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Message: <blockquote data-quote="BackdoorArts" data-source="post: 240314" data-attributes="member: 9240">Bokeh is a function of two things, aperture and lens focal length (actual focal length, not effective focal length).  Bokeh increases as aperture widens and focal length increases, since both of those factors decrease depth of field (i.e. more stuff is out of focus).  Cropped sensors, because of their reduced size and increased effective focal length, lose about 1 stop's worth of depth of field.  For example, an FX camera with 50mm lens and a DX camera with a 35mm will take pretty much the same photo from the same spot since the effective focal length of the 35mm is ~52mm.  Because the FX camera has a longer lens, the depth of field at the same aperture setting will be smaller.  A 50mm lens at f/2.8 shooting a subject 6 feet away has a total depth of field of about 9 inches, while a 35mm lens at f/2.8 shooting a subject 6 feet away has a total depth of field of about 11 inches, so you lose 2 inches of bokeh.  To match the photos the 50mm will need to be set to f/4 where it will also have 11 inches of depth of field, or the 35mm will need to shoot at f/2.Whether or not and bokeh difference will be perceptible depends mostly on what elements are in the photo to actually render the bokeh.  In other words, if the out of focus elements are largely nondescript then you will likely not even notice.  But if there are many elements to be seen then you will lose some level of bokeh on the DX camera.  That said, it's possible for lens used on the DX to render more pleasant bokeh if the lens is of sufficient quality, particularly when compared to the lens used on the FX.  One more thing to point out.  The same lens used on both cameras will produce exactly the same level of bokeh at the same settings, but your effective focal length will increase, so that 50mm at f/2.8 will act like a 75mm at f/2.8 - same bokeh, but you only get the middle 1.5X portion of the photo.</blockquote>

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