Nikon D850 Review For Underwater Photography

• High resolution
  • 45.7 megapixel full-frame BSI (back-side illuminated) sensor
• Exceptional autofocus 
  • Shares the AF system as the Nikon D5
  • 153 AF points, 99 cross-type sensors and a dedicated AF processor that can focus down to -4 EV 
• Speed
  • 7 fps shooting with a 51 shot buffer
• Incredible image quality 
  • Great dynamic range and ISO Performance
• Video
  • This camera easily boasts the best feature set of any Nikon DSLR camera. 
  • True full frame 4K 30fps video and 1080p 120fps slow-mo

NIkon D850 Full Specs

• 45.7 megapixel, backside illuminated full-frame sensor  
• 7 frames per second and a 51 shot buffer
• ISO 64-25600 (expandable to 32-102,400)
• 4K UHD video 3840 x 2160 at 30/25/24p
• 1/8000 to 30 second shutter speeds
• Flash sync speed of 1/250 
• 4K and 8K timelapse 
• 120 fps slow-motion 
• Focus peaking
• Zebra stripe highlight detection 
• Focus stacking
• Wireless connectivity 
• Rugged body with weather and dust sealing 
• TTL exposuring metering using RGB sensor with 180k pixels 
  • Matrix
  • Center-weighted
  • Spot
  • Highlight-weighted 
• Same autofocus sensor module as the D5/D500
• 153 AF points, 99 cross-type sensors 
• Dedicated AF processor that can focus down to -4 EV 
• Autofocus fine tuning
• Full-frame 4K UHD video 
• Great dynamic range and ISO Performance
• Great battery life
  • Up to 1840 stills or 70 minutes of video per charge
• Silent shooting modes
• Tilting touch screen monitor 
• Dual XQD/SD card slots
• Bluetooth

Overview

With specs like these, you might ask yourself, what’s the catch.  To be honest, there really isn’t one. The Nikon D850 delivers.  A combination of resolution, dynamic range, ISO performance, exceptional autofocus and a speedy 7 frames per second is nothing short of spectacular.

With improvements across the board, you are getting more tools to help you nail your shots, whatever they may be.  By combining the sensor’s exceptional dynamic range with a base ISO of 64, you get more control to balance vivid reefscapes with the brightest sunballs, while maintaining exceptional colors and detail throughout.  When the diving isn’t all clear skies, sunshine and great viz, you get plenty of room to bump the ISO to capture more detail and light in the darkest of wrecks, caverns, and caves. The amount of detail able to be pulled up from shadows is quite astonishing.

 The NIkon D850 handles combining the smallest of critters and strongest macro diopters with ease, and does so effortlessly with it’s incredibly fast and accurate autofocus even dim, fading light.  Not only is the autofocus extremely accurate, it’s also remarkably fast, absolutely one of the best autofocus systems available, matched only by the D500 and D5 in the Nikon world.

For the fast-paced, high intensity action you get 7 frames per second coupled with an array of autofocus and auto-iso options; letting the camera do some of the heavy lifting for you allowing you to focus on the rare encounters you traveled halfway around the world to experience. The 51 image buffer is pretty amazing considering each image is 45.7 megapixels! The buffer ensures that there will be no slowdown in your photo taking for image processing. The lag between taking burst shots and reviewing them is greatly reduced as compared to the D810. 

For the cases when, despite your best efforts and practice, you couldn’t quite nail the shot with absolute perfection, you still have one remaining tool at your disposal:  a hefty 45.7 megapixel raw file. In addition to being able to print massive images, this extra resolution can come in handy in some other situations too.  

• Did you forget to change your strobe batteries and are now forced to shoot natural light, far above your standard ISO, as a one in a lifetime event unfolds in front of you?  

• Did you jump the gun on that sea lion as it buzzed by, leaving the subject smaller in the frame than you wanted?  

• Did your subject flee as you were inching closer before you were able to fill the frame?  

This much resolution gives you room to touch up in post, cropping and reframing as needed. In the event that you need to shoot with an ultra-high ISO (such as a dead strobe), the camera can still produce stunning images if you don’t need the absolute, full resolution. Downsampling the image will easily eliminate a lot of the noise with resolution to spare, rendering a useable image. Accepting a “less than full resolution” image where you would otherwise end up with nothing is a tradeoff I would make every day. Even at half resolution, you still have an incredible 20 megapixel images to work with!  

Some Nikon D850 underwater photos:

Autofocus 

There are a few things worth digging deeper into with regards to the autofocus of the D850.  This camera has the same autofocus system as the flagship Nikon D5. This high-performance sensor module (the Multi-CAM 20K) combines 153 focus points, of which 99 are cross type sensors, with a dedicated AF engine.  Of these 153 focus points, 55 are user selectable.

Cross type sensors are more accurate and help to minimize focusing errors, while having more sensors helps the camera track focus in the different autofocus modes. When you combine these focus points with the dedicated AF engine, the camera is able to speed up the autofocus calculations - much like a current computer gets faster with more CPU cores or threads. The end result is faster and more accurate focusing and tracking, essential for both fast-moving and high speed shooting.

It’s also worth noting the low-light performance of the autofocus, as we often shoot in dim underwater conditions. The D850 is able to focus in the center point down to -4 EV, and -3 EV at all the other AF points. This is roughly the equivalent of a dark moonlit night, with the light given off during a full moon being around -2 to -3 EV. Although we recommend using a focus light, it’s nice to have that extra flexibility to not use one when you’re shooting shy subjects.

D850 Autofocus modes 

• Auto-area AF
  • The camera will detect subjects and focus on them accordingly.  
  • Letting the camera choose very critical settings is not recommended, though your results may vary. 
• Single-point AF
  • The camera focuses on a single point selected by the photographer.  
  • Best used when you want very specific control over what is in focus, such as macro or super macro, when your subjects are fairly still.
• Group-area AF 
  • The camera uses all the points in a group to determine focus.  
  • Like single-point, this is useful for still subjects such as macro and super macro, and is useful when camera is having a hard time getting focus with single point. Priority is spread across multiple points, so the camera does its best to keep them all in focus.
• Dynamic-area AF
  • The camera focuses around a single point, using 9, 25, 72, or 153 of the neighboring points to continuously maintain focus. 
  • Great for fish and other moving subjects, allowing you to frame the image and still allow for some movement.  Priority is weighted toward a single focus point so this relies on you keeping the AF points over your subject.
• 3D-tracking AF
  • The camera focuses on a single point, and attempts to intelligently follow the subject as it moves across the frame using all 153 focus points.
  • Great for fish and erratically moving subjects.  This mode allows you to lock focus and follow the subject as it moves throughout frame.  This is really powerful and allows flexibility to quickly adjust your framing without having move the focus points on the camera, potentially missing the shot.  

The D850 is the first Nikon camera to offer full-frame 4K video, something few other cameras support.  Previous Nikon cameras would only use subset of the sensor resulting in a crop factor while the D850 is able to use the full width of the sensor.  This means you aren’t losing any FOV, which is great for wide angle video while options are still there to enable the DX crop of 1.5x for macro to allow for tighter framing.

• Best underwater white balance performance of any Nikon DSLR. If underwater video performance was keeping you from switching to Nikon, be prepared to reconsider your options!
• 4K 30 fps full frame video with a bitrate of 144Mbit
  • Full frame or DX crop
• 1080p 120 fps
  • This automatically uses a DX crop
• Video compression using H.264/MPEG-4
  • More manageable file sizes over M-JPEG
• Flat color profile (unfortunately, no log gamma profile for better tonal reproduction)
• Separate video settings in the camera allow easy switching from video to stills
• Video frame size and rate
  • 3840 x 2160 (4K UHD); 30p (progressive), 25p, 24p
  • 1920 x 1080; 60p, 50p, 30p, 25p, 24p
  • 1280 x 720; 60p, 50p
  • 1920 x 1080 (slow-mo); 30p x4, 25p x4, 24p x5
• Improved settings allow easily setting white balance using the Live View

With a little background in optics and understanding of how lenses and ports work underwater, or more specifically, what happens to light as it travels from one medium to another, it starts to become clear that dome ports are not the solution for everything.