Worth getting 20mm f/2.8 if I have a 17-55mm f/2.8?

[chaosboi]

Is it worth getting a prime lens if my telephoto covers the same range at the same speed?

Eg, I currently have the Canon 17-55mm f/2.8 IS, what, if any, would be the advantages of a 20mm f/2.8 prime?

[bushbikie]

IMO only if the 20mm prime gives you better image quality, you don't mind using your feet to zoom in/out, and you will use it often enough to justify the purchase. Do some research on the lens you are thinking of getting and see how it compares to your existing lens.

[Brian500au]

Do you really think you are going to see some improvement with a prime over what some rate as the best non "L" zoom around? What is your purpose to consider the 20mm prime?

[kiwi]

Portability

[chaosboi]

What is your purpose to consider the 20mm prime?

This question is just out of interest, I have no immediate plans to purchase a 20mm prime. I'm just curious if a prime would be much the same as a telephoto if the speed of the lens is the same.

[fabian628]

might consider the 28mm f/1.8 and get the advantage of 1 and a bit stops of light

[Brian500au]

This question is just out of interest, I have no immediate plans to purchase a 20mm prime. I'm just curious if a prime would be much the same as a telephoto if the speed of the lens is the same.

Generally speaking (and this is general) most primes are traditionally sharper than the equivalent in the zoom - but the 17-55 is a stellar lens and is considered the best non "L" zoom canon make.

[KeeFy]

Advantages - Size, weight, Image Quality (not by much vs the 17-55)

Disadvantages - No zoom, no IS, Extra $$ out of your pocket for something you already have. Carrying extra glass that you won't use unless you have a full frame (EF mount vs EF-S mount).

Now if you said the 24 1.4L. It's a different case altogether. The 17-55 is a 1/2 L lens in my opinion. All the goodness of a L lens without the weather sealing and build quality.

[Bennymiata]

What Keefy said.

If you find you are often using the 17-55 at around the 28mm mark, and you are finding some problem with your current lens at that focal length, then it might be worthwhile, but I doubt that you will see any difference in quality between the 2 lenses at that focal length.
I have the 24-105L lens, and I also have the 28mm F2.8, but I generally only use the 28mm lens when I'm going out to a party etc., and just want a small, light, wide-angle lens on the camera.
It takes good pics, but they aren't better than the 24-105, it's just that the 28mm is convenient when you are doing inside shots and just want have a very small lens on your camera.
Personally, in your position, I'd be looking at a much wider angle lens to compliment your other lenses.