The 36mp Sony A7R with 35mm f/2.8 Zeiss Sonnar lens.

I had a chance to handle the Sony A7 and Sony A7R at the recent PhotoPlus show in New York. The camera itself is quite impressive - very compact and well balanced, particularly with the hand grip. The view finder seemed very quick and responsive, but all in all very similar to the current accessory model made to fit the RX1 and RX100. I have this accessory and found the behavior characteristics to be very much the same.

The menu system and controls bear a strong resemblance to the RX1 and RX100 cameras.

Seeing the camera next to some of the lenses intended for it confirmed one of the chief concerns and suspicions I had about such a small sized, full frame camera. Wide aperture lenses for full frame cameras are very large, disproportionately so on a camera as small as the Sony A7. For this reason Sony had slow aperture lenses made for the series. The two Zeiss zooms are f/4. The 35mm is f/2.8, and the 55mm is f/1.8, which is as fast as it gets and is a rather large lens for this camera body.

A slow f/2.8 maximum aperture on the 35mm lens allows for a compact package on the A7, but it isn't going to win any kudos in low light shooting, which is where this prime lens type is often used.

There is nothing wrong with slow aperture lenses except when you want a lens that delivers good bokeh and low light capabilities. A 36 megapixel camera costing over $2000 is a pro level machine. Fitted with the slow aperture Zeiss lenses, good as they are, is going to hamper its usability for many.

Another thing to consider with the A7r is that a 36mp camera demands exceptional optics to take advantage of what the sensor can do. Buying a camera like this and putting a kit lens on it is a complete waste of money. On top of that, a high megapixel camera puts a  high demand on how the camera is used. Sloppy technique will result in sloppy pictures.

To obtain the image quality a 36mp camera can deliver is going to mean putting the camera on a tripod, using a cable release or delaying the shutter to eliminate motion blur. I learned this lesson the hard way working with a Nikon D800. Returning from a scenic shoot out west I found that many of the images had a softness to them that was much more severe than I ever obtained from smaller megapixel cameras. I finally traced this back to those images where I had not used a tripod. Even though I photographed on a sunny day with what would normally be considered a sufficient shutter speed to stop motion, the shots were soft from slight blurring. I learned my lesson and ever since then have only used a D800 on a tripod. Nikon had warned about this problem in its description of the D800. Turned out to be solid advice.

The 28-70mm variable aperture f/3.5-5.6 zoom is the kit for the A7 series. I am just not sure of the wisdom of putting a kit lens -- especially one starting at 28mm and with a slow variable aperture -- on a camera of this quality and price. 

The smaller and lighter f/4 version of the 70-200mm lens is shown on the right next to its bigger brother, the f/2.8 model on the left. A large lens like the f/2.8 zoom is going to dwarf this camera and probably be so out of balance that it will be difficult to hand hold comfortably. I have a 70-200mm Nikkor lens that I use on the D4 and D800 where it handles quite well, I have also adapted it over to fit a Fuji X-Pro1, which is similar in size to the Sony A7. It works well, but is very cumbersome to use. 

This is not to say the camera cannot deliver sensational images. I am certain it can do that. It is just that I do not see the Sony A7 as a system replacing the best of what is out there high resolution, full frame machines. Like it or not, we are still stuck with a larger DSLR full frame camera if we want the ultimate in performance in all situations.

The attractiveness of mirrorless camera systems is their small size and comfort coupled with high resolution capability. This has worked quite well for cameras up to the APS sensor size because lenses and accessories can also be small and comfortable without sacrificing quality and desired features. As mirrorless systems begin pushing out to a full frame sensor size, they are going to encounter roadblocks that hamper the combination of convenient design with high quality in a professional sense.

That said, I am sure the Sony A7 and Sony A7R will become runaway best-sellers and top notch cameras. I might even pick one up myself, although I won't be rushing off to do so. I just can't see this camera system replacing my pro DSLR system, particularly because it will cost as much.  That means I would have to maintain both systems, and I am not sure the convenience of the smaller scale, full frame mirrorless system is worth a sizable investment for an occasional use camera.