04-22-2016, 04:00 PM
I like the Ring drive USM, I've dismantled the Nikon AF-S 70-300mm VRII, because of a problem of non use of the lens, I was very pleasantly surprised to find how simple the motor is and how well it is made, using the principle of crystal's dilatation (expansion and contraction with voltage) at high frequency as a drive medium, the motor drives the focus ring itself, which in turn makes it a simple to have full time manual, power or no power..... In fact it has really very few moving parts and focuses very fast.
I've nothing against LEMs the principle is also simple, however it starts to make me nervous if we start finding three or four of these LEMs controlling movements, and when unpowered the fact the whole system goes limp.......four motors, giro stabilization and all the appropriate electronics......electric diaphragms......add to that lens docks for fine tuning element alignment, in plastic bodies....
.......I like the "KISS" principle......
Keep It Simple Stupid.........
Edit.....make that KISSS....
Keep It Simple Stupidly Solid.......and pass it on down the family.....
I've nothing against LEMs the principle is also simple, however it starts to make me nervous if we start finding three or four of these LEMs controlling movements, and when unpowered the fact the whole system goes limp.......four motors, giro stabilization and all the appropriate electronics......electric diaphragms......add to that lens docks for fine tuning element alignment, in plastic bodies....
.......I like the "KISS" principle......
Keep It Simple Stupid.........
Edit.....make that KISSS....
Keep It Simple Stupidly Solid.......and pass it on down the family.....