Getting the most from Canon's hot new entry into the mirrorless market when using it in an underwater housing.

Canon's start in the mirrorless marketplace was a bit rocky at first, but after slowly warming to the concept they have now entered in force with the EOS R5 that has caused more buzz than almost any recent camera offering. 

The EOS R5 has clearly been created to outperform the popular Canon 5D cameras in virtually every regard - and not by a small margin. It would be surprising if we did not see a whole lot of Canon DSLR shooters making the switch to mirrorless for the first time specifically because of the EOS R5. So as underwater shooters, what can we expect and what is going to be a bit different from what we are used to?

First, a quick review of what the camera promises:

• 45MP full-frame Dual Pixel CMOS sensor
• 8K video, with option for Raw or 10-bit 4:2:2 C-log or HDR PQ 
• Up to 4K/120p, or oversampled 4K up to 30p
• 100% coverage Dual Pixel II AF system with human and animal detection trained by machine learning
• 12 fps / 20 fps bursts (mech. / elec. shutter)
• 5.76M-dot OLED EVF with 120fps max refresh rate
• 3.2" 2.1M-dot fully articulating touchscreen
• 10-bit HDR photos in HEIF format
• 1x CFExpress slot, 1x UHS-II SD slot
• 2.4/5Ghz Wi-FI with Bluetooth and FTP connectivity
• About 320 shots (using EVF) battery life
• In Body Image Stabilization up to 8 stops of compensation

So lots of numbers, but what are the highlights for us underwater image makers? The resolution is sort of the sweet spot for high resolution cameras right now and 12-20 frames per second is enough for any action we will likely encounter. But it is some of the other numbers that qualify as groundbreaking. The EOS R5 is the first consumer camera to offer 8K (remember when 4K was a big deal?) video recording - and the option to record it in Canon RAW in camera. Equally amazing are the options to record 4K 120P or beautiful 4K oversampled from 8K.

With Canon's well regarded dual-pixel autofocus now improved and stretching edge to edge of the sensor, this camera will definitely deliver the best live AF of anything available to date. Add in Canon's new sophisticated In Body Image Stabilization (IBIS) that works in conjunction with lens based IS and you have, potentially, one of the more competent video cameras ever offered in a hand held format. Yes, there has been some talk of camera heating limiting some of the video potential, but it remains to be seen how significant this is when in an aluminum housing with water contact.

For still shooters, beyond the beautiful high resolution sensor with enhanced dynamic range, there are some very notable features. In the past, Electronic View Finders (EVF) left a lot to be desired if you were use to using an optical viewfinder. EVFs are like miniature computer monitors with much higher resolution than your home HD TV. Canon's 5.76M-dot OLED EVF is tops in resolution and the fast refresh rate makes it much more like using an optical viewfinder, but with advantages optical can't offer: Like being able to playback and review images without taking your eye away from the viewfinder. The EVF is much higher resolution than the rear LCD, so far more effective for critical focus and composition.

Having full sensor, corner-to-corner AF points means unlimited composition capabilities and really should be the standard for high end cameras these days. Low light capability has improved and Canon is rapidly expanding it's R lens line up.

So who should consider this camera for use underwater?

The EOS R5 is truly a do-everything camera with very few weaknesses. But it is first and foremost a fantastic action-oriented high resolution stills camera. There were many who love the functionality of the 5DMkIV but thought it fell a little short of optimal specs, and those that craved the resolution of the 5DSR, but just found it too slow. For those folks, the R5 is your answer and then some. Virtually every aspect of those cameras has been improved upon. Those that are still holding on to the 5DMkIII or 7DMKII are in for an incredible leap in sophistication and performance. The EOS R5 should also be a serious contender for everyone who has been shooting smaller sensor mirrorless cameras and has been torn as to what direction to upgrade.

Should someone primarily interested in shooting video go for the R5? The answer is a qualified "probably". By all accounts the video quality of the R5 is impressive and beautiful. To be able to shoot 8K RAW or 4K 120P at this price and form factor is phenomenal. But if this is your main focus and you want to shoot at these most data intensive levels, it may be worth investing in an external recorder like the Atomos Ninja V in a housing. This will reduce the heat build up internally of the camera which can shorten the record and lengthen recovery times. Choosing a Nauticam Housing system and NA-Ninja V supports this set up well. The battery life can also be a limiting factor at these processing intense video levels. A final note is that high resolution cameras, with smaller photo-sites, will not be as low light sensitive as lower resolution cameras. So depending on your shooting needs, this may or may not be a factor.

But all that being said, what video shooters do have is Canon's enviable ability to manually white balance underwater. State-of-the-current-art IBIS. The R5's best-in-the-industry live AF capability, and incredible video spec flexibility that can produce amazing results if handled properly. Not to mention a whole lot of Canon glass to choose from.

Current housing options

This is an important camera and will likely have several housing options eventually. Below are some of the better known and their virtues.

Nauticam NA-R5 - A world leader in aluminum housing design and manufacturing, the NA-R5 (pictured at the start of the article) is expected to start shipping by Sept/Oct. Extensive lens support, custom water contact optics, maximum accessory options and well regarded ergonomics make the Nauticam housings popular among both professionals and enthusiasts.

Ikelite 200DL for Canon R5 - Ikelite is a venerable US manufacturer of poly-carbonate underwater housings and their housing for the R5 (above) is available now. These housings provide a remarkable amount of control access for a modest price. While the ease of set up, use and flexibility can not match the leading aluminum housings, they offer a good solution for the price conscious image maker who does not need all the accessories (external monitors, remote release options, corrected optics, etc.) that a professional might need.

Sea & Sea MDX R5 - This long time maker of rugged Aluminum housings has not announced their housing yet, but it will be expected by the end of 2020

Subal CDR5 - Subal makes elegant European aluminum housings with traditional simplicity of function. Expect a housing in in December 2020 or January 2021.

Best lenses to use on the EOS R5 for underwater

The RF series lenses will be offering a growing arsenal for years to come, but there good choices for underwater now and there are plenty of EF lenses to fill the gaps. Some housing manufacturers may not support every lens, but most will likely handle some.

The best RF lenses currently available for our use:

• Canon RF 15-35 f/2.8L IS USM - an ideal wide angle blue-water pelagic lens and excellent pool modeling option. For the ultimate in very wide angle rectilinear performance, the RF 15-35 can be mated to Nauticam's exceptional WACP-2 for striking 130 degree coverage and full zoom through.
• Canon RF 24-70 f/2.8L IS USM - not always a versatile focal length range for underwater, but for certain portrait framing applications it can be useful. The Canon RF 24-105 f/4L IS USM covers a similar focal length range, but with a greater zoom range, certain focal lengths will give up some image quality.

• Canon RF 85mm f/2 Macro IS STM - This just-being-introduced lens should be an excellent medium/long macro lens for underwater.

Of course, if you are migrating from an existing Full Frame Canon, then you may already have some excellent EF lens options. There are also a few niches not yet filled by the RF series. Fortunately the Canon Mount Adapter EF-EOS R allows full use of your existing lenses. Lenses to consider using on an adapter even if starting from scratch are below.

• Canon EF 11-24mm f/4L USM - This super wide rectilinear zoom lens performs surprisingly well behind a large dome.

• Canon EF 100mm f/2.8L IS USM Macro - A tried and true longer macro with a bit more reach than the RF 85mm.
• Canon EF 28-70mm f/3.5-4.5 II with Nauticam WACP-1 - This discontinued (but readily available) lens performs brilliantly with Nauticam's ground breaking water contact conversion port. This combination of near fisheye coverage with full zoom through, focus-to-the-glass performance and superior image quality makes it one of the best all around lens options.
• Canon EF 28-80mm f/3.5-5.6 V USM with Nauticam WACP-1 - Another excellent choice similar to the 28-70, but with a bit more zoom range.
• Canon EF 8-15 f/4L - This is the only full fisheye option available at this time and fortunately it is excellent.

Other options to improve your R5 experience underwater

With such a brilliant high resolution EVF to take advantage of, a still shooter will definitely want to take advantage of an enhanced viewfinder like the Nauticam 180° Straight Viewfinder or Nauticam 45° Viewfinder. This can be even more important if you lower the EVF refresh rate to save battery life.

Ikelite offers enhanced viewfinders for their housings here.

 The Subal GS 180 viewfinder is a popular option for Subal.

With the compact dimensions of aluminum housings, the minimal air space leads to a negative buoyancy in the water. So some flotation is a must. Most people opt for float arms such as the Nauticam Carbon Fiber Arms or Inon Mega Float Arms. 

 Vacuum systems for underwater housings have become the norm these days for most housing makers and for good reason. They are our safety check to our housing preparation work and let us know if something is not a perfect. Nauticam was one of the first manufacturers to make vacuum monitoring electronics standard and still makes an optional vacuum valve that is one of the easiest to use as seen here. It will also work on Subal housings. Ikelite provides a mechanical Vacuum option for their R5 housing and can be seen here. Sea & Sea uses the Leak Sentinel.

Want to shoot underwater TTL and rear curtain sync with the EOS R5? No problem! There are several Solutions: The Nauticam TTL Flash Trigger for Canon offers an Optical solution. UW Technics has several options for TTL converters to work in different housings and can function with optical or electrical strobe connections.

Video shooters will often find that a tripod will make the difference when it comes to professional looking results. The same is true underwater, but not everything is designed for such a harsh environment. Fortunately the Zen Tripod Plate is designed for the job and matches well with standard arm clamps and strobe arms to create a stable filming platform.

Call or write us and we will be happy to help with your best options on your EOS R5 configuration!