I understand, because of the size of the CCD vs. 35mm film, lenses have an approximate 1.5 multiplier for field of view (20mm = 30mm for a D1/D100). My question is does the hyperfocal distance and depth of field remain the same for a lens or are they affected as well?
#1. "RE: Hyperfocal Distance & DOF" | In response to Reply # 0lordnikon Registered since 17th Feb 2002Thu 08-Aug-02 06:43 AM
I am probably wrong, as my DSLR knowledge is not up to my 35. I lurk around here to learn, and I can not seak in regards of hyperfocal, but I am of the understanding from what I have seen here that DOF and the apperture does not change, though I could be wrong so don't swear 100% by it.
Aaron J. Heiner
Team Coast Guard Photographer
US Department of Homeland Security
#2. "The DOF characteristics of a lens do not change..." | In response to Reply # 0RRowlett Charter MemberThu 08-Aug-02 12:30 PM
...in a digital SLR compared to a 35 mm SLR. This is becuase the focused image in the DSLR is exactly the same as the focused image in your 35 mm camera. The only difference is that the DSLR image sensor is about half the area of a 35 mm film frame.
However, there are some other subtle differences between the digital medium and film that affect the effective DOF and hyperfocal distance. Both DOF and hyperfocal distances are determined by three variables: the focal length of the lens, the aperture of the lens, and the circle of confusion (the maximum blurred diameter of a focused point of light in the image that can be tolerated as "acceptably sharp".) The first two of these variables are exactly the same for both digital and film. The last is more subjective, but arguably different for film and digital.
In film, a typical circle of confusion (COC) is about 0.025 mm or 25 um. How big or small this number should be is somewhat subjective becuase of the analog nature of film, but 25 um is an average value used for film by experienced landscape photographers. In digital, the COC is a little more objective: a digital sensor cannot resolve more detail than defined by 1 or 2 pixels. Since the D100 pixel sensing elements are 8um in diameter, a reasonable COC is 16 um or 0.016 mm. (Choosing 1 pixel for the COC is probably overkill because of the anti-aliasing filter present in all digital cameras to prevent image artifacts.) So, using these numbers you can calculate useful hyperfocal distance tables for both film and digital, and they won't be exactly the same, even though the inherent DOF characteristics of the lens is the same. I know this is long-winded, but then again you asked
I have constructed wallet-sized hyperfocal distance cards for both 35 mm film and the D100 using the COC values quoted here.