Hello, I'm new (as of yesterday) to the DSLR world. I bought a Pentax K-x because I have 3 additional lens that I had for my K1000 and they do not have the "A" on the aperture ring. I put my Osawa 85-300 macro on and after going through the setup of the Green button and the focal length i got it to work. However, the image, when compared to the one taken with the kit lens, has a yellowish tine to it. Can anyone tell me why?