Various K20D users at the PentaxForums have reported that they experienced strange pattern noises which appear in particular regions of a frame and are particularly noticeable at ISO speeds higher than ISO 1600:-http://www.pentaxforums.com/forums/pentax-dslr-discussion/47584-strange-k20d-high-iso-noise-patterns.htmlAll the user reports in the above thread are self-explanatory, with sample
