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F* 250-600/5.6 ED [IF]

General Description

Pentax sometimes cited the optical construction of this lens as 17-15 and other times as 18-16. The reason for this confusion is that sometimes they counted the rear-filter other times they didn't. But since a rear-filter is required for proper operation (it can be a clear one, but there has to be one in place), I've decided to count the filter as part of the optical construction and therefore report the numbers 18-16.

Product Information
Exact Nameunknown
Years of Production1988 ~ 1998
Availabilityused, once in several years
Catalog Number27900
Sold with Hoodunknown
Sold with Casededicated trunk: no name

Technical Specifications

Optical Formula18 elements in 16 groups
Aperture Rangef/5.6 ~ f/32
Number of Aperture Blades8
Minimum Focusing Distance3.5 m
Maximum Magnification0.2 X
Special Featuresextra-low dispersion element(s), internal focusing
Front-Filter Threadno
Rear-Filter Diameter43 mm
Maximum Diameter149 mm
Length435 mm
Weight4900 g
Special Featurestripod collar, AF/MF clutch
Capsoft leather tie-on cap, 150 mm
Fitting Hood(s)unknown
Fitting Case(s)dedicated trunk: no name