New to DSLRs, Need help deciding on next lens.

[Thar]

Hello everyone, I recently bought a Canon 450D/XSi as my first DSLR (not my first choice, but the price was too good to pass up) and have the kit 18-55mm and the 70-300 IS USM and so far I've been having a pretty good time messing around with settings and shooting things around the house. I've been shooting film SLRs for a while now (Canon AE-1 and Minolta X-700) but I still don't really have a favorite subject matter, I like snapping all sorts of pictures. I do a lot of shooting indoors (events/concerts, candid shots of friends, various items around the house) and it has occurred to me that I will definitely be needing a faster lens.

I am undecided between a Canon 50mm 1.4 USM and a Tamron 28-75mm 2.8. I can get and try both locally, but I'm not sure which lens will serve me better in the long run. I've tried the 28-75 and was impressed by the results, but the local shop is really well lit so I don't know how it will work in the poorer lighting of some of my friends apartments. The Canon is cheaper and has a smaller f/stop, and I typically use the 50mm on my X-700, I'm just not sure if I will like 50mm as much on a crop sensor as I am used to the standard 50mm crop, and the range will be covered by the 28-75, but at the same time lots of people recommend getting a decent prime as one of your first lenses.

If you had to choose between one of these lenses (going to be used for ALL kinds of photos) which would you pick and why?

 

[TCampbell]

I'd probably go with the 50mm f/1.4 if you're worried about low light.

Since you're used to 35mm bodies, a "full frame" body has a digital sensor which is the same size as the 35mm film negative frame. The XSi is a bit smaller -- it's like cropping down the size of your negative a bit. To get the same field of view you'd need a wider lens. Something around 30mm would give the same field of view as the 50mm lens you'd be used to using on your AE-1. Canon doesn't make a 30mm... but they do a make a 28mm and a 35mm. (actually they make several).

As for the f/2.8 zoom... the 28-75mm focal length is designed as a good walk-around lens for a full-frame digital camera. On your camera it'll go from "normal" to a mild telephoto focal length, but no wide angle at all. To get a wide angle you'd need something like the EF-S 17-55mm f/2.8. Sigma and Tamron make some 17-50mm f/2.8 lenses as well. You can find reviews of them at the-digital-picture.com. He does a pretty good job of comparing lenses to the other likely lenses in the class.

 

[markspend1]

Hey Guys well i think that the crop aspect is the sensor's dimension in comparison to a full-frame 35 mm sensor. It is because when using a 35 mm lens, such an sensor's has successfully crops out of the picture on its external.Thanks!!

 

[Ryan0751]

The focal length of a lens remains the same regardless of the sensor size. It's the optical distance from where light converges to where it hits the focal plane of the sensor (or film). Since 35mm film size was such a common format for so long, many are "used to" certain relative fields of view when using different focal length lenses. 14mm would be considered ultra wide, 50mm is "normal", and 200mm would be telephoto, etc.

By using smaller sensors, you effectively are getting a smaller field of view from the same focal length. They therefore use a "crop factor" multiplier; you can take the focal length, multiply it by the crop factor, which gives an idea of the equivalent field of view for if you were using a 35mm camera or full-frame digital.

The opposite is also true. As you go large into the focal plane size, say for medium format cameras, what would be considered telephoto on a 35 mm camera is actually "normal" on a medium format.

For the OP's original question, the Canon 1.4 50mm is a great lens and is a very good value. Image quality is top notch. The second lens I'd recommend is the Canon EF-S 17-55mm F2.8, also very high quality, though a bit more expensive (around $1000).