I'll not go into WHY you might want/need to use an adjustable "focusing rack" (there's plenty of expert discussion on the net), but here's pictures of three useful racks I assembled from cannibalized bellows racks.
A combination bellows and focusing rack may only require that you remove the unnecessary bellows parts. Some brands, e.g., an older Minolta slide copier/bellows set which has the bellows on the upper rails and the tripod mount in an adjustable slide on the bottom double rails with a camera mount fixed to the rear end of the lower rails just requires removing the top bellows rail.
Other brands, a Vivitar set on single rails for instance, required sawing (yes, a hack saw) the bellows supports off the movable tripod- and fixed camera-supports to eliminate the bellows hardware. This type typically has L-shaped support rails as well as the round slide rods as seen in the picture.
Not wanting to waste parts, I converted the spare bellows rail components into a shorter (and much more convenient) focusing rail. This involved removing the bellows and supports (hack saw again), reversing the left-right position of the focusing rail rods, inverting the focusing block to match the left-right re-position, and drilling and tapping a new mount socket (1/4 x 20 thread). The wounds have been cosmetically cleaned up with files, sand paper and flat black enamel.
Since the length of the focusing rails is much longer than I find useful (they're actually designed to accommodate max bellows extension), I took this opportunity to reduce the rods to half the original length. This make a much more compact device with no reduction in utility for my needs.
A portrait orientation L-bracket was designed to fit only the K200's dimensions for simplicity.
One nice thing about these accessories is you can cobble them together from older, non-Pentax components available at bargain prices. Total cost: about $45 and there's still one more set of parts for a fourth unit if I fabricate end blocks for the rods.
A Quantaray/SunPac mini-tripod as shown has worked well with these rails for table-top close-ups as well as field use when combined with other natural supports.
Directions for finding the "entrance pupil" of a lens for panoramic setups with this sort of adjustable rail are also readily available on the web. Since ulta-long lenses aren't often used for pans, the short rail is quite satisfactory for this purpose with only 2-1/4 inch adjustment available. A micro bubble level attached to the rails is also useful but not shown here.
H2
Coupl'a questions arose:
- as to whether the rails were 'bass-ackwards' on the fourth pix. Yes, and no, The camera/lens can face either way and still use the movement to adjust the focus. Whatever is most convenient (and stable).
- Search the web for tutorials on how to find and set the "entrance pupil" to compensate for parallax for panoramic shots.
Last edited by pacerr; 06-25-2009 at 09:22 AM.
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