Must watch video on full frame vs crop cameras. "Full frame look" covered. In: Cameras Posted May 22, 2014 tupp, you didn't check the meaning of 'circle of confusion', did you? You take for granted, that when you see a projection, there don't need to be reflective textures that are fine enough to define the individual picture element you recognize?No.I do not wish to get into a semantics argument, but the definitions of depth-of-field and circle-of-confusion involve basic, well-established optical properties that apply to imaging. The resolution of the sensor/film (and projector/monitor) is not a consideration, as depth-of-field is a purely optical characteristic.The Wikipedia page on depth-of-field addresses this very point (note limitation #6). This is, excuse me, a rather naive way of understanding optical laws.No need to get personal, but you would be mistaken if you considered sensor/film resolution as an optical property. Softer? You mix up resolution and sharpness. Low resolution images may look out of focus when scaled to the same size as a high resolution image.The term "Softer" is generic. It can apply to the properties of both resolution and sharpness. I never wrote: CoC is the most important factor for DoF, but it is inseparable,I never stated that you wrote so. and therefore your statement 'a given depth-of-field optically remains constant, regardless of sensor/film resolution.' is wrong, given, that there always has to be a medium that receives the light coming through the lens - be it dust or smear on a glas pane, chalk grain on a wall, silver nitrate crystals, pixel circuits, your retina's rod cellsThe focal plane/surface is part of the optical system, but the resolution of the medium at the focal plane/surface has nothing to do with optics. Instead of arguing, you could make a test of your own. Open the aperture, then film with your camera's highest ISO/gain. You will find a considerably bigger depth of field than with your lowest ISO.It's not proportional to what would change with closing the aperture, but nobody said so.Huh?I am not sure what you are proposing, but it appears that you are suggesting that the depth-of-field will change if I merely vary the ISO setting on my camera while the lens and its aperture remain the same.Is that what you are saying?If so, would you be interested in a little wager?