Why Buy a Compact Camera?


Camera classes have gotten very blurry recently... DSLR cameras do HD video incredibly well, and are now reaching 4K UHD resolutions with a “look” unmatched by any camcorder.  “Pocket” cameras are getting better lenses and bigger sensors, and they are no longer in the pockets of most.  That space has been occupied by smart phones.  Mirrorless interchangeable lens cameras have taken the camera world by storm, seeking to merge the image quality of larger dslr systems with a small form factor.

Fixed lens compact cameras are certainly improving, and some real enthusiast features are showing up in higher end models like Sony’s RX100 MIII, but the larger sensors are making it harder and harder to get great wet mate lens compatibility.  The ability to change lenses underwater has long been a hallmark of this segment, but that functionality is diminished in many of the higher end models.  When examining the issue more closely, the entry level mirrorless systems begin to look pretty attractive. 

Sony A5000

As the photo above illustrates, this very capable entry level mirrorless system is only a bit bigger than the leading compacts.  This matters if you want to stick the camera in your pocket, but who does that anymore?  When you build an underwater system around the camera any size difference is negligible, and the price points are a lot closer than you’d think…

A5000 is built around a big 20 Megapixel APS-C sensor.  This is the same sensor size used by some of the most popular DSLR cameras over the past few years (Canon 7D, Nikon D7100 anyone?), and images from these sensors have graced the covers of dive mags the world over. This is an interchangeable lens camera, allowing use of the right lens for the job, both topside and underwater.

Pardon the technical digression, but it is typically accepted that bigger pixels yield better image quality. While you can find an exception to every rule, here is a relative example of the photosite sizes in some common systems:

Relative pixel size (µm):

This photosite size in a $500 camera is pretty incredible!

The A5000 ships with a 16-50 power zoom.  This lens on the A5000 is just like the mid-range zoom lens built in to every compact camera. When using the comparative focal length formula, the 16-50mm is like a 24-75mm on full frame - slightly better coverage than the RX100III's 24-70mm. This is a very useful midrange zoom for fish portraits, closeups, and skittish big animals that won’t let you approach close enough for a wide angle lens.  And the best part… you can take it off!  The interchangeable lens mount allows for a dedicated wide angle or macro lens to be used.  If chosen well, each lens option can outperform the wet lens alternatives that are found for a fixed lens compact.


When using compact cameras, many people have come to expect the "fish tail syndrome."  Traditionally, compact camera users have learned to deal with a certain amount "shutter lag" that is actually a combination of focus acquisition and shutter response.  This characteristic has been greatly improved on compacts in recent years, but this delay between finger action and actual picture taken does still lead to many perfectly sharp fish tail photographs as the fish moves out of the frame.  Almost any modern mirrorless interchangeable lens camera will generally have a more immediate response when focusing and releasing the shutter than any current compact camera.  Several mirrorless cameras claim to have the fastest autofocus in the world and the A5000 would certainly be in the hunt.

Those of us who take our cameras underwater love to be able to get through two dives without opening the housing.  But few compact camera batteries, when required to fire a flash, will last for two dives.  The Sony A5000 battery, by virtue of having more storage capacity, will easily last for two dives. 

The Nauticam NA-A5000 housing requires no zoom gear to operate the 16-50 zoom, so the user can operate it from a lever on top of the housing - just like a compact camera housing.

Ruggedness for Travel and Longevity

Compact cameras with built in zoom lenses pack an awful lot of electronics, motors and moving pieces into the smallest possible package.  Thanks to the engineering that allows for all this miniaturization, it is pretty difficult to make a compact system like this as rugged and long lasting as a mirrorless system like the A5000 that has the luxury of more room and a detachable lens.  But the good news is that everything is still easy to pack in carry-on luggage!

One of the things we have often observed over the years here at Reef Photo & Video is that some people are intrigued about moving into a new category of camera systems (ie; compact, mirroless interchangeable lens, DSLR, etc), but often reluctant to move beyond their comfort zone.  The most common concern is "more complexity."   But there is a secret that most people quickly learn:  the more sophisticated the type of camera system you progress to, the easier your underwater photography becomes.  So what is the most common complaint from customers advancing into a mirrorless system or DSLR? Just six words - "Why did I wait so long!"

An A5000 will give a better user experience than a compact in almost every regard - even if you just shoot it like a compact camera. But when you are ready, it can do so much more.

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