Is there any type of equipment that I could place on the viewfinder of my camera that would provide magnification? Problem: I'm blind as a bat (okay...it's not as bad as all that, but I do wear bifocals). When I look thru the viewfinder with my glasses, I find that I'm having a problem determining sharpness as I focus (it's especially noticeable when I use my new 10-20mm). My eyeglass prescription is fairly new and I have no problems seeing otherwise (when I wear my glasses, that is...). Does anyone else have vision problems when looking thru the viewfinder, and do you know of any product that could be added to the camera that would help?