f-stop test strips

I would like to make exposure test prints using f-stop intervals rather
than constant intervals. Purchase of an RH Designs timer is not in the
budget. I suspect that resetting the timer for the deltas between exposure
steps is not the most efficient way.

How do folks do this?

Thanks,

Rich


Rich Shepard

"Rich Shepard" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> I would like to make exposure test prints using f-stop intervals rather
> than constant intervals. Purchase of an RH Designs timer is not in the
> budget. I suspect that resetting the timer for the deltas between exposure
> steps is not the most efficient way.
>
> How do folks do this?
>
> Thanks,
>
> Rich


I'm not sure entirely what you have in mind, but...

To increase a time interval by 1 stop, double it.

To increase a time interval by 1/2 stop, multiply it by 1.414 (the square
root of 2).

So you could go 5, 7, 10, 14, 20, 28 seconds... at half stop intervals.


The stops on your lens are numbered 2, 2.8, 4, 5.6... and each transmits
half as much light as the previous one, because light transmission depends
on area, which is proportional to aperture squared.

Go buy a Kodak "Print Projection Scale". It is a
step wedge designed to show exposures with about a
8 stop range. Not looking at mine now so I am
guessing. It works great.
--
73 es cul

wb3fup
a Salty Bear

"Michael A. Covington"
<(E-Mail Removed)> wrote in
message
news:Be2cnXzyl8inVpOiU-(E-Mail Removed)...
>
> "Rich Shepard" <(E-Mail Removed)>
wrote in message
>
news:(E-Mail Removed)...
> > I would like to make exposure test prints
using f-stop intervals rather
> > than constant intervals. Purchase of an RH
Designs timer is not in the
> > budget. I suspect that resetting the timer for
the deltas between exposure
> > steps is not the most efficient way.
> >
> > How do folks do this?
> >
> > Thanks,
> >
> > Rich
>
>
> I'm not sure entirely what you have in mind,
but...
>
> To increase a time interval by 1 stop, double
it.
>
> To increase a time interval by 1/2 stop,
multiply it by 1.414 (the square
> root of 2).
>
> So you could go 5, 7, 10, 14, 20, 28 seconds...
at half stop intervals.
>
>
> The stops on your lens are numbered 2, 2.8, 4,
5.6... and each transmits
> half as much light as the previous one, because
light transmission depends
> on area, which is proportional to aperture
squared.
>
>

In article <Be2cnXzyl8inVpOiU-(E-Mail Removed)>, Michael A. Covington
wrote:

> I'm not sure entirely what you have in mind, but...

What I would like is a more efficient method than setting my first
exposure strip at 2.8 seconds, the next strip at 1. seconds (for a total of
4 seconds), the third strip at 1.6 seconds (for a total of 5.6), ... and so
on.

Rich

In article <beml0s$6apnb$(E-Mail Removed)>, WB3FUP (Mike Hall)
wrote:

> Go buy a Kodak "Print Projection Scale". It is a step wedge designed to
> show exposures with about a 8 stop range. Not looking at mine now so I am
> guessing. It works great.

I have the Souffer Graphic Arts exposure scales -- 1/3-stops and
1/6-stops. Yes, they are exceptionally useful as I get to the proper
exposure in 1-2 test exposures -- most of the time, anyway.

However, in Tim Rudman's book (as well as two others) he illustrates the
difference between a test print at arithmetic intervals versus one at f-stop
intervals. All the books say, "It's easy! Do it.". But they don't provide
more explicit instructions. I assume that calculating the time deltas and
resetting the timer between each exposure is not the most efficient way to
achieve this -- without the exposure scales.

However, from the responses so far I guess there is no more efficient way.

Thanks,

Rich

Are you sure you are not over engineering the
solution you think you want. A "f" stop is 2x's
the one smaller, or 1/2 the one bigger. Trust me,
I have done the math. I do not remember the wedge
increments on the Kodak scale, forgive me it has
been a while since I have used it. I do know that
if the 60 second starting exposure did not produce
a useful starting point 30 seconds (1 "f" stop
less) or 120 sec (1 "f" stop more) put me right in
the ball park for a starting point. Yes, the
result was not the "exhibition" quality print.
That print generally required selective exposure
(dodging and burning) and area development (dektol
at 1:6, dektol straight, dektol at 100 degrees) to
capture what my eye saw when the camera went click
(the Graphic) or "Crik" (the Ashai). You need a
good straight print to start from, but that is not
the ending point by any means.

--
73 es cul

wb3fup
a Salty Bear

"Rich Shepard" <(E-Mail Removed)>
wrote in message
news:(E-Mail Removed)...
> In article
<beml0s$6apnb$(E-Mail Removed)>,
WB3FUP (Mike Hall)
> wrote:
>
> > Go buy a Kodak "Print Projection Scale". It
is a step wedge designed to
> > show exposures with about a 8 stop range. Not
looking at mine now so I am
> > guessing. It works great.
>
> I have the Souffer Graphic Arts exposure
scales -- 1/3-stops and
> 1/6-stops. Yes, they are exceptionally useful as
I get to the proper
> exposure in 1-2 test exposures -- most of the
time, anyway.
>
> However, in Tim Rudman's book (as well as two
others) he illustrates the
> difference between a test print at arithmetic
intervals versus one at f-stop
> intervals. All the books say, "It's easy! Do
it.". But they don't provide
> more explicit instructions. I assume that
calculating the time deltas and
> resetting the timer between each exposure is not
the most efficient way to
> achieve this -- without the exposure scales.
>
> However, from the responses so far I guess
there is no more efficient way.
>
> Thanks,
>
> Rich

On 11 Jul 2003 18:05:18 GMT, Rich Shepard
<(E-Mail Removed)> wrote:

> I have the Souffer Graphic Arts exposure scales -- 1/3-stops and
>1/6-stops. Yes, they are exceptionally useful as I get to the proper
>exposure in 1-2 test exposures -- most of the time, anyway.
>
> However, in Tim Rudman's book (as well as two others) he illustrates the
>difference between a test print at arithmetic intervals versus one at f-stop
>intervals. All the books say, "It's easy! Do it.". But they don't provide
>more explicit instructions. I assume that calculating the time deltas and
>resetting the timer between each exposure is not the most efficient way to
>achieve this -- without the exposure scales.

What do you want to do, that you can't do with the Stouffer Exposure
Guides? (Since they ARE f-stop, rather than arithmetic, it seems that
they do exactly what Tim Rudman is suggesting.)

Chris Ellinger
Ann Arbor, MI

Rich Shepard wrote:
> I would like to make exposure test prints using f-stop intervals rather
> than constant intervals. Purchase of an RH Designs timer is not in the
> budget. I suspect that resetting the timer for the deltas between exposure
> steps is not the most efficient way.
>
> How do folks do this?
>
> Thanks,
>
> Rich

Maybe not the most efficient, but I've been "resetting the deltas" for
years with my old Gralab timer. Since I have to reset it for every
exposure anyhow, I just vary the time I set it to. (e.g. about 5.5 sec
for first exp. then about 2.5, then 3, then 5, then 6 to get approx
eposures of 5.5, 8, 11, 16, 22 sec) I know they are only approximate,
but it get me in the ballpark quickly and experience and guestimation
take it to the next stage.

I was always going to get a "better" timer, but this old beast keeps on
ticking (the Gralab).

Dave

Rich,

Start with a base exposure of 32 seconds for the first exposure. Cover it
up.
Total so far 32 seconds.
Now work in quarter stops.

Expose for 8 seconds that is 25 percent of 32, a quarter stop.
Total so far 40 seconds.
Expose for 10 seconds, 25 percent of 40, a quarter stop.
Total so far 50 seconds.
Expose for 12.5 seconds, and so on. Each exposure adding a quarter stop more
exposure.

You can use half or sixth stops in much the same way.

rharrisa
"Rich Shepard" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> I would like to make exposure test prints using f-stop intervals rather
> than constant intervals. Purchase of an RH Designs timer is not in the
> budget. I suspect that resetting the timer for the deltas between exposure
> steps is not the most efficient way.
>
> How do folks do this?
>
> Thanks,
>
> Rich

In article <(E-Mail Removed)>, Chris Ellinger
wrote:

> What do you want to do, that you can't do with the Stouffer Exposure
> Guides? (Since they ARE f-stop, rather than arithmetic, it seems that
> they do exactly what Tim Rudman is suggesting.)

Chris, et al.:

I've not explained myself well. Let me try once more.

I suppose that if one has an f-stop timer then it can be set for 1/2-stop
intervals and will automatically expose test strips for the proper time.

Not having a f-stop timer, I would create the test strip series thusly:
for example, to produce test strips exposed for 2.0, 2.8, 4.0, 5.6, 8.0,
11.0, 16.0 and 22.0 seconds I would set the timer for 6.0 seconds and expose
the first strip (covering the rest of the paper). I would then uncover the
second strip and expose that for 5.0 seconds. The third strip is uncovered
and exposed for 3.0 seconds. This continues, with each stip uncoverd and the
paper exposed for 2.4, 1.6, 1.2, 0.8 and 2.0 seconds.

The purpose of my question was to learn if there was a more efficient way
of generating this same series of exposures.

Rich