Front spacers configure your Mercury Stereo camera for particular lenses and focal zones.
Most lenses require a Base Spacer and one Focus Spacer. Focus Spacers are the same for all lenses, but yield different results for a given lens.
Some lenses use S Spacers instead of Base and Focus spacers. These are very thin pancakes that are meant to be sandwiched in between the camera front and the lensboard.
Download the "Lens Info and Focus Scales" spreadsheet for information on all spacer combinations for all tested lenses. Green highlighted spacers are the "essential" spacers for a given lens, and yellow highlighted spacers are "recommended." Others can be used according to your needs.
The above spreadsheet also lists the bolts needed for any given combination. You can order extra bolt sets here.
