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

I have had many inquiries for an assembled version of
my f-Stop timer.

A fully assembled/tested/documented timer is now available
for $159.

http://www.nolindan.com/da/fstop/index.htm

 

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

 

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.

 

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.

 

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

 

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.

 

So how much will you sell me the schematic for? (With an NDA, of course.)

 

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?

 

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.

 

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

 

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 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,

 

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].