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<blockquote data-quote="WayneF" data-source="post: 205296" data-attributes="member: 12496">Well, if we want pixel density on the sensor, we should get a little compact point&amp;shoot camera.&nbsp;&nbsp; 12 mp or 16 mp in a tiny 4x5 mm or 5x7 mm sensor.&nbsp; Now that's density!&nbsp;&nbsp; But that density is not what it is about (and is actually the opposite of what we would want, smaller pixels, noise, etc).&nbsp; &nbsp; Simply because we cannot look at the image on the sensor.&nbsp;&nbsp; We must enlarge that image to print perhaps an 8x10 inch print.&nbsp;&nbsp; Enlargement spreads the pixels out wider... 6x wider than FX for the compact, 1.5x wider for DX.&nbsp;&nbsp; In this 8x10 inch print (which result we can actually see), which one would permit the higher resolution, 12mp, 24mp, or 36mp?&nbsp; Seems pretty obvious.Truth is, they all have ample pixels for an 8x10 inch print today, but 36 mp images allow amazing 100% crops.... amazing detail.&nbsp; Smaller sensors, not so much.Pixel density is NOT a factor in the Depth of Field formula, which is a film-oriented concept of enlargement.&nbsp; Actual concept is that a 16x20 inch print will not appear as sharp as a 4x5 inch print.&nbsp; The lines per mm on the sensor (from the lens), when enlarged greatly, become far fewer lines per mm in what we can see.&nbsp; If using the SAME lens on DX and FX, then of course it is the same image, but DX has to be enlarged more (regardless if you step back 1.5x farther or not, for same view).&nbsp; This greater enlargement of a smaller image is exactly what gives DX its telephoto effect (zoomed in, so to speak).&nbsp;Sensor size is of course a factor because it affects necessary enlargement, which also affects the arbitrary Circle Of Confusion number (as related to DOF, simply that small images have to be sharper and more detailed to withstand the greater enlargement - however, their shorter focal length for same view is the opposite factor.)&nbsp; The CoC number is arbitrary, whatever sharpness you want to assume it, however, the divisions of it due to smaller sensor is exact, not arbitrary.</blockquote>

[QUOTE="WayneF, post: 205296, member: 12496"] Well, if we want pixel density on the sensor, we should get a little compact point&shoot camera. 12 mp or 16 mp in a tiny 4x5 mm or 5x7 mm sensor. Now that's density! But that density is not what it is about (and is actually the opposite of what we would want, smaller pixels, noise, etc). Simply because we cannot look at the image on the sensor. We must enlarge that image to print perhaps an 8x10 inch print. Enlargement spreads the pixels out wider... 6x wider than FX for the compact, 1.5x wider for DX. In this 8x10 inch print (which result we can actually see), which one would permit the higher resolution, 12mp, 24mp, or 36mp? Seems pretty obvious. Truth is, they all have ample pixels for an 8x10 inch print today, but 36 mp images allow amazing 100% crops.... amazing detail. Smaller sensors, not so much. Pixel density is NOT a factor in the Depth of Field formula, which is a film-oriented concept of enlargement. Actual concept is that a 16x20 inch print will not appear as sharp as a 4x5 inch print. The lines per mm on the sensor (from the lens), when enlarged greatly, become far fewer lines per mm in what we can see. If using the SAME lens on DX and FX, then of course it is the same image, but DX has to be enlarged more (regardless if you step back 1.5x farther or not, for same view). This greater enlargement of a smaller image is exactly what gives DX its telephoto effect (zoomed in, so to speak). Sensor size is of course a factor because it affects necessary enlargement, which also affects the arbitrary Circle Of Confusion number (as related to DOF, simply that small images have to be sharper and more detailed to withstand the greater enlargement - however, their shorter focal length for same view is the opposite factor.) The CoC number is arbitrary, whatever sharpness you want to assume it, however, the divisions of it due to smaller sensor is exact, not arbitrary. [/QUOTE]

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