Has anyone tried adding a filter holder to lens adapters?

hindesite wrote:

ProfHankD wrote:

SmoothOperator wrote:

Gato Amarillo wrote:

Since we're mainly adapting to mirroless cameras which focus from the sensor image focus shift should be accounted for and not be a problem - the one problem being if the shift prevented the lens reaching infinity focus.

Gato

The adapter should take that into account, drop-in filters in telephotos are included as part of the optical formula.

As I said in my post that started this sequence,

if the adapter is designed to have a filter with a specific optical thickness, you'd need one even for clear to keep the same rear focus distance, which would still degrade IQ a bit.

In practical terms, I've never noticed this with m4/3 - I have several long telephoto lenses (500 and 800) with rear filters, and all will achieve infinity focus with room to spare with and without out any filters on any adapter combination I've used.

Assuming those lenses were not intended to take rear filters (or that you're comparing with/without a rear filter), that's because of two things:

1. The amount of movement needed to focus a long focal length lens is correspondingly larger, so 1mm doesn't move the focus point much. Infinity is also very far away, not just a few hundred feet, so make sure you're really checking infinity focus.
2. Many long focal length lenses can focus past infinity to allow for thermal expansion of the barrel.