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-   -   Lens reflection in filter problem (https://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/107329-lens-reflection-filter-problem.html)

Andris Krastins November 6th, 2007 05:59 AM

Lens reflection in filter problem
 
Hi,
I always use a UV filter on my XHA1 so that the lens is protected from dust and other environmental factors,
but sometimes, when I shoot straight at a spotlight or sun, I get a reflection of the lens in the filter and so that reflection is filmed on tape and I get an end picture with visible camera lens.

Is it because of a cheap filter or it's just something to avoid and a question of right technique?

Thanks

Shiv Kumar November 6th, 2007 06:07 AM

Andris,

I've used UV filters on the A1 and done what you say but not seen the camera lens' reflecting on the filter. :)

What was the aperture setting at that time?

Typically, when you shoot towards the sun or other bright light, you'll see all the dust on the UV filter and lens, as a result, I tend to take off the UV filter for such shoots and clean lens really well too.

Andris Krastins November 6th, 2007 06:14 AM

I had iris fully opened at about 1.2, shutter speed was at 24 frames, gain was +0, sometimes +6 (was shooting a live concert in a darkish club) and I use a HOYA UV filter.

Thanks for your suggestions, I gathered as much myself, but am curious if maybe there are simply better, more suitable filters.

Nathan Quattrini November 6th, 2007 09:26 AM

it may be the uv protector. I have the same issue, using a basic tiffen protector that I got free with the camera...so its probably bottom of the line :\

Ivan Mosny November 6th, 2007 12:08 PM

These are differences between coating of UV Filters - but you will have this problem on Wide angle even with best filters. To eliminate this you need a French Flag or bigger Matte Box. Something like this:
http://picasaweb.google.pl/ivamosmeister/HardCase

Andris Krastins November 6th, 2007 12:33 PM

Thanks.
But what brand UV filters do you suggest for non-wide angle?

Ivan Mosny November 6th, 2007 12:50 PM

I am using UV only to protect my lenses. It will be not a good idea to buy expensive filters for this an have need to protect the filters. These are no noticeable differences in Camerapicture for me - electronic devices can`t make use from UV protection. Due to this i use cheap Hama or Hoya UV Filters.

Andris Krastins November 6th, 2007 12:55 PM

I'm using them for the same purpose, but I'd like ones with a less reflective surface.

Ryan Avery December 27th, 2007 12:45 PM

Quote:

Originally Posted by Ivan Mosny (Post 771136)
I am using UV only to protect my lenses. It will be not a good idea to buy expensive filters for this an have need to protect the filters. These are no noticeable differences in Camerapicture for me - electronic devices can`t make use from UV protection. Due to this i use cheap Hama or Hoya UV Filters.

I would have to disagree. UV filtering is still important for digital use. UV rays can cause a blue cast to your video. Removing the UV rays from the spectrum recorded creates an image free of unwanted color balance which is independent of white balance issues. A quality UV filter is also very important because high quality UV filters are coated on both sides of the lens thereby reducing reflections internal to the lens and keeping your camera from imaging the reflections caused on the backside of your filter.

Ryan Avery
Schneider Optics

Steve Wolla December 27th, 2007 04:47 PM

I use a B&W UV filter and have never had any problems with reflections, etc with it. Go with quality, you won't be disappointed. The A1 is a beautiful $3500 +/- $$$ cam, I personally do not see why a "cheap" filter would be desireable. To save maybe $25 to $35??? Don't handicap that nice "L" series lens.
With respect to removing reflection from frames already shot, you may be able to load the offending clip into Photoshop and remove it, then send it back nto your NLE.

Allan Black December 27th, 2007 04:51 PM

I agree Ryan, a long time ago I found that out the hard way.

Unfortunately when you buy an expensive camera like the A1, there's a tendency to baulk at having to spend more on quality accessories like filters and mics.

But the weakest link in the chain will let you down, then you waste time, money and good video catching up.
Cheers.

Tom Roper December 27th, 2007 09:38 PM

Quote:

Originally Posted by Steve Wolla (Post 798944)
I use a B&W UV filter and have never had any problems with reflections, etc with it. Go with quality, you won't be disappointed. The A1 is a beautiful $3500 +/- $$$ cam, I personally do not see why a "cheap" filter would be desireable. To save maybe $25 to $35??? Don't handicap that nice "L" series lens.
With respect to removing reflection from frames already shot, you may be able to load the offending clip into Photoshop and remove it, then send it back nto your NLE.

I use a B&W UV filter as well, but there can still be circumstances where you will see a reflection of the lens.

Bill Busby December 28th, 2007 02:02 AM

go with multi-coated filters & you shouldn't have those reflection issues... or at least much minimized.

Bill

Don Palomaki December 31st, 2007 08:56 AM

All lenses, even multi-coated, have reflections, just that quality multi-coated lenses have a significantly lower level of reflections. Uncoated lens surfaces reflect about 4% of the light, single-coated lens surface about 1-2%, and multi-coated even better at on the order of 0.5%

In most shooting situations involving average scenes, the reflections go unnoticed, even from low cost lenses, because the scene is brighter than the reflection and scene complexity masks what reflection might other wise be visible. However, if the scene contains large dark areas, the reflections may become apparent. Also, they may be more apparent if the lens (not just the CCD) can see very bright point sources of light.

Use filters when they improve the image, provide an image effect you are seeking, or provide protection from unacceptable environmental risks. Avoid using filters when there is no clear benefit. UV is most likely to be an issue during outdoor daylight shooting, especially at high altitudes. Not likely to be an issue for most indoor shooting.

And practice with the filters you plan to use under various lighting conditions to determine that artifacts they produce, and when they become objectionable.

Nik Skjoth January 6th, 2008 11:30 AM

The hoya UV-Filter effectivly removes that lens reflection effect. I had the same issue in the past, when shooting towards the sun... Now thats all history. I would even give Hoya so much credit that you can almost ditch the mattebox. "almost"


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