About lens again
 

I saw Sony DSR-PD170 has a lens says F1.6to2.4 , but Panasonic AG-DVC30 has a lens of F1.6, does it mean Sony has a better lens ? and about Filter diameter, true that the bigger the better it is ?

The quality of a lens is not measured by the maximum lens opening (f/1.6 vs. f/2.0 for example) nor is it measured by filter size. Lenses can be compared objectively by their MTF (modular transfer function) and subjectively by your eye (do you like the image your camera produces).

Jeff,

I fully agree to what you said. However, the maximum lens opening may be important in low light situations and, of course, if you want a shallow depth of field.

T-Stops are more relative than F-stops when it comes to lens speed.

<<<-- Originally posted by Richard Alvarez : T-Stops are more relative than F-stops when it comes to lens speed. -->>>

This is true of course. But for zoom lenses with roughly the same number of elements and similar multicoating the difference in T-stops should not be too large.

Or is there a flaw in my thinking?

If there is a flaw, it lies in the words "similar" and "roughly". No guarantee that the t-stops for "Roughly simlilar" lenses would be the same. The question "Does Sony have a better lens" is of course subjective in terms of visual aesthetics, but by measurable quantitites, Jeff's reference to MTF is correct.