> My advice is to forget using a 2X converter with a 600mm lens. Well, yes and no, Paal...
> One thing is that no lens will give good result with a 2X > converter (in spite of what some people claim, no good 2X > converter has ever been made - you get visible image degradation > with all 2X converter [snip] Yes, all 2X TC's (and, to a lesser degree, all 1.4X and 1.5X TC's) cause some image degradation. However, sometimes the degradation is small enough, and the use important enough, that such use is justified. In addition, the A 2X-L is a better optical match for the 600/5.6 than are the typical garden-variety 2X TC's with almost any lens. > another issue is that a 1200mm lens is virtually impossible to > support. Difficult, yes - impossible, no. > In addition, you need to stop down at least two stops to get > even half decent results from a 2X converter something that > gives you a shooting aperture of F:22. Again, this is true for maximum image quality. However, sometimes the use of a TC with a wide open lens is justified. > You are going to be constantly plagued by vibration problems and > can only shoot still life. Or, you would constantly have to be concerned with, and would constantly have to compensate for, vibration problems. Are you still showing the effects of your frustration with trying to use the 600/4 on a zodiac? <g> > The Pentax 2X-L converter doesn't really work with the 600/4 if > you are even the slightest quality concious, at least you need > two tripods, so I doubt it will work any better with the > 600/5.6. Well, the 600/4 is somewhat longer and ~over~ twice as heavy, so its tripod requirements are a lot more substantial. While both lenses have the same FL, the ~much~ lighter 600/5.6 will tax a tripod's stability significantly less. Related to this is the fact that I can do a reasonably good job of hand-holding the 600/5.6 under bright light conditions, but I doubt that I could ever support the 600/4 without a year's worth of weight training at the local gym - <g>. > The 1.4X-L converter should work great though. I do agree with that point. Fred - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
