Strange problem with Bronica SQ-A mirror lockup.

windchill · Mar 20, 2015

Hi all,

I'm testing my new Bronica SQ-A (it's not a camera that I'm familiar with, so forgive me if this is a stupid question).
I'm dry-firing by setting the multiple exposure lever. Nearly everything is working perfectly. If I take the back off I can see the shutter opening and closing. The wind is working and re-cocks the shutter. Basically it all seems to be in working order - except for one thing:
If i turn the mirror lock-up to s or to c the shutter will not fire - I have to move the mirror lockup lever back to 'n' and wind the crank again.... but here's the strange part: if i take the film back off the camera it all works perfectly, I can set the mirror lockup, the shutter fires, i turn the crank and the lever returns to the 'n' postion.
So that's my problem: when the film back is attached the shutter won't fire if mirror lockup is set to 's' or 'c'. The shutter does not seem to be cocked when this happens (i know this because I can't remove the lens).
Possibly the back is faulty - but there is no problem with firing the shutter unless I set mirror lockup. The shutter cocks and fires every time
I checked the back to make sure the pins weren't jammed and they seem to be ok - i can't remove the back if the dark slide is not inserted.
Any ideas? It seems very odd that mirror lockup is only faulty when the back is attached - and especially odd given that the back does not seem to effect normal shutter firing.

ParkerSmithPhoto · Mar 20, 2015

Chill,

This is a common problem on all Bronica SQs. I've owned three and they all had this problem. I've never been able to figure out why, but, truth be told, I haven't tried very hard.

For me it falls under Austin Idol's maxim: you might not like it, but you better learn to love it.

windchill · Mar 20, 2015

Thanks for getting back to me. So basically you're saying that my mirror lock up is broken and that if i buy another film back it won't get any better? Do you find that mirror lockup is unnecessary?

pschwart · Mar 20, 2015

see chapter 23 of the SQ-A manual

windchill · Mar 20, 2015

pschwart said:
see chapter 23 of the SQ-A manual

Maybe I'm missing something - but I've already been through that and it's not helping.

jimjm · Mar 20, 2015

Have you tried this with film loaded? There are a number of interlocks on these cameras, especially with a film back attached, so to thoroughly test functionality I would try it out with film first.
I believe if there is no film loaded, the MLU only functions correctly with the multiple exposure lever engaged.
Also make sure the battery is good. If in doubt, replace it.

My SQ-A also fires with the back removed, so this is not unusual. The back is locked to the camera when the dark slide is removed, to keep from accidentally exposing a frame.

When you moved the MLU lever to S or C, did you turn the crank again? Mine rotates about a half-turn, raising the mirror and then the shutter will fire (without the mult exp lever engaged).

With film loaded, the body should function as follows:
1. Lens attached, dark slide removed
2. Wind crank to next frame (if it isn't already)
3. Switch MLU lever to "S" (I've never used C). This should raise the mirror.
4. Shutter in lens should fire normally
5. Wind to next frame, MLU lever should return to "N", mirror should drop back down

I use the mirror lockup with this camera frequently, so it's definitely a must-have for me.
The moving mirror has a lot of mass, so I use it on a tripod with the mirror lockup for anything slower than 1/125.

windchill · Mar 20, 2015

You may have a point there.
What I just found out is that if I wind the crank, then set the mirror lockup, then disengage the multi-exposure lever, the shutter will now fire. I can then re-engage multi-exposure and repeat the cycle.
This suggests that it may work fine with film loaded.
It's different from a demo video that I watched online, where the whole MLU cycle worked fine with the multi-exposure lever engaged, but that was an SQ-Ai and maybe that model behaves slightly differently.

DWThomas · Mar 20, 2015

jimjm is on point; there is a set of interlocks that create surprisingly complex behavior for such simplistic mechanics. To do much of anything without film in the camera, you need to operate the multi-exposure lever if the back is installed. When you do that, the winding crank just operates the mirror and the shutter cocking. The shutter will not trip if the dark slide is in.

On an SQ or SQ-A, the shutter will fire at 1/500 without a battery, but it will fire. My understanding is the SQ-Ai needs a battery, period (though I'm not sure why, mayhaps there is a solenoid in the trip process).

Where the mirror lock-up behavior gets a little strange is when you set it, then change your mind. The chapter referred to above discusses how to get back to normal operation by either wasting a frame or doing some devious work-around. I seem to have generally avoided that problem with mine, though I do generally use MLU (and have film in it!)

hsandler · Mar 21, 2015

Windchill, it may be the lens, not the back or body. I have an intermittent similar issue, but it only happens with one lens. Sometimes the shutter sticks open, but only with both mlu and multiple engaged without film. Disengaging multiple, cranking and reengaging resets it. Its not a real problem because I never use multiple when there is film. There is a sticker indicating the lens was serviced in the 90s.

ParkerSmithPhoto · Mar 22, 2015

windchill said:
Thanks for getting back to me. So basically you're saying that my mirror lock up is broken and that if i buy another film back it won't get any better? Do you find that mirror lockup is unnecessary?

I have this problem with my SQ-B, with film in two different backs and with multiple lenses. It has also occurred on two previous SQ bodies that I've owned. I don't think a new back will cure the problem.

At one point with my old SQ-A (I think) the problem was only with my 150mm lens. Now, as I said, it seems to be all of them. It does sometimes work, but at risk of burning a frame if it doesn't.

It hasn't been a problem for the type of work I make, but lately I've been shooting more macro so I may finally have the incentive to track this down and fix it. Please let me know if you find any resolution.

windchill · Mar 23, 2015

Seems to work correctly with film

Well, there's a lesson learned - and worth noting for anyone else testing an SQ-A without film: the mirror lockup seems to work correctly now that I have film in the camera.

Thanks everyone for getting back to me.

DWThomas · Mar 23, 2015

Excellent! Enjoy it -- I like mine.

Your experience is a good argument for keeping a couple of old spools with backing paper wound on them for mechanical testing purposes. The reduced thickness might not work well for frame space checking, but it will work to check the basic advance and shoot stuff without jeopardizing a roll of usable film.

macfred · Mar 23, 2015

windchill said:
Well, there's a lesson learned - and worth noting for anyone else testing an SQ-A without film: the mirror lockup seems to work correctly now that I have film in the camera.

Same here with my Bronica ETRSi - it takes a time for me to understand

jeztastic · May 10, 2015

I have encountered a similar problem - only in my case the film was in the camera. I was using mlu on the S setting. The frame counter stuck at 6, but turning the crank just kept advancing the film. I ended up winding it all through and wasting 6 exposures. Another back worked fine. Faulty back?

wiltw · May 10, 2015

Normally it is NOT POSSIBLE to cock and release the shutter with NO film loaded!...there is an interlock between back and body which only operates to cock shutter (and allows shutter to be fired) after the film is advanced to next frame -- unless the Multiexposure lever is in the horizontal position (red dot visible)

The N, S, D control for mirror lockup operation: N=normal, S=single frame, D=continuous.

'S' flips reflex mirror up immediately as will the light baffle; the shutter can then be released as normal with shutter button or cable releease; the lever automatically returns to N position as the shutter is cocked for the next exposure.
'C' is continuous mirror lockup, which is somewhat similar to 'S' but the mirror returns to locked up as the wind crank is operated. After you are finished in 'C', move lever either to 'N' or 'S' before cocking the shutter, and this will resent the mirror into its usual viewing position as the wind crank is operated.

Strange problem with Bronica SQ-A mirror lockup.

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