World First: We've got the new Tamron SP 70-200mm f/2.8 Di VC USD lens in for testing, and are currently putting together our full review, but in the meantime, feel free to have a look at our sample photos and test data from the lens. We are testing the lens on the Canon EOS 5D Mark II.
How to read our charts
The blue column represents readings from the centre of the picture frame at the various apertures and the green is from the edges. Averaging them out gives the red weighted column.
The scale on the left side is an indication of actual image resolution. The taller the column, the better the lens performance. Simple.
Chromatic aberration is the lens' inability to focus on the sensor or film all colours of visible light at the same point. Severe chromatic aberration gives a noticeable fringing or a halo effect around sharp edges within the picture. It can be cured in software.
Apochromatic lenses have special lens elements aspheric, extra-low dispersion etc. to minimize the problem, hence they usually cost more.