I've wanted an ultra wide lens since I got my first SLR in the early '70s. I just couldn't justify taking the money from the budget. Now that I have retired and travel more, it was time. I just received a Tamron 10-24 zoom to use with my K-01. On first inspection, I think it will be a nice addition to my lens collection. I'm now able to seamlessly cover from 10 to 600 mm, with an odd prime thrown in here and there.