Video shooting advice....A77 disappointed vs iphone 5

I took my cameron out over the weekend filming the kids on a local hill covered in snow on sledges .. I used both the video features on my a77 using a 17-70mm hsm sigma lens and my iphone 5...

The iphone was sharper and clearer than the a77 obviously photos shot with the a77 blow the iphone away...

I used basic auto setting af with program auto mode in i50 mode I thought it was the lens so I took a few minutes with my 50mm 1.7 the results were still not as good as the Iphone???

too my surprise the iphone took overall beter video in this situation....So the question is what am i doing wrong....if anything or is the iphone just better at point and shoot video..

thanks or if anyone has a quality link to video using the a77

I love my sonys and I am no hater I just need some advice.

Most of the work is hand held using os on the sigma.........