Re: [OM] Birds, Bokeh, and DZes

[Chuck Norcutt]

Perhaps some of our zooms will provide excellent bokeh at one or at 
least a restricted range of focal lengths.  And I believe it varies 
considerably with distance to subject and distance to the out of focus 
elements.  A prime has got to be easier to deal with just for having far 
fewer variables.

Chuck Norcutt

Ken Norton wrote:
> I'm reminded of a lesson learned with the Vivitar 2X macro extender. This
> device sat between the lens and the camera body and not only provided
> variable extension but included the 2X multiplier optics.  The rule of thumb
> is this:
> 
> The multiplier sitting behind the extension provides magnification of the
> image being transmitted through it.  However, if the multiplier is sitting
> in front of the extension, the image will have the characteristic of the
> multiplied focal length of the lens used. The resulting images are
> completely different.
> 
> Inotherwords, if you placed a 2X multiplier behind a 50mm lens, you
> generally got a similar image to that from a 100mm lens.  And then you just
> extend this lens-combination to get the close-focusing you want. However, if
> you place the extension between the 50mm lens and the multiplier, you got
> the image characteristics of a cropped 50mm lens image. This had a
> tremendous bearing on the resulting bokeh.
> 
> I suspect that many lens designs today (especially zooms) are essentially a
> short focal-length followed by a multiplier (or variable multiplier in the
> case of zooms).  Since most lenses now are IF (internal focusing), the gap
> between the front group and the back group is being extended during
> focusing.  This would explain why many zoom lenses give the image results of
> a crop of a lesser focal length instead of the bokeh of a fixed prime lens
> of say a classic Tessar design.
> 
> AG
> 
> You want beautiful bokeh?  Get yourself a classic Zuiko 35/2.8.
-- 
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/