Tamron AF 70-300mm f/4-5.6 LD Di macro (Pentax K) - Review / Lab Test Report
Lens Reviews -
Thursday, 27 December 2007 00:39
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Special thanks to Oliver Kirchner for providing this lens for testing!
The Tamron AF 70-300mm f/4-5.6 LD Di macro is a lens with a quite interesting
background. In the mid 90s Tamron and Nikon used the same optical formula in
its predecessors (Tamron AF 70-300mm f/4-5.6 LD and Nikkor AF 70-300mm f/4-5.6 ED).
Unlike Nikon Tamron decided to continue to improve the original design and the current
lens is the third generation which features a macro mode as well as a new optimized
("Digitally Integrated") lens coating. The Tamron is still a full format lens and
when used on an APS-C DSLR the field-of-view is equivalent to about 105-450mm in classic
The Tamron is obviously a low budget lens - locally it sells for just ~130€ - it does
hardly get any cheaper than this. However, it is amazing that Tamron didn't really
sacrifice too much build quality. The quality of the plastic is quite decent, there's
a metal mount and the build tolerances are tight. The tested sample had no wobbly
parts. The rubberized zoom and focus control rings have a higher than average friction.
The low price tag shows up a bit in the zoom and focus mechanism. The lens extends
significantly when zooming towards the long end of the zoom range and the front element
rotates during focusing - using a polarizer is no fun but this is probably not a
priority in the target market anyway. If you want to take advantage of the "macro" mode
you've to set the lens to a focal length longer than 180mm. By using the macro switch
you can extend the focus range down to 0.95mm which gives you a max. object magnification
of 1:2 @ 300mm. If you want to use shorter focal lengths again you need to focus beyond
1.5m and switch back to the standard mode - otherwise the zoom mechanism will be blocked
at the 180mm setting. Don't expect that this "macro" mode is really comparable in
quality to "true" macro lenses (with close focus optimizations).
Typical for most Pentax-K mount lenses the Tamron has no internal AF motor and
relies on the conventional slotted drive screw operated by the camera. The lens uses
a focus extension system so the AF motor of the camera is fairly busy during operations.
The AF is reasonably fast and somewhat noisy.
|Equiv. focal length||105-450 mm (full format equivalent)|
|Equiv. aperture||f/6-f/8.4 (full format equivalent, in terms of depth-of-field)|
|Optical construction||13 elements in 9 groups inc. 1 LD element|
|Number of aperture blades||9|
|min. focus distance||1.5 m (max. magnification ratio 1:4), 0.95 m in macro mode (1:2)|
|Dimensions||77 x 117 mm|
|Filter size||62 mm (rotating)|
|Hood||barrel shaped, snap-on type (supplied)|
|Other features||macro mode|