Before we look at specific comparisons, it is worth studying the range of macro lenses currently tested in the labs on an EOS 5D Mark II. As of today, there are 7 lenses in this group. While the test results for this new lens may seem disappointing in isolation, there is only a 6point difference in DxOMark scores between the very best (Carl Zeiss Makro-Planar T 100mm f/2 ZE Canon scoring 28) and the very worst (Canon EF100mm f/2.8 Macro USM scoring 22). Although this lens is only one up from the bottom in terms of DxOMark score, the price of this lens ($460USD) compared to the Carl Zeiss lens ($1,840USD) makes it seem like a good purchase since the real-world difference in optical performance is not as great as the price difference.
Comparing this latest version of the Tamron 90mm Macro lens, with its predecessor, we can see that in actual fact, in all lab-test areas with the exception of chromatic aberration, the older version matches or outperforms the new version. However, they are very close – sharpness scores of 13P-Mpix for the new version and 14P-Mpix for the older version are close enough that in the real world there is no obviously discernible difference at normal print sizes. It is only the chromatic aberration score that is better on the new version than the old, scoring 5µm to the older lens’ 9µm – a difference that will be visible in final images.
So why would you choose the new lens over the older model? The answer lies in features beyond those tested in lab conditions - this lens includes both Tamron’s Vibration Compensation system and an ultrasonic motor. It is possible that the VC system is responsible for the lower sharpness than expected, as often non-stabilized lenses perform better than stabilized versions. However, the stabilizer offers extra benefits in terms of shooting by allowing sharp images are slower shutter speeds.
The ultrasonic motor combined with an internal focusing system is another big plus in terms of handling and real-world use for the new lens. Instead of slowly moving through the lens range, the USD focus motor promises smooth and fast focusing. Combined with internal focusing, the handling of the lens is much improved because the lens length and balance does not change during focusing.
Choosing between these two Tamron lenses will come down to how important the Vibration Compensation and Ultrasonic Drive AF is to you. If you already have the older model, then upgrading will not gain you any optical performance, but you will find the handling improved. If you are looking to buy and don’t yet have the previous model, then the choice will be driven by price and features more than performance.
Form most users looking at buying a macro lens to use on a Canon camera, these three are usually the main options in consideration. Looking at the DxOMark scores, the Canon lens comes out on top, scoring 26 and the Tamron lens is at the bottom of the list with 23. In P-Mpix scores, the story is the same – the Canon tops the scoring with 16P-Mpix, the Sigma lens is just a fraction behind with 15P-Mpix and the Tamron lens is at the back with 13P-Mpix
In terms of transmission scores there is very little to choose between them, all three models performing around the same level. It’s the same for the distortion scores and the vignetting scores, with all three lenses showing essentially no distortion and equal amounts of vignetting when shooting wide open.
Finally, the chromatic aberration scores show a chink in the Canon armor, with it coming last with 11μm, while the Sigma and Tamron lenses are matched on 5μm.
If price is not an option, then the Canon lens is clearly the best of these three options. However, it is also the most expensive. The Sigma falls somewhere in the middle and the Tamron is a little behind. However, while the figures may suggest the differences are large, in the real world, they are quite minimal and are unlikely to be anything to worry about unduly. Given the $250USD saving of the Tamron over the Sigma lens, it does actually still make a very good macro lens choice.