Making a DOF Table for a Cambo WDS

[Mark_Tuttle]

I've started using a Cambo WDS with a 55mm Rodenstock Apo-Sironar Digital lens.  The DOF scale on the lens is useless since it is for 6x9 film.  I'd like to have a table with me to refer to on occasion.

How I ran the calculations for the traditional 8x10 at 1 foot away:

1 micron = 0.001mm

The P45 uses 6.8 x 6.8 micron sensors

Your point of focus is at the 5 to 10 micron range?
Is the COC for a digital sensor about equal to the pixel size ?

So do I have a CoC of .0068mm  or .04624 when using the DOF calculators?  I used .0068mm because the 645 film calculations use .050mm or .045mm.

My depth of field is SO slim according to these calculations

For example:

DIGITAL  (CoC 0.0068mm) at 10 feet I get a DOF of 0.93 feet with the DOF 48% in front and 52%      behind the point of focus.

FILM (CoC 0.045mm) at 10 feet I get a DOF of 6.56 feet with the DOF 35% in front and 65% behind the point of focus.

The disparity tells me I'm doing something wrong here, my guess is in the CoC number for digital is too low.

Help appreciated.

Thanks,

[Jonathan Wienke]

For digital, use the pixel pitch of the sensor as your CoC value. Digital resolves mor detail per unit of sensor area, so the DOF requirements are correspondingly more stringent. It's the price you pay for the resolution gains you get over film. Read http://www.visual-vacations.com/Photograph...calculation.htm for a more detailed explanation and a spreadsheet you can download.

[Mark_Tuttle]

For digital, use the pixel pitch of the sensor as your CoC value. Digital resolves mor detail per unit of sensor area, so the DOF requirements are correspondingly more stringent. It's the price you pay for the resolution gains you get over film. Read http://www.visual-vacations.com/Photograph...calculation.htm for a more detailed explanation and a spreadsheet you can download.
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I was aware of the trade-off of resolution for DOF, and your nice Excel spreadsheet confirms the same numbers that I had after including a lens multiplier of 1.1x for the 'smaller than film format' digital back.

Thanks