Tamron SP 150-600mm f/5-6.3 VC USD review – Image quality
Image: f/8
Image: f/10
Image: f/16
We haven’t been able to put this lens through our usual lab tests, but it is easy to see that when used wide open, fur and feathers do not render brilliantly. Closing to f/10-16 produces the best results, and then quality tails off towards f/40. This isn’t a surprise, and I think most of us could have guessed that without even looking at the images. The softness at wide apertures is uniform across the frame at 600mm, but becomes an issue only when we’re shooting at 400mm and longer. At the long end of the zoom, f/6.3 is to be avoided if possible, in favour of apertures with better definition – starting with f/10 and running until f/16 and f/22. The difference in depth of field at normal distances between f/10 and f/22 is marked, and will suit different subjects equally well, and in practical terms the range between f/10 and f/22 should provide enough for all of us to get by.
For distant subjects I favoured f/16, and was very pleased with the results of silhouetted cranes against a setting sun. With the aid of the VC system and an elbow dug into my leg for extra support, I was able to achieve 1/400sec at f/16 and ISO 400 – and the lens rendered a very pleasing level of detail.
With as many elements as it is necessary to use in the construction of a lens of this type, flare and internal reflections are extremely difficult to deal with. Tamron has done a splendid job of it, though, and only when I shot almost into the sun did I experience anything that I would describe as reduced contrast. The shot, the seed head of a reed, still retains plenty of detail, and the main patch of flare is extremely well contained in a small area. The same shot shows the characteristics of out-of-focus highlights – not quite round at f/11, despite the nine curved iris blades, but pleasant enough for my liking.
Chromatic aberrations are also very difficult to deal with in a long lens like this, and for the most part Tamron has managed very well. The shot here, of birds flying against an orange sky, demonstrates clearly the success of the LD elements. The hard edges of the silhouettes in the centre of the frame are delightfully clean, while those on the left have a mild cyan edge, and those on the right an outline of red. But these coloured outlines are slight, and not nearly strong enough to destroy our images.
Yes, the lens suffers from corner shading, to a noticeable degree when shooting flying birds against a clean blue sky, and it delivers pincushion curvilinear distortion too – at both ends. But really, I’m not sure we all care too much about either of those two faults. If you intend to use a lens like this for document copying or architecture, you should expect all that is coming your way. In natural subjects, such as wildlife, these faults will go unnoticed most of the time, and if there were compromises to be allowed, the designers have chosen well.
