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-   -   Nasty lensreflection with Tiffen UV protector (https://www.dvinfo.net/forum/open-dv-discussion/22895-nasty-lensreflection-tiffen-uv-protector.html)

Tom Stas March 14th, 2004 12:27 PM

Nasty lensreflection with Tiffen UV protector
 
I have a PD150 and i'm very happy with it. I bought the Tiffenfilter with it to protect the lens, but this one gives a bad mirror immage of the lens on sunny days.
Can anyone tell me why this is happening, if this is normal and what i can do about it (buy different filterlens, or add a polarisationlens??) I don't even have to face directly to the sun for this nasty mirrorimage to appear. I know that sunflare is normal, but what about this. It's really bothering.
Check it out here:

http://home.hvc.rr.com/debbiestas/With.png
http://home.hvc.rr.com/debbiestas/Without.png

Thanks for anyone that can help me out

Ken Tanaka March 14th, 2004 01:29 PM

Tom,
Part of what I see in "with" is normal extreme lens flare, caused by the angle of the sun with respect to the axis of the lens. Yes, I can also see the reflection of the lens from the filter.

Lens flare is principally a matter of camera handling and light control. Shifting the camera slightly or flagging the light would have taken care of this in your shot. There are also much subtler versions of lens flare that appear as a haze in the image, when strong lights are allowed to skim across the lens at nearly right angles to the lens' axis. (This is where the flags and wings on matte boxes come into play.)

There are multi-coated UV filters that can help to minimize internal reflections, although none will eliminate them entirely in certain conditions. Shooting in dark conditions with bright point sources often produces a "firefly" effect as the lights' reflections bounce merrily between the lens and filter.

It has become common, and somewhat thoughtless, practice for many people to keep a UV filter on their camera for protection of the len's outer element. Personally, I only use filters when absolutely necessary. If shooting in dusty, wet or otherwise hazardous conditions I will use a UV filter. Otherwise I shoot without one.

I recommend doing some experimention to gain a good understanding of your camera's optical characteristics.

Jeff Donald March 14th, 2004 02:27 PM

This a known optical defect that all lenses have. It is covered in our articles here (see number 9, Ghost Images). A better filter will help (B +W, Heliopan) but it will still be present.

Johann Adler March 15th, 2004 07:09 PM

Hi everyone,

Thanks for sharing that information. I bought a multi-coated UV filter for my camcorder in the first week of use to prevent dirt/scratches on my lens. If the UV filter causes this effect in certain conditions, then are there ways to safely clean a camera lens?

I have eyeglass cleaning solution and wipes; can they work?

Also, does modern camcorders have a built-in UV filter. If not then, isn't one necessary in bright light?

Sorry, one more; does a neutral density filter also cause this ghosting effect?

Thanks,

Frank Granovski March 15th, 2004 07:26 PM

You can pick up a lens cleaning kit from most camera shops. It consists of a bulb-brush, cloth and sometimes a bottle of solution---which I don't recommend. A blow bulb/brush and cloth is all you need.

If I read what you wrote correctly, I suggest keeping the UV on, and not off, use a lens hood, and don't shoot into the light.

Cams don't have built-in UV filters. Why would you what that? The UV is to protect the lens---and what if you want to use a polarizer? You won't be able to get the UV off because it's built-in. Less glass is better, but you also need to protect this glass.

Regarding ND filters: don't shoot into the light. :-))

Jeff Donald March 15th, 2004 09:33 PM

Some eye glass cleaning materials contain silicon and will leave a residue on the lens surface. I prefer micro fiber cloths for cleaning optical surfaces. They can be used wet or dry.

Rob Belics March 15th, 2004 10:40 PM

Just leave the UV off if that's causing the problem. Unless you shoot in high elevations, you don't need it. I haven't used one in years. Protect the lens? That's what lens caps are for. UV filters are to filter UV.

One of the best lens cleaners is free. Breath your hot breath on the lens and wipe with lens tissue. But just use a brush or bulb to get dust off.

Johann Adler March 16th, 2004 01:58 PM

Thanks everyone for your advice.


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