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
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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
    Peter De Smidt, Jun 4, 2005
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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
  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
  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
  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
  7. So how much will you sell me the schematic for? (With an NDA, of course.)
    David Nebenzahl, Jun 5, 2005
  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
  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
  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.
    Peter Chant, Jun 6, 2005
  11. http://www.photovisionmagazine.com/articles/fstopprinting.html

    There is discussion of the technique on the various photo forums:
    apug, photo.net, pure silver ....

    Articles courtesy of the competition - RH Designs:

    The third f-stop timer on the market:
    Nicholas O. Lindan, Jun 6, 2005
  12. Nicholas O. Lindan a écrit :
    Hmm, you missed one, mine:
    Well, not really competition as this one is free and not only a timer ...

    Claudio Bonavolta, Jun 6, 2005
  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

    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
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