I agree. One of the first things I noticed about this digital camera was that I could shoot without UV filters. With my old SLR film camera, (which has great sensitivity to UV) I had to suffer monies worth of wasted film (and time) due to unnatural peak frequencies. No film, no problem. 
Jim
Jim
Bottom line for me is that we've tested this in years past with the
F505 and the F505V. I doubt that the response in the F707 is any
different.
We've also had comments made by Sony on the issue. The word is that
you wouldn't notice a significant difference filter on or off. It's
just another piece of glass in front of the lens. If a difference
could be demonstrated, you'd need a spectrographic representation
to see it.
Noticeable differences could be as simple as metering or white
balance drift issues.
This is not to dispute or argue with what others notice. Just that
some of us haven't seen those same results.