Bjorn Nilsson
29-Apr-2007, 10:54
Hi all!
On all "modern" Sinar cameras there is a built-in DoF scale on the fine-focusing knob. I take it that all of you who reads this knows what I'm talking about. It is very easy to operate and really saves a lot of time.
Now, a while ago I stumbled into a french page which describes the use of this scale. The author states that when you zero the scale at the farthest object in the picture you should not set the scale at the zero setting but rather at the max open f/stop of the lens used. There is nothing written about this in the Sinar manuals.
He claims that the reason for using the max f/stop would be that e.g. a f/9 lens already have a bit more DoF at full opening than a f/5.6 lens and this have to be compensated for.
During the many years I have used Sinar cameras I have never really thought about this, nor have it caused me any problems to always start with a "zero" setting instead of e.g. f/9.
But I got a bit puzzled here and I know that many of you are very knowledgeable on this matter.
(I do know that I could do the same thing on any camera by simply marking and measuring the distance the back standart travels and calculate the f/stop to use from that distance and the film format. Then it's simply a matter of setting the standart in the middle of the two points. But where did I put that calculator... :) )
//Björn
On all "modern" Sinar cameras there is a built-in DoF scale on the fine-focusing knob. I take it that all of you who reads this knows what I'm talking about. It is very easy to operate and really saves a lot of time.
Now, a while ago I stumbled into a french page which describes the use of this scale. The author states that when you zero the scale at the farthest object in the picture you should not set the scale at the zero setting but rather at the max open f/stop of the lens used. There is nothing written about this in the Sinar manuals.
He claims that the reason for using the max f/stop would be that e.g. a f/9 lens already have a bit more DoF at full opening than a f/5.6 lens and this have to be compensated for.
During the many years I have used Sinar cameras I have never really thought about this, nor have it caused me any problems to always start with a "zero" setting instead of e.g. f/9.
But I got a bit puzzled here and I know that many of you are very knowledgeable on this matter.
(I do know that I could do the same thing on any camera by simply marking and measuring the distance the back standart travels and calculate the f/stop to use from that distance and the film format. Then it's simply a matter of setting the standart in the middle of the two points. But where did I put that calculator... :) )
//Björn