Can you turn 2" filters into unmounted 50mm round?

Antlia SII Ultra Narrow Band 2.5nm 2" Filters Filter Wheel
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John Stone avatar
John Stone avatar
Hi,

I want to buy a new Player-One Zeus full-frame camera and I want to use the new Antlia Dark LRGB (which is available in 50mm unmounted) and the Antlia Ultra 2.5nm SHO (which is only available in 2" mounted).

Do you think it's possible to remove the 2" filter retaining ring and turn the SHO filters into 50mm unmounted that will go in the corresponding Player-One 50mm filter wheel?

Anyone ever done this before?
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Alex Helms avatar
Alex Helms avatar
I recently got screwed with this assumption and had to overnight a new set of 50mm unmounted filters to a dark site smile

I just removed an Antlia L 2 inch mounted and measured it. The actual filter substrate is 47.5mm. The clear aperture of the filter is 45mm.
Médéric Hébert avatar
Médéric Hébert avatar
It most likely won't fit, 2" mounted filter are sligthly smaller because of their mounting frame & thread. I've got to say I'm surprised Player-One makes their FW to be either 50mm unmounted or 2" mounted. Most FW I've seen accept both, but it doesn't look like the Player-One does.
Concise
John Stone avatar
John Stone avatar
Okay,  this begs the question.

would it be better to have Antlia V-Pro 50mm 3nm SHO or 2” Antlia Ultra 2.5nm SHO on a full frame camera?

opinions?
Alex Helms avatar
Alex Helms avatar
I don't think the extra cost is worth it but I'd expect them to be fine.
Médéric Hébert avatar
Médéric Hébert avatar
How fast is your system?
Someone posted a nice spreadsheet of which target is visible with which filter depending of wavelenght shift. Sadly I can't remember in which thread.
I have no experience with Antila filters, but I've heard that the 2.5nm have some light leaks in the infrared, which the 3nm do not suffer from.
John Stone avatar
John Stone avatar
I’m putting together a TOA-130 F7.7 system.

the 2.5 Ultra filters have better transmission are made of better glass and a “flat top” so a little wiggle in manufacturing doesn’t impact as much.

i asked about the Oiii directly and was told the IR leak was fixed in an updated manufacturing proceed a while ago.

this question is more about whether or not 2” filters are the best choice for full-frame.

in another words:  vignetting vs filter performance.

ill imaging from a B1 site but NB filters are great for moonlight filled nights
Médéric Hébert avatar
Médéric Hébert avatar
The 2" mounted should be fine but cutting it close
Alex Helms avatar
Alex Helms avatar
I was using 2 inch mounted Antlia filters for 18 months on a QHY600 (not the SBFL version) and vignetting was minimal. Recently I went up to 50mm unmounted filters with the same camera but now on an f/3 scope and vignetting is still minimal. You'd have no issues with either mounted or unmounted for full frame.
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Ped avatar
Ped avatar
Médéric Hébert:
It most likely won't fit, 2" mounted filter are sligthly smaller because of their mounting frame & thread. I've got to say I'm surprised Player-One makes their FW to be either 50mm unmounted or 2" mounted. Most FW I've seen accept both, but it doesn't look like the Player-One does.

The Player One 7x2" FW accepts both 50mm unmounted and 2" mounted filters.

The 7x50mm FW version only accepts 50mm unmounted filters.

They've stated that the reason they offer two versions is that the 50mm unmounted version has a larger diameter opening (49mm vs around 47mm) to reduce vignetting with full-frame cameras.
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Médéric Hébert avatar
Médéric Hébert avatar
Médéric Hébert:
It most likely won't fit, 2" mounted filter are sligthly smaller because of their mounting frame & thread. I've got to say I'm surprised Player-One makes their FW to be either 50mm unmounted or 2" mounted. Most FW I've seen accept both, but it doesn't look like the Player-One does.

The Player One 7x2" FW accepts both 50mm unmounted and 2" mounted filters.

The 7x50mm FW version only accepts 50mm unmounted filters.

They've stated that the reason they offer two versions is that the 50mm unmounted version has a larger diameter opening (49mm vs around 47mm) to reduce vignetting with full-frame cameras.

Didn't knew that. Makes a lot more sense in that case.