Back focus adjustment

D

Doby45

Member
I just need what would appear to be a simple question answered for me. I have looked and read most every thread on DIY adapters but I have yet to find the exact answer I am looking for. When I am building my vibrating adapter do I adjust the back focus with the adapter off the camera or on it? I am building mine with the Nikon mount and the Canon EE-a focus screen. I know my distance from the front of the Nikon mount to the front of the focus screen should be 43-45mm and adjust from there. I plan to start mine at 44mm and have the 50mm Nikon lens attached and set to infinity. Is any certain aperature better to use for the focusing aspect, such as 5.6? So should I have the adapter attached or should I just look through the CO at the focus screen?
 
Nevermind, in my continued search I found that you need to look directly at the back of the GG and adjust it back and forth until it is in focus, with the lens on infinity. Just in case anyone else needed to know.
 
OK, I know I answered my own question above, but I would like some input from the gurus if possible. My questions is "What have you found to be the best way to get crisp back focus/focal distance?" I mean I used a house about a half a block away from mine with the lens set to infinity and moved the GG back and forth until I thought it looked pretty crisp. But, is there a "better" way to get a more precise focus? The image is tiny, so I am thinking I might readjust it using something that is more high contrast to achieve a more accurate focus. Can you use a magnifying glass to see the image better, kind like using the "peaking" function on some cameras LCD? I know this stuff may sound a bit stupid but I would like to do the best job I possibly can.

I have gotten my adapter completely built with except to the pentiometer for my battery voltage. I hook the motor up with my Maha 1.2volt AA and it rattles the whole camera, even to the point that the actual image looks like it is vibrating. LOL So I have disconnected the battery and have played around with it today as a static adapter.

I just want to list the settings I have used so far in testing and see if any of them sound like "WHOA, thats out of whack dude!" to you guys..
Nikon 50mm 1.8 @ 5.6 (mainly) I have tried other apt settings
Canon EE-a screen in a Daniel vibrating holder
Focusing screen approx 44mm from front mount of tube.
CO +7 about 1.5" from the GG
SonyVX2100 zoomed in just a tad past the image filling the LCD
Then playing with the focus on the VX2100 until something comes in "crisp"
Exp on the VX2100 is set to OPEN (figured it did not need to be closed down any)

Does anything just seem whacked, other than me running a VX2100 and posting on a DVX board? It is just that so far I have found the best adapter info right here, regardless of camera. I will work on getting some test fottage together as soon as I get the pentiometer at RadioShack tomorrow.

http://i22.photobucket.com/albums/b327/Doby45/DOF%20Adapter/DSC_0282.jpg?t=1183948738

http://i22.photobucket.com/albums/b327/Doby45/DOF Adapter/DSC_0272.jpg?t=1183948849

http://i22.photobucket.com/albums/b327/Doby45/DOF Adapter/DSC_0271.jpg?t=1183948944
 
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