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None are truly parfocal, but some claim to be. For visual maybe they are?
The astronomiks are the best, $350+ for L,R,G,B filters. It's worth spending the money on them. I had the baader set and sold them because they just didn't cut it for high-res planetary imaging.
There's not a great deal of focus change between the channels - very little usually and sometimes none. But sometimes it does require a tweak.
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