I saw a number of questions in the original post I didn't see answered directly (although I may have missed it), so:
Originally posted by alamo5000 Maybe I am incorrect but I am directly correlating bokeh capability to the f.stop numbers...
The term "bokeh" refers to the *quality* of the out of focus area, not the *quantity*. The quantity of out of focus area does indeed depend on aperture (also focal length and/or shooting distance), and is measured as "depth of field". More DOF means less is out of focus, and that comes from small aperture (large f-numbers); less DOF means more is out of focus, and that comes from larger apertures (small f-numbers). But "bokeh" is how you compare to images at the *same* DOF - which one renders the out of focus areas more pleasingly, in someone's laregly subjective determination.
Quote: I have a 28mm f 2.8 but I find that lens only creates marginal bokeh.
Translation: f/2.8 does not create very shallow DOF at 28mm, whereas it does at 100mm. But the *quality* of the bokeh is another matter.
Quote: If I could go the other direction too... say a 28mm lens with a 1.4 or 1.8 or whatever the best I can get in manual lenses...
They exist, and do give shallower DOF than a 28/2.8, but these lenses are not known for the stellar *quality* of their bokeh.
Quote: I have even heard of people using macro lenses to take regular pictures with...for the exact reason I am talking about...
I have never laid hands on a macro lens so I don't know what's different about those...
Nothing that is relevant here. You are mistaken if you think people take regular pictures with macro lenses for this specific reason. They do so becuase a macro lens is not fundamentally different from a regular lens and can thus do everything a regular lens can do, so why *not* use them to take regular pictures? The only significant difference between a macro and non-macro lens is that the former allows you to focus from closer. It might happen that any given macro lenses might also have nice bokeh, but it won't have any shallower a DOF than a non-macro lens, and there is no special reason macro lenses would have better bokeh for the same aperture. Although the D-FA100/2.8WR does have rounded aperture blades - that is a factor that affects the quality (not quantity) of bokeh in a good way. There are non-macro lenses that have rounded aperture blades too, though.
Quote: For example if you look at Pentax's website they have a 300mm fixed lens that has a f4 to an f 32 range... its all auto...why can't they put an f 2.0 on a lens like that????
1. price
2. size
3. weight
A 300/2 would be the size and weight of a 15 pound sack of potatoes and cost about as much as not just one but *two* brand new Honda Civics. See the 300/2 Nikon once made:
Nikon F 300/2