|A comparison of size and weight - left to right the Nikon D800 at 900g, the Fujifilm XT-1 at 440g and the Sony NEX-5n at 269g
Setting aside the downsides to a mirror-less camera, the over arching positive is that by removing the mirror, its large housing and the complex mechanics, the overall size and weight of a mirrorless camera is brought down significantly in relation to that of even a small DSLR. Another supposed positive is that with the complexity of the mirror removed, the manufacturing cost of a mirrorless camera is also considerably lower than that of a DSLR. So, in theory a mirror-less camera should also be a whole lot cheaper than a DSLR. So what is the reality when dropping the mirror and moving to mirrorless?
Loss of Optical TTL
The first thing to get one’s head round is the loss of the DSLRs optical viewfinder. For myself, this was the single biggest stumbling block when deciding whether to venture into the mirrorless waters. Currently, the best (according to a number of reviewers as well as my own opinion) electronic viewfinder available is that built into Fujifilm’s XT-1. Other EVFs that I have used have simply failed to impress. The image is pixelated, slow to refresh, sometimes quite small, and very, very obviously digital. But, what an electronic viewfinder does offer is things like a live histogram (if you can see it in this small guise) and exposure changes in situ.
Of course your basic mirrorless camera might not even have an EVF. The majority of compact system cameras on the market still lack a viewfinder of any description, relying instead on the LCD screen to compose and shoot the image. Personally, I hate shooting this way as I find it very difficult to work quickly in this fashion, harder still to manually focus accurately and extremely difficult to hold a camera steady effectively. My personal criteria for a mirrorless camera is therefore first and foremost that it has a decent EVF. This doesn’t entirely solve the problems caused by the loss of an optical viewfinder though.
The problems with EVFs become most evident when trying to shoot in low light situations. Because the viewfinder works off the camera’s imaging sensor, it means that high ISO work is also going to mean a noisy viewfinder. On top of this, shooting things in the near dark like stars in the sky is a near exercise in futility (there is a work around I’ll discuss in a moment). With a DSLR it is possible to carefully focus the lens manually with the camera switched off (this avoids any night blindness caused by the small control numbers that glow in the optical viewfinder). There simply isn’t enough light caste by the stars to be able to focus on them using a mirrorless camera.
The big gotcha with mirrorless systems and shooting night skies is that the lenses tend to be ‘focus-by-wire’. This means that although you might be turning the focus ring, the lens isn’t physically focused. Rather, turning the ring sends a signal for the lens to be focused electronically. Traditionally, you could turn the lens to infinity stop and you would know that your stars would be in focus. Not so with most mirrorless cameras. Turn the lens and it just keeps on turning. Worse, on the Olympuses the focus direction changes dependent on how many times you twist the ring. Focus goes from infinity to minimum to infinity to minimum all turning in the same direction! Basically the work around for this is to buy one of the manual focus lenses that are now becoming available for mirrorless cameras (Olympus’ 12-40mm f2.8-4 is another option as it has a physical manual focus) such as the Samyang, Kowa, Voightlander or Zeiss Touit lenses. As they are manual focus they have infinity and minimum focus distance ‘stops’, and even better, have a workable focus distance scale that can be used for zone focusing.
As an aside, an interesting feature on my XT-1 is that there is a digital focus scale readout when the camera is set to manual focus. In theory this means that I could turn the focus ring until the scale indicates infinity focus and infinity should theoretically be in focus, even if I cannot personally see anything in the viewfinder. It’s something I’ll be testing soon on star-trails and timelapses.
Loss of oomph
By oomph I am referring to battery life. Battery life in mirrorless cameras can by summed in quite succinctly. It sucks. When shooting with a Nikon D7000 it is more than possible to get over 700 frames out of a single charge. With the XT-1 or my wife’s Sony NEX-5n I’m lucky to get over 300). Be prepared to carry plenty of spares if you plan to do serious shooting.
Here is where some manufacturers just don’t get their user base. Sony, and now Nikon, with some of their high spec point and shoots, sell the camera without a separate battery charger. For this you have to pay extra. What they think you will do is charge the battery while in camera via a supplied AC cable. This of course means that as long as you are charging your battery you can’t be shooting. Sony’s decidedly upmarket A7r works in this way. One would think that for a camera just shy of $3000 they’d include the flipping charger. But they don’t.
Fast is not the same fast.
Despite the myriad claims that come out with every new mirrorless announcement, the autofocus on these cameras is not the same as that on even entry-level DSLRs (the Nikon V series 1 cameras might be an exception to this rule). My old Nikon D80 (long gone now) could keep up with my then 1 year old daughter as she scrambled around. My XT-1, as fast as its focus on static subjects is, just doesn’t seem to want to keep up with my now one year old son. I expect my D3 and D800 to keep up with moving animals and soccer players alike. I’m not sure I’m ready to entrust my Fujifilm with the same responsibility.
Still, with the above in mind, it’s not that the focus on any of the mirrorless cameras is actually bad. They’re just not as snappy as their DSLR brethren. I repeatedly find myself switching to manual focus whereas I might have been more comfortable trusting the autofocus of my Nikons.
However, manual focus has never been easier or more accurate than with the current crop of mirrorless cameras. Almost all of them have something called ‘focus peaking’ which causes objects that are in focus to shine around their focused parts (it’s been used in video cameras for decades). Personally I enjoy the new split screen function of my XT-1 which shows the full image on one part of the EVF and a magnified loupe on the other side, allowing me to compose and fine tune focus at the same time with a level of accuracy I haven’t had since I last used an old split-screen viewing screen on a Nikon FE 2.
Mirrorless cameras are like designer women’s clothing
The less there is, the more expensive it is. One would think (and I inferred it at the beginning of the article) that with the loss of the complex mirror assembly that the complexity and cost of mirrorless cameras would be less than that of DSLRs. One would assume that by not having a mirror, and having focus and exposure governed by the sensor, thereby removing two more sensors that DSLRs require, that the cost of a mirrorless should be significantly lower than that of a DSLR. One would think that because a mirrorless camera is smaller it requires less material than a DSLR and would therefore be cheaper. One would be wrong.
Right now the Nikon D7100 is cheaper than the Fujifilm XT-1. The Sony SLT-99 (which technically also uses an EVF) is cheaper than the Sony NEX A7r and the same price as the A7 (admittedly with a lens attached). The Sony SLT-58 and two lenses is cheaper than a Sony A6000 without any lenses. Meanwhile you can get a Nikon D5200 for less than a Nikon V2 and the same seems to be the case between the D5300 and the new V3. In all examples here, the better camera is the former, the DSLR. Basically mirrorless is not cheaper, it is decidedly more expensive than buying a DSLR. The strange thing is that feature for feature, the DSLR completely destroys mirrorless cameras. Except for one thing that is, size and weight.
Still, mirrorless cameras have rejuvenated the joy of photography for many serious photographers. I would be wary of nbuying a mirroless as my primary camera though. Despite what Trey Ratcliffe rapsodises on the Sony mirrorless cameras, they are not all-round performers just yet. If, however, you want a light carry around camera reminiscent of the old Nikon FG, EM, or Olympus OMs, then mirrorless might just be what you are looking for. Just be aware of the limitations before pulling out the credit card.