Crap-o-filter round-up

Started Aug 15, 2011 | Discussions thread
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micksh6
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Crap-o-filter round-up
Aug 15, 2011

Hi! I'm a newbie who's recently got micro 4/3 camera and became obsessed with shallow DOF. Wanted to use full aperture even at bright sunlight, realized I needed ND filters and bought a bunch. And polarizers too. Mostly crap, you will see.

I had no idea how EXACTLY cheap filters could affect image quality. Only after first day outside with my new camera I realized how bad it can be.

I did this test to find out if I can use something what I've got. My intent was to minimize number of step-up rings and to have filters for each size. Now I see that I can't have decent filters for every diameter with my budget. It's way easer to buy the most expensive stuff there is and be done with it. Well, not for me.

I still needed to test. If I buy one filter with maximum thread size for all my lenses that would be 67mm. Imagine how it would look on Olympus E-P3 micro 4/3 with Panasonic 20mm pancake. And I wanted to use that attractive metal hood which is only good for 46mm diameter. For kit zoom and upcoming 45mm F1.8 prime (37mm filter thread) step-up ring to 67mm would look kind of weird, wouldn't it?

Experienced photographers would probably know the results I got in advance. And with cheapo stuff sample-to-sample variations may be significant.

The practical significance of my test may probably be limited. Read only if you are curious.

I made a test fixture to see differences in resolution and color representation at once. With my test setup I'm able to see, for example, that Panasonic 20mm lens is a bit sharper at F2.8 than at F1.7. But that's not the point of my test. The point is to compare effect that different filters make to image quality.

So I shot everything with the same aperture, ISO, WB setings, only exposure time was different. Made two shots for each configuration to see if focus differs. For autofocus lenses used autofocus at the same area. For manual lens refocused each time. I'm sure that the focus is very consistent. Used remote shutter on tripod, no vibration.

Here is how test picture looks. I don't think there are any major flaws with this methodology but I can be wrong.

What's more important, some filters don't show major IQ degradation on test fixture but in real life shooting they add too much haze and ruin contrast.

Message is too long, I have to split it

 micksh6's gear list:micksh6's gear list
Olympus PEN E-PL5 Olympus E-M1 Olympus M.Zuiko Digital ED 9-18mm 1:4.0-5.6 Panasonic Leica Summilux DG 25mm F1.4 Olympus M.Zuiko Digital ED 40-150mm 1:4-5.6 R +6 more
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