Monday, October 22, 2007

Choosing a normal prime lens for a Canon mount.

I just purchased a new normal prime lens for my Canon 30D and it took a lot of research to decide which one to get because there are a ton of them on the market ranging from $75 to $1300 or more. If you're in the market for such a lens, I hope my research can benefit you as well.

First, let's define the terms "normal" and "prime" for those who may not be "hip" to the "lingo" (I'm cool like that).

"Normal" lenses are usually 50mm lenses. This is the sweet spot between wide angle lenses and telephoto, hence, they're called "normal". There's one caveat these days, though, and that's the crop factor of your camera's sensor. Make sure you take that into effect. If you have a cropped sensor Canon camera, you'll most likely be looking for a 28mm - 30mm lens in order to get as close to normal as possible.

"Prime" means the same thing as "fixed" and all that means is that it's not a "zoom" lens. You can't zoom in or out with it. It has just one focal length, so you have to "zoom with your legs". Prime or fixed lenses are usually cheaper and sharper because they are more simple to manufacture and compromises don't have to be made so that they can work at sometimes dramatically different focal lengths (I have a 50-500mm lens, for example!).

The research:
There are many options out there for Canon mounts. If you're looking for a 50mm prime there's 3 main choices including the Canon 50mm f/1.8 which goes for $75 or so new! It's surprisingly sharp as well and many people are very happy with this lens. The downside seems to be bad bokeh (background blur) and the build quality isn't great (it's fragile and very plastic-y). Still, for $75, it'd be a nice first prime if you're just wondering what they are all about!

50mm choices include:
  • Canon EF 50mm f/1.2 USM L
  • Canon EF 50mm f/1.4 USM
  • Canon EF 50mm f/2.5 Macro
  • Canon EF 50mm f/1.8 II
30mm / 35mm choices:
  • Sigma AF 30mm f/1.4 EX HSM DC (EF-S mount)
  • Canon EF 35mm f/2.0
28mm / 24mm choices:
  • Canon EF 28mm f/1.8 USM
  • Sigma 28mm f/1.8
  • Canon 28mm f/2.8
  • Canon EF 24mm f/1.4L USM
  • Canon EF 24mm f/2.8
  • Sigma 24mm f/1.8 EX Aspherical DG DF Macro
Prices, MTF Sharpness test results, Vignet or light falloff test results, chromatic aberration test results, distortion, SQF ratings, plus comparisons, sample images, lens tests, and lens reviews can all be seen side by side here in my online spreadsheet:

And for those who are interested, I ended up purchasing the Sigma AF 30mm f/1.4 EX HSM DC -I'll post a review soon!


Mark said...

So have you formed an opinion about your Sigma 30mm?

Erica said...

Yes! It's exactly as described. It's a bit soft in the corners and CA can be an issue at times.

Also, for my birthday I got the Canon 50mm f/1.8 II so I can tell you that this $70 lens is just as sharp as the Sigma although the build quality isn't nearly as good and the manual focus ring is annoyingly small and impossible to adjust with a Cokin filter on the lens.

In the end I see little use for owning both and if my husband hadn't stolen the Sigma 30mm from me, I would probably sell it and keep the 50mm because I'm cheap like that...

I have sharpness test shots for both lenses here if you are interested:

Erica said...

Here's the link to test shots

Mark said...

Thanks Erica! Very nice test results and presentation.

If the 30mm was wide enough I'd be tempted. But I have the Canon 35mm f/2 and it's not wide enough for what I need it for. So I am now looking into the Canon 24mm f/2.8 but I am concerned it will be 'fast' enough.

I had a 50 f/1.8 once upon a time but sold it because I didn't like it. (I just did not realize what I had!) But I eventually replaced it with the 50 f/1.4 and it is outstanding. I can highly recommend it!)