If we ignore the price and take only the features in account then the best option among these three is Sony SLT-A57. It has a cropped sensor however it crop the original size of the picture by 1.5x however Canon crop it more 1.6x. Image stabilization in the body is the huge advantage as you will not have to always pay $200 extra for a lens with image stabilization. Although Canon T2i offers more resolution 18 as compare to Sony 16.1 however its not much of a difference and can be ignored.
Sony A57 offers better higher ISO which can be used in extreme low light conditions, even if the picture is grainy at such high ISO still at-least you can get an image. Sony offers more focus points so you don’t have to move around your camera a-lot to focus anything you wish to. Built in flash is not as powerful as Canon or Nikon however it will be compensated with higher ISO. Although its bit heavier than Nikon and Canon however its shooting speed of 12 frames per seconds is not even close to 4 frames per second in Nikon.
If you are not interested in Sony brand then among these cameras I would chose Nikon as a second option because of its higher ISO, better shooting speed, moveable LCD screen.
Similarities between Sony Alpha SLT-A57, Canon 550D/T2i & Nikon D5100
- Same sensor type CMOS
- Same 3″ inch LCD size
- All cameras are cropped sensor cameras, not a full frame camera
- All camera offer live view to use LCD like a simple point and shoot camera
- Pop-up flash
Differences between Sony Alpha SLT-A57, Canon 550D/T2i & Nikon D5100
|Features||Sony SLT-A57||Canon EOS 550D/T2i||Nikon D5100|
|Highest ISO with boost||25600||12800||25600|
|Focal length multiplier||1.5x||1.6x||1.5x|
|LCD||Fully articulated||fixed||Fully articulated|
|Sensor Size||23.5 x 15.6mm||22.3 x 14.9mm||23.6 x 15.77mm|
Sony Alpha SLT-A57
Canon EOS 550D / T2i