|
|||||||||
|
Thread Tools | Search this Thread |
June 25th, 2006, 09:31 PM | #16 |
Regular Crew
Join Date: Oct 2002
Location: Los Angeles, CA
Posts: 82
|
Remember when you were a kid and used a magnifying glass on a leaf to burn it?
That was focusing that wide area of sun to a smaller area, thus concentrating the light. Your lens does the same thing only it passes through several maginifying glasses. So you effectivly, rather than a ant or leaf you are focusing the sun on your $6,000+ CCDS. It probaly won't get hot enough to do damage, but it's still a bit silly. I would reccomend using a Glass ND filter of you must get the shot. my 2 cents.
__________________
Thanks! Adam Craig Los Angeles, CA www.showiki.com - Entertainment Biz Wiki www.filmexposure.org - My Media Company Last edited by Adam Craig; June 26th, 2006 at 12:48 PM. |
June 26th, 2006, 11:08 AM | #17 |
New Boot
Join Date: May 2006
Location: Boulder colorado
Posts: 16
|
Adam Craig put my dilemma clearly:
"Remember when you were a kid and used a magnifying glass on a leaf to burn it? That was focusing that wide area of sun to a smaller area, thus concentrating the light. Your lens does the same thing only it passes through several maginifying glasses. So you effectivly, rather than a ant or leaf you are focusing the sun on your $6,000+ CCDS." This leads me to wonder about what John Mitchel describes: "CCD's seem to be more prone to gamma length radiation (ie that experienced at high altitude in an aircraft) - no doubt prolonged overexposure to high UV could damage them, but ND'd down correctly and with a single UV filter should be fine." I certainly will take these precautions in the future, but I'm afraid that I already shot the sun (at least, at max telephoto and with a Haze 1 "lens protector" filter that Tiffen claims absorbs almost 3/4 of UV light) without thinking about it, and of course shutter speed is irrelevant, and I did it at 8,200 feet, which probably counts as "high altitude." So, my concern is about what I may have already done. I know what to do next time (and thanks to all for their suggestions!)! What Jiri Bakala says is reassuring, "I have never heard of damage to a CCD camera caused by shooting the sun." I hope that his never having heard is because it doesn't happen, but intuitively I am nervous. Testing and time will tell. But, if anyone has ever heard of such damage, I would like to hear about it. Thanks, Robert Schaller |
June 26th, 2006, 01:12 PM | #18 |
Major Player
Join Date: Apr 2005
Posts: 512
|
I've got an idea. Detach the lens from the camera and hold it up pointing at the sun so that it's focusing the light on a thermometer bulb. Now we can see exactly how much energy is getting transmitted to the CCD.
|
June 26th, 2006, 01:39 PM | #19 |
Trustee
Join Date: Apr 2006
Location: United States
Posts: 1,158
|
gamma radiation damage shows up as bad pixels. to do this, you need to put the camera on a plane. the fix is the dead pixel mask routine to remove them.
AFA shooting the sun, I put several hours on my 327A a few years back shooting elciplses, with welders ND filter and no extra filter. no damage. YMMV, but I would not expect a problem. Again, its making the image of the sun SMALL that is of potential harm - meaning a wide angle shot, not a full the frame long lens shot. I would not worry about it. we put wide angle lenses onto cameras everyday with the sun in the shot - is there ever a problem ? ( tube cameras excluded :) ).. nope. Steve Oakley |
June 26th, 2006, 05:16 PM | #20 |
Major Player
Join Date: Apr 2006
Location: Kingman Arizona
Posts: 298
|
just don't look threw the vf, could damage your eyes from the uv rays.
|
June 26th, 2006, 05:51 PM | #21 |
Major Player
Join Date: Jul 2004
Location: Phoenix, AZ - USA
Posts: 300
|
I'm thinking this is the kind of thing visual effects were invented for. And rental shops.
|
June 26th, 2006, 06:16 PM | #22 |
Capt. Quirk
Join Date: Apr 2002
Location: Middle of the woods in Georgia
Posts: 3,596
|
Or cheap cameras.
__________________
www.SmokeWagonLeather.us |
June 26th, 2006, 09:34 PM | #23 | |
Major Player
Join Date: Apr 2004
Location: Kelowna BC Canada
Posts: 706
|
Quote:
__________________
www.ascentfilms.com |
|
| ||||||
|
|