I am planning on buying this in couple of days, PENTAX SMC 55mm F2 SCREW M42 LENS on eBay (end time 01-Mar-11 16:30:55 GMT) and this adapter M42 Lens to Canon EOS Mount Adapter7D 30D 500D 550D etc on eBay (end time 17-Feb-11 18:50:27 GMT)

Correct me if i am making a mistake !!

M42 lens are great low cost lenses, I'd recommend getting a 50mm 1.8 M42 lens - 50mm 1.8 m42 items - Get great deals on Photography, Pentacon items on eBay UK!

I've used a 28mm 2.8, 58mm 2.0 and a 200m 4.0 and all are pretty good, none are better in low light then my 1.8 Canon 50mm though, but I recon the 1.8 50mm M42 lens would be just as good in low light.

I just played with 550d for a lil while, a friend had it. Was mostly checking the 18-55mm viewing angle and found out that 55mm is too zoomed for me so it wont be gud for the type of shots(low light, small area) i will be taking. So now i have to look for something around 28mm with f1.8 etc but cant find a cheaper one on ebay, might just leave all this m42 stuff and get the tokina 11-16mm f2.8 later.

Well the 50mm 1.8 M42 would be great in low light because of the low f-stop, the only reason the 55mm end of the 18 - 55 isn't good in low light is because maximum f-stop is 5.3.

But if you're find the focal length of the 55mm too much on the kit lens, the M42 50mm would be like a 80mm on the 550D.

hmmm will the m42 lens have more multiplication added to the cropped sensor of 550d?

no, it'll just fit the camera

No, the reason why it'd be around 80mm is because of the 1.6x crop but the kit lens is a EFS so the 18 - 55 kit lens that is correct focal length for the crop.

Not really explaning it too well, but basically the EFS lens will have correct focal length, other none EFS lenses will have the focal length times 1.6

Alright i knew about the 1.6x crop but i thought m42 lens will add some more. Anyways i think i might just buy 50mm f1.8 m42 for outdoor shots at night where i will have no issue's of the zoomed view of 50mm, it aint much expensive so there is not much harm in it.

That's completely wrong.

The 18-55 kit lens is 29-88 equivalent. The 55 end ofthe lens is exactly the same as a 55mm prime of any kind.

No lens in the market shows equivalent focal lengths. EVER.

Lens focal length is a real number in milimeters that can actualy be measured. the "equivalent" focal length depends on the sensor or film size. In the case of the Canon 550D you can find it by multiplying with 1.6.

I believe that your best choice right now is the Tamron 17-50 2.8. in either the VC or the simple non-vc version
It's not that expensive anway.

Otherwise you can take a look at some lower cost vintage primes on ebay
Vivitar 24mm F2 Super Fast wide angle NIKON AI FIT - eBay (item 250763981218 end time Feb-06-11 12:12:04 PST)
M42 Vivitar wide 28mm f2.5 Kiron made lens - eBay (item 280622849623 end time Feb-05-11 15:38:05 PST)
Accura 28mm f/2.8 Wide Prime Lens Pentax M42 Mount - eBay (item 220734589620 end time Feb-10-11 19:16:20 PST)
Vivitar 28mm Fast f2 Wide Angle Lens for Olympus OM - eBay (item 250768199703 end time Mar-05-11 09:44:33 PST)
Vivitar 28mm f2 for Pentax M K - Komine 28403407 - eBay (item 270697645112 end time Feb-05-11 18:00:38 PST)

I am buying lens form ebay uk so there the best ones are Pentax Takumar 50mm f1.8 at 50£. Wat about the Canon EF 50mm f1.8 II which is on 70£, which one would be better Canon or Pentax?

Ah right, I read that EFS were like that on another fourm a while back, I guess not.

For video the pentax is better.The canon doesn't have a smooth focusing ring.

Also worth checking out are Olympus Zuiko lenses, very compact, and can be purchased for a very good price. These lenses are exceptional for video.