Mirrorless cameras are currently seeing a huge surge in popularity among videographers for shooting video. Whether this trend is spurred by the design aspects of the cameras or by manufacturers advancing their capabilities, the end result is that mirrorless cameras can now deliver up to 4K video in a small, lightweight form factor that most DSLRs cannot match.
Evolving from their humble origins as consumer-oriented, point-and-shoot cameras, mirrorless cameras are now available with advanced image control, and are available with sensors as ample as full frame. The lack of an optical mirror viewing assembly, once considered essential, has become a strength for mirrorless cameras. The mirror in a DSLR's optical viewfinder must be moved out of the way when shooting video, rendering it useless, and forcing you to use the rear LCD or an external display to focus and frame your shots. The weight savings of omitting the mirror assembly on mirrorless cameras, combined with advances made in the quality of electronic viewfinder screens, make mirrorless cameras an attractive choice if you are primarily planning on shooting video with your camera.
The smaller form and lighter weight of mirrorless cameras allow you to use smaller, lighter-weight support rigs for shoulder mounting. When using a camera-stabilizing rig, the lighter weight means a less fatiguing work day. This also makes mirrorless cameras an attractive option when shooting with drones, as the lower weight increases flying time per battery charge.
Another distinct advantage mirrorless cameras have over their DSLR counterparts is that of lens adaptability. The flange-focal distance of mirrorless cameras is much shorter than that of DSLRs, which allows you to adapt a wide variety of lenses made for DSLR, SLR (film cameras), and cinema to your mirrorless camera using a wide range of readily available adapters (for more information on this, check out the B&H Mirrorless Camera Buying Guide). There are far fewer mounting adapters available for DSLRs, and in some instances, lenses can only be adapted with expensive mount-replacement servicing. So as far as lens choice goes, mirrorless cameras win, hands-down. Using adapters with mirrorless cameras enables you to use a wider choice of lenses, including vintage and specialty glass that you would have a hard time mounting on a DSLR. It should be noted that most adapters do not support a lens's electronic functions, turning AF lenses and auto iris lenses into manual lenses. However, there are a few adapters that will support the lens's electronic functions, and I suspect that this trend will continue.
Metabones is a company that manufactures a variety of adapters called Speed Boosters, some of which can benefit mirrorless camera users. When you use a full-frame lens on a mirrorless camera with a Micro Four Thirds (MFT) mount, there are Speed Boosters available that can optically shrink the full-frame image to fit the smaller MFT-sized sensor, reducing the “crop factor” and, essentially, making the lens faster (brighter image) in the processes.
There are increasing numbers of mirrorless cameras available that support formats from full frame to APS-C, and MFT. We're going to take a look at a selection of these cameras, and some of the more interesting lens options available.
If you want to shoot 4K video with a mirrorless camera, the top two choices right now are the Sony Alpha a7S and the Panasonic Lumix GH4. The Sony Alpha a6000 is a good choice if you only want HD video. The a7s and GH4 both shoot 4K video (in addition to HD), but they each take a different approach.
The Sony a7S sports a full-frame sensor with a minimal, by today’s standards, 12MP of resolution. This is more than sufficient for 4K video, and although there are similar full-frame sensor mirrorless cameras that feature 24 and 36MP of resolution, they aren't capable of shooting 4K video. Sony chose to go for larger, more light-sensitive pixels with the a7S, which provides a ground-breaking 409,600 maximum ISO rating. This enables you to take advantage of the shallow depth of field afforded by using full-frame sensors, even in low light. You can use Sony E-mount lenses with the a7S, as well as a wide variety of other lenses via available adapters. The camera shoots 4K, but will only record UHD 4K (not the more cinematic DCI format) to external recorders such as the Atomos Shogun.
The Panasonic GH4 features an MFT mount and sensor, and can record 4K internally, without the need for a separate recorder. It supports both UHD and DCI Cinema 4K recording at 24p. The smaller frame size allows you to use a wide variety of lenses, even those that don't cover full-frame sensors, such as lenses for the Super 35mm format (when using the appropriate lens adapters). 4K is also available via the camera's micro-HDMI output, allowing for 10-bit 4K recording, as opposed to the 8-bit internal recording.
If you're looking for an HD-only option, the Sony a6000 records Full HD video at 24 and 60p to a variety of SD and Memory Stick Pro data cards using AVCHD compression. It's available in Silver or Black and features a Sony E-mount, and an APS-C-sized sensor. The a6000 can also be purchased as a kit with an included 16-50mm Zoom lens.
No matter what camera you choose, you're still going to need lenses. There have recently been some exciting new developments in lens design and construction. A few interesting choices are suggested below, just to get you started.
MFT Lenses
Olympus has an interesting line of incredibly compact "body-cap lenses" that protect your camera from dust, as a normal body cap would. They allow you take pictures similar to a pinhole lens, except with the addition of quality optics. These lenses are available in a 9mm Fisheye and 15mm version, and although at a fixed f/8 (not so great in low light), they allow you to manually focus, which is something no pinhole lens or average body cap will let you do.
The Rokinon 7.5mm Ultra Wide Angle Fisheye Lens is a lens with a more standard construction. It's wider, faster, and significantly larger than the Olympus body-cap lenses. The Rokinon is designed specifically for the MFT format, with an adjustable iris ring with a maximum f/3.5, and manual focus with a minimum distance of 4". Shooting that close to the lens really enhances the fisheye effect. The built-in petal-type lens hood protects the lens from flare, while remaining out of the shot.
Panasonic has released lenses to go along with its cameras, with an 8mm T3.5 Fisheye, and a 14 to 45mm Zoom lens, both for with MFT mounts. The fisheye lens features Contrast AF, or can be focused manually, and features a seven-bladed iris for round, out-of-focus highlights. The lens accepts gel filters via a filter slot in the back. The 14-45mm zoom also features a 7-bladed iris for round out-of-focus highlights. It also incorporates Panasonic's MEGA O.I.S. (Optical Image Stabilization) that allows you to stabilize the image with degrading it as electronic stabilization systems will.
Rounding out the MFT lens suggestions is the Voigtlander Nokton 17.5mm f/0.95. The appeal of this lens ought to be apparent. It's a wide, sharp lens, with a maximum f-stop less than f/1.0. Obviously designed for shooting in low-light situations, the Voigtlander is becoming a much sought-after lens for low-light/night shooting.
APS-C Lenses
The Sony 20mm f/2.8 is sometimes referred to as a “pancake” lens, given its low profile. This lens features the Sony E-mount, but only covers an APS-C sized sensor. It contains a smooth, quiet stepper motor for focus control, and can be used as an autofocus or manual focus lens. It also features a Direct Manual Focus mode that allows you to manually adjust focus, even when the lens is in AF mode.
Full-Frame Lenses
The Sony Sonnar T* FE 55mm and Sony Vario Tessar T* FE 24-70mm lenses are extremely sharp lenses for full-frame sensors. Using the world renowned Zeiss T* coatings for flare protection and a sharp, contrasty look, these lenses utilize Zeiss optical design to deliver tremendous image quality. The 55mm prime lens features an f/1.8 maximum aperture, and stays extremely sharp over the entire aperture range. The 24-70mm is a compact zoom that maintains a consistent f/ 4 maximum aperture that does not ramp as you zoom. Each lens supports autofocus, and is designed with a dust and moisture-resistant housing that protects your lens from the rigors of location shooting.
As you can guess, these are only a few suggestions from a vast array of lens choices you have for shooting video with mirrorless cameras. I suspect that in the future there will be an even greater adoption of mirrorless cameras used for video, as their feature sets and advantages over DSLRs will continue to evolve.
