Is this CA?

H

handiman15

New member
Hey guys, I just got my HPX package all together (minus lens - still pondering what to get). I have a shoot for the next week and we are using Fujinon HD Prime lenses. I have used these before on a Varicam and have had good success. We one time rented digiprimes and had the same effect I am getting w/ the fujinon hd primes on the hpx500. I have a link to video to let you guys see.... I figured on such $$$ lenses that this wouldn't happen.

Link to video:
http://www.mediafire.com/?sharekey=5f6f580c76541fa5d2db6fb9a8902bda
 
I'm not sure what that is, but I'm pretty sure it's not CA. Something definitely seems wrong though.
 
Not sure either. Its like a magenta, and was only when it was totally off focus. Could it be this lens is offsetting the image slightly so the RGB CCDs are seeing it incorrectly? Just a theory.
 
lens shading is a bit fuzzy to me. this is my first picnic with an eng camera. can somebody give me the reader's digest version of what it's all about?
 
I don't know how to explain it best but its sort of like a variable white balance for your frame. 3-chip camera lens systems have certain color casts (that often graduate like shown) Doing a lens shading with a new profile will let the camera know how your specific lens is shaded. It then compensates for the color shifts. You can read how to do it in a camera manual.

Here is how I would go about it:

After setting backfocus with a new lens, you evenly light a pure white sheet of paper (or large white balance card). Mind your exposure so you don't get into using your ND's. Than perform a normal white balance (make sure your exposure is letting the white paper be "white" and not under exposed). Then you go under the lens menu and go to profiles, set up a new one and perform the shading adjustment (this is automatic, like the white balance) Save the profile for that lens and your good to go. This should be done when you are using a new lens, if you are using a color-matched set of lenses (like Canon HD primes or Digiprimes) you should only need to shade one lens(as they should be matched)
 
ok so i did the shading per the instructions in the manual. it said to do the same thing you just said. the last step is while shooting the paper, you go into the shading section and set the luma. it said to completely fill the frame with zebra which i did. but every time i hit "ok" it tells me i don't have enough light. the only way to make it accept the shading is to open the iris to the point the zebra goes away. confusing... i def had plenty of light. 500w softbox 4 feet from the paper. my zebra came in at f8 which is within the range specified (f4-f11). any thoughts?
 
What are your zebras set at? They should be at 100% for this. You might want to use 2 lights on both sides of the paper to flat light it. If the shading looks ok- (check on full resolution monitor) than your done.
 
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