Shark, you cannot use the lens cap with the CLA-7 on. That's why I wish they had made the CLA a wee bit longer so that the filter can remain when the CLA is fitted on and serve as a protective layer. Guess they were worried about image quality. In my case, if I have the TCON on, I just put on the TCON lens cap. Otherwise I just loosely put the lens cap in the "wide hole" of the CLA. Not a good solution though. Can't add anything in front of TCON though as no threads. Any bayonet fitted filters around I wonder?
Slacker I got the filter free when I bought my camera (John 3:16), 40.5mm HOYA UV. Yes you have to remove the filter to fix up the TCON. To quote my mail in another thread:
"However, if you wish to use the TCON-1.7c or the WCON-0.7c then you need to install the CLA-7. The CLA-7 adapter is only to attach lenses. Note that the filter must be removed in order to use the CLA-7 with a lens attached. "
BTW lens cap does fit snugly with the filter on.
I would recommend at least a UV filter. OLY UV and polarizer filters are also available here in SIN.