I have never actually sorted out the exact electrical and mechanical operations of these cameras. The fact that with no battery, we can get 1/500 sounds as though the electronic action pulls a mechanical catch in place to catch the shutter mechanism while it's open. then releases it after the set time; if that never happens, the shutter closes at the fastest speed which is marginally 1/500. Incidentally, since my earlier post I found something suggesting the shutter may draw 15 ma which I think is a pretty heavy load for those button cells. And I believe the AE finder has some LEDs and such? (more load)
Originally Posted by fotoobscura
What bothers me is that if it was purely a battery strength issue and the camera seemed to work at four seconds, I would expect an eight second exposure controlled as described to be OK for more than four seconds, then maybe fizzle at five or six, not drop to a 500th.
So, do you have another finder? If what you describe in the excerpt I quoted is the way I understand it, you're saying the shutter was OK without the prism finder in place? I thought I once heard that at least one model of those metered finders was a serious power hog -- or perhaps prone to develop that problem. Mayhaps it's less than 100% (or maybe the batteries are a bit weary -- or maybe both!)
I'm thinking I may have avoided a lot of difficulty by doing 98% of my shooting with the WLF!
Last edited by DWThomas; 02-10-2013 at 11:32 PM. Click to view previous post history.
The batteries do need to be measured under load.
Sometimes they will have enough poop(techie term) to give an exposure or two but then crap out when a heavier load is needed. 4S=OK 8S=NOT.
Sometimes with warmth and rest they'll sorta kinda temporarily recover, then relapse to the dead mode.
Discovered through the process of elimination...
Originally Posted by John Koehrer
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.
Ah, glad I may have been some help. I own 3 SQ-A bodies, one with an unhappy shutter release, and 50, 65, 80 and 110 1:1 macro PS lenses that I hope to be able to keep going with for a decade or two, but there isn't (that I've been able to find) much info around on what goes on inside the boxes. Someone pointed me to a service manual .pdf file for an ETRSi, which I downloaded, but it doesn't appear to cover anything but the body itself, which is only a portion of what's happening.
The combination of irregularities you describe doesn't quite make sense to me, weighed against what I 'think' I understand about the little buggers, but that may mean, Zeus forfend, that my understanding is incorrect -- not that that has ever happened before .... Hopefully APUG may become a 'knowledge base' for some of this stuff as time goes by and we decipher things.
I suspect that some "data parameters" might be communicated via analog current or voltage in these beasties, since the design is pretty old. There are only a few contacts connecting the back and viewfinder to the body, implying a serial communication, although I guess it could be some sort of crude digital as opposed to analog serial hookup. I'm thinking an analog method might rack up extra current drain at one extreme or the other for ISO and light measurement. As a long time tinkerer in many fields, both hobby and professional, I own an oscilloscope and a few other things that might permit some deeper investigation -- "one of these days."
I often tell myself "sometime in the winter, when it's too cold to be doing stuff outside, I'll dig into [insert object here]" but here it is February and I've got a million things going on. (Maybe I need to switch to "summer when it's too hot to ...")
Anyway, good luck with it.
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