A polarised opinion

Once again there’s an article ( Exposed to perfection, AP 13 October) praising polarising filters without the warning that they are not suitable for use with some wideangle lenses. After a similar AP article a few years ago I made an expensive mistake and bought one to use with a Sigma 1020mm lens. It worked as expected at the 20mm setting, but with a shorter focal length the effect became uneven across the sky because of the lens’s angle of view.

The article also suggests that if you use screw-in filters ‘you can end up with two or more of the same filter type’. Has James Abbot never heard of stepping rings? Just buy one filter of the largest size you need and get a few (very cheap) stepping rings so that it can be used on other lenses with smaller filter threads. Chester Willey