Re: [ATM] A Null Test

["Richard F.L.R. Snashall" <rflrs@rcn.com>]

Donald Good wrote:
> Richard;
> So how does this compare to the Ross Null Test?  Advantages?  Disadvantages?
> Is it more accurate?  Does it cover a wider range of conic constants?  f#s?
> The example prescription given is for conic constant=-1.2 and f/2.5.  Do the
> lens separations need to be adjusted for each change in cc and/or f#?  Since
> this has more than 10 surfaces, those of us who use OSLO-LT will have
> difficulty.
> Thanks
 From what I've read, the Ross Null Test is good at f/4 or slower.  The
instigating request here was for f/3.

The spacing does have to be adjusted to change goal f/# and conic constant.

Peter Ceravolo's site has some code for the Ross test.  Wonder if it could
be adapted to a new situation...  That might still leave you out in the
cold as far as "seeing" the results, but it might be better than nothing.
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