Bokeh on shots of large objects at a distance

Yes, I realize that bokeh is just a term that means: the quality of the OOF region of a photo. That being said:

We know that there are some lenses that render some really nice bokeh, like the 135L, 70-200L, 85L, etc. Most frequently you see this being used on portraits. Is it possible to get similar results when shooting large objects like cars, airplanes, etc? I'm guessing that it's harder since when you focus on large objects, you're focusing at closer to the hyperfocal distance, so the background would have to be really far away to get it blurred in a similar manner. However, if I'm doing aerial photography at 10,000 ft and focusing on an object that's ~270 ft away with a 70-200 @ 200mm I would think you would start getting a nice blur of the ground in the background of the shot.

To summarize, I guess my first question is, is it possible.

My second question is, if it is possible, how can I determine how far away the background needs to be to get the effect? I would think that it would be a function of aperture (obvoisly), distance to the object, distance to the background, and focal length.

Check this out.

http://howmuchblur.com ….8-on-a-0.9m-wide-subject

Well this is the amount of blur you are going to get from the listed lenses, at maximum aperture, when framing an area that is 65 feet wide, which seems to be a reasonable size for most air to air shots of light aircraft.

Interesting, I knew I could count on someone here to provide an answer. Thanks for the replies.

Unfortunately, I don't quite understand the y-axis of those plots. As a relative comparison it's use-able, but doesn't make much sense to me by itself. Do you know what equations they're using to generate those plots (and where they come from)?

Using that website, I looked at the results for photographing person with the 70-200 @ f2.8. The y-axis asymptotically approached 2.4 at large values of x for 200mm and .8 70mm. With an object of approximately 30ft long (14m), which is reasonable for the light aircraft I'm most interested in, the plots approach .51 and .18 @ 200mm and 70mm, respectively.

So I can achieve approximately 4 times less blur with my airplane than a person with the same lens. Thoughts on the analysis or explanations of why this occurs?

First, consider what a 'sharp point' is vs. a 'blurred circle'. A small object is merely 'a collection of a small number points', while a large object is 'a collection of a large number of points'...so if I have a small object and a large object, both at the same distance from the camera, both will have equally large size blur circles in lieu of points. That is, the blur quality is no different for the two, when both are at the same distance, the blur circle size (how 'blurry') is also no different for the two, when both are at the same distance, merely the quanitity of points or quantity blur circles (more points/circles for the larger object)