"Standard Lens" for 40D

[klindup]

I am thinking about buying a prime lens that equates to a standard lens on a 35mm (50mm) to give me an f1.4 or 1.8 with the advantages of a faster lens.  I am assuming that I need a 30mm prime lens or thereabouts.  Offerings from Canon and Sigma are up for consideration but which to buy?  I would appreciate the opinions of members of the group.
Thanks

Ken Lindup

[Bob Atkins]

Unfotunately there's no real equivalent (pricewise) to the very inexpensive Canon 50/1.8 in crop sensor lens. A minimum cost option would be the Canon EF 35/2.0. It's a full frame lens, so even if you move to full frame at somw point it will still be usable. The Sigma 30/1.4 is the fastest option under $500 - though it's only for crop sensor cameras. Another option is the Canon 28/1.8 which also covers full frame and just sneaks in under $500.

Much depends on whether you like a slightly long or slightly short "normal" lens.

35mm APS-C = 58mm Full Frame
30mm APS-C = 48mm Full Frame
28mm APS-C = 45mm Full Frame
24mm APS-C = 38mm Full frame

"Normal" lenses are usually in the 40-50mm region. Technically a "normal" lens is one with a focal length equal to the diagonal of the frame. For 35mm that's 43mm and for APS-C it would be 27mm.

I often use a Canon 24/2.8 as a "normal" lens on my 40D, but I do tend to prefer a "wide" normal lens.

[klindup]

Thanks Bob
Having been a film user for 45 years (Pentax and Rolleiflex) I have got used to working with 55mm and 85m (on 6x6).  That said provided the image is sharp i favour the wider angle lenses since I can always crop if necessary.  I think I will go with the Canon 28mm 1.8.

Regards

ken