Perry Pellechia wrote:

>> >Unusual length for 35mm.
>>
>> Yeah, they should have made it 77mm :)
>
>This comment reminds me of a question I always had about the
>Limited's.  I know the reason for the 43mm focal length (true normal),
>but what is significant about 31mm and 77mm?  Anyone know?


Well the word is that there really isn't anything special about the
numbers 31 and 77, it's just that most lenses, from all manufacturers,
aren't named with their actual focal length but with the "standard"
number that's closest. In other words, a "100mm" lens might actually
be anywhere from 95mm to 104mm, but gets the "100" designation just to
make it easier to remember. Sometimes lens tests will list the actual
measured focal length as well as the designated focal length.

With the 31 Ltd and 77 Ltd, Pentax apparently just gave the lenses
names that were indicative of their actual focal length. An unromantic
explanation, I realize, but what can you do? :)
 
 
-- 
Mark Roberts Photography & Multimedia
www.robertstech.com
412-687-2835

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