man & nature # 86 ~ the shallow end of the gene pool
Tuesday, January 13, 2009 at 12:36PM 
2 views of a dead flower • click to embiggenOne of the things, photography wise that has changed with the advent of digital picture making is the photography characteristic of DOF (depth of field).
Actually, to be more more precise, the laws of optics hasn't changed at all, it's the "normal" / "statement" magnification factor of dslrs relative to slrs that has changed. Given the same aperture, lets say f8, the amount of DOF that is rendered by that aperture is entirely dependent upon the magnification factor of your subject. DOF is entirely independent of lens or camera format used.
In other words, if you are picturing an object (at f8) with both a 35mm film camera and an 8×10 film camera and that object measures the same size (lets say 1/2 inch across) in the view finder and on the ground glass, the DOF for both camera formats will be be identical. The same is true for a dslr - if the the same object measures 1/2 inch across in the viewfinder, at f8 the DOF will be identical to the other camera formats.
But, if you change the subject magnification factor by, say, having the object occupy the same amount of space within the frame of each different format, the DOF (at that same f8) will be different on each camera format. As the magnification factor shrinks with each progressively smaller camera format (keeping the same view/crop factor) the DOF increases.
That said, and considering that the sensor size of a dslr is smaller than the frame size of an slr, not to mention that the sensor size of a digicam is smaller than both, given the same crop factor digital cameras do, in fact, render more DOF than a 35mm slr.
All of that said, one of the things that I miss with digital picturing is shallow DOF. Not so much at the tele end of things, but most certainly at the wide-angle and "normal" end of the lens spectrum.
Full frame dslr sensors, of course, have exactly the same DOF characteristics as a full frame 35mm film camera, but until the price of those things drop more inline with "consumer grade" dslrs, shallow w-a / normal lens DOF will be a thing of the past or, at least limited to those using the big guns.
Reader Comments (1)
With digital photography is there is no fixed image - just files comprised of 0s+1s so you can manipulate them to your hearts content prior to viewing/printing. Selective blurring would be a method for producing the illusion of shallow DOF.