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Posted: Tue Jan 29, 2013 2:58 pm
by ggroess
You should create a new file for the pins if these are ones you want to save long term.

you can also edit the line:
#section Zone System
Zone 0 Lab(2,0,0) pin brightness ;GGroess 2010
Zone 1 Lab(12,0,0) pin brightness ;GGroess 2010

in an existing file.  Copy the line and change the text after the statement #section.

So you could add #section  My New Pin to the file and the program should generate a new tab.
You will have to refresh the pins or close and re-open CM to see the changes.


Posted: Sun Feb 03, 2013 7:34 pm
by mikemeister_admin
The Zone system with Digital images have both interested and confused me.

The example Greg has shown is from

Reading this page, all seems to make sense until he starts correcting an image - it just did not look right to me.

So I copied his example image into Photoshop and then place his Zone image (Greg's 3rd post image) to the right of it to compare the tonal values.  This is my first attachment.

I have written L values on his first scale in blue (the right scale is already marked).

You can see that although the IX and I Zone values/percentages roughly agree between the two wedges, they then go quite mad in the middle range, jumping by almost a stop.

Can anybody put me out of my misery and explain why?

While we are on this subject, if you do as he suggests and take a series of exposures at different EV values of a grey scale - you can then read the L values and see how they change by f/ stops.  You will find that today's digital cameras apply a curve to the linear response of the sensor and thus the Exposure Wedge you can construct is not linear. 

The second attachment is the result of constructing a 9 step wedge in photoshop, displaying it on the screen and then photographing it through a set of 9 exposures in +/- 4EV steps.
I've stacked them under the actual wedge and then plotted the result.

So my second question is how will this help me determine a Zone value?  i.e. Do linear zone wedges show 1 EV differences when displayed/printed, or should one use the ones from the camera curve (which are the photo representations of real life tones and non-linear).


Posted: Mon Mar 04, 2013 1:08 am
by imported_julie
Hi Greg

I noticed you were talking about a 201 class.
I know I am thinking ahead but...
I would love to be able to do this and will be away on holidays in May and June.
If you are thinking about running this would it be possible to avoid these months?
Its a big ask but I just love the interaction and opportunity to learn that the classes provide


Posted: Mon Mar 04, 2013 6:01 pm
by ggroess
If it is run it will be repeated.  No worries.

I have a ton of material I just need someone to organize me...and package it into a nice easy to follow program that makes everyone completely happy...


Posted: Mon Mar 04, 2013 6:29 pm
by mikemeister_admin
if anybody wants to spend a few minutes with nothing better to do (!), then have a read through

I have been experimenting with the Zone System and have recorded my finding during the journey - which is only really just beginning.

Nearly everybody says... Zones are one-stop changes in exposure - I disagree!  I'd love to know if you agree with me or not - and if not, where you think I've gone wrong.

A very interesting subject and the free to download book "The Practical Zone System for Film and Digital photography" by Chris Johnson
is worth reading.

Good luck!

Posted: Mon Mar 04, 2013 8:33 pm
by RonBoyd
" the free to download book "

Zog, is this "free" after the $9 one-day buy-in? Or am I missing something?

Posted: Tue Mar 05, 2013 9:22 am
by mikemeister_admin
I just hit the download and it came - perhaps I found a loop hole!
I will PM it to you

Posted: Tue Mar 05, 2013 11:40 am
by RonBoyd
Thank you. That worked fine -- it is downloading as I write this. I tried (the original link) again and again couldn't get past the pay wall. Perhaps, there is a "one free" limit and sometime in the past I used it. Who knows?