18-250mm Superzoom Lens Group Test

Introduction

Compact cameras have led the way as far as massive zoom ranges are concerned but interchangeable lenses are starting to catch-up. It could be argued that whole point of being able to change lenses is that different lenses can be fitted to meet the needs of a variety of different picture-taking situations but that is not always preferable.

One Size Fits All?

Wouldn't it be great if there really were a single lens that could be fitted to a dSLR to cover the vast majority of picture-taking situations? That is a tall order but it is exactly what the lenses in this month's round-up attempt to provide.

Of course there will have to be sacrifices. All five of the tested lenses start at 18mm and extend to either 250mm or 270mm, giving a 14x or 15x zoom range respectively, so it is reasonable to expect some variation in maximum aperture. As it happens, all of these lenses contract from f/3.5 to f/6.3 although according to its image data Sony's lens stays a shade wider at f/5.6 (even though it shares the same headline specification).

Reading the MTF Graphs

Despite their phenomenal zoom ranges these lenses are all remarkably compact, lightweight and affordable. Their optical characteristics vary but all five zooms display good performances across at least part of their focal-length ranges. Regular readers will spot that the MTF curves cover a greater number of focal lengths than usual and that the aperture axis extends to smaller values. These changes have been necessary to characterise lenses with so large a zoom range and so small a maximum aperture (at the longest focal-length settings).

Somewhat unusually, there are no Canon and Nikkor lenses in this test: their places are taken by a Canon-fit Sigma and two Nikon-fit Tamrons. This does not mean, however, that Canon and Nikon shirk away from super-zooms but rather that, on this occasion, we are turning our attention elsewhere.

SEE TEST REPORTS OF THESE LENSES

Pentax SMC DA 18-250mm f/3.5-6.3 ED AL (IF)

Sigma 18-250mm f/3.5-6.3 DC SLD OS HSM

Sony DT 18-250mm f/3.5-6.3

Tamron AF 18-250mm f/3.5-6.3 DI-II (IF) LD Macro Aspherical

Tamron 18-270 f/3.5-6.3 DI-II (IF) LD VC Macro Aspherical