Pixel Grid in Lens flare? at DVinfo.net

Go Back   DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XH Series HDV Camcorders

Canon XH Series HDV Camcorders
Canon XH G1S / G1 (with SDI), Canon XH A1S / A1 (without SDI).


Reply
 
Thread Tools Search this Thread
Old June 23rd, 2007, 02:06 AM   #1
Regular Crew
 
Join Date: May 2005
Posts: 29
Pixel Grid in Lens flare?

Hey guys, I just got a Canon A1 this week and I'm really excited about it. Today I went out to shoot some test footage.

Here's a clip.

And here's a still with the problem I'm having.

As you can see, there seems to be an ugly grid of colored pixels in the highlights. I guess I was pointing the camera directly at the sun, which is not a good idea, but I was wondering - what's physically happening here? I assume those pixels are from the CCD. Is light hitting the CCD's and reflecting back into the prism?

Anyway, I was not using an ND filter when I was shooting this. Would that have solved the problem? I thought that since I barely even had to stop down the aperture there was no point in using the ND filter, but I don't really know what I'm doing... Next time I'll experiment.

Anyway, has anyone else encountered this problem? Do you know what's happening? And will the ND filter solve it even if it's exposed the same way?

Thanks!

--Colin
Colin Levy is offline   Reply With Quote
Old June 26th, 2007, 07:40 AM   #2
Major Player
 
Join Date: Mar 2007
Location: Sussex, UK
Posts: 317
Hi is this one of the areas you are talking about, it looks normal, the tiny grid artifacts look like HDV compression.

James
Attached Images
 
James Miller is offline   Reply With Quote
Old June 26th, 2007, 04:58 PM   #3
Regular Crew
 
Join Date: May 2005
Posts: 29
Hey James, thanks for the response. No, I'm not talking about the artifacting due to the HDV compression, I'm talking about the big bright colored dots that show up in the flare.

The offset red, green, and blue circles. Like this:

Know why that's happening?
Attached Images
 
Colin Levy is offline   Reply With Quote
Old June 27th, 2007, 08:02 AM   #4
Wrangler
 
Join Date: Sep 2001
Location: Northern VA
Posts: 4,298
Some folks would probably pay to have that effect available as a filter in their NLE.

What f-stop was the image?

The sun is bright, perhaps 10,000-to-100,000 times brighter than the rest of the stuff in the image. What that means is even a wee bit of stray reflection or refraction in the optical path can cause the direct sun component to appear bright in the image, and going through the 3-CCD beam splitter may cause it to be displaced giving the rainbow effect. You are probably seeing the results of a stray internal reflection/refraction. The several distinct spots may relate the the number of blades in the iris.

Solution is to keep the direct sun out of the image; e.g., move the camera a bit to shade the lens from the direct sun. Using a ND would not have helped if you were interested in things other than the sun, because it effects the whole image, not just the direct sun.
__________________
dpalomaki@dspalomaki.com
Don Palomaki is offline   Reply With Quote
Old June 27th, 2007, 08:52 AM   #5
Major Player
 
Join Date: Mar 2007
Location: Sussex, UK
Posts: 317
Sorry Colin, I see what you mean now.

I love that look, I sometimes simulate the colour shift using FCP filter Prism.

As Don said move the camera so the sun is not in direct view. Or put a Matte Box on the front with french flag and keep the same camera angle. Formatt do a cheap robust box 175 FM-500.

A couple of links with pics.

http://www.formatt.co.uk/matte-boxes/products.aspx
http://www.mvsvideo.co.uk/equipment_formatt.htm


James
James Miller is offline   Reply With Quote
Old June 27th, 2007, 01:43 PM   #6
Regular Crew
 
Join Date: May 2005
Posts: 29
Hmm! I had no idea this was actually desirable...

I don't know, I love a good lens flare - you know, the photoshop variety.... But the grid surrounding the entire sun is just very distracting to me. I think if it truly was a rainbow effect, with more blending between the three distinct colors maybe it would look better.

Anyway, thanks for your tips and explanations, guys! I appreciate it. Don, I believe my iris was at around f8, but I don't remember exactly. I'll play around with the aperture next time and see if it has any effect on the number of iterations it has.

--Colin
__________________
My Film, Animation and Visual Effects Work:
http://www.colinlevy.com
Colin Levy is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon HDV and DV Camera Systems > Canon XH Series HDV Camcorders

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 11:20 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network