Why is digital bokeh so weird?

[Alpha]

So I've seen a lot of posts recently by digital users, and the bokeh looks, well, weird. To say the least, it's markedly different than film bokeh.

Anyone have a technical explanation?

 

[fmw]

I believe the technical difference would be gradation. While digital has millions of colors, it has just 256 gradation "steps" from pure black to pure white while film has infinitely variable gradation. The tonal changes on film aren't steps like they are on digital. Gradation would affect out-of-focus areas just like it affects those that are in focus.

 

[EOS_JD]

Different lenses also provide different effects and affect the image output eg: Things like the shape of the aperture and size of the aperture

 

[chops]

Ever see the bokeh from a mirror lens before? Talk about weird looking.

 

[xfloggingkylex]

can someone post some pictures showing this difference? Having jumped into photography at the digital level I dont have any film experience and have therefore not seen (at least not knowingly) film bokeh before.

 

[Alex_B]

never realised a distinct difference between film and digital.

The bokeh depends on the shape of the aperture, and hence on the lens .. be it in digital or in film photography. Maybe "kit" lenses of digital cameras just create strange bokehs.

Not sure about what fmw mentioned about gradation differences ... that would also mean that different types of film would create different bokeh? OK, there is no real steps, but differences in contrast behaviour. There might be an effect, but to me it was never visually apparent (but then again I maybe did not look intensly enough).


Another thing is, that "crop" sensors or the even smaller sensors in p&s cams have a deeper DOF.. together with a slow lens they sometimes hardly produce any blur/bokeh in some situations. For that reason people then sometimes blur the background in postprocessing (gaussian blur or whatever) and hence create a "bokeh", which might look very different from a bokeh resulting from limited depth of field of the optical system.

 

[neea]

I too would like to see some samples.

 

[grafiks]

I believe the technical difference would be gradation. While digital has millions of colors, it has just 256 gradation "steps" from pure black to pure white while film has infinitely variable gradation. The tonal changes on film aren't steps like they are on digital. Gradation would affect out-of-focus areas just like it affects those that are in focus.

Brilliant explanation! :thumbup:

 

[Alex_B]

I too would like to see some samples.

true, I haven't seen any strange digital bokeh, exept the artificial bokehs. So where are the examples? to me bokeh varies with lenses (shape of aperture) and the set aperture on that lens, and it varies with the size of the medium (35mm, APS-C, ...).