Will a dSLR and compact camera produce the same bokeh output at f/2.0?

Question

Will a Nikon D80 + 50mm f/1.8D and a Lumix LX5 set both at an aperture of f/2.0 (50mm @ f/2.0 for D80 and 24mm @ f/2.0 for LX5) have the same bokeh ouput? I plan to get the LX5 as a second camera, and I love "bokeh-ish" shots, so I'd like to know your thoughts.

I don't know if the distance between where I am and where the subject is will matter (i.e. I have to be closer to the subject with 24mm to get a similar framing as with the pic I take with 50mm), but I do know that the degree of "out-of-focus" of the background will depend on the distance between the subject and the background. Again, I don't know if this is relevant to the question or not...just thinking out loud. :D

Asked by Eric

Answer

No. The sensor size plays a major part in bokeh. Sensor dimensions of your dSLR are about 3 times bigger than sensor of the compact, so a photo taken with compact's 5.1mm f/2 will look similar to one taken at 16mm f/6.3 using APS-C sensor. Also, the shorter focal length will reduce bokeh effect, because wider angle of view means more background has to fit into same image space and therefore each background object will be projected smaller (more dot-like, i.e. sharper).

Here's a quick comparison of two photos with similar subject, both at f/2, first taken with a compact camera (at its widest focal length) and second with a dSLR (58mm lens):

The angle of view will be similar near the longer end of the LX5 lens, where maximum available aperture is f/3.3; to see how its bokeh would look like, set your 50mm on D80 to f/10.

Here's a quick comparison of two photos with similar subject and similar angle of view, first taken with a compact camera (at its longest focal length) at f/3.2, second taken with a dSLR (58mm lens at f/11):

To get bokeh effect on a compact camera, you have to pay up for a large sensor, such as in Fuji X100 or Sigma DP2. And even then, the effect will be weaker, because the angle of view of those cameras is wider than your 50mm on a dSLR. Or, you could rely on some alternative techniques to get good background separation.

Answered by Imre

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