I currently use a 150mm lens (49mm) filter thread and a 90mm lens (82mm) thread and I am thinking that a square filter system would be the best route as I already have the holder and required step down rings.
The ones I am looking at are Hitech (see link below) and would value any advice before making the purchase.
http://www.ebay.co.uk/itm/Hitech-100...FlrbgMQlYFUhwA
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