The stupid question regarding filters

[LewisM]

Does it make any difference if a filter is mounted backwards to usual orientation? I have a Tak adapter that presents an m48 filter thread on the rear of the adapter meaning the filter gets screwed on bass-ackwards.

Does it make any difference (it’s going to hold a UV/IR cut filter) or since the light will be going through it anyway won’t make a jot of difference.

If it does I’ll just get a custom one made ;)

[multiweb]

Unless there is an anti reflection coating on one side only it shouldn't matter.

[LewisM]

Just been informed there is a filter adapter in the inside end of the draw tube so cool beans

[JA]

Hi Lewis,

It can make a difference as Marc has already said, but if it ever becomes an issue for any filter you'd like to use you can VERY carefully unscrew or unclip the filter retaining ring on the filter assembly itself and invert the filter inside its holder. I have done that for a different reason on some Nikon 39mm threaded filters that I wanted to convert to use 36mm unmounted astro type filters.

I do recall an issue once raised to do with the "directionality" of some early ZWO filters

Best
JA

[Stonius]

The way to tell is to hold something near the filter and observe the reflection in the filter. If one side gives you a double reflection and the other gives you a single reflection, the filter is directional.


Cheers,


Markus