How to improve DOF with a VR Micro 105 mm when used as a telephoto lens?

[Andrew Garrard]

<p>Vince: The defocus control lenses (135mm f/2 DC and 105mm f/2 DC) give you some control over the <i>quality</i> of the background blur (bokeh), but the <i>quantity</i> of background blur is no more than any other lens of the same aperture and focal length (ye cannae change the laws of physics). By contrast, Sony's STF lens (which has an even more extreme effect on the shape of bokeh than the DC lenses do) effectively have <i>less</i> background blur than a conventional lens.<br />

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To follow on from Frank's (interesting) suggestion of abusing the depth of field, I believe there was a recent patent on the subject of taking one photograph deliberately focussed very short of the subject, so as to throw the background far out of focus, and then compositing it with a correctly-focussed shot, thus giving a similar background blur to a much wider aperture (the patent was, I believe, aimed at compact cameras). It would not be easy to get the transition between sharp foreground and blurred background to look right, but it might be worth a try.<br />

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A related thought would be to use a tilt/shift lens to try to place your background farther behind the focal plane than it would be with a conventional lens by adjusting the angle of the focal plane. This way you can throw the background a long way out of focus (it's a technique that's used to make life-sized scenes appear "toylike" by giving them an apparently thin depth of field), but it places restrictions on where the focal plane sits and your choice of camera location. All tilt/shift lenses are more awkward to use than the average autofocus telephoto, and most are expensive, but I mention it for completeness. At the cheaper end of the tilt/shift range, there's always a lensbaby, which deliberately loses sharpness away from the centre as well as letting you mess with the focal plane. Whether I could use one effectively to take a concert shot is another matter, but you might like to look into it. I hope that gives you some ideas.</p>