f-Stop timer - not a kit - shameless self promotion

Discussion in 'Darkroom Developing and Printing' started by Nicholas O. Lindan, Jun 4, 2005.

  1. Nicholas O. Lindan, Jun 4, 2005
    #1
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  2. Looks like a nice outfit. If I didn't already have an RH Design F-stop
    timer, I'd be very interested. Folks, F-stop timing really is a huge
    improvement. Considering the cost of regular linear timers, the cost is
    very reasonable. No footswitch option, though?

    -Peter De Smidt
    www.desmidt.net
     
    Peter De Smidt, Jun 4, 2005
    #2
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  3. Nicholas O. Lindan

    Alan Smithee Guest

    OK but you need the 25 word blurb on why this thing is going to change my
    life -- and my workflow. I kind of get an idea by reading the manual. A
    statement about why the f-stop method beats the timing method.
     
    Alan Smithee, Jun 5, 2005
    #3
  4. It has a jack to take a footswitch. The standard GraLab
    footswitch works, as will any momentary closure footswitch
    with a Walkman headphone-style plug at the end of the cord.
     
    Nicholas O. Lindan, Jun 5, 2005
    #4
  5. Are you still selling the kits? I had looked into that last year but
    it was just following my purchase of another analyzer/timer system. I
    had saved the info and see that the kits were $68. Are they still
    available? Thanks.


    Craig Schroeder
    craig nospam craigschroeder com
     
    Craig Schroeder, Jun 5, 2005
    #5
  6. No more kits.
    With circuit boards and enclosure the kit came to $108;
    the price difference was small. They are a lot more cost
    effective assembled.
     
    Nicholas O. Lindan, Jun 5, 2005
    #6
  7. So how much will you sell me the schematic for? (With an NDA, of course.)
     
    David Nebenzahl, Jun 5, 2005
    #7
  8. Nicholas O. Lindan

    Peter Chant Guest

    David Nebenzahl wrote:

    Surely if you have the ability to build from a schematic then could you not
    just design your own one? I am of course assuming that such a timer is a
    simple timer and relay, but the timings can be adjusted by halving /
    doubling, and small incremets for part F-stops?
     
    Peter Chant, Jun 5, 2005
    #8
  9. Nope, don't think so; otherwise Nicholas would be really raking in the dough.

    I'm assuming it's either microprocessor-controlled, or at least with some
    analog/digital circuitry (a 555?) driving a power controller of some kind,
    like an SCR or a solid-state relay.

    And just because one can solder together a circuit doesn't mean one can design
    it. You gots to know stuff about electronics that I don't know. Plus we're
    still waiting for Nicholas to explain the difference between f-stop timing and
    regular old timing, for those of us who were sleeping through that class.
     
    David Nebenzahl, Jun 6, 2005
    #9
  10. Nicholas O. Lindan

    Peter Chant Guest

    I was just assuming that if you could build from a shematic and solve the
    inevitable problems then a bit of simple design would not be an issue.

    Not that I've ever tried it but I believe that F stop timing is basically a
    timer that adjusts the time the bulb is on for in 'stops' or fractions of a
    stop, so basically the times halve, double etc. Probally not to difficult
    to do with a 555.
    Pete
     
    Peter Chant, Jun 6, 2005
    #10
  11. http://www.photovisionmagazine.com/articles/fstopprinting.html

    There is discussion of the technique on the various photo forums:
    apug, photo.net, pure silver ....
    http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=0050ln

    Articles courtesy of the competition - RH Designs:
    http://www.ephotozine.com/techniques/viewtechnique.cfm?recid=71
    http://www.rhdesigns.co.uk/darkroom/html/f-stop_printing.html

    The third f-stop timer on the market:
    http://www.unique-systems.co.uk/pages/f1.html
     
    Nicholas O. Lindan, Jun 6, 2005
    #11
  12. Nicholas O. Lindan a écrit :
    Hmm, you missed one, mine:
    http://www.bonavolta.ch/hobby/en/photo/fotolab.htm
    Well, not really competition as this one is free and not only a timer ...

    Regards,
     
    Claudio Bonavolta, Jun 6, 2005
    #12
  13. Missed a lot of them...

    The simplest 'freebie' f-stop method is in Lambrecht & Woodhouse,
    'Way Beyond Monochrome'. It is a reworked dial for a GraLab timer,
    www.ktphotonics.co.uk/pdf/Edition1Errata.pdf page 2

    The dial is still in seconds, which I think is not as useful as
    a simple stop scale:

    time seconds
    stop

    0 1
    1 2
    2 4
    3 8
    4 16
    ... ...
    10 1024

    One can make the dial as a spiral, allowing a greater
    timing range.

    Then the dial can be marked at 2 1/4 stops, 2 1/2 ... The even
    tempered timer.

    There are lots and lots of f-stop timing tables floating around
    on www. The numbers are all the same.

    Palm-pilot programs for the darkroom seem to abound; again, search
    the web.

    * * *

    There has to be a better term than 'F-Stop timer': it is sort of
    like having a 'gallon ruler': stops is stops and times is times.

    I thought 'T-stops' might work, but the term is already taken.
    In the movie industry a 'T-Stop' is a calibrated f-stop. The
    lens is mounted on an optics bench, the light transmission
    (hence the 't') is measured at each click of the aperture ring
    and the true f-stop is engraved on the lens [f5.6 is remarked as f6.3].
     
    Nicholas O. Lindan, Jun 9, 2005
    #13
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