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-   -   XL1S Lens Flare (https://www.dvinfo.net/forum/canon-xl1s-xl1-watchdog/563-xl1s-lens-flare.html)

Don Parrish December 25th, 2001 12:45 PM

XL1S Lens Flare
 
During a recent shoot I found myself having a few extra moments waiting for the next shot, After shooting the normal stuff I turned off the video light and decided to shoot an existing light shot of a medivac helicopter. I found that almost all existing light shots suffer from lens flare from surrounding lights, headlights, strobelights, almost all lights, understandibly from bright lights but almost any light gives my lens lens flare. can anyone offer suggerstions for eliminating this in the XL1S 16x standard lens with a promaster skylight filter.
thanks
Donny

Mike Bebber December 25th, 2001 09:42 PM

I had the same problem when shooting night shots of city lights with my XL1s. The lens flares had a green tint to them too. While changing lenses I noticed that the CCD chips behind the lens was the same color. It appears that the light was reflecting off the CCD chips and shining back onto the lens filter. I tried removing the UV filter and nearly all the lens flares were gone. Any time I shoot at night now I always remove any screw on filters I have on the lens. I don't know what you would do if you wanted a starburst effect.

Chris Hurd December 25th, 2001 10:02 PM

You're not seeing the CCD chips behind the lens... you're seeing a prism, which splits the incoming light to each of the three CCD's.

As the XL1 manual warns, you must *always* take great care when pointing the camera toward a bright light source. Green lines and other lens flares are a common by-product.

In other words, it's not a "bug" or a problem with the camera... it's just the hazards of shooting video that you must be careful to watch out for.

Don't purposefully drive your car into deep pot-holes; likewise, don't point your camera at bright lights. Hope this helps,

Mike Bebber December 25th, 2001 10:29 PM

Well, Excuse me for being sooooo stupid!!! I stand corrected I was looking at the prism not the CCD chips.

As for the lights its not like I was trying to look at an arc welder. I was just looking at normal city lights from eighteen floors up and twenty blocks away and no zoom. The lens flares are only visible when I have a filter screwed on the lens. I don't think its a camera bug. Its just a result of the extra layer of glass on the lens and the low light sensitivity of the camera.

Ken Tanaka December 26th, 2001 01:13 AM

I, too, have noticed this lens flare-like phenomenon when using the standard 16x lens with UV filter. It's particularly pronounced whenever bright sources are at the field edges. While shooting a night football game last autumn the stadium lights became rather troublesome. Indeed, removing the filter seemed to eliminate the problem for me. I believe that the brighter light hits the lens at an oblique angle and bounces between the filter and the primary lens to create this effect. Interestingly, it does not seem to happen nearly as badly with my 14x manual lens. Fun with physics, eh?

-K-

Don Parrish December 26th, 2001 06:41 AM

Thanks
 
The next opporunity I have to try this I will, Thanks for the replies and to Chris for this forum, Great place.

Chris Hurd December 26th, 2001 10:46 AM

For Mike Bebber -- I was not aware of this issue with the UV filter -- I'll have to try this myself and experience it. Thanks for the heads-up,

Ken Tanaka December 26th, 2001 12:43 PM

Chris & Mike,
For the record I'm not at all certain that the flare phenomenon is specific to a UV filter. It might very well occur with any filter. I just happened to be using a UV, and removed it, when I noticed the problem. My lens was "nekkid" after removal. I'd bet that any glass filter might produce the same results under the same conditions, although perhaps placing another filter in front of the first might also mitigate the problem by mixing-up the reflective/refractive situation.

Don Parrish January 2nd, 2002 05:48 PM

Lens Flare solved
 
Mike and Ken get an at-a-boy for the suggestion to remove the UV filter, shooting another medivac chopper at a ball field and lens goblins were everywhere, bad, reached around removed the UV filter and they disappeared 100 percent, thanks for the help.
Donny

Ken Tanaka January 2nd, 2002 06:02 PM

Bravo!
 
Delighted to hear that this trick worked, Donny. Strange, isn't it? You'd think that the coating on the lens might keep light from bouncing around out there.

When I get a chance I think I'll experiment to see if other filters also cause the goblins or avoind them. Shooting without any lens protection makes me feel like my fly's open.

Thanks very much for feeding your results back.

Don Parrish January 2nd, 2002 08:54 PM

Yep, Fly being open describes it
 
I was 300 feet from a Bayflight chopper (leeward side) and when I went to screw the UV back on I could here the grit (yes I stopped), but the shot was completely without flare and this included the choppers strobe lights, the bright orange vapor lamps of the surrounding parking lot and some lights on the field. The lens flare is so bad with the UV on that I will repair or replace the lens rather than watch my best shots chopped because they were unusable. Perhaps a different manufacturer (better quality) dosn't have the problem, I am using a promaster UV, it says, filter factor 1 exposure factor 0.
Donny

Mike Bebber January 3rd, 2002 08:16 AM

Glad to hear that removing the UV filter helped you get rid of the weard lens flares on your chopper shots. I shoot lots of video of choppers at night where the only light in the shots are the red anti-collision strobe lights and the small red, green and white clearance lights. I noticed that when I had my Century 1.7X lens on the front of the 16X lens I didn't get the lens flares but when I took the 1.7X off and put the UV filter back on the lens flares came back.

Chris said that he had not noticed these lens flares but was going to experiment with it to see if he could get the same results. I haven't heard anything back from him yet. I hope he can come up with a fix. I am like you, I don' t like running around with my lens nekid!!!! Especially around the helicopters with all the dirt and grit blowing in the wind. Speaking of dirt blowing in the wind have you found a good way to keep it off and out of your XL1. A rain slicker or scuba diving case?

Chris Hurd January 3rd, 2002 08:25 AM

Mike, I should clarify myself a little when I say I'm going to experiment with something like this... hopefully I might be able to do it, maybe, next month... which is not at all timely, I know.

I'm leaving for MacWorld in San Francisco this weekend, which is a week long, then there's a bunch of other work to do before VideoMaker Expo West at the end of the month.

Man, I've got so many little sideline projects in mind, it feels like it's going to be *another* very quick year. But I do hope to do this and it fits some other stuff going on. Hope this helps,

Don Parrish January 3rd, 2002 11:04 AM

dirt
 
My shooting vest is an x-navy life vest with the bladder pulled out. sometimes when I think water or dirt is going to get into the camera I snap the life vest around the camera and use the arm holes put my hands thru, the neck is around the lens. It's not perfect but it's better than nothing.
Donny

telcta99 January 3rd, 2002 11:41 AM

I used the plastic wrap that came with the camera during a shoot in a factory. The camera was locked down so I didn't need to touch the controls. Some tape and a couple of clips and I breathed easier knowing at least I did something to protect the camera.

It worked so well and folds to almost nothing that I always keep it in my bag, just in case.

- Tim


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