Canon R or Sony a9 underwater

sg103d wrote:

Hey yall -- I have a Canon R and a Sony a9 and am trying to decide which to purchase an underwater housing for. Does anyone have any experience or suggestions?

I cannot make a real recommendation, since I do not have these cameras (I have Oly EM5II and EM1II in Nauticam housings for UW use). Since I am considering to change to mirrorless FF in the farer future (presumably next year), I follow the reviews and can describe what I think - maybe this helps:

#1.: Generally the decision should not be on a specific camera model, but more on a lens mount system, since the entire system costs will be many thousands of $ and the pure camera body is a small amount. For instance, once you have got your system around the Sony A9 (or Canon R), it will not be a big step to upgrade to a Sony A7RIV (or R5) after some time.

When it comes to the current mirrorless FF systems, I excluded already Nikon for me, since the technology (mostly AF) is behind competitors and also the use of Nikon DSLR lenses via adapter is difficult ("screwdriver"-AF Nikon lenses work only in manual focus via adapter on Z bodies).

#2.: Very important are the lenses that are available for a specific system (and in your case the lenses that you already have) - Important here is, that not every lens that is excellent over the water is also good for UW. The problem with Sony is that many lens types that are important for UW-use are lacking (see below). The advantage of Canon RF mount is, that many adapted EF lenses AF at least as fast/good, if not faster/better, on Canon R bodies than on the EF mount DSLRs (have a look into the Canon R forum here). Hence, one can regard EF lenses practically as "native" on RF bodies. See below a discussion of different lens types, important for UW use for Sony and Canon R:

#2.1.: Fisheye: This is a very important lens-type for UW. For both Sony and Canon you would use the Canon 8-15mm fisheye (or Sigma 15mm fisheye), that is an EF lens, with a domeport (e.g. Nauticam 140). No Sony fisheye lens exists. Adaptors reportedly do not make problems with AF, not on Canon R bodies, nor on Sony.

#2.2.: WA is either achieved with WA lenses and enormous domeports (result is o.k., but not really brilliant IQ) or via a "normal" range zoom lens with Nauticam WACP(=excellent IQ). For smaller budget and transportation also a wet lens (e.g. Nauticam WWL1) with normal range zoom lens and planport gives very good results (this latter configuration is possible with a zoom lens so far only with Sony in form of the new Sony 28mm-60mm; as far as I know no Canon zoom lens works with a wetlens for WA for FF)

#2.3.: "Normal" range works with both systems in regular sized (e.g. 180mm) domports.

#2.4.: Macro: here comes the problem with Sony. For AF speed not only the camery body is important, but also the AF drive(s) of the lens. While the Sony 90mm offers great optical IQ, AF is reportedly slow and hunting (see UW reviews of this lens in internet). The new Sigma 105mm macro with Sony mount is reported to be similar. This is contrasted by the Canon EF 100mm IS macro, that is very fast, even on R bodies. In addition, longer focal lengths (Sigma 150mm and Canon 180mm) exists for ultra macro at longer subject distances.

Bottomline is that both Canon R and Sony A9 are great to start a FF UW system. I personally do not have any Canon or Sony body yet, but the Canon EF 8-15mm and the 100mm IS macro lenses, so I sway towards Canon RF mount, but will carefully check the Sony macro "problem" before I make a final decision. Will be interesting to read what you and others think on that issue...

Wolfgang