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Old 13-08-10, 19:47
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Don Hoey Don Hoey is offline  
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Join Date: Dec 2005
Location: Norfolk
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Default MkII part 2

Precision dof stacking guide.

To overcome the problem of precision dof stacking I resorted to using workshop clocks otherwise known as dial guages. I have two of these. One with a max travel of 10mm with face graduations marked at 0.01 mm. The second unit is an imperial one with max travel of 1/2 inch with face graduations in 1/1000 inch. I just know my computer will struggle with massive stacks so they will do.

The clock stand is just a weighted steel base. The base is heavy enough not to move in use but easy to slide out of the way to set up focus on the front point . The base is then moved into position and the clock zeroed. A simple matter then to determine far focus by moving the whole camera/bellows/lens assembly forward using the chromed handle on the Myford slide. The total depth of the zone of required sharpness can then be read off the dial and some calculation made as to a suitable increment for each exposure. Move the slide back to the start position as indicated on the clock and snap away. The major advantage of using a clock as opposed to the micrometer dial on the slide, is that you do not have to take backlash in the slides leadscrew into account. Any movement of the slide will record on the clock.

Don
Attached Images
File Type: jpg Clock assembly.jpg (161.7 KB, 12 views)
File Type: jpg Clock face.jpg (143.0 KB, 5 views)
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