I saw a discussion thread to verify the focii of a TLR between the viewing and taking lenses. People advised using a wax paper on the film plane with shutter in Bulb mode. Question: 1. Can I get an accurate result if I use a new tracing paper sheet? 2. What should I use as the subject to do the verification? Can I use a strong light bulb or a high contrast indoor layout (like a white wall with dark coloured furniture in front). The distance from camera to subject will not be more than 10-15 feet. The camera in this case is a 45 year old Yashica MAT LM (the LM stopped working 20 years back!). The camera has just been serviced. But I have never suspected the lenses to have become different in focussing. I am apprehensive that the photos may be off focus when I get the prints!