Martin Pugh
05-02-2020, 08:37 PM
Hi.
It is generally accepted that a 3mm thick filter adds 1mm to your overall backfocus (refractive index of glass). A 2mm thick filter adds 0.6mm.
If said filter (UV/IR block) causes internal reflections, and you choose to remove that, and place a UV/IR block filter on the front of your lens instead, am I right in thinking that this does not impact your backfocus or if it does, and since those kind of filters are very thin, the impact is minimal to negligible.
cheers
Martin
It is generally accepted that a 3mm thick filter adds 1mm to your overall backfocus (refractive index of glass). A 2mm thick filter adds 0.6mm.
If said filter (UV/IR block) causes internal reflections, and you choose to remove that, and place a UV/IR block filter on the front of your lens instead, am I right in thinking that this does not impact your backfocus or if it does, and since those kind of filters are very thin, the impact is minimal to negligible.
cheers
Martin