Hi, I am having trouble finding information regarding the 'dual lens system' on the Epson V700/V750

For the record I bought the V700 a week ago and I am trying to get the best out of it. I have read somewhere online that the 'better' lens only comes into play when you select 6400dpi resolution on the scanning software. Now my questions are:

1. is that true? or is the dual lens system always in action whatever resolution you select in software?

2. if you use a third party software (like silverfast) what happens to the dual lens system? does it come in effect the same as with the epson scanner?

Cheers