Hey guys so im deciding whether or not if I should buy the Letus extreme for my HMC to help with DOF shootings, but after reading some reviews on the extreme, alot of people do no recommend it. I see that the main problem is the back-focus adjusting, but I've never really tested the product in person so I can't really say much. Letus do sell upgrades for the extreme, but at a price tag of $600, I think that maybe a little steep just to upgrade. I have a friend that selling his so whats a good price that I should offer? Any help is appreciated. Thanks guys