This video shows you go to make your own alternative FTZ adapter to use astro filters:
The needed parts come from Baader and Geoptik and their resellers – there are some details at the end of the video:
This video is about FAstroTZ, an experimental make-it-yourself adapter that is an alternative to the Nikon FTZ for connecting F-mount lenses to Z bodies, allowing the use of 1.25 inch astrophotography filters in-line. The parts to make it can be bought on-line and no special experience or tools are needed. The video contains a brief introduction to show you how to build FAstroTZ, then goes into more detail on topics such as aperture control, fine-tuning of focusing, limitations, minimising vignetting. At the end links are provided for the necessary components.
Important note on spacers: as always when spacers are used on a connecting thread, the spacers added should not be to an extent that the connection is destabilised. You are strongly advised to use the system without any spacers at all in initial use. If you choose to do the advanced calibration discussed later, I strongly advise NOT USING MORE THAN ONE SPACER from the Baader set, and so staying at no more than 1.4mm of spacer extension. I have found that without a filter at all, one 0.8mm spacer is enough to cause the point of infinity focus to be about where it is on the Nikon FTZ (the system is not as short on optical length as the manufacturer figures suggest), and my Optolong L-Enhance and Baader Halpha are calibrated well at 1.2 or 1.4mm of spacing. With the thinner Astronomik 1mm filters you will probably need less, and should use less. Astrodon filters are about 3mm thick and I suggest that if you wish to make use of these you live with some short-focusing, and NOT add still more spacing. The prototype under development for 2 inch filters is intended to cope with thicker filters as well without undermining the connections.
