My options are:
1. 49mm Tiffen circular poleriser filter
2. 55mm Tiffen circular poleriser filter (with 49-55 step up ring)
3. 49mmB+W circular poleriser filter
4. 55mmB+W circular poleriser filter (with 49-55 step up ring)
5. 49mmHama circular poleriser filter
6. 55mmHama circular poleriser filter (with 49-55 step up ring)
A. the advantage of using a 55mm size is that I can leave the step up ring and filter on the camera permanently so that I can connect my 55mm TCON-17 x1.7 tele converter quickly. The downside might be (i) lens hood might not fit; (ii) I need to search for a new 55mm lens cap that will fit.
B. I could use a 49mm filter (such as the A1 Skylight currently installed) and leave the 49-55 step up ring on the TCON-17. I would then need a lens cap to protect the TCON-17 whilst detached (since the lens cap provided only fits without the step up ring connected.
a. which manufacturer/size is preferable/adequate/forgetit?
b. where can I find an objective comparative measurement of the optical acuity of filters by manufacturer?
c. Do I need a multi-coated filter or just the plain brown paper bag version?