Pimping my Intrepid MK3--Bellows Extension Compensation
Amongst the seemingly endless list of skills and tasks I need to understand and master is the subject of bellows extension compensation. This subject is covered in many places but I can summarize here. On a camera with any kind of bellows one has to compensate for the extension of the bellows as one gets very close to the subject. Recall that the distance from the lens to the film plane is defined by its focal length when focused on a subject at infinity. (This gets more complicated with the compact retrofocus optical designs of 35mm lenses.) As the subject gets closer to the lens then the lens needs to move farther from the film plane. On large format cameras and many medium format cameras (like the Mamiya C220/330 TLRs) it is possible to extend the bellows very far to get very close to the subject. As the lens moves further from the film plane more of the light falls outside of the film plane. This means a correction of more exposure is required. (A readable paper on the subject...