Model 05A
Adaptall-2 Symbol70~350mmF/4.5
Powerful 5X Tele-Zoom Yet Featuring Maximum Aperture of F/4.5
Tamron Adaptall-2 70-350mm F/4.5 Model 05A Lens

Tamron 70-350mm F/4.5 Model 05A: The 70-350 F/4.5 was expensive and was designed for specific applications such as daytime aviation, sports and nature photography, and surveillance work. It abolutely has to be tripod mounted due to its size and weight. We have absolutely no idea how well this lens performs optically, but have found several positive comments and reviews by owners which are posted on the Internet. This lens features a revised optical design compared to the earlier Adaptall 70-350mm F/4.5 model CZ-735 lens. The front focus and master lens groups were also revised compared to the earlier CZ-735 optical design. Tamron states that this lens uses high refractive index glass elements in both the variator and compensator groups for sharp images across the field of view. These changes, in conjunction with the new high refractive index glass for the variator and compensator groups, lead us to believe that this lens has very little chromatic aberration. Off-axis performance should be fairly good since this lens features a large and conventional optical layout which makes it easier for the optical designer to control off-axis aberrations. Also note that the six element master lens group possesses very low optical power and mostly functions to correct off-axis aberrations and field curvature. Although this lens is large and heavy, it likely has somewhat above average optical performance.

Lens Specifications:

Lens Model 05A
Focal Length 70 — 350mm
Aperture Range f/4.5 — 32, AE
Angle of View 34°~7°
Optical Construction
(Groups / Elements)
13 / 15
Min. Focus from Film Plane 98.4" (2.5m)
Macro Mag. Ratio
Filter Size 82mm
Diameter 3.5" (90mm)
Length at
[w/Nikon mount]
10.8" (274mm)
[11.0" (278.5mm)]
Weight 76.5 oz. (2170)
Lens Hood Built-in type, retractable.
Accessory Accepts SP 2X tele-converter #01F. Supplied with exclusive tripod mount ring.
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