1 ACCEPTED SOLUTION
You might be able to close to subjects using the 50mm. It would naturally depend upon the size of the subject, whether or not you are using an APS-C camera body, and exactly who close you're looking to get. Did you notice the link I posted to the lens comparison tool? Yes, a 50mm gives great shots on either a FF or an APS-C body, but ... ... compare the specs, too.
The EF 50mm on a Canon Rebel will give an equivalent 80mm focal length, which is almost ideal for portraits. With a field of view of about 46 degrees will not give you much "room" to take capture landscapes, although it could be ideal for using a tripod, turning your camera 90 degrees, and constructing a panorama out of 2-5 shots. It has a minimum focus distance of just over a foot, which is pretty decent.
The EF-S 24mm will give an equivalent focal length of 38.4mm, which is great for taking in the sights. It will give you an angle of 59 degrees, and a minimum focusing distance of about half a foot.
The EF-40mm has a misleading "diagonal angle of view" specification of 57 degrees, which is measured corner to corner, not side to side. It is nowhere near as wide as the 24mm. I have owned them both, and passed them on to my sons. The 40 also has a minimum focusing distance of just a hair under a foot.
How wide of lens do you want? Use your existing lens to do a crude comparison of field of view at different focal lengths. I have used the 17-55 kit lens with a set of closeup filters to capture some excellent pictures of garden flowers.
That shot was taken with a T5 and the 17-55mm kit lens with a 2x closeup filter attached to it. In other words, a poor man's way of testing the waters of macro photography. The closeup filter set was relatively inexpensive compared to a macro lens. Once you install them, you can no longer focus out to infinity, but who cares about that when you're shooting macro close-ups. Another thing with the filters is that they REDUCE the minimum focusing distance. I installed the 2x filter, and it cut my minimum distance by roughly one half. I took that shot with a tripod, and LOTS of sunlight.
I would have thought that your 17-55 f/2.8 should cover most walk around and shoot scenarios, though. I'd advise to explore a lower focal length, like the 10-22mm, which I think has far less barrel distortion than the 10-18mm. Use the lens comparison tool to compare them to another. Or, you go up to big telephoto zoom, like the Sigma 150-500, which has been discontinued and is on a deep discount until they run out of them.
