Hi folks, My name is Ric Hochulski. I hale from the frigid north of Western New York, I shoot with a K5 with a K7 as a back up camera. I operate palladinphoto.com and have been involved in photography for over 25 years. All of my lenses are designed for full frame except for one a Tamron 10-24mm. That said the reason this is important is that with a full frame lens on a body with a APS sensor you are using only the center of the lens, which is the best part of the lens as far as quality glass. In my years of photography I've learned that most if not all of the problems that lenses have involves the edges and not the center so with an APS sensor these problems are not an issue. I have enlarged some of my images to 30x40 using these sensors with no loss of quality or sharpness in the image. If you go to my website you can see samples of my images. I also have an image in the still life gallery entitled Makers Mark. Thank you for allowing me to bloviate a little on this subject.