I'm using sony system thus i probaly expect 3rd party lenses
so does the quality of the bokeh depends on apeture alone or does it also depends on the focal lenght?
the lower the apeture=better bokeh right?
It's an oft-advertised thing that rounder aperture blades allow for smoother bokeh. However this is not the only thing that affects the quality of bokeh. Assuming the same scene, same focal length, same settings, one lens may still produce better bokeh than another even at wide open aperture because of other design characteristics of the lens. That is far too advanced for me to explain unfortunately.
We're photographers, not physicists! :bsmilie: And some of us are measurebators.
Anyway, the Sony system does boast some Carl Zeiss lenses, but I have never tried any of them and hence cannot comment. It's also incorrect to generalize that German lenses have better bokeh than Japanese lenses, or vice versa. The best thing to do is to hunt down reviews of lenses you are interested in, and then look for sample pictures, either on Pbase or Flickr...
Personally I believe it's better to first decide what focal length you need, and then focus on the lenses that you believe have the best bokeh in that focal length range. For example, I currently use the 35mm focal length on a Canon system. The options available to me would be things such as a Canon 35mm f/2, the 35mm f/1.4L, all manner of Leica and Carl Zeiss lenses etc. Then, bearing in mind the price, compare the characteristics and see which one you like best.
Bokeh is really subjective. I'll bet my life that if you showed me a photo from a lens that supposedly produces 'bad bokeh' according to a lot of reviewers, I may still say otherwise. I think it's difficult to judge bokeh on its own. If it adds to the rest of the image, it's good bokeh. If it detracts, it's bad bokeh. This in itself means the photographer needs to take care of the choice of background, avoiding bright, distracting specular highlights, or gaudy colors (if it detracts from the idea of the image). This refers to the
quality of bokeh.
Okay, thought to add some examples here...both were taken with the exact same lens and same aperture. Of course the subject to camera distance and distance from subject to the background is different in each photo...but notice how much more pleasing it seems to be in one photo compared to the next. Choice of background is important:
Fairly bad streaky bokeh (especially top left):
Bokeh appears smoother:
But the
degree of bokeh can be controlled by the photographer to a large extent, irregardless of the lens in use. If you want a greater degree of bokeh, then:
-increase the focal length of your lens while maintaining the same subject distance (thereby increasing magnification...remember that depth of field decreases when magnification is increased)
-decrease the subject to camera distance (thereby also increasing magnification)
-use a larger aperture setting (ie. smaller aperture number such as f/2, not f/16)
-increase the distance between the subject and the background (the further away the background is from your zone of depth of field, the more blurred it will become)