The XSi is an older body and hasn't been in production for years. That means pretty much every camera in current production will be an upgrade.
Here's a basic outline of the Canon lineup:
Canon's entry level bodies are all called "Rebel" but only in North America markets. In the UK you would know these by the number of digits in the model number.
If it has 4 digits in the model number such as the 1200D then it's at the low end of the entry-range. Those cameras are primarily designed with affordability in mind (minimum features / lowest price point.)
If it has 3 digits in the model number (100D, 700D, 750D, and 760D) then it's higher in the entry-range and the higher the number, the higher it is in the line-up (the 760D is marketed as the Rebel T6s in North America). The only oddball in that range is the 100D -- that camera was designed to be the most compact true DSLR body on the market. It is a DSLR (it's not a mirrorless camera) but the body is physically smaller than all other DSLRs -- not just from Canon -- from anyone.)
If it has 2 digits in the model number (currently just the 70D because the 60D is no longer made) then it's a mid-range camera. The mid-range cameras start getting features found in "pro" level bodies such as a control layout that is more similar to the pro bodies, a better build, weather sealing, the ability to control auto-focus micro-adjustments to fine-tune the focus accuracy of your lenses, etc.
Here's where it gets a little strange.
When the cameras only have a single digit in the model number they are somehow a high-end camera, but might not be considered pro.
7D II is the most advanced camera with an APS-C size sensor (the same size as all xxxxD, xxxD, and xxD series bodies). It has a very advanced focus system, amazing burst speed when shooting in continuous burst mode, it's built like a tank. It has several optimizations that make it attractive to photographers who shoot action photography (sports, wildlife, etc.)
Everything else in the Canon line-up is a "full frame" sensor body. The imaging sensor is physically the same size as a single frame of 35mm film... which would measure 36mm wide by 24mm tall (35mm refers to the width of the film-strip when you include the part of the film that has sprocket holes -- not just the area where the image would appear.)
Full frame cameras CANNOT use "EF-S" lenses.
The 750D and 760D are the top of the entry range. They were released together. The 760D has an extra LCD panel on the top as well as a rear-dial -- more similar to what you'd find in the mid-range and above models. The rear-dial is especially nice when shooting in manual mode because the front dial would normally control shutter speed and the rear-dial controls aperture. In the 750D or below the camera only has the front-dial and you have have to press-and hold a button while rotating the dial to adjust secondary functions. But the sensors on these two cameras are the same.
Tim Campbell
5D III, 5D IV, 60Da
