unsharp, your screen may need repair. It is possible to DIY repair, you just need to replace the rotted foam framing with something more durable like strips of moleskin. The difficult step is disassembly: the screws holding the screen frame are fragile and often slightly rusted: great care must be taken. I did this with mine, but it was a white-knuckle experience.

 

A schematic showing the screen assembly can be found here:

 

Dépoli Bronica S2

 

A photo illustrated screen replacement/focus accuracy tutorial can be found here (scroll down about a third of the way to reply #11 by contributor "Skorj":

 

Review - My First SLR - Zenza Bronica S2A.

Edited October 28, 2019 by orsetto

[cameragary]

Thank you for the info.I have not yet check screen focusing problem yet.l will probably just dive into it.great info on the links you provided.thanks.

I want to really understand these camera's, the noise associated with the shutter won't be a problem as I want to shoot landscape,car shows, and natural light macro photo's.eventually ill try with a flash for inside work.that's down the road tho.

Again thanks for the info.just have to shoot some pics to see where we'll be

Gary

[orsetto]

If you discover you need to replace the focus screen foam, send me a private message and I'll forward you an excellent set of instructions and tips that are unfortunately no longer easily available due to the website they were posted to disappearing several years ago. They were compiled by Bronica enthusiast Sam Sherman back in 1999, when the S2A was more expensive and in wider use than it is today.

[AJG]

Thanks for getting back to me.

is there a chart of sorts that gives magnification rates of each tube?.

As far as measuring the image,you do need to remove the wlf . Correct.let's day said flower has a real size of 3 inches ,you would measure the size of the flower in viewfinder let's say 1 inch ,you would add 3+1 to come up with a factor of 4 stops ?.sound a little correct?

I'm not aware of a chart for the Bronica (which I've never used) but to use your example, a 3 inch flower that is 1 inch in size on your groundless is .33 magnification. 1.33 squared is roughly 1.77, or slightly less than 1 stop additional exposure.

[cameragary]

Thanks for getting back to me.I will

Use the formula you provided and maybe bracket my shots to check.

Thanks again - gary

[orsetto]

Received your PM, I'll send you the Sam Sherman focus screen document shortly. Your other questions I'll answer here, just in case any other Bronica S2A newbies might need it:

 

The camera shutter won't fire without film loaded in the magazine, so the only way to check the shutter speeds for accuracy is get the back off somehow (once the back is removed the interlock opens and you can fire the camera normally).

 

The only way to get the back off is to insert the dark slide, then press hard against the edge of the dark slide handle hinge (push the DS further into the camera against spring pressure) until the back releases and tips downward from the top. The dark slide must be a genuine Bronica: knockoffs don't always have exactly the right shape to release the latch.

 

The stuck aperture blades are a complete PITA with S2A lenses. I had that develop on two of my Nikkors for Bronica and its really hard to DIY diagnose or fix. Eventually I gave up and replaced the lenses (paying for pro repair would have cost more than to sell the bad lenses and buy replacements).

 

Usually with this system it isn't actually the blades that stick (unless you can literally see grease or something on them). When the aperture drags, almost always its due to a sluggish actuating arm in either the body, the focus helicoid or the lens barrel. Determining which is the culprit would require having another lens or two to check with: if they have normal quick stop down/reopen the issue is localized to your 75mm lens. If they're all sluggish, its probably the camera body or helicoid.

 

You could try removing the helicoid for inspection (press the little silver button on the camera front, and twist the focus ring barrel until it comes off). Clean around the aperture arm area of the helicoid (a tab rides along the rear brass inner barrel of the focus ring, connecting camera to lens), and exercise it with your finger for as many times as you can. Keep exercising it and eventually it will function better, at least for awhile. If cleaning and exercise don't get the blades to move snappy, a workaround is to press the DOF button to manually stop down the lens just before you fire the shutter. This two-step is annoying but gets the job done. You can try replacing the focus helicoid with another one, this almost always solves sluggish aperture issues (since its the middleman between body and lens mechanisms). Helicoids turn up on eBay by themselves occasionally, or attached to a 75mm Nikkor lens.

 

If its the camera body at fault, forget any thought of repair: sell it immediately and cut your losses. At this point pretty much nobody is left who wants to touch the focal plane Bronnies. They are the most convoluted medium format SLR ever designed: repairs and parts are beyond most technicians. The last S2 specialist was Jimmy Koh, who like many niche camera techs has retired and no longer accepts new clients. The old S2A, EC, etc Bronicas were abandoned almost overnight once Bronica introduced the much simpler, more flash-friendly, smaller, lighter, electronic ETR system in 1976. Occasional-use amateurs bought most of the surviving S2As, and most of them either didn't need or refused to pay for repair services. So the skill set and parts dried up: the ETR and SQ were wildly more popular than the S2A ever was. To be fair, nobody really services those anymore either, the advantage of their popularity is you can just replace instead of repair.

 

The Bronica S2, S2A and C are mechanical marvels of engineering, their Nikkor lenses the biggest price/performance bargain in medium format, but they are also ancient and sometimes trouble-prone in ways not easily DIY fixed. If found at a very affordable price in perfect working condition, they are still great cameras/lenses. Unfortunately the value evaporates if problems develop: this is not a system worth investing serious money to repair or swap parts. Like the Kowa Six system, when focal-plane Bronicas break down it is best to just keep them (or sell them) as display pieces.

[tom_chow]

<snip>

 

The focus screen "floats" between a leaf spring frame at the bottom and a foam frame at the top. Like all camera foam, it rots to a gluey mess after a few years, which throws focus accuracy out just enough to kill true sharpness.

 

<snip>

This is not quite correct, and can be misleading. The ground glass sits on a hard stop (2 plates with shims to adjust correct focus), and is held there by the foam pads. The metal springs on the bottom push the Fresnel plate up against the bottom of the ground glass. The hard stop is stable, but in the 60 years since they were made, people may have removed the shims trying to figure out the focus screen. Even with the foam in bad shape it usually holds the ground glass correctly on the hard stops - but when the foam is gone, then the springs pushing the Fresnel plate up can lift the ground glass, throwing off focus.

 

However, I usually find the focus is off because of deteriorated foam in the mirror cage, and due to many internet comments about the focus screen foam, people try that, cannot make it work, remove the shims, etc... and now you have something that is not easily fixed. And never look at the mirror

 

The camera was designed to be periodically service, and the foam replaced every ~10 years (All Hasselblad film backs were designed to have the dark slide foam replaced yearly). It was designed to be field replaceable - the screen foam (as many people have found) is easily replaced, likewise the mirror foam - the mirror cage is designed to be hinged open by removing 2 easily accessed screws.

 

Check the mirror first. Then the screen.

[cameragary]

Wow a lot of info here.thanks a lot!!!

I have to keep this short right now so here we go.

It is an aftermarket slide I bought.I only had a minute to check in the camera so tomorrow I will have more time.it measures exactly to the specs I got from other posts.will let you know.

The lens itself is stiff when operating the aperture pin and I can see oil or some crud on the blades.the camera depth of field function is clean and smooth.the helicoid is clean and smooth.with lens mounted and preview button pushed I only get to about f11.and it does not come back open.I paid next to nothing for the camera so ill look for another lens for it.ill try opening up the stiff one and see what happens it may become a shelf queen but ill sure try to get her working first.

Ill keep you informed and again thanks for all the info

Gary

[orsetto]

Thanks to tom_chow for the correction: its been some years since I replaced the stock screen in my Bronica C and S2A with brighter Arax/Kiev split image screens. I forgot the ledges, remembering only the spring holding the fresnel plate underneath to press upward, with the groundglass pressed down via the foam (tom_chow's description is illustrated in the links I posted earlier). I'm surprised I forgot all about the ledges, as they cause no end of grief if you want to use anything but the stock groundglass screen (I had a heckuva time getting the Ukrainian screens installed).

 

The ledges are solid, but when the foam above rots it contracts into a sticky tar and shrinks, which pulls the screen up off the ledge rails enough to cause focus problems. Removing the top metal frame, cleaning off the tar, and replacing with felt strips or moleskin will usually fix the problem permanently. The screen foam issue is subtle: if you only shoot landscapes at infinity in bright light at smaller apertures, it could go unnoticed for years. If the lens is set to its hard infinity stop for an infinity subject, you will never experience an issue. But if you shoot in lower light at moderate distances at wider apertures, you can end up with slightly softer images than the camera is capable of. I only noticed after I got a Hasselblad and used both for a portrait project. The 'blad images were clearly in better focus, when I cross-referenced the focus rings my S2A was off. After repairing the gluey foam, my 150mm f/3.5 Zenzanon gave the 150mm f/4 Sonnar a run for its money.

 

I've seen the mirror issue discussed in S2 threads in other forums, but didn't experience it with my own Bronica C or either of my S2As (while ironically I did have that mirror pad problem with my Hasselblad, which is decidedly not DIY-friendly). There is a photo-illustrated forum thread on the Bronica mirror pads here, referencing Rick Oleson:

 

Bronica Z, D. S, C, S2, S2A, EC, EC-TL, and EC-TLll

 

Other lesser-known causes of unsharpness to check:

 

A surprising number of Bronicas came direct from the factory with redundant shims between the ledges and screen: taking these out can correct some stubbornly unsharp bodies (try this before fooling with the mirror). Also, some versions of the film magazine loading insert are fussy. The insert can appear to be installed properly and advance the film correctly while it is in fact not quite planar-aligned with the magazine film aperture. The cure is to pay close attention when loading, to be sure the insert is fully seated properly. (This was covered in the old Sam Sherman usenet thread I PM'd to cameragary this morning.)

Edited October 30, 2019 by orsetto

[peter_fowler]

"Orsettos" remarks earlier about the repairs causing some of the earlier mechanical wonders becoming shelf queens might be illustrated

in this photo . This is a Kowa Super 66 that was advertised as jammed . Quite the understatement ! This is the classic cause of shelf queening

a Kowa . The arrow points to the single tooth responsible for engaging the gear which winds the film on , and cocks the shutter in the lens .( Being

recently retired and in search of a project ) I removed a carbide tooth from a circular wood saw blade and ground it to size and brazed it in place . That

was some delicate welding torch work ! There were many other problems with this camera too ,a more time consuming repair would be hard to imagine .

The second one ( either a bear for punishment or a room temperature IQ ?) took 1/2 the time of the first and it still took 60 hours ! Approach some

projects with caution :) , Peter

[orsetto]

I removed a carbide tooth from a circular wood saw blade and ground it to size and brazed it in place .

 

I'm in awe of guys like you and andyfalsetta. :)

 

Incredible perseverance, inspired improvisation, astonishing resurrections.

[cameragary]

just an update.i recieved my aftermarket dark slide yesterday.i only had a minute to put in the back yesterday and it did not come off the camera.now today after watching a couple of tutorials on the camera i took it out and re-installed in the back.after giving it that last little push lo-and behold the back popped off with nary a problem.so i was finally able to fire the camera with the back off.all shutters seem accurate.and brother you guys aren't kidding this old girl is LOUD.good thing i am not a nature or portrait photographer.i took off and re-installed the back a couple of times to check and everything seems o.k.now i just have to get the lens either cleaned or get another one.i contacted the camera wiz in va. and am waiting on a response to cleaning the lens.that roll of film i have in my cabinet is calling me to put it the camera also.

this journey is certainly moving foward

keep you posted

gary

again all your help and info is greatly appreciated

[peter_fowler]

^^ Thanks "Orsetto" , after a life in motorcycle mechanics , it's nice to play with something that weighs less than I do :) . Peter Edited October 30, 2019 by peter_fowler

[peter_fowler]

Great news "Gary" , one of my favorite photos was taken with an S2 I had ( and it was taken by someone else ! )

You should have seen the look on her face when she pulled the shutter button ! Peter

[cameragary]

funny you mention that.i was sitting on my couch with the camera , wound up the next frame and pushed the release button,my cat who was sleeping flinched and stood up.NO LIE.this camera is loud,very loud but i love it.reminds me of my 1970 plymouth road runner in the day.loud very loud but i loved every minute of it.

gary

[orsetto]

BTW, cameragary, in case you were wondering: the ghastly rough herky-jerky feel of the S2A winding crank is normal. It is a long rough wind because the mechanism is more complicated than other 6x6 SLRs, and theres a distinctive "notch" toward the end of the turn where you have to crank just past some heavy resistance to complete the cycle. That last jerky notch resets the roller blind that covers the focus screen once the mirror drops during exposure.

[cameragary]

from watching some videos and reading posts on this site i was aware of it.but if you never felt it before it is quite alarming to feel.that last clunk has to make you wonder of sorts.but i am really digging this camera.it is all new to me and i hope to have a blast with it.if its not my cup of tea i'll sell it off and stick with my other family, my canon fd family.

one other thing about these camera's , when looking thru the wlf you get a sense of taking a step backward , by that i mean there is nothing in the finder just a layout of your picture ,no electronics,needles ,led's nothing but an un-obstructed view of what your going to take a picture of.makes one think of how to take a picture if you know what i mean.

thanks -- gary