Model 140F
SP Symbol1.4X Tele-Converter
Flat-Field 1.4X Tele-Converter
Tamron SP Adaptall-2 1.4X Tele-Converter Model 140F Lens

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.

Lens Specifications:

Lens Model 140F
Focal Length 1.4X the focal length of original lens
Aperture Range f/2.8 — 45, AE
(Original lens F number x 1.4)
Angle of View
Optical Construction
(Groups / Elements)
3 / 5
Min. Focus from Film Plane Retains the min. focus of original lens.
Macro Mag. Ratio 1.4X the mag. ratio of original lens.
Filter Size
Diameter 2.5" (64.5mm)
Length at Infinity in. (mm)
w/Nikon mount
0.86" (21.9mm)
[1.04" (26.4mm)]
Weight 6.0 oz. (169g)
Lens Hood
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