Well basically yes. The 3200/3500 have a 3x zoom range (3-9, 4-12 etc), the 4200/4500 have a 4x zoom range (2.5-10, 4-16 etc) and the 6500 have a 6.5 times zoom range. There is a difference in the glass quality even though they list all of them as having FMC (Fully Multi Coated), UWB coatings (ultra wide band coatings) which in this case Bushnell claims to have improved or widened the "visible color spectrum" the human eye can see, all lines are now Argon gas charged vs nitrogen charged and they all have the improved version of Rainguard HD that is more durable and repells water and fog better too. So where is the improvement then ? Light transmission. The 3500 claims to have a 91% level of light transmission and the 4500 and 6500 have, I believe, 95% light transmission. You have to remember that there are tons of grades of glass used today, the amount of polishing each lens gets varies greatly and the number of coatings each lens gets after all the grinding and polishing is done also varies quite a bit. Some of the high end euro glass, for example, can get as much as 60 layers of coatings and all this translates into time and final performance of the scope, bino or spotter. Obviously all this translates into final cost as well.
