Easy test for determining the shutter speed of an older camera

Discussion in 'Medium Format Cameras and Accessories' started by jaapdijks, Aug 27, 2008.

  1. jaapdijks

    jaapdijks Member

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    Hello All,

    I have recently been given old Ernemann Film K camera.
    I googled the camera and found some data.
    The lens is probably a fixed f12,5 lens.
    Production data probably 1920's

    I would like to use this camera and am trying to find out the shutterspeed.
    Fot shutter speed there are three settings on front of the camera:
    A fixed shutterspeed of unknown length and two time settings.

    First, is there anybody around here who knows the originally designed speed?
    Or who can make an educated guess?
    Two, is there an easy way to test the shutter speed without losing a whole
    or several rolls. Given that there is only one f size and one shutterspeed
    the only variable in the equation is the filmspeed and the light conditions.

    I suppose there are probably devices available for testing shutterspeeds
    however i have no access to them.


    Kind regards Jaap Dijks
     
  2. ntenny

    ntenny Member

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    What I've done in the past, with some success, is to record the sound of the shutter firing on a computer, then look at the waveform. There should be distinct peaks for the sound of the release and the sound of the close; the time between them is (close to) the shutter speed.

    It's not a real precision technique---I don't think I'd trust it to distinguish between 1/400 and 1/500 or anything like that---but it'll give you an approximate answer.

    -NT
     
  3. sun of sand

    sun of sand Member

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    I've never done it really but you could shoot a television show.

    shoot all speeds the camera has then rewind the film
    put into camera with known speeds
    and fire the rest of the roll

    1/25 should show a full screen
    1/100 will show like 70%
    1/250 will show 35%
    1/500 18% ?


    It does use film


    Maybe hold a digi behind the camera with back open on BULB or TIME and fire the shutter (while pointing at TV) so the digi records it
    Might work for free that way
     
  4. Larry.Manuel

    Larry.Manuel Member

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    If you can buy slide [transparency] film for your camera, you may be able, by making test exposures at various apertures, determine the effective shutter speed. Slide film is quite sensitive to proper exposure. I suggest photographing the same scene, side-by-side with a camera with known shutter speeds as a control device. I leave the experimental design details to you.
     
  5. Frank R

    Frank R Subscriber

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    Shooting one roll on a sunny day would be the simplest solution. You could get a close starting point if you have (or can borrow) another camera and compare the sounds.
     
  6. raucousimages

    raucousimages Member

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    I bought a shutter tester to test speeds for about $60.00 I was suprised to find how far off some lenses were. It paid for it's self by reducing bad exposured after I knew how to compensate for each lens.

    This is the same tester a lot of repair shops and camera stores have, see if someone can test it and give you the times.
     
  7. Anscojohn

    Anscojohn Subscriber

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    Place a reference mark of some sort on the edge of a turn table of record player---if you can find one; from directly above, photograph this moving mark at 33 rpm. The amount of distance of the blurred mark can be extrapolated into a time the shutter was open.
     
  8. srs5694

    srs5694 Member

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    The TV test that sun of sand mentions can be done without film; just open the back and look through the film gate as you shoot a TV. This Web page describes the process in more detail. Note that this technique works only with older raster-scan TVs and computer monitors, and you must be aware of the TV/monitor's refresh rate. (This can be just about anything for a computer monitor.) If you've got a new high-def LCD, plasma, etc. TV or computer monitor, this technique won't work. It's a bit of a seat-of-your-pants approach, since you can't get an exact number from it, just a guesstimate of "oh, that looks about right for 1/125s" (or whatever). FWIW, I used this technique to adjust the shutter speed on my Kiev 6C, which arrived with shutter speeds that were very badly off. I'm sure my Kiev's shutter speeds are still off, but not badly enough to cause me serious problems.

    I've seen plans on the Internet for an elaboration of the sound card technique described by ntenny: one, [url=http://www.baytan.org/prak/shutter.html]two, three. The idea is to hook up a phototransistor to a computer's sound card, position that phototransistor behind the film gate, shine a light through the lens or lens mount, use an audio recording program to record the output from the phototransistor as you fire the shutter, and measure the time the shutter was open using the audio program. Parts are supposed to cost about $5. There's a guy who sells these on eBay for $51 (shipped) if you're completely hopeless with electronics. I'm planning to put one of these together myself soon (maybe this weekend, in fact), but I've not gotten around to it yet.
     
  9. ic-racer

    ic-racer Member

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    I agree, the easiest way would be to use a shutter speed tester. All the other ways are much more difficult.
     
  10. jnanian

    jnanian Advertiser Advertiser

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    i would guess the typically the "I" setting
    on a fixed shutter speed camera
    from that period was around 1/100S
    a roll of film is cheep, you could alway shoot 2 rolls
    - one with that camera, and one with another, process them at the same time
    and compare the negative density to determine the shutter speed.
    i have a few cameras that say "I" and i rate the shutter at about 1/100...
    even if it is off a little bit, it doesn't really matter too much :wink:

    nice camera!
    have fun :smile:

    john


    with
     
  11. Kino

    Kino Member

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    If you have access to a video camera, point the film camera out the window, videotape the back of the lens element and fire the shutter. The shutter speed will be (roughly) the number of frames the shutter is opening and closing times the frame rate of the video camera.

    100th of sec should be 3 or 4 frames if NTSC @ 29.97 fps.
     
  12. DaveOttawa

    DaveOttawa Member

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    If you use the turntable method make sure it's a wind-up one:smile:
    Less than 1/125, may be 1/30 or 1/15
    In my limited experience with this type of simple camera substantial overexposure is most likely (slow shutter speeds = very dense negs) so maybe shoot a roll under the lighting conditions you think you are likely to use and cut it into maybe three pieces. Dev one normally, if it is too dense dev the next piece for less time (go in at least 15% steps), with any luck you'll get a good idea of the right dev time for those lighting conditions and that film with just one roll. The principle is that you control neg density by selecting a film and dev time for the lighting conditions rather than adjusting the shutter speed and aperture.
     
  13. jaapdijks

    jaapdijks Member

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    Thanks everybody for your suggestions.

    I think I will try both DaveOttowa's suggestion about the testroll and various developments.
    My guess for the speed would be somewhere in the region of 1/25 to maybe 1/100s.
    Film speed in the 1920's would be around 12 to 50 asa.
    Sunny f16 for a f12.5 lens would give a speed of around 1/25 to 1/50s
    Trix 400 would probably be way overexposed, so i will try it with some Rollei Pan 25 Film


    I will also try the soundcard options. The tester will also come in handy for some other cameras i have.
    Tinkering with electronics is a nice way to pass a rainy day.

    Regards Jaap
     
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  15. jaapdijks

    jaapdijks Member

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    Hi everybody,

    I have done some testing with a homemade plug it in to your soundcard shuttertester.
    The speed comes out at approximately 1/30 to 1/40s. Which is quite slow for modern films on a sunny day.

    I will try the camera with some Rollei 25 film.

    Regards Jaap
     
  16. nick mulder

    nick mulder Member

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    Forgetting the drop frame carry on for the time being - 3 frames of 1/30 is 3/30, 1/10 of a second - your 1/100 exposure will take up one frame, assuming it fires when the shutter is open (%50 chance with a 180deg shutter angle)

    It aint gonna be helpful :sad:

    p.s. out of interest, anyone know how shutter speeds testers work ? integrating op-amp circuits ?
     
  17. jnanian

    jnanian Advertiser Advertiser

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    hi nick

    i have a calumet shutter speed tester.
    there is a sensor that measures the blip of light that passes through the shutter ..
    there is a number that tester then displays / spits out onto a lcd screen

    there is also a chart that one looks at that is filled with numbers / shutter speeds ( fractions of seconds ).
    one matches the number on the lcd to the closest in the sequence and it gives the time / speed it measured from the blip of light.

    at least that is how i think mine works,
    i am sure others will say differently :wink:

    john
     
  18. nick mulder

    nick mulder Member

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    sounds like an omp-amp integrating circuit :wink:

    [​IMG]

    ... the magnitude of its output is proportional to the duration and strength of voltage present at its input, if we make the strength (i.e. light) constant - then the output is purely representative of the shutter time - could make one, but calibrating it would be an exercise involving another similar bit of gear anyway - heh

    I looked into them for random/cloudy day DOP exposures in Pt - but getting the sensors to read only UV was going to be more of a hassle than building a UV box
     
  19. DaveOttawa

    DaveOttawa Member

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    Jaap,
    As I mentoned the objective is to control negative density which can be done using dev time as well as exposure. An example is here:

    http://theonlinephotographer.typepad.com/the_online_photographer/2008/09/forgotten-cam-5.html

    the photographer is pulling FP4 by quite a bit to account for the slow shutter speed and getting good negs.

    Another possibility is to use a neutral density filter in front of or behind the lens.

    Post something once you get it sorted!

    PS if one has access to a digital storage scope and a photodiode (I do but obviously not everyone will) then it is easy to measure.
     
  20. Pupfish

    Pupfish Member

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    Sub $20 shutter tester

    I already had Audacity and Goldwave sound editors on my MacBook Pro, so it was a cinch to buy an $8 Phototransistor detector to make a really simple and super accurate sound card shutter tester as per one of the tutorials readily available on the web, like this one:

    http://www.davidrichert.com/sound_card_shutter_tester.htm

    Might mention I used a slightly more spendy detector that switches on in two microseconds (works with both a flashlight and a laser pointer as the light souce) though much cheaper ones are often recommended. Mine happens to works best with no resistor in the circuit, using a single 1.5V AA battery. Scrounged a 3.5mm headphone jack and a battery holder I already had. Didn't bother with an on/off switch, there's no load with it unplugged.

    Turns out that my newly Ronsonol-soaked and lubricated 60 yr old Wollensak Raptar shutter is very consistent, within an 1/8 stop of indicated speed where it matters, from 1s to 1/100th.
     
  21. vet173

    vet173 Member

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    If I was going to take that camera out I would assume "I" to be 1/30 sec.
     
  22. michaelbsc

    michaelbsc Member

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    I'm not so sure that something that old would have been 1/100 for the instantaneous setting. Clearly this is "just a guess" on my part, but I'd bet it was closer to 1/20 or 1/25 for the film speeds of the day, particularly if it has a fixed f/12.5 aperture.

    Of course that doesn't mean a thing about what it currently fires. However it can't be a complicated mechanism, so getting it back in proper order should be possible, especially if it works now. Clearly all the parts are there an not broken if it fires.

    MB
     
  23. bobwysiwyg

    bobwysiwyg Subscriber

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    This seemed like the logical thread for more of my newbie questions. I'm new to 4x5, I've exposed perhaps 20 sheets. Note I didn't say I've taken 20 photographs.:wink: I have three lenses; 135mm, 150mm and a 210mm, all used from eBay. I've wondered just how accurate they are. I finally got around to acquiring the gadget described above. Pretty interesting gadget and I've used it to check all three lenses. Now that I have, it raises several questions for this newcomer.

    I've seen references to CLA, which I'm assuming stands for Clean/Lub./Adjust? How accurate, in terms of absolutes are shutter times after a CLA? Is there some sort of allowable +/- deviation and the shutter is still considered OK?

    I compared each shutter, at each speed and now have values for deviation from the absolute. My next question is, if one were to compute the % difference from the absolute, correct value for a given shutter speed, could this be used to translate into an f-stop difference? That is, say a given speed were off by 25%, would that correlate into a 1/4 stop difference?
     
  24. ic-racer

    ic-racer Member

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    Close enough for practical purposes.

    To be exact, use the log scale. On the log scale the 1/4 point between 1/30th and 1/60th is 1/35.6th. If you just figure 25% then the (close but technically incorrect) answer is 1/37.5th.
     
  25. bobwysiwyg

    bobwysiwyg Subscriber

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    I'll go with that, thanks. I would have thought I was unlikely to be able to detect anything below a half stop visually (that is by the negative or the print) but is seems I can. I took notes on my shots and one negative in particular seemed "thinner" than I would have expected or liked. Turns out I could trace it back to a lens and shutter speed that turns out to be off by 30% so maybe there's hope for me yet.

    I thought keeping a record of the shutter speeds might help identify future changes or declines in performance.

    Any sense for what the level of accuracy, +/-, one might expect after a professional servicing?
     
  26. Anupam Basu

    Anupam Basu Member

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