One last thing and it probably doesnt apply to this forum but does anyone out there know where to get a step ring that goes from around 28-30mm (spot meter) to 49mm (lense) male threads on both ends. I have found some but not that small on the spot meter end. Otherwise I am down to fashioning plastic pipe to fit over the end of the spot meter.
[FONT=Comic Sans MS]The Center for Desease Control just called. I have pegged the needle on their machines with this photography bug I have.[/FONT]
Michael J. Taylor
Film Speed/Developing Confusion
Without the proper steps determining film speed can be an elusive item. I have mostly used the Zone VI Fred Picker method and found it to be the easist and most certain. What I do is expose the film of choice to a white card and with a spot meter determine the exposure for Zone I at various assumed film speed ratings. To keep track of the work I put notes on the white card indicating the film, developer to be used and the assumed film speed for each frame exposed. After developing the film with the developer I plan to use consistently I check to find which frame has a density of 0.1 above film base plus fog using a densitometer. If you dont have a densitomer perhaps the local photo lab you use would perform the readings. When the film speed is determined for the combination of film, camera, lens, spot meter and development scheme, I then proceed to expose a new set of films to determine Zone densities from Zone I to Zone X for various development times for the standard developer I plan to use. With this data I can plot the Zone versus density curves for various development times and now I have the data I need to establish camera exposure times to create the negative contrast range I am seeking for a particular subject. There is a bit of front end effort in this but well worth it in the final results that have a reasonable preditability.
Fred Picker's method is absolutely fool proof for determining film speed as outlined above. It is also pointed out in Fred's book "the Zone VI workshop" which is always available on ebay for less than $10.00. If you don't have a dentsitometer, you can mail your films to Richard Ritter who used to work for Fred, and he will provide test results for $7.50. Here is his address below along with his website:
Originally Posted by engbobs
For testing send the developed film along with a check or money order for $7.50 to;
Townshend, VT 05353-0401
I sent my original tests to Fred 15 years ago before he passed away. Also, I was going to send him 5 or 6 films to test. He said "son, you are hopelessly lost if you need to test that many films"... "stick to one film, one developer and one paper and you may eventually find out what the hell you are doing"..... I took that sage advice, and I am glad that I did...
Often wrong, but never in doubt!
With changes in development the EI will change some
Originally Posted by Donald Miller
what. A shift from N-2 to N+2 development will likely
at least double if not triple the EI. The SBR, in it's
self, has nothing to do with the EI. Dan
As I've stated in previous threads, call the View Camera Store and talk to Fred. For the effort of developing the 5 sheets of film (he sends you) at 4, 5:30, 8, 11, and 16 minutes, and a little bit of money ( I think $40.00) you will receive back ALL OF THE DATA you need to make as perfect a neg possible in just about any light condition. (You don't need a densitometer) That includes the various film speeds for your plus and minus developments. And, this will be tailored to fit your printing paper like a glove! It really is that easy.
I get no compensation for promoting this, I just think it's a shame that more people aren't aware of it!
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
While I would agree with you on the face of what you said, I would go on to say that you did not follow what I said to it's logical outcome.
Originally Posted by dancqu
My point being, and I think that you will agree, that SBR determines development and development affects EI...so SBR does effect EI. Agreed?
Additionally BTZS does not have N+2 or N-2 development designations. It would appear that you are intermingling BTZS and Zone system practice.
"While I would agree with you on the face of what you said,
I would go on to say that you did not follow what I said to
it's logical outcome."
"My point being, and I think that you will agree, that SBR
determines development and development affects EI...so
SBR does effect EI. Agreed?"
I don't agree save for the special case where one wills
that the SBR dictate development. That special case is
one where there exists only one paper of one grade and
A specific chemistry to be used. That's the fit the film
to the paper way.
I shoot roll film and fit the paper to the film. The two
most used methods are VC paper and Graded papers. A.
Adams used a modified two part Ansco 130 developer.
My own tests with Beer's two part VC developer
look very good.
"Additionally BTZS does not have N+2 or N-2 development
designations. It would appear that you are intermingling
BTZS and Zone system practice."
Well I'm not the only one intermingling. Reading a D-Max
Newsletter I see that Phil Davis equates his Beyond with the
Zone System. "... Diafine is not a practical developer for
BTZS ( or Zone System )..." . I think Ansel and the f64
group would understand. Dan
Just to throw a little humor into the mix: note from Fred Picker on my densitometer test I sent him once; "son;these are all over the barn" I still laugh to this day! And he wasn't wrong either.
Best, Peter Schrager
You apparently have a peliminary knowledge of both the Zone System and BTZS. Your response indicates an elitist attitude when no apparent basis for this attitude seems to exist.
Originally Posted by dancqu
But IMHO, having the SBR or N situation dictate development is the common case, not a "special case," for most photographers who have established good control of their process. The normal case is to expose and develop for a mid-range contrast of the process, say for a #2 graded paper or a #2 VC filter, and then adjust for more or less contrast in the negative by applying process controls. That is basically what people who shoot 35mm and roll film do, even if their methodology is no more sophisticated than following time/temperature charts for a specific film/developer combination.
Originally Posted by dancqu
I agree about the mingling of SBR and N terms when talking about BTZS. Phil Davis does it, and I do it also. In fact, the Winplotter program of Davis will allow one to calcualte exposure and development based on either SBR or N values. Of coure, both are simply linked to required negative DR and print ES by average gradient.
Last edited by sanking; 09-05-2005 at 11:44 AM. Click to view previous post history.