So I scrapped my old hobo- version of 20x24 (saved back and bellows, of course) and rebuilt it, after few trials.
Your basic plywood, aluminum, cabinet hardware, stain, some nuts and bolts.
20x24 v2.5 by Sergei Rodionov, on Flickr
20x24 v2.5 by Sergei Rodionov, on Flickr
Now i am trying to figure out decent way to control focusing and back tilt movement
Any good links on rack/pinion style control? Or anyone can spare parts?
Congratulations! Looks like mahogany. Also notable is the clever use of what seems to be drawer or tablet rails.
But maybe the front frame should be held by some triangulated structure (diagonal braces); as it is, it must be quite susceptible to swing front-back. Just a suggestion.
Hm, thanks. These are actually heaviest cabinet rails i could have findOriginally Posted by Bernard_L
I tested it yesterday with heaviest lens i got - 36inch Cooke, it didn't seem to go funny much, but it could be b/c my bellows just didn't go as far ( i do have plans to add intermediate frame to allow for more than 37" extension - whole thing can extend to about 48-52" as far as hardware
But i get what you saying - i was thinking about making extra layer on the bottom to make center to be more sturdy anyway - adding extra extendable rails under the base, might be an idea there. Got to think on prototype..
For a moment though - there is always Alex T. solution with Bogen's extendable support for heavy lenses
Sorry I wasn't clear. I do not question the rigidity of your horizontal bed. My concern is with the front standard (vertical), more precisely, the mechanical linkage that should ensure that it's perpendicular to the camera bed. That linkage is made by two pieces of plywood held together by two pairs of rather small metal angle brackets. You might of course make these more massive, but you will gain a lot more rigidity with a pair of diagonal bars running from the mid-height point of your front standard to the camera bad; inclined at maybe 30° from vertical. It's a basic principle of mechanical design that a triangulated structure is more rigid mass-for-mass. Other view cameras are often built that way, and you would benefit even if you do not want to implement fron tilt (which would be an easy fringe benefit).Hm, thanks. These are actually heaviest cabinet rails i could have find
But i get what you saying - i was thinking about making extra layer on the bottom to make center to be more sturdy anyway - adding extra extendable rails under the base, might be an idea there. Got to think on prototype..
For a moment though - there is always Alex T. solution with Bogen's extendable support for heavy lenses
Again, congratulations.
Would something like this work? http://www.ebay.com/itm/T8-800mm-Sta...8AAOSw~gRV5Xzb
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
thanks Peter, yeah it would work , i was pondering on Amazon for a slightly different set up. I have tried longer leading shaft
tests with hack focusing shaft by Sergei Rodionov, on Flickr
but it turns out they are more of hindrance than help - you never truly get past about 10 inches, specially if its more than few rotations per inch. Plus original friction mounting didn't help - it was touch to move front standard..
But now that i have decent sliding system it doesn't need to be as pushy - may be all i need is just another T-nut to match thread i already have laying around. Hmm... That would certainly work for focusing. Rear tilts seems to be more tricky b/c mount should be few inches off axis (judging by old studio 8x10 i have laying around - i am almost tempted to just steal hardware from it ..)
Another concept i am toying with is to allow camera to be foldable. I started from there, but i couldn't source good hardware in nearby stores (except for hinges of course) to allow camera to be unfolded and staying firm in place. So for now rear standard doesn't fold. Which kind of sucks, b/c whole camera is not super heave and i would love to get it back in the field to shoot outdoors (as i did with original version)
Thinking about my sliding-box, baseboard style camera I decided that a simple screwed rod would be slow to use, heavy and difficult to fold up. On the table-vice there is a sprung half-nut for sliding the movable jaw prior to tightening it with the handle - did anyone ever try a half-nut for the last adjustments on a friction-fit sliding lens-standard or back?
The device I am describing as a 'half-nut' is a threaded half-cylinder female portion which can be lifted off the threaded rod (by means of a small lever, working against a spring) to allow coarse manual adjustment by sliding, prior to letting the half-nut spring back on to the rod for final adjustment. Under the half-nut location would be an un-threaded half-cylinder bearing to support the spring force of the half-nut.
That's acme thread
When I made my 8 x 20, I put a rack and pinion on the front assembly for focusing, but found out that it's was too difficult reaching around the back frame to focus it that way. The back rail also slides forward and backward and I found that focusing is pretty easy just sliding it with your fingers. I have a screw in the side of it that I just tighten up to lock it in place.
Also, mine doesn't fold up, it comes apart in pieces.
Hope this helps.
Dan
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