Tamron SP 1.4X Tele-Converter Model 140F: The 140F
converter was designed to be used with Tamron's SP 90mm models 52B and 52BB, SP
300mm F/2.8, SP 400mm F/4, SP 200-500 F/5.6, and the SP 350mm F/5.6 and SP
500mm F/8 mirror lenses. Tamron's literature states that this converter is
compatible with all Tamron fixed focal length lenses of 90mm and longer. This
converter also performs well with all Tamron zoom lenses which have a
stationary master group (the rearmost group of lens elements), and can also be
used with many Tamron wide to tele zoom lenses for increasing maximum macro
magnification by 1.4X. The optical design uses high dispersion glass and
features a doublet combined with an air spaced double concave lens (thus
forming a strong air spaced triplet) for creating the magnification effect. The
rearmost doublet decreases the magnification effect and serves to flatten the
field and to correct off-axis aberrations. Overall optical performance is quite
good both on-axis and off-axis.
||1.4X the focal length of original lens
f/2.8 45, AE
(Original lens F number x 1.4)
|Angle of View
(Groups / Elements)
|3 / 5
|Min. Focus from Film
||Retains the min. focus of original lens.
||1.4X the mag. ratio of original lens.
|Length at Infinity in.
||6.0 oz. (169g)