Tamron AF 70-300mm f/4-5.6 LD Di macro (Pentax K) - Review / Lab Test Report |
Lens Reviews -
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Review by Klaus Schroiff, published June 2007
Special thanks to Oliver Kirchner for providing this lens for testing!
Introduction
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
terms.
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).
![](/images/8Reviews/lenses/tamron_70300_456_pentax/lens.jpg)
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.
Specifications |
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 |
Weight | 435 g |
Filter size | 62 mm (rotating) |
Hood | barrel shaped, snap-on type (supplied) |
Other features | macro mode |
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