Large Format Electronic Shutter Arduino Project

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210mm f5.6 Schneider Symmar, Electronic Shutter *10804672 – MrCad Online Store

www.mrcad.co.uk www.mrcad.co.uk

I was thinking with todays arduino technology I was thinking it might be possible to open this up, attach an arduino to the correct bits and have near millisecond perfect shutter speeds. It would not be pretty and no scaleability but perhaps a fun project involving electronics and cameras and the scurge of in accurate mechanical shutter speeds faster than 1/100

210mm f5.6 Schneider Symmar, Electronic Shutter *10804672 – MrCad Online Store

www.mrcad.co.uk www.mrcad.co.uk
 
I haven't checked or looked it up, but I have a recollection that that shutter has a reputation for not being terribly reliable. It might to worthwhile to see if my memory is correct, and if so, what the weaknesses were.
 
acrobatic_Citron said:
scurge of in accurate mechanical shutter speeds faster than 1/100
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Are they? the ones I've tested always seem to be pretty close. You might be better of making a shutter timer and seeing if there really is a problem. What would be handy though is a focal plane shutter
 
As far as mechanical shutters go, back in the 1960s Amateur Photographer published the actual tested speeds in their camera tests. Apart from the 1/1000 (which could be out by 10%) speeds were pretty good. New cameras of course...

Greater variation can actually occur due to shutter efficiency, which isn't actually caused by the shutter per se. A 1/500th on a leaf shutter can be only about 1/300th depending on the aperture used. The smaller the aperture, the more exposure it gives relative to what you'd expect.
 
Having measured them with my aruduino laser thing bob most are 1/3 out at 1/125 and most 2/3 to a full stop out on 250 and 400.

Hmmm youve made an interesting point about apeture size, for fun I think ill restest with a stop down lens

Would you worry too much about a 1/3 stop under? I know over exposure is fine but I would want to miss any detail Ive metered for, I can always open up a third but thats one more thing to worry about/go wrong
 
I'm a black and white photographer, so this is written without implying it applies to colour. The first film speeds set by Kodak were done on the basis of making umpteen negatives of the same subject at different exposures, then making the best possible print from each negative. The prints were then compared, and the film speed determined from the print with the least exposure that wasn't inferior to the next in the sequence. Putting it another way, there were exposures above the minimum that still gave the same print.

Fast forward to about 1962. Up to that point, film speeds had a safety factor built in to prevent weekend or holiday only snapshotters from underexposure. The factor was removed, and film speeds doubled (literally) overnight.

Hence I'm personally relaxed about exposure. Overexposure increases grain and reduces sharpness, but only 35mm film has much of a problem with this. I'd say that most of my negatives are at least one stop overexposed judging by how texts say they should look, but they suit me.

Ansel Adams used to calibrate his large format lenses because of inaccuracies in the aperture markings. Some Zeiss lenses automatically open up the aperture as you focus closer to compensate for the required increase in exposure, well before anyone would think "macro" (I have a 135mm Sonnar that does this).

Where do you draw the line?
 
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Less worrying more shooting! Got It! Its all large format for me now, sold my 35mm and med format film gear, I've only the time and mental capacity for 1 digital camera and 1 film camera, and the digital (fuji xf) covers medium and 35mm. Also black and white mainly but will dabble in colour/slide once im happy I wont waste too many sheets.

The large covers film but also is a completely different shooting experience that 35 and 120 dont really differ from digital
 
Just to burst your happy bubble... When you start to look a little more closely at arcane things like characteristic curves, the subject brightness range that darkroom printing papers can hold and gamma, then it is possible that severe overexposure can create problems, and the actual minimum exposure will best fit the printing paper which is the bottleneck in the whole process as far as tonal range goes. These problems are largely non existent if you scan and print digitally (I do), and indeed even conventionally in my limited experience you have to go a long way over before you really have a problem with most subjects.

I have a set of negatives (5x4) made at Housesteads on Hadrian's Wall. Having left my light meter in the car in the car park, I worked without it, with no apparent difference in the end result. Don't get hung up on correct exposure, if only because there's no such thing. Exposure is a creative decision based on the effect you want to achieve. If we're being brutal about this, a scanner can recover more than you'd think. Some day I'll post a photo of a clear piece of film (it looks clear to the naked eye) which I scanned and recovered an image. I had two "blank" sheets of film, as I thought, but then noticed a very faint image on one if the sheet were held in a certain way. Both had images. Poor, after scanning - very few tones, muddy, But the subject was clear enough. You can get away with a lot, and you'll get away with more images if you don't miss taking them by worrying about the exact setting.
 
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acrobatic_Citron said:
Having measured them with my aruduino laser thing bob most are 1/3 out at 1/125 and most 2/3 to a full stop out on 250 and 400.

Hmmm youve made an interesting point about apeture size, for fun I think ill restest with a stop down lens

Would you worry too much about a 1/3 stop under? I know over exposure is fine but I would want to miss any detail Ive metered for, I can always open up a third but thats one more thing to worry about/go wrongp are
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Unless you’re planning to make all your exposures under laboratory conditions, concerns over 1/3 of a stop are in real life terms, irrelevant .

There are so many other variables where you can gain or lose 1/3 of a stop or indeed, considerably more .


Even then , putting slide film aside, negative film be it colour or monochrome can easily absorb such differences in their latitudes.

As for the 1/250 and 400 speeds, how often do you actually use those speeds with LF?

It’s very rare that I use speeds in excess of 1/60, more typically 1/15 or slower .


Tbh , depending on subject matter, if you’re going to spend time making finicky adjustments to compensate for 1/3 stops , it’s highly probable that you’ll end up missing the planned shot as the subject moves and /or light changes..

It’s not for anyone to tell you how accurate to meter, our words are simply opinions based on experiences ……perhaps worth taking on board, perhaps not.
That is of course you’re personal choice ;)
 
Oh Ill definitely take on board Asha, coming from a science background I get too invested and enjoy the precision and techincal aspects of the hobby too much sometimes and in fact forget to go out and take photos!
 
I have a degree in chemistry. At school, the chemistry teacher always stressed the need for precision, and had a memorable phrase to cover less exact people as "bucket chemists". Switching from science fact to science fiction, Scotty on "Star Trek" once remarked that having literally written the manual on the engines, he knew exactly what safety factors were built in, and how far he could push the engines beyond what they were "safe" to do before it really became unsafe.

I tend to treat photography the same way. I know how big an error you need to make before things actually do irrecoverably fail, and so long as I work within that margin I don't worry. The ONLY thing I obsess about is one that most people here treat in a more cavalier fashion - processing temperatures and keeping everything within a half degree Fahrenheit of the magic 68 degrees. And measuring out the small volume of Rodinal accurately!
 
And you'll be amused to know that I use a small (10cc) measuring cylinder!
 
StephenM said:
Scotty on "Star Trek" once remarked that having literally written the manual on the engines, he knew exactly what safety factors were built in, and how far he could push the engines beyond what they were "safe" to do before it really became unsafe.
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Only a dedicated Trekkie would know that !

I did wonder about your ´darker’ side :exit::LOL::LOL::LOL::LOL:
 
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