mandab 2 Posted January 31, 2021 I am currently looking into options for fisheye lens with the Sony A7RIII. I understand the options in relation to the sigma 15mm and Canon 8-15mm but curious to see if anyone uses the Sony 28mm lens with fisheye converter with the Nauticam 230mm port. This is not one of the options on the Nauticam Sony port charts. What size extension ring is required? Share this post Link to post Share on other sites
Phil Rudin 461 Posted January 31, 2021 (edited) The problem with the Sony 28mm F/2 and the fisheye converter is, where do I begin, first it only focuses to a minimum focus distance of 22cm (8.8 inches) while most fisheye lenses like the Canon 8-15mm and Sigma 15mm focus to 15cm (5.91 inches). This may not seen like a big difference but with a 180 degree lens it is huge. To answer your question yes it can be used with the 230mm port just like any fisheye. If you already own the port and the 28mm lens this is a way to get you into fisheye but it would be my absolute last choice. Having used the fisheye adapter briefly two dives I think about the only good thing I can say about it for underwater use is that it was marginally better than I was told it would be. At around $750 retail for the lens and fisheye adapter I would strongly suggest other options many of which have been discussed on this site. Edited January 31, 2021 by Phil Rudin Share this post Link to post Share on other sites
ChrisRoss 150 Posted January 31, 2021 Optical quality of the fisheye adapter as Phil mentions is not that great and the close focus is another issue, the whole point of the fisheye is having a lens that can focus on the dome for CFWA use. The 230mm port will certainly work , but limits how close you can get to subjects. Fisheye lenses are not as sensitive to port size as rectilinear lenses, which is why Nauticam recommends its 140mm dome as most optimised for use with fisheyes. Share this post Link to post Share on other sites
mandab 2 Posted January 31, 2021 @ChrisRoss @Phil Rudin Chris and Phil... thanks for responding on this. You have both clarified my query. I will be looking at getting the sigma lens, and there is one for sale in the classifieds here!! Share this post Link to post Share on other sites
