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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

Don Parrish January 4th, 2002 04:17 PM

Banding without UV / floating dots with
 
Interesting enough, my next shot without the UV in bright lighting presented some vertical banding as warned by Chris. With UV floating dots occur, without UV banding occurs. I guess I will have to purchase a second UV filter and see what happens when 2 UV filters are screwed together. I need to find an answer to this problem bad. Since filters have such a great effect on the problem, I'm hoping the answer will be with filters. I guess I need a filter guru, anybody out there a specialist on filters???
Donny

Don Palomaki January 4th, 2002 04:53 PM

Look for high quality filters with anti-reflective coating if possible. Low cost filters may be prone to refelctions and light scatter.

Chris Hurd January 4th, 2002 09:30 PM

Donny, I can probably get a filter guru to pay us a visit here. Do you have some frame-grabs showing each kind of problem? Just a full-size, full-resolution .JPEG still image taken from the video will do.

Nathan Gifford January 6th, 2002 09:43 AM

Check for dust too.
 
You might want to check for dust both inside and outside the cam. Dust on any of the surfaces will will be easily illuminated in bright light.

When I first got my (first) cam I found dust on the inlet to the CCD. When I had really bright conditions they became readily apparent. After a lot of cleaning and inspecting with my jeweler's glasses I finally got it clean.

The reason those dots could look like floaters is the image stabilizer is on. Heck, I had a flagpole move once with the stabilizer on and the XL on a tripod.

I returned the first cam later because the banding problems were related to a faulty tape drive.

Happy Mardi Gras,
Nathan Gifford

Vic Owen January 6th, 2002 10:01 AM

Nathan--

Was your banding problem similar to mine? (Check my post under "Audio Dropouts.)

I've had several instances when the start of the tape was either horizontally banded (old video interlaced with new), or nothing at all, sometimes for several minutes.

It always occurs at the start of a tape-- once it's recording OK, it stays that way.

A trip back to Canon didn't fix it.

Just wondering....

Vic

Paul Robinson January 7th, 2002 05:30 AM

Hi Vic.

Funny you should mention this banding.

I bought an XL1 to begin with, and was bitterly disappointed with it, so returned it with this exact fault (happened right out of the box).
Canon returned it saying "Operator Error" which is technical speak for "Naff off and stop bothering us", but suspiciously the problem had disappeared.
I managed to get hold of the technician notes off my reseller, who had only passed on an abridged version of the notes, and it said on there that the tech had cleaned the tape transport path which was 'seriously soiled'. Funny it should be soiled right out of the box huh? I have my suspicians that they replaced the heads and just wrote that crock to cover their tracks. Technicians do that kinda thing (Being a tech myself at one point :) )

It's bad Karma telling a customer that the unit was seriously faulty right out of the box.

I'd suspect my video heads if I were you...

Nathan Gifford January 7th, 2002 09:27 AM

How close to the beginning of tape?
 
If its happening near the absolute beginning of tape, I might not worry as I always start in a few seconds. My NLE likes to give itself a few seconds before it starts capturing anyway.

If you are recording over previously recorded tapes, that always gave me intermittent problems. I try to avoid that except on practice tapes with my wife as the operator. I certainly know plenty of other XL-1 owners who never had a problem and maybe I would not now, now that I am more experienced with the cam.

As for Paul's comments about filth, believe me that first cam was FILTHY! There were black flakes in optical sections, heaven only knows what the tape drive must have looked like. Four passes of the head cleaner (the max recommended) did not fix the problems.

Since I was still within the first two or so weeks of ownership, the vendor just swapped out the cam. The one I have now has work flawlessly for me ever since.

Happy Mardi Gras,
Nathan Gifford


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