architect Loc: Chattanooga

I am very fond of my Nikkor VF 18-200 zoom lens and my Nikon D90, as I seldom need to change lenses when traveling. However, after our last trip I was very disappointed in some of the results using the maximum zoom settings (135 to 200 mm) using a polarizing filter, which lost a lot of detail on the edges. So I did a test comparing the lens at 200 mm with:
1. no filter,
2. the UV filter I normally keep on the lens for protection and
3. the polarizing filter set at two different settings.

As you can see, the polarizing filter causes the image to deteriorate a great deal. Even the UV filter showed significant deterioration.

I have not seen negative effects on the same lens with polarizing filter set at 18 mm wide angle, but I will test for that also.

My question is this. Is this just limited to zoom lenses set at maximum zoom, or do filters (mine are Sunpak) effect all images negatively? What is your experience?

Bigdaver

Sunpak is really cheap.
I use Hoya,Tiffen, SchneiderKreusnach?sp
Toss that filter, buy the bare minimum amount of top quality filters you need.

travlnman46 Loc: Yakima WA

Hi architect: I find it interseting that most of us beginning photographers and even some more experienced ones will research lenses until the sun goes down finding the very best value for dollars spent, then turn around and buy filters solely based on cost the cheaper the better. Then wonder why our photos don't come out right. I would rather risk damage to a quality lens than put a cheap filter on it. Better, put on a quality filter and help protect the lens and be happy with the outcome. One Idea I've read here is when you purchase a quality filter the size of the largest diameter lens you own then by adaptors to fit the various lenses that are smaller. One filter with adaptors to fit all your lenses instead of a cheap filter for each lens. I liked the idea. Hope this helps.

docrob Loc: Durango, Colorado

[quote=architect]I am very fond of my Nikkor VF 18-200 zoom lens and my Nikon D90, as I seldom need to change lenses when traveling. However, after our last trip I was very disappointed in some of the results using the maximum zoom settings (135 to 200 mm) using a polarizing filter, which lost a lot of detail on the edges. So I did a test comparing the lens at 200 mm with:
1. no filter,
2. the UV filter I normally keep on the lens for protection and
3. the polarizing filter set at two different settings.

As you can see, the polarizing filter causes the image to deteriorate a great deal. Even the UV filter showed significant deterioration.

I have not seen negative effects on the same lens with polarizing filter set at 18 mm wide angle, but I will test for that also.

My question is this. Is this just limited to zoom lenses set at maximum zoom, or do filters (mine are Sunpak) effect all images negatively? What is your experience?[/quo

Looking at your comparison image makes me suspect the lens did not auto focus correctly - run the test with manual focus then decide if it is the filter - you - or something else.

Mac Loc: Pittsburgh, Philadelphia now Hernando Co. Fl.

I have that same 18-200mm lens. My CP filter is B+W and I have no problems.

architect Loc: Chattanooga

I did try manual focusing with the same focus for each shot. The shot with the filter was way out of focus. Setting it back on autofocus, I noticed that the lens focus changed noticeably from no filter to the polarizing filter. The center of the polarizing filter is pretty much in focus. But the image deteriorates rapidly near the edges.

I did test at the 18mm (wide angle) end of the zoom, and both images were just fine. It only is a problem at the long zoom end. I am pretty sure that the cheap filter is the problem.

architect Loc: Chattanooga

Thanks for the specific information Mac. Another friend has the same lens and the B+W MRC filter and also has no problem at the 200 mm setting.

Leo6745 Loc: Auckland, New Zealand

I have given up on filters for the effect they have on the image. I do mostly low light photos so maybe the degrading is more pronounced ? I have tried expensive filters but without acceptable results - I just try to be more careful of the glass.

jsenear Loc: Hopkins, MN.

I just recently removed the protective filter (Quanatary) from my lens. Made a world of difference. About the same as your before and after pictures. Will use the lens cap for protection from now on.

richnash46 Loc: Texas

I too noticed significant degradation of shots taken with filters (even what are supposed to be top notch, expensive filters) and so I personally decided to just quit using them altogether and haven't experienced any issues since!

Rip Tragle Loc: Estes Park, CO

Using high quality (yes, expensive) filters I have never had such
problems.

kbarnes42 Loc: North Carolina

You didn't say if the filter was a regular polarizer or a circular polarizer. You need to be using the circular polarizer with the D70. I have a D90 and D300 and use the 18-200 with a circular polarizer with no problem.

architect Loc: Chattanooga

It is a circular polarizer, but a very cheap one, (Sunpak) for my D90 with the Nikkor 18-200 VR zoom. I love the control I have over reflections and sky using a polarizing filter, so I will invest in a good one next. I am considering a Hoya HD or a B+W MRC filter. Anyone have experience with those?

jbrown

I had the exact same problem with my Pentax K20d, using a Vivatar CPL, on a Pentax 85-200mm zoom, on a trip to Hawaii in March. I switched to manual focusing and it improved slightly. I diagnosed that the internal auto-focusing was "fooled" by the image reflected in the filter. p.s. it was a really cheap filter. No problem wiht different filter (tiffen)? on my smaller lens.