back to Photography page
Here's the results of a test of the Tamron SP AF series of 1.4x and
2x teleconverters. They were fitted to a Nikon 180/2.8 lens and carefully
manually focussed and the distance from camera to test chart varied so
that the image size came out the same in all cases. For interest I also
included the Sigma 28-300 lens at two apertures to see how it compares.
The test images shown are a very small portion of the centre of the slide (Fuji Sensia 100 film used) and at a later date I will include edge details. The individual images were scanned at 4,000 dpi and a 200x200 pixel sample taken. The jpg compression on these images is very low and makes negligible difference.
The smallest pattern in the centre comes out to 40 line pairs per millimetre at the distance photographed, 41x focal length from test chart to film plane in all cases.
I apologise for the load time of the whole page, but it was the only way to give a realistic view of the test.
|Nikon 180/2.8||Nikon 180/2.8
Tamron SP-AF 1.4x
Tamron SP-AF 2x
You can come to your own conclusions from the above data, but I suspect that the f/11-16-22 shots with the 2x TC suffered from camera shake despite the careful use on a heavy tripod. The Sigma acquits itself very well indeed at 180mm by comparison and shows how well the super-zooms behave now. A later test of the Sigma will include all apertures at all focal lengths and edge and centre details as well as a few examples of the 1.4x and 2x TC on it at 300mm to see how it behaves.
The 2x on the Sigma 28-300mm lens at 300mm (=600mm) auto focussed OK on a Nikon F80 in daylight and yielded great results, the 2x and the Sigma on my N8008s (F801s) would not auto-focus even in daylight, the combined aperture was just too small for the older AF logic.
The lettering on my Nikon fit teleconverters is.......
TAMRON SP AF TELE-CONVERTER 300F-FNs 2X JAPAN
TAMRON SP AF TELE-CONVERTER 140F-FNs 1.4X JAPAN
They both have 8 contacts on the camera side and 10 contacts on the lens side. They both make the camera body report the actual aperture the lens is set to and not the modified smaller aperture due to the 2x or 1.4x tele effect. It is reported that the Nikon S series lenses do report the correct modifies aperture. In all cases I get correct exposures. Evidently the Kenko Pro series is exactly the same device.
The conclusion for me is that the Tamron SP AF 1.4x TC is as good as having a real lens, and the 2x doesn't degrade things too much. I'd try to keep the 180/2.8 lens at f/5.6 to get the best performance either alone or with either TC.
back to lens test page
back to Photography page