More Weather-Sealed Mirrorless Differences

Mirrorless cameras have evolved rapidly compared to DSLRs. For this reason and because they are relatively new, there are much more differences between mirrorless models than between DSLRs. Specifically, each is designed to offer a different balance of compromise between image-quality, performance and size. Now that major differences were covered in the previous page, it is time to cover the less obvious ones.

Focus

The latest generation sensors have extremely fast read-out speeds. This significantly reduced the performance gap between Phase-Detect and Contrast-Detect autofocus. Both focus very fast now but Contrast-Detect AF is more sensitive. This is why all these cameras fall back to Contrast-Detect when light is very low. Still, both Panasonic mirrorless here are sensitive down to a class-leading -4 EV.

Phase-Detection can only be performed at specific locations on the sensor. On the other hand, contrast-detection can be done on any area of the sensor. Both Panasonic cameras take this to the extreme by offering a high number of areas in several sizes which can be combined into shapes to precisely control where autofocus occurs. Other cameras here limit the selection to a square or rectangular area.

Early EVF and LCD were so lacking in resolution that it was impossible to confirm if focus was achieved or not. This made it impossible to focus manually. Luckily, this is no longer the case. At 2.4 megapixels, the EVFs of weather-sealed mirrorless cameras are all incredibly sharp. This is generally sufficient to focus manually but nearly all these cameras have MF-Assist functions:

• Electronic Zoom - Shows a zoomed-in view of the scene which moves around along with the focus-point. Very easy to use but may require a few refinement to nail. Implemented on all these except the AW1.
• Focus Peaking - Highlights edges of maximum contrast. Usually hit-or-miss because there can be lots of local peaks. Also available on the all but the AW1.
• Digital Range-Finder - Renders a monochrome split image as seen by Phase-Detect sensors. Easy to align and efficient. Implemented by both versions of the Fuji X-T1 only.

Speed & Drive

The lack of a mirror which defines mirrorless cameras allows them to reach speeds not possible on a DSLR. This removes the slowest mechanism part from the system. Mirrorless cameras can also use an electronic-shutter to avoid another limiting component. The bottleneck that remains is the sensor read-out speed which depends on resolution.

Table 4 below compares the maximum speeds of weatherproof mirrorless cameras. Note that the Nikon 1 AW1 does not have a mechanical-shutter at all while both the original Fuji X-T1 and Panasonic GH4 do not use an electronic-shutter. All these cameras offer Bulb mode for longer exposures, some are rather limited compared to DSLRs.

Table 4 - Shutters
Shutter-Speed	Maximum		Minimum		Bulb	Continuous	Buffer
Camera	Mech	Elec	Mech	Elec	Limit	Drive	Depth
Fuji X-T1	1/4000	N / A	30s	N / A	1 Hour	8 FPS	47 JPEG 24 RAW
Fuji X-T1 Graphite	1/4000	1/32000	30s	1s	1 Hour	8 FPS	47 JPEG 24 RAW
Nikon 1 AW1	N / A	1/16000	N / A	30s	2 Mins	60 FPS	60 JPEG 30 RAW
Olympus OM-D E-M1	1/8000	N / A	60s	N / A	30 Mins	10 FPS	95 JPEG 41 RAW
Olympus OM-D E-M5 Mark II	1/8000	1/16000	60s	60s	30 Mins	10 FPS	19 JPEG 16 RAW
Panasonic GH4	1/8000	N / A	60s	N / A	1 Hour	12 FPS	100 JPG 40 RAW
Panasonic GX8	1/8000	1/16000	60s	1s	30 Mins	8 FPS	Unlimited JPEG 30 RAW

Continuous drive at maximum resolution hovers between 8 and 12 FPS except for the Nikon which manages an incredible 60 FPS. To reach this speed it must lock focus on the first frame, otherwise it can do 15 FPS which is still faster than all its competitors. The Panasonic GH4 and Panasonic GX8 offer 4K Photo mode which is a burst of 4K imagesRoughly 12 megapixels. at 30 FPS for up to 30 frames.

AEB is available on these digital cameras except for the AW1. Fuji offers a minimal 3-frame bracket with up to 1 EV steps. The remaining cameras can bracket 7 frames with 2/3 EV steps for Olympus ones and 1 EV steps for Panasonic. Wider increments are available for brackets with fewer frames. Again, other than the Nikon, all these mirrorless offer an Interval-Timer and Multiple-Exposures. Panasonic offers another level of sophistication on its GH4 and GX8 with Stop-Motion Animation, allowing to manually trigger each exposure.

TIP The complete specifications of any digital camera can be compared using our Camera Compare page: Compare all 7 cropped-sensor weather-sealed mirrorless cameras now.

Ergonomics

When it comes to professional photography, efficient controls are essential. This means giving quick access to exposure parameters and common photography controls. As mentioned in the introduction, the Nikon 1 AW1
Nikon 1 AW1 does not target this audience. It actually has no control-dials, just two directional switches which mimic a single control-dial.

The Olympus OM-D E-M1
Olympus OM-D E-M1, Olympus OM-D E-M5 Mark II
Olympus OM-D E-M5 Mark II and Panasonic Lumix DMC-GX8
Panasonic Lumix DMC-GX8 all provide dual control-dials. This gives direct controls to 2 of 3 exposure parameters. The Panasonic Lumix DMC-GH4
Panasonic Lumix DMC-GH4 adds a third control-dial which unfortunately does not control the last parameter. The GH4 adds one dial for Drive mode and the GX8 adds one for EC. There is a tremendous amount of customization possible for all these cameras. The E-M1 and GX8 each offer 8 customizable buttons while the E-M5 Mark II and GH5 have 5.

Fuji offers a completely different approach with dedicated analog dials, plus generic dual control-dials. With any X-T1, ISO and shutter-speed have dedicated dials. Aperture is normally controlled by the aperture-ring which is present on all weather-sealed X-mount lenses. One control-dial controls the aperture when there is no aperture-ring is present, while the other adjusts shutter-speed ±2/3 EV. Additionally, the X-T1 offers dedicated dials for Drive mode and Metering mode. There are 6 customizable buttons these Fuji mirrorless cameras. Despite being freezeproof though, controls on the X-T1 are too flat to be usable with gloves on.

Overall, the easiest and most direct controls to use are on the Panasonic GX8. The other Panasonic and both Olympus cameras are quite efficient but slightly more error-prone since their interface is more modal. Customization greatly helps, particularly on the Olympus. Fuji controls almost completely modal but their analog aspect makes it easier to keep track of current parameters.

Continue to page 4 to compare image-quality and overall performance of all these mirrorless digital cameras.