The EVF Translucent Mirror Reality
I know that this section is not going to endear me to anyone in the Sony community, but as always I have to call them as I see them. I have been a big fan of Sony's new EVF. In late 2011 and early 2012 I spent five months living in Mexico and shot more than 8,000 frames with my NEX-7. I realized and discussed in my review at the time the realities and shortcomings of using an EVF, but my comments were on the whole benign. The reason that I wasn't more critical at the time was not because I didn't see the shortcomings, but that they were ameliorated by the entire gestalt of the NEX-7 itself. Here was an almost pocket sized APS-C 24 Megapixel camera with a pretty terrific EVF. It was almost like the story of the talking dog. It wasn't so much what it had to say, but that it could talk at all.
Now we have Sony taking this same EVF technology (still one of the better ones on the market), and marrying it with their so-called translucent mirror technology, and putting them both into a full sized, full-frame DSLR. And, if hints from Sony executives are to be believed, this model likely spells the end of the use of rapid-return mirrors and glass prisms in that company's DSLRs (or DSLT's as they perversely prefer to call them).
Speaking as plainly as I can – I don't care for it. While the Sony EVF works fine on a NEX camera, and even on an APS-C sized model, it just seems out of place on a pro-grade full-frame DSLR. I stress the word full-frame, because to my mind this lies at the core of the issue. Previous Sony DLSR/DSLTs have used this same EVF, but they are competing with other brand's APS-C sized sensor cameras, which typically have small, dim and distant appearing optical viewfinders. But one of the big selling points of full frame DSLRs is that they have larger, full sized (usually 100%) viewfinders, and they are bright and with natural clarity, contrast and dynamic range; essentially the same as what the human eye sees unaided.
When I first picked up the A99 my very first impression (I'd been using my Nikon D800e the day before) was that there was something wrong. What it turned out to be was the outcome of virtually a lifetime of using full-frame film and digital cameras with their large and bright viewfinders. Holding up the A99 side by side with a camera like the D800, or new Nikon D600 or Canon 6D, brings the matter to light – so to speak. As good as it is, the Sony EVF just can't compete in terms of realistic contrast, brightness and overall clarity to a full frame glass prism viewfinder.
And in reality, that's one of the things that attracts photographers to full frame cameras. A large bright viewfinder has a definate role in both the pleasure of use as well as the functionality of such a camera. So why isn't this as much of problem with Sony's APS-C cameras, and especially their NEX series? In the case of the APS-C cameras it's that the relative difference to competitive optical VF models is less. In the case of the NEX cameras it's one of expectations and willingness to accept trade-offs.
I have no beef with Sony's translucent mirror technology. There's a small light loss, and likely a small resolution reduction, but nothing to get fussed about. It also has real advantages, such as the ability to feed an optical image directly to the sensor and the Phase Detection sensor at the same time. Canon used a pellicle mirror back in 1965 with their Pellix camera and again in 1989 with the EOS RT.
Sony could have (and in my opinion should have) used an optical prism and finder with the A99. It would also have eliminated the EVF switching lag, which can be annoying when going back and forth quickly between the EVF and LCD. Of course one would lose the fully electronic image, with instant playback in the EVF and other things that video people like. Amateur video users like EVFs but serious film makers will still have to purchase accessory electronic viewfinders or clip-on external monitors. They need these regardless.
There's one other downside to an EVF, and that's that the camera needs to be powered on to be able to see though it. With a traditional DSLR's optical / prism viewfinder that camera can be lifted to ones eye for framing and composition without power. The image can be focused and if a zoom lens is attached the focal length changed before turning the camera on. No battery waste, particularly at the end of a long shoot when the battery may be low and you've left your spare battery back at the car a mile or two away.
The issue of OVF vs. EVF has to also be seen in the context of competitive price point and market positioning as well. Currently (early October, 2012 from B&H) the Nikon D800 is $2,999, while the Sony A99 at $2,798 is just $200 less. The Canon 6D at $2,099 and the Nikon D600 at $2,096 are both a significant $700 less expensive. There is no denying that the A99 offers a lot of camera for the money, and as we've seen above it has almost every feature enthusiast photographers want. But when it comes to its use of an EVF rather than a prism / optical viewfinder in combination with its translucent mirror I feel that Sony has sailed on the wrong boat. Loyal Sony fans will undoubtedly not be swayed, but I believe that when a prospective customer is standing at a sales counter looking though the viewfinders of these four cameras by way of comparison, Sony will have a tough sell on its hands, particularly at its current uncompetitive price point.
Nick Devlin's View
My friend and collegue Nick Devlin spent the better part of a week shooting alongside me in Algonquin, trying the A99 himself (he was shooting with an Nikon D800e), and listening to my stream of conscious praises and complaints. Here are his comments...
My view is that there is nothing inherently good about EVFs. They are at best a necessary evil, chosen for the form-factor advantages they bring and the cameras they make possible. Sony clearly does not share this view, since they built this camera around an EVF simply for the sake of doing so. It offers no notable advantage of any sort, most notably not in price. I can see no reason to chose an EVF in any context where it does not significantly reduce the size, weight or price of the camera, or substantially enhance its usability. The case is simply not made out beyond, "It's cool new technology".
To me, the experience of viewing the natural world through an EVF is like crashing at a cheap motel, closing the blinds, and turning on the small, fuzzy old cathode-ray tube TV on the dresser. It's a shame, because this is otherwise a cracker of a camera, really nice to hold and behold. – Nick