The low light capability, short focal length of the 18X55 lens, huge sensor (comparative to camcorder) and enormous fun of playing with depth of field in video, and smooth realtime video autofocus make the a57 just hugely fun to plan and shoot video with, and there is a uniqueness to DSLR video shot with this feature set.

The A57 can record 1080p HD 1920 x 1280 pixel movies at either 50fps or 25fps (PAL), or 60fps and 24fps (NTSC) in the AVCHD format, or 1440 x 1080 pixels at 30fps/25fps in the MPEG-4 format, useful as this format can currently be shared more easily.

The Sony SLT A57 is a fast, quality camera with impressive video capturing capabilities.

Noise doesn't rear its ugly head until ISO 3200 for JPEGs, although the A57 does apply some pretty aggressive noise reduction to keep the files clean, resulting in some loss of finer detail.

The shooting speed is excellent, at least twice as fast as rivals and a57 has a HUGE BUFFER SIZE (21 raw+jpeg) that takes fast shooting experience to a higher level.

the resolution of the slt a57 is better at iso 3200 and above.

The A57's top plate features the aforementioned shutter release button encircled by an on/off switch that visually apes the zoom levers found on some compact cameras.

Instead of a flipping mirror, the a57 uses a semi-transparent one that doesn't need to flip which enables this $700 camera to take rapid 8 (full control), 10 (aperture control), and all the way up to 12 (cropped resolution) frames per second.

If you know what you want from both a visual and a technical perspective and have the right lens for it, the a57 will get you there.

If ISO set to auto then camera can choose any ISO 100 to max, Nikon D5100 we can set max ISO for auto ISO, this way we can instruct camera not to go beyond say 1600 ....* Kit lens focusing has difficulty focusing in some normal focusing condition.

From my experience, in auto (or auto+), the a57 rarely identifies the proper scene, rarely meters correctly except for really simple scenes or outdoor scenes with consistent lighting across the scene (not high contrast as mentioned above), rarely gets the iso right on indoor shots (in room lighting, it often chooses a really hi iso which will result in terrible noise, rather than pop the flash or lower the shutter speed).

The Nikon D5100 also has ISO Sensitivity Auto Control, activated from the shooting menu.

The Sony A57 is a new SLT / DSLR camera with a 16 megapixel sensor, 12fps burst shooting, 50p Full HD movies, high-resolution viewfinder, 3-inch free-angle LCD and an ISO range of 100-16000, all for under £700 / $700 with a lens.

Last the a57 will shoot at 16000 ISO which for all of us old film buffs translates to a lot of pushing in the darkroom.

The D5100 produces noise-free JPEG images at ISO 100-1600, with ISO 3200 also looking pretty good.