Steve'sDigicams

daffy · Jan 7, 2006, 9:53 AM

Somehow I managed to find a 55mm circular polarization filter, about 10 years old or so? Now I wonder whether this filter is still ok...

I have attached a test image shot straight into a bright light source. The thing that really concerns me are the spots that show up around the light source in the middle of the image. Would a new filter get rid of these? I also see many short, tiny streaks going around in circles within the filter - I don't see any obvious scratches on the surface of the filter.

To what extent would these spots show up in real-world scenarios - is the filter still usable as is for my rather low abilities?

I have cleaned the filter to the best of my abilities.

Thanks!

daffy · Jan 7, 2006, 9:54 AM

... and this is almost the same view / light source without the polarization filter attached.

genece · Jan 7, 2006, 12:00 PM

The filter will work .. but I think you have an incorrect idea of what a polarizer does.

You do not shoot into the sun ..Ideally the sun should be to your left or right and you point the mark on the filter toward the sun for maximum effect.....If the filter has no mark you rotate it till you get the effect.

It will reduce glare on glass or water also...again you turn for the maximum effect.

And a good rule to follow, never shoot into the sun except for sunrises or sunsets.

And its not a good Idea to use a polarizer indoors as it blocks too much light.

The marks you see are lens flare or ghosting which is why you do not shoot into the sun and it also makes a good point for using a lens hood.

daffy · Jan 7, 2006, 12:37 PM

genece, thanks for your insight!

I only shot straight into the light source in an attempt to verify the optical "cleanness" of the pol filter, fully expecting *some* flaring :-) Because the additional, scattered flares compared to the no-polfilter-shot are obvious and visual inspection showed the streaks on the filter itself, I was worried and decided to ask :-)

If there are better ways to verify that the complete optical subsystem of my FZ5 is, well, "clean" (glass) and working (sensor-wise) without too much of an infrastructure, I'd be very interested in learning more.

Thanks again!

daffy

squirl033 · Jan 7, 2006, 10:45 PM

all those little bright spots around the light source should not be there... if they show up on this test shot, they will very likely show up to a greater or lesser degree on your other photos as well. the circular streaks are probably from your efforts to clean the filter over the last 10 years or so... frankly, i'd toss it and get a new one. a 55mm polarizer doesn't cost that much - you can get a perfectlygood linear polarizer for under $25 - and it's far better to spend a few bucks to replace a worn or damaged filter than to have it ruin a priceless or irreplaceable shot...

genece · Jan 8, 2006, 7:51 AM

Squirl may well be correct, I am not sure.

To check a camera...........

others have said to take a photo of an empty sky or a white or gray wall and look for defects.

How does the filter do in the outdoors?

I will just through this in ..to clean a lens I believe,a microfibre cloth is the best way.

On real tough marks a little lens cleaning solution on a lens tissue to dampen them may help.

Jan 7, 2006, 9:53 AM	#1
daffy Junior Member Join Date: Jan 2006 Posts: 3	Somehow I managed to find a 55mm circular polarization filter, about 10 years old or so? Now I wonder whether this filter is still ok... I have attached a test image shot straight into a bright light source. The thing that really concerns me are the spots that show up around the light source in the middle of the image. Would a new filter get rid of these? I also see many short, tiny streaks going around in circles within the filter - I don't see any obvious scratches on the surface of the filter. To what extent would these spots show up in real-world scenarios - is the filter still usable as is for my rather low abilities? I have cleaned the filter to the best of my abilities. Thanks! Attached Images

Jan 7, 2006, 9:54 AM	#2
daffy Junior Member Join Date: Jan 2006 Posts: 3	... and this is almost the same view / light source without the polarization filter attached. Attached Images

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Jan 7, 2006, 12:00 PM	#3
genece Senior Member Join Date: Jun 2003 Posts: 2,111	The filter will work .. but I think you have an incorrect idea of what a polarizer does. You do not shoot into the sun ..Ideally the sun should be to your left or right and you point the mark on the filter toward the sun for maximum effect.....If the filter has no mark you rotate it till you get the effect. It will reduce glare on glass or water also...again you turn for the maximum effect. And a good rule to follow, never shoot into the sun except for sunrises or sunsets. And its not a good Idea to use a polarizer indoors as it blocks too much light. The marks you see are lens flare or ghosting which is why you do not shoot into the sun and it also makes a good point for using a lens hood.

Jan 7, 2006, 12:37 PM	#4
daffy Junior Member Join Date: Jan 2006 Posts: 3	genece, thanks for your insight! I only shot straight into the light source in an attempt to verify the optical "cleanness" of the pol filter, fully expecting some flaring :-) Because the additional, scattered flares compared to the no-polfilter-shot are obvious and visual inspection showed the streaks on the filter itself, I was worried and decided to ask :-) If there are better ways to verify that the complete optical subsystem of my FZ5 is, well, "clean" (glass) and working (sensor-wise) without too much of an infrastructure, I'd be very interested in learning more. Thanks again! daffy

Jan 7, 2006, 10:45 PM	#5
squirl033 Senior Member Join Date: Dec 2004 Posts: 6,915	all those little bright spots around the light source should not be there... if they show up on this test shot, they will very likely show up to a greater or lesser degree on your other photos as well. the circular streaks are probably from your efforts to clean the filter over the last 10 years or so... frankly, i'd toss it and get a new one. a 55mm polarizer doesn't cost that much - you can get a perfectlygood linear polarizer for under $25 - and it's far better to spend a few bucks to replace a worn or damaged filter than to have it ruin a priceless or irreplaceable shot...

Jan 8, 2006, 7:51 AM	#6
genece Senior Member Join Date: Jun 2003 Posts: 2,111	Squirl may well be correct, I am not sure. To check a camera........... others have said to take a photo of an empty sky or a white or gray wall and look for defects. How does the filter do in the outdoors? I will just through this in ..to clean a lens I believe,a microfibre cloth is the best way. On real tough marks a little lens cleaning solution on a lens tissue to dampen them may help.