Introduction to Mirrorless Cameras for Underwater Photography

A Focus on Micro Four Thirds Cameras
By Scott Gietler


What is a mirrorless camera?

  • High-end compact alternative – mirrorless cameras are marketed as an alternative to high-end compact cameras, and are designed for amateur photographers. “Great image quality in a small size”.

  • Live View – these cameras have live view like a compact camera, not an optical viewfinder like a dSLR

  • No Mirror – the lack of an internal mirror allows the camera bodies to be a smaller size. FYI –the mirror in a dSLR, in conjunction with a pentaprism, reflects the image through the optical viewfinder. The mirror flips out of the way when a photo is taken.

  • Interchangeable lenses – unlike compact cameras, mirrorless cameras support different lenses


Mirrorless camera features & benefits

  • Larger Sensor - the sensor size of a mirrorless camera is much larger than a compact camera, resulting in more dynamic range, and less noise when using high ISOs. Greater depth of field than a dSLR at the same aperture

  • Contrast detection for focusing. These cameras focus more like a compact than like a dSLR, which uses the quicker phase-detection

  • Smaller lens size – lenses specifically designed for mirrorless cameras are often much smaller than equivalent dSLR lenses

  • HD Video with autofocus – the video from these cameras is quite nice

  • Kit lens with small zoom range. Some high-end compacts will give you a much larger zoom range for telephoto, because it is easier to make lenses with a large focal range for compact cameras

  • Lens mounts are available for many different “old” lenses, although they may not autofocus

Olympus E-PL2 Micro Four Thirds camera


Micro Four Thirds Cameras

The Olympus E-PL2, E-PL3, E-PM1, E-PL5, OM-D E-M1, E-M5, E-M10, Panasonic GX1, GF2 & GH3/GH4 are called Micro Four Thirds cameras.

What is a micro four thirds camera?

Most (but not all) mirrorless cameras are micro four thirds cameras. The name refers to the a standard created by Olympus and Panasonic, and also to the dimensions of the sensor in the cameras. You can read more here.

These cameras are becoming a popular niche in underwater photography. All share the same size Micro Four Thirds sensor, and have the same lens mount. This means that a lens for the E-PL2 can be used on the GF2/GH2, and vice-versa.

The sensor size is 6-9 times the size of a compact sensor, but half the size of a cropped sensor dSLR. Olympus dSLR cameras like the E520 and E5 share the same sensor, but a different lens mount than a Micro Four Thirds camera.  Sensor size is 18mm x 13.5mm; 4x3 aspect ratio.


Some popular micro four thirds cameras:

  • Olympus E-PL2 – 12 megapixels, discontinuied. Popular choice in the US for a mirrorless camera.

  • Olympus E-PL1 – Discontinued. Almost the same as the E-PL2.

  • Olympus E-PL3 - 12 megapixels, discontinued. Replaces the E-PL2, with a new sensor and faster auto-focusing

  • Olympus E-PL5 - 16 megapixels, $499, same sensor as the OM-D E-M5

  • Olympus E-PL7 - newest of the PEN line, $699, read the full Olympus E-PL7 review here

  • Olympus E-PM1 - 12 megapixels, discontinued. Less expensive version of the E-PL3

  • Olympus OM-D E-M1 - read the full Olympus OM-D E-M1 review here

  • Olympus OM-D E-M5- 16 megapixels, $999 for body only. High-end choice.

  • Panasonic GX1 - 16 megapixels, discontinued. Was a good high-end choice.

  • Panasonic GF2 – 12 megapixels, discontinued. Smallest mirrorless 4/3rds camera out there. Touch screen controls instead of dials.

  • Panasonic GF1 – top pick by Thom Hogan,  but hard to find.

  • Panasonic GH2 – 16 megapixels, discontinued has great hi-def video quality of mirrorless cameras, best image IQ, very fast auto-focus. Larger sensor size.

  • Panasonic GH3/GH4 - these cameras takes some of the best professional video out there and are top picks for stills and video. You can see some sample Panasonic GH4 underwater video here.

Mirrorless Camera Underwater Housings

  • Olympus: By far the most popular underwater housings are the Olympus housings for the E-PL1, E-Pl2, E-PL3, E-PL5, E-PL7, E-PM1, considered a great value

  • 10-bar: Makes mid-range housings for the E-PL1, GF-1, GF-2 and GH-1

  • Recsea makes top of the line housings for the E-PL1, GF-1, GF2, GH-1, NEX-5, NEX-5N, NEX-7 and GH-2 

  • Nauticam makes housings for almost all of the mirrorless camera models, including the new Olympus OM-D E-M1 & Olympus OM-D E-M5

  • Aquatica, Acquapazza make NEX-5 & NEX-5N housings, all considered good quality. Aquatica also had a new housing for the Olympus OM-D E-M1.


Where to Buy

You can call the staff at Bluewater Photo for more advice on mirrorless cameras and mirrorless camera housings.


Part II - Mirrorless camera Lens Selection

Lens selection is very important when looking at mirrorless cameras, please read out guide to the best micro four thirds lenses for underwater photography. A guide to the best Sony NEX lenses will be coming soon.



Further Reading




Scott Gietler is the owner of Bluewater Photo, Bluewater Travel, and the Underwater Photography Guide. Bluewater Photo, based in Santa Monica, CA is one of the world’s largest and most prestigious underwater camera stores, serving many thousands of customers each year, where nothing is more important than customer service. The Underwater Photography Guide is the world’s first website to feature free tutorials on underwater photography, and has become the most trafficked resource on underwater photography worldwide. Bluewater Travel is a full-service dive travel wholesaler sending groups and individuals on the world’s best dive vacations. 

Scott is also an avid diver, underwater photographer, and budding marine biologist, having created the online guide to the underwater flora and fauna of Southern California. He is the past vice-president of the Los Angeles Underwater Photographic Society, has volunteered extensively at the Santa Monica aquarium, and is the creator of the Ocean Art underwater photo competition, one of the largest underwater international photo competitions ever held in terms of value of prizes. He lives in California with his wife, newborn girl and scuba-diving, photo taking 4 year old son.


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