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View Full Version : Backfocus Plug Revisited



Joe Kocsis
02-19-2009, 03:39 PM
There was mention on someone starting to possibly sell these.. I've looked around and come up empty.. So I designed my own, both based on the design in the sticky thread...

Here are two prototypes that I built....

Built into the smallest and best looking plug I could find, to make it look it pro, make it sturdy, and keep it as out of the way as possible..

The two are based on a 1k pots.. 1 is a 20 turn pot which seems to be more accurate than necessary, and may be replaceable with something larger to get a wider range.. and the other is a 1k single turn pot. The insides are epoxied to insulate and keep the components safe from breakage. I was worried the 1K single turn might not be accurate enough it seems to work well. If there's interest I may build a few of these for resale..

I am using a Brevis, but I can custom build to meet a specific focus range on the HVX for other adapter..
Tx..

Joe

http://www.nooneuknow.com/backfocusplug/bfpside.jpg
http://www.nooneuknow.com/backfocusplug/bfprear.jpg
http://www.nooneuknow.com/backfocusplug/bfpincamerab.jpg
http://www.nooneuknow.com/backfocusplug/bfponcamera1.jpg<BR>

Jason Miller
02-19-2009, 05:32 PM
cool,can you take a few pics of it opened up?

Joe Kocsis
02-19-2009, 05:54 PM
Once they're screwed together, they're sealed for life I'm afraid... The epoxy bonds to sleeve of the plug, I haven't bought extra parts yet... But it's just a resistor and a pot.. as in the sticky backfocus thread... not a lot of room in there, so I used a single 3K 1/8watt resistor.. Which unless I hear otherwise should be fine, since it wouldn't make any sense to have any kind of current running through it.. gives me a range of MF8 to MF12.. My setup is at the edge of MF9 and MF10...