Upload & Sell: On
My FD85L (untouched) was not half as expensive as my 5D which I bought used.
For that reason I am reluctant to shave the mirror.
Second, the resale value of the lens is much higher if it does not require mirror shaving.
3 amigos, caught with there parts down, or at least their backsides removed, awaiting identical machining for all 3:
There are many common parts to the back construction of these lenses, save for the rear element of the left 2. Other common measurements are the outmost distance of the rear element, as detailed in AlexTokyo's drawing to be 10.4mm above the lens body base.
I am no lens designer, and have no interest in redesigning an otherwise excellent lens, or playing what-if concerning lens spacings. I can't help you with that. I can suggest that removal of the rear element will ruin the image qualities of the lens and the lens will be worthless.
In the process of determining accurate placement of the rear element, I moved the rear element further away from the sensor, and then, the main group had to be moved toward the sensor to get back infinity focus wide open. This brought the 2 groups too close together compared to the original lens spacings. As a lens technician, my only concern is to retain the original lens orientation and lens group placement relative to each other.
My replacement back, will place the rear element of the L lenses at exactly the original position, and AlexTokyo's 10.4mm position of the rear element on all 3 of the above lenses will be a tad under 2mm protrusion from the EOS adapter backs I use. There is a slight chance the FD50/1.2 will provide slightly more mirror clearance as it has no mounting frame like the L elements.
Stay tuned for the mirror shave episode.
Edited on May 21, 2009 at 12:23 AM · View previous versions