How to adjust rangefinder slow shutter speeds?

[andrew_b7]

<p>Hi, I have been testing shutter speeds (photo transister hooked up to mic/sound package) and have noticed a trend across a few cameras (Canonets, Hi_Matics). Most are pretty spot on at 1/500, 1/250... but begin to slow progressively at about 1/60, but not enough to worry about I don't think (not a whole stop off).<br>

But at 1/2 and 1 second they are quite a way off. Konica Auto S2 reading 1.34 at 1 second, and a Hi-Matic 9 reading 1.48 at 1 second. I understand this method might not be 100% accurate but believe it does give a good indication. I like to do some long exposures at night so often use 1 second at f1.8<br>

I understand that how a camera has been stored over time, if it was stored cocked, hasn't been used for a while etc. will have an effect on speeds. I read that if a shutter hasn't been fired for a long period repeatedly reworking it might do the trick but that hasn't worked thus far. <br>

I just wondered if anyone knows a fix for this? Will a lube do the trick if so where to lube and what with? Or is it more complex than that? <br>

Many thanks!<br>

PS. Original Canonet I have was spot on at every speed. </p>

[donnie_strickland]

<p>I understand what you mean, but I think you might be looking for a problem where none exists.<br>

1.34 seconds at a setting of 1 second, is only off by a third of a stop, which is perfectly reasonable, and within specification for almost any leaf shutter. Even 1.48 isn't bad; it would never show up on print film and would hardly be noticeable on slide film.</p>

<p>Exercising a shutter can often bring it back to its nominal capacity, but if mine are as close as you're describing, I have learned through experience to leave them alone.</p>

[subbarayan_prasanna]

<p>In olden times, when clock work was not incorporated in the cameras, we used to count the elephants! Set the shutter dial on B and count "One elephant one"; at the first "One" you open the shutter and at the second "one" you close it. It is advisable to check the elephant pronunciation with your watch to make sure that your rhythm is correct to the second. Of course, those years used slow speed films in B&W that had a lot of tolerance to exposure errors. I know some who still follow this method for slow speeds. sp.</p>

[leighb]

<p>Most such problems are caused by lubricant that's dried out or gummed up or collected dirt.</p>

<p>I would not suggest trying to correct the situation unless you have an ultrasonic cleaner and the proper lubricants, and knowledge of how to use same.</p>

<p>- Leigh</p>

 

[chuck_foreman1]

I would also be satisfied with the results you have. I've been considering building one of these testers too Did you use a USB sound card or did you mount a PCI (is this still valid??) version? I have also done the "elephant walk" (sorry SP) but in my neck of the woods we used either the thousand count (one thousand one) or the touch football Mississippi rush rule (one Mississippi, two Mississippi etc)! Cameras or rather shutters that feature slow speeds have an escapement (special gear) that theoretically may need attention, but it probably would benefit from a professional cleaning and let them decide if it needs lubing! Basically if you've never done this kind of work! Leave it to the experts!

 

Yours Truly

 

Bernd Fingers!

[leighb]

<blockquote>

<p>Cameras or rather shutters that feature slow speeds have an escapement (special gear)...</p>

</blockquote>

<p>The escapement is not "a" gear, it's a whole bunch of gears in an assembly.</p>

<p>I definitely would not suggest messing with it unless you have the tools & expertise to do so effectively.</p>

<p>- Leigh</p>

 

[andrew_b7]

<p>Hi, thanks very much for the responses. First off I like Elephant, I often struggle saying Mississipi, get a bit tongue tied will remember that when using my Argus C3. <br>

Thanks for letting me know the times are acceptable. I just looked at the decimal and thought it was way off but when you consider it as 1/3 stop etc it's not too bad. <br>

Chuck, I built a simple circuit with 1AA battery connected to a photo transistor and a 3.5mm audio jack that goes in the mic in on the back of my mac. It works really well. <br>

I have a lot of tools and can easily get to the escapement, (although I haven't got into it yet) I just wonder if there are any tell tale signs I should look for and where? Gunk or dust I can blow out etc? Or where to put a drop of lube? I found this on Rick Oleson's web page which is helpful, although it's from a Compur I assume they are all fairly similar? I don't mind breaking anything in the course of discovery so don't worry about that. </p>

<blockquote>

<p>Often, without removing the escapement from the shutter, you can clean the speeds up by applying a drop of solvent to the shafts of the Star Wheel and Pallet. The photo below should help you identify them: </p>

</blockquote>

<p><img src="http://rick_oleson.tripod.com/28c-detail.jpg" alt="" width="447" height="583" /><br>

Also found this online of a Contaflex shutter. </p>

<blockquote>

<p>The following picture identifies the slow speed escapement (green), the self timer escapement (red) and the flash contacts (blue).</p>

</blockquote>

<p><img src="http://www.monopix.co.uk/contaflex_images/6.jpg" alt="" width="500" height="485" /></p>

[k5083]

<p>Generally you should not lube these things, just apply a little solvent. Any kind of oil will improve it in the short term, but soon either go away or gum it up worse than before. These mechs were meant to run dry.</p>

<p>The solvent may or may not work. I've done this with quite a few shutters but I don't bother unless they're most of a stop off, and if I get it to within a third of a stop, I declare victory and quit. </p>

<p>In your position I would just keep the error in mind and compensate, or maybe not compensate. I was brought up being taught that there is a phenomenon with film, it is driving me crazy that I can no longer recall what it was called, but anyway the sensitivity at longer shutter speeds was nonlinear and we used to build in extra exposure and such speeds as a correction. I would view it as an automatic convenience feature of this camera!</p>

 

[jeff_guthrie]

It's generally not the escapement gear which is the culprit, but the "watchworks" of the slow speed mechanism which

controls it. A cleaning with solvent usually does the trick. Lubrication can be difficult because only a trace of lube is

necessary, and getting into the middle of the mechanism is difficult. A syringe with a fine tip, and a q-tip (to mop up

excess oil) can be used.

[markus_keinath1]

<p>Additionally you could look at some sites I have linked on my<br /><a href="http://www.4photos.de/camera-diy/index-en.html">DIY Photo Repair Directory</a><br>

There is a section about shutters with ~ 40 links and some more links about Canonet in the Canon section</p>