Why tape down focus and zoom?

dantewaters

dantewaters

Well-known member
Take a look here:
_MG_1638-leveled.jpg
 
dantewaters said:
Take a look here:
_MG_1638-leveled.jpg
Click to expand...

In order to use a DOF adapter the camera must focus onto the Ground Glass and maintain that position. Most cameras dont give you the option to deactivate the manual focus and zoom rings, so in order to avoid bumping them and losing focus most people choose to tape them with gaffers or electrical tape.
 
Assuming this is safe practice (dust and debris bonding themselves onto these gearing mechanisms) it makes sense. Thanks a lot mate.
 
Back focus can and does often change with camera temperature. I wouldn't set focus and tape it unless you're pretty sure the camera is not going to heat up or cool. Resetting focus also makes sense on the EX1 if you're engaging or disengaging the internal ND filters as there are known issues in that department. What I generally suggest these days is to set your best focus for a shot using your 35mm lens, and then periodically see if you can get it any better using the camera focus ring. The back focus adjustment is so critical to an adapter's performance, that during a longer shoot your image can actually soften as the camera body heats up.

Hope that helps :)
 
Wow dennis that very interesting...
And back focus what is it exaclty? I would assume another focus point between the lens adapter and the actual camera focus rings?
 
I've learned not to fear the focus ring. On my HVX200a I just leave the focus/zoom display on the LCD and check periodically to make sure the numbers haven't changed. Due to slight edge/center focus differences, even with an HVX-optimized LEX, in a few circumstances the ideal setting may be best a tick one way or the other, so having the flexibility is good there too.
 
I recommend checking focus to the adapter GG at each setup change (i.e. every time you move the camera). Temperature and other factors can throw things off. I used to tape down the rings but focus would slowly be lost and my shots would eventually become soft.


Marco
 
I never tape down the focus ring. Always tweak when changing setup. It takes two seconds and can make a noticeable difference in sharpness. Though I do leave the zoom in servo so I dont accidentally adjust it by hand.
 
Yeah, this is what happens when you don't keep your zoom in check.
I didn't catch this little flub in all 4 takes.
messedupzoom.jpg
 
Now I know to keep it on servo. :p


Yo the screening for the Bronx Paradise feature is tonight. You going? 7:30pm and then a party in the Bronx.
 
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