You are right in that the depth of field creates the bokeh (the out of focus area)...but good bokeh vs bad bokeh has to do with how the lens handles the OOF areas......some produce splotchy (distracting) vs creamy (enhances foreground) textures for the same aperture. A telephoto lens will generally produce a better bokeh (using a longer focal length) for close-up work.

Here is an example of "good" bokeh to me... on my 70-300G

This link may be helpful...

http://www.kenrockwell.com/tech/bokeh.htm

Here are my examples of what I find as "good" bokeh.

Queen Anne's Lace

Picture taken with Sony Alpha 700 Camera and Sigma 70mm F/2.8 EX DG Macro Lens, F/2.8, and 1/2000 sec exposure time. ISO speed set at 100. Exposure Compensation -.3. Metering Mode Center Weighted Average.

Green Foxtail

Picture taken with Sony Alpha 700 Camera and Sigma 70mm F/2.8 EX DG Macro Lens, F/8, and 1/320 sec exposure time. ISO speed set at 200. Exposure Compensation -.3. Metering Mode Center Weighted Average.

Thank you Vois and Nikola for the great examples and for the hypertext link to the in depth explanation. I learn a lot here at AMW.

Dave

Hi Vois and Nikola,

These are good examples you've posted. I may dig out a few to post too, the link to Mr Rockwell's site was interesting. I actually paid a little more attention to the bokeh test he did with the Nikon lenses- IMHO they are not a patch on Minolta glass! I think the only truly nice bokeh there was from the 80-200!!

Andrew

Here I did a test few days before to compare bokeh between Minolta 85/1.4G and 135/2.8STF

Please download and save the picture below:

Inside the picture, the left and right hand side is 85/1.4G and 135STF at the same distance from the object, the middle shows 85/1.4G move closer to the object, in order to make a same composition of picture with 135STF, DOF also decreased.

Please notice the pictures showing 85/1.4 @ f1.4, 85/1.4 @ f4.5 and 135STF @ f4.5

Can you find the differences between both pictures? The bokeh of 135STF is more blur than 85/1.4 @ F4.5 or even F1.4, as we say that's a "good bokeh"
The double-line effect (Japanese called nisen-bokeh) comes out at bokeh of 85/1.4G, for the meanings of double line effect, please see the website below:
http://www.vanwalree.com/optics/bokeh.html

You can also take a look on my other samples for the Minolta 135/2.8STF
http://s342.photobucket.com/albums/o415/henrywhs/135stf_a700/

I know my English is poor, hope it can help you :/

Henry

Hi Henry,

Firstly let me welcome you to AMW, good to have you here. Thanks for taking the time to shoot and post the above, I'm sure it will help a lot of people. As you say bokeh is not simply just a matter of DOF, rather how the lens can handle to OOF areas and how these are produced. In this regard the 135 STF is superior to pretty much anything else- this much is evident from the samples you've posted.

Andrew