In the November 2011 issue of Practical Photography magazine, one of their writers ran a group test of superzoom lenses. The Tamron came out of this pretty badly.
If it had been a fair test, then I’d have accepted the results. After all, it is based on one person’s opinion of the lens, just as this blog is. However, I feel that the Tamron 18-270 was let down in this situation by the way that the tests were conducted.
It’s a well-known fact of scientific study that if you want to compare two of anything, then you have to make absolutely certain that all other variables match perfectly. In the case of a lens test, this would mean shooting the same scene from the same tripod at the same combination of aperture and shutter speed (ideally with the same camera, although this isn’t always possible).
What you don’t do, Practical Photography magazine, is shoot completely different scenes (particularly those with moving objects in them like flowers, boats and water) with different settings and try to compare your results.
I actually suspect that they wanted the Tamron to fail this group test.
The shots used to evaluate this lens (which I won’t reproduce here for copyright reasons) were of a featureless, greyed-out lake, and a plant which I know stands about 50cm above the ground. I know from looking at the photo of the lake that it was a windy day, so there was always going to be movement in the images, whether taken from a tripod or not. Other lenses in the test featured shots of jetties, or even a white boat: images with geometric shapes and higher contrast ranges which give auto-focus systems a better chance to lock on to something. Other plants were also used, but were closer to the ground or more robust. Distortion tests were carried out with a series of signs around the lake, with each lens tested against a different sign.
The main points of the article said that: 1. the Tamron was cheaply made; 2. that the autofocus was poor and manual focus unreliable, and 3. that the lens was soft. Here are my findings:
1. It’s a compact lens, but I have no concerns about the build quality. I only rush to put it in the bag if it starts chucking it down with rain, but I’d do that for any of the lenses tested (Canon 18-200; Nikon 18-200; Sigma 18-250; Tamron 18-270). There was so much wobble in the long end of my first kit lens (with a much shorter zoom range) that the edge sharpness was affected, and have seen no such adverse affects from the Tamron.
2. I have no concerns with autofocus, and think that the camera you put it on has more of a bearing here. I’ve had no issues whatsoever with front or back-focus with the Tamron 18-270, and the piezo drive system makes it very fast and quiet. Focusing manually, I’ve already found advantages to the short travel of the focus ring. There is a tiny degree of play in it when locked for autofocus, but I’ve found that even this can help if you want to fine-tune your focus point.
3. It’s sharp enough for the end use. You can certainly print at at least A3 sizes without any discernible softness, regardless of focal length. If you have to print a wall covering, you’re going to see some issues, but I’d not expect someone with those needs to expect that of any lens with a zoom range over about 5x.
I can’t say that the running order wouldn’t be the same if Practical Photography’s tests were carried out under lab conditions. What I can say is that you have to make it a fair test, and use any lens within accepted limits (how far you push those limits is up to you). If people are looking for a compact travel lens with expectations of a few compromises, test it as such and don’t expect miracles. Give us some Practical, real-world Photography. I have a summary of the advantages and disadvantages here, which are based on using the Tamron every day.
I’d like to think I’ve shown on numerous occasions that the Tamron is capable of providing the goods. When Ephotozine sent me the 18-270, I didn’t expect much, but the reality is that it has produced a lot of shots that I love, and has allowed me to shoot in a free and unencumbered way. I’m prepared to fight off anyone who tries to take it from me.