What f-stops are used to capture short depth of field?
[General Answer - applies to DSLR & 35mm] The smaller the f-stop value, the smaller the depth of field. In typical "snap-shot" working distances, f2.8 - f4 typically provide small DoF and nicely blurred backgrounds.BUT - there are a couple of 'Gotchas'(Examples below assume 35mm film or full frame DSLR)Focal length effects DoF 24mm lens @ f/4 working 10 ft from subject = DoF 20.9 ft35mm lens @ f/4 working 10 ft from subject = DoF 6.47 ft50mm lens @ f/4 working 10 ft from subject = DoF 2.94 ft100mm lens @ f/4 working 10 ft from subject = DoF .71 ftSubject distance effects DoF 50mm lens @ f/4 working 20 ft from subject - DoF 12.7 ft50mm lens @ f/4 working 10 ft from subject - DoF 2.94 ft50mm lens @ f/4 working 5 ft from subject - DoF .71 ft50mm lens @ f/4 working 2 ft from subject - DoF .11 ftAnother DoF 'Gotcha'The bigger the image sensor, the longer your focal length.The smaller the image sensor, the shorter your focal length. A typical point a shoot camera will have an actual focal length of 5mm - 35mmThat provides the same effective viewing angle as a 20mm - 140mm zoom on a full frame DSLRBecause of the smaller sensor, you must shoot at 24mm instead of 100mm (See 24mm vs 100mm above)