Bokeh

Photographers among us know that one of the new measures of lens performance is "Bokeh". This is a vaguely defined quality of the out of focus areas of the image. The lens must now be sharp where it should be sharp and also soft where it should be soft.

Here is an example of lovely creamy Bokeh. The passing tractor has been rendered as a beautifully smooth background that does not distract from the image.

And now here is an example of bad Bokeh, where the background is fussy and distracting, not at all smooth. (There are many that regard bad Bokeh like this as good and would gladly use a lens that did this on a regular basis). 

The problem here is that both of these pictures were taken with the same lens, a 1960's Jupiter 9 engraved proudly with "Made in the USSR" and provided with no lens coating at all...

This just goes to show that Bokeh is a fickle feature of each lens. It depends on distance, background and aperture setting. Perhaps we should all just focus on that....