There is a very good article in May/June 99, Photo Techniques magazine about thi s subject. The author spent six years using a new 4x5 view camera not realizing the film and ground glass were mis aligned by the thickness equal to 3 sheets o f film. He thought enlargements were suppose to get blurry becasue he had nothin g to compare them to. I have been hearing this from many LF photographers, many of them using new equipment!
The method of testing this seems quite easy (with the proper measuring device of course) - with the 4x5 back removed, measure the distance from the ba ck to the ground glass and then insert a film holder loaded with film, and measu re from the same back position to the closest part of film. With any luck they should be close to equal. I am unsure what tolerance should be considered accep table? Does anyone know? However, what none of these articles ever mention... where do you measure to if there is a factory installed fresnel lens in front o f the ground glass. Should you still take your measurement from the back to the fresnel, or do you remove the fresnel lens and measure through to the ground gl ass? Any input would be appreciated. Thank you. .
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