Quote:
Originally Posted by gts055
Fpl 51 or Fpl 53 means nothing. Its the mating elements used in the design that give maximum correction to the parameters sought. The only advantage of using FPL53 over FPL51 is that a shorter f ratio may be achieved in using FPL53 glass. The same color correction can be achieved using FPL51 at an albeit longer focal length. Mark
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Not too sure how it can mean nothing and then you go on to state exactly why FPL53 glass is preferable in the short tube designs discussed!
Isn't this the point - Markus has a scope which uses glass suited to a longer FL design and is suffering CA as a result and FPL53 type glass might perhaps be better?
Doug