In checking on the Swarovski DCA on this site: http://swarovskioptik.com/en_us/products/camera-adapters, I found the following, which seems to indicate it would work with the 30X eyepiece. Is this correct?
When Swarovski released the DCA around 7 or 8 years ago, they had two versions: 49206 (DCA for Zoom) and 49306 (DCA for Fixed). Unfortunately, the DCA for Fixed eyepieces was discontinued several years ago. Swarovski made this decision based on the fact that the zoom eyepiece is overwhelmingly more popular in terms of sales than any of their fixed magnification eyepieces. This morning I attempted to fit the 49206 DCA for Zoom to a 30X eyepiece; there were problems. The inside diameter of the bottom half of the DCA that fits to the eyepiece is about 2mm wider than the outside base diameter of the 30X eyepiece where it’s supposed to be tightened via a thumbscrew (this created a 4mm gap at the other end near the eyepiece ocular opening). Also, the upper half of the DCA will not slide all the way down to the proper locking position on the bottom half of the DCA. The end result is that the eyepiece ocular opening is not on axis with the opening of the upper half of the DCA and it’s not stable even when the thumbscrews are tightened. You might be able to digiscope with it, but as a veteran digiscoper of over 10 years, I foresee inconsistent alignment and mechanical difficulties.
Apparently, Swarovski’s website has not been updated to reflect the fact they discontinued the DCA for Fixed eyepieces.
Please let me know if there is anything else I can do for you.