greyflash said:Not that I disagree with what you have to say about the crop factor your explanation still leaves me wanting. When you say the lens was made for digital bodies, what makes it so. Again, my understanding is that it focus the light onto a smaller area than the 35mm film size. This means that they can use smaller and lighter internal elements in the manufacture of the lens. As an example I believe it will not be suitable for a full frame digital camera and if that is true then your explanation about the lens being made for digital cameras is not correct. Am I wrong? As to the crop factor, you may be correct but again, I am not sure.