{mosimage width=125}At the beginning of March 2006, two teams of Canadian Innuit Sled Dogs set off from Cape Arctichesky in Russia in order to cross the Arctic Sea ice to Canada via the North Pole. They were the driving force behind a four-person team of humans who were the participants in the Adventure Ecology "Top of the World" expedition.

Martin Hartley specialises in documenting the most inaccessible parts of the planet. His sustained commitment to capture the beauty of unadulterated landscapes and remote communities has taken him to some of the most isolated and challenging locations in the world.

{mosimage width=125}SFR, or Spatial Frequency response, is another way of expressing MTF, or Modulation Transfer Function. But isn't that just stuff for Geeks?

 Well, no, it does have a bearing on a lens' ability to produce sharp images that goes beyond the photographers technique and goes a long way to explain the difference in prices between apparently similar lenses.

What is 'True Macro'?

{mosimage width=125}The term Macro has been used for some time now by manufacturers to describe what is really only close-up photography and a number of companies, Sigma included, sell lenses with the word 'Macro' appended on the description of them...

{mosimage width=125}Check out any photograhic internet forum, or for that matter any Photographic Magazine's letters pages and you will inevitably come across posts discussing focussing. The terms 'Back focus' or 'Front focus' crop up regularly, and often it is the lens that is blamed. But is it always the case? We decided to look a little further.

{mosimage width=125}Many publications, both in print and on the web, will test a product and give you, the reader, a definitive rundown on how good the product is from that single test. Often the results are at a variance to one another and sometimes they can be totally contradictory.

{mosimage width=125}Sigma have come up trumps yet again with a lens designed for the modern photographer. This time it is a macro lens, which is the ideal focal length for macro photography with a cropped sensor camera, but can also be used on full frame (35mm) cameras.

The standard was good and the entries varied with a number of interpretations of the theme and it has taken a bit of Umming and Ahhing here in the SigmaUser office to sort out the winners but here they are:....