I'm becoming quite a researcher of eos ef, ef-s, and is lenses now (although I don't think I'll ever say "expert" with a straight face

)
The kit lens with the EOS 500d is the 18-55 IS, so at only an extra £50 on the body price, I went for it. I reasoned that if I ever went for the 18-200 IS, I could sell it more easily through
fleabay.
The camera hasn't even arrived yet (expected today !

), so I don't want to get too far ahead of myself.
I have been amassing bits and bobs from eBay though, a spare battery and car charger (£12), a pentax m42 adapter (£4), a pentax k adapter , with focus electrics (£17), and the mini hdmi lead (£4).
I have a few fixed length film camera lenses (mostly Pentax K, eg the 50mm f2), that should give good results, albeit without the advantage of IS, or auto diaphragm, and maybe not even focus "assistance", although I'm hoping the PK adapter's electrics might help there. It mentions some sort of coupling to the EOS's focusing electronics with a light the comes on when the focus is turned manually. This'll be good (if it works), because I understand that the 500d is devoid of any centre split manual focusing aids in the viewfinder ?
I found this page made good reading on the subject of using non Canon lenses on an EOS body,
http://photonotes.org/articles/eos-manual-lenses/It seems as though ,any older high quality film lenses will adapt quite nicely, and focus to infinity etc.. The danger area is with some "older" eos fitting (but non Canon) lenses, where the electronics of the ef can be incompatible and cause the focus to hang the camera.
I still have some quality pentax k & m42 accessories too, macro bellows, rings, & a microscope adapter (and the "proper" microscope that it fits on to !) So the adapter rings should enable some use of those.
----------------------
Getting back to the Canon ef-s lenses, I'm beginning to think the IS is a very desirable feature as well, so have been narrowing down my options there for the longer focal lengths.
The Holy Grail (for me anyway, can't even look at the "L" series !), is the 18-200 with IS, but they seem to be up around the £400 mark, so no chance while they're the latest thing.
The close second, at about £140-150 is the 55-250 Canon with IS, to compliment the 18-55 IS that comes with the camera. It still means changing lenses, but I guess the payoff is maybe a smidgen less distortion, and 50mm more at the top end. On the downside, they both have the same maximum aperture, but then to offset that, they take the same 58mm filters....
But... I'm still slightly tempted by the much cheaper ef-s 75-300 lens which can be had for about £60, but alas, no IS.
