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Sony A7s First Impressions Review

by Michael Reichmann

Sony is what is known in the business world as a "spoiler"While many manufacturers are satisfied to add new chrome and bumpers to last year's model, Sony constantly pushes the envelope, sometimes fumbling the ball, but often scoring a home run – if you'll excuse the mixed metaphor. This is true in almost every business segment in which Sony competes, and certainly is the case when it comes to the photographic equipment business.

Several years ago I attended a Sony press event and found myself sitting for a while and having a drink with the President of Sony USA. This was at a time when Sony had purchased their camera business from Minolta and was just getting into gear with their first "new" products. I asked him how he saw the future of Sony in the camera marketplace, and his reply was telling. He said that Sony corporate had targeted cameras as a strategic business opportunity, and it was their intention, sooner rather than later, to become the new #2 player, displacing either Nikon or Canon.

"A daunting task", I replied. His response was that they knew it would take some years, but that they had significant product plans and new technologies in mind, and that while it might take five or more years, the company had the will and the resources to accomplish its goal.

Well, here we are not that many years later and Sony has certainly been true to their intentions. While still a distant #3 in terms of sales, Sony is producing more new and interesting cameras, in more categories, and with more new technology than the two market leaders combined. If leadership were judged by inventiveness they would already be #1. Sony may be a relative newcomer when it comes to the photographic marketplace, but they are jet propelled.



The Sony A7s – What is it and Who it is For?

In a word or two – the A7s is a small full-frame 12 Megapixel mirrorless stills camera, using the same body and design as the 24 Megapixel A7 and the 36 Megapixel A7r. The camera is also capable of shooting 4K video while delivering it to an external recorder in 8 bit 4:2:2. It takes Sony's FE mount lenses (if you want full frame) and other A7 series accessories.

Since in many respects the camera is similar to the A7 and A7r there is little point in discussing the camera's common features, as the Net abounds with detailed reviews, including here on this site.

So – you may well ask the obvious question – in 2014 who would want a 12 Megapixel camera, and why? The answer is two-fold.

Firstly, by making the sensor just 12MP, along with its full frame size, each sensel (or pixel) is relatively huge. This means that its light gathering power is tremendous compared to sensors with higher pixel density. This is evidenced by the A7s' ability to shoot at up to ISO 409,200, though as we'll see, you wouldn't necessarily want to.

The camera is also aimed at videographers. In 4K video shooting mode, 3840 × 2160 (30p/24p) the pixel ratio is 1:1. In other words, no line skipping, binning, or compression is needed. The sensor itself is 4240 x 2832 pixels, at full frame's standard 3:2 aspect ratio, while 4K video has, like HD, an aspect ratio of 16:9.

Shell. Clearview, Ontario. June, 2014
Sony A7s with 24-70mm f/4 Zeiss Sonnar @ ISO 100

Is 12MP Enough?

Now that MFT and APS-C cameras have settled in the 16-18 Megapixel range, and Full Frame is 24 MP, with the Nikon D800/e and Sony A7r at 36 Megapixels, where does a 12 Megapixel sensor fit in? It's been years since we saw a new camera with a pixel count this low. 

But a lot has changed in the world of cameras. What hasn't changed is the math for calculating print size, because how large a print you can make is basically the issue one ponders when dealing with pixel count. Other factors such as dynamic range, high ISO capability, and colour accuracy are separate issues.

My rule of thumb is that I can make an exhibition quality print as long as I can start with a print resolution of at least 180 PPI. This means that a 12MP file from the A7s can be printed at a size of 16 X 24" when upressed to 360ppi. By comparison, and using the same criteria, a 36 Megapixel file, such as from an A7r, is capable of printing roughly 27 X 40" print.

Sidebar: The way I print is to set Lightroom at 360ppi, which is the native print resolution of Epson printers. If starting with something below 360ppi (and not less than 180ppi) I allow the print engine in Lightroom to res-up the image. I find this to produce excellent results, and is comparable to upressing in other programs. Careful comparisons have shown over the years that if you have a good quality, properly sharpened image to start with, this technique works very well.

The answer then to the question of whether 12 Megapixels is enough, is answered when you know what the largest print size that you want to make will be. If course the ability to crop comes into the equation as well, since most photographers rarely shoot at the given aspect ratio, or don't have a need to crop now and then.

Is 12MP Enough – Part 2

Another consideration is that of spatial resolution. Because there are less pixels recording a given area of a subject with the 12MP sensor than with a 24MP or 36MP sensor, then the fine detail which can be recorded is less with a lower pixel count sensor than with a higher count sensor. This is typically not an issue with a multi-megapixels sensors in general because in most scenes the fine detail falls within the Nyquist limit of 2 pixels needed relative to the object image size. It does though mean that when the very highest resolution lenses are used, and the subject matter contains extremely fine detail, the 12MP of the A7s may not resolve micro-detail as well as a camera with a higher resolution sensor.

This is one of the reasons for the popularity of medium format backs and cameras among pros and others seeking the best of all possible worlds. They offer large pixels (greater dynamic range and colour depth) along with high pixel density (greater resolving power).

I do not have an optical test bench so as to put hard numbers to this in the case of the A7s, but its fair to say that one of the reasons that photographers looking for extreme resolution turn to high Megapixel count sensors is for this reason, not just so that they can make big prints. The A7s may, for some photographers and types of subjects, therefore prove less satisfactory than one of its higher resolution siblings, such as the A7 (24MP) and A7r (36MP).

Sidebar: I'm adding this paragraph just as I prepare this article for publication. I have been looking closely at and make prints from images that I've shot during the few days that I had to work with and test the A7s. All technical considerations aside, the ultimate arbiter has got to be ones own eyes. Technical and theoretical analysis are one thing, but people see images, not numbers. That being the case, I have to say that the Sony A7s produces some of the cleanest, most pleasant images I've seen this side of a medium format system. 

People have long claimed that CCDs produce more pleasing images than CMOS. Medium format has, until this year, been exclusively CCD. But now that Sony has produced a 50MP CMOS sensor, currently being used by several medium format camera makers, we see that impressive image quality isn't just the purview of CCD. So – wrong presumtion.

With the Sony A7s we see that Megapixel count isn't the be-all and end-all either. There is something to the look of A7s files that reminds me of medium format, and the only thing that I can think of that could be at work here are the large individual sensels. I can't say why, but like the US Supreme Court judge, when asked for his definition of pornography replied – "I can't say, but I know it when I see it".


HIGH ISO

Of course, what everyone wants to know is – can the A7s produce usable images at its claimed astronomical ISO ratings? Is the compromise of having lower sensor resolution worth the possible trade-off for potentially greater dynamic range and higher ISO capability.

Full Frame of  A7s Test Image

A Word of Explanation

There is always a problem when doing any sort of comparison with gear that isn't exactly the same. It is especially difficult when one is dealing with devices such as the A7s (12MP) and the A7r (36MP) because at 100% on-screen their magnifications are vastly different. This means that if an A7s image, the smaller of the two, is shown at the same size as one from the A7r, then the latter will have a much higher magnification. This makes any sort of comparison not terribly revealing, because noise will appear quite different at differing magnifications.

The only solution that made sense to me is that the larger A7r images are ressed down to the same size as those of the A7s. This is equivalent to printing them both at the same size, which in the real world is what one would do. If you need bigger prints, you need a higher resolution sensor. So equalizing image size to the maximum of the smaller one is a logical procedure under the circumstances.

Keep in mind that the act of ressing an image down (done in this case in Photoshop) reduces apparent noise. This serves to make the A7r more competitive in terms of ISO with the A7s, but I maintain is the only reasonable way of making a comparison that reflects real world practice.

I am sure that some will find fault with this procedure. If so, please feel free to do your own comparisons, write them up with a full explanation of how and why the tests were done the way that they were, and I promise to publish them here.

The same lens was used on each camera, and the cameras were mounted on a heavy duty tripod, with 2 second self timer. As can be seen, exposures were identical. The A7r is in a slightly higher position because it had a battery grip attached. Focus was manual. All tests were run twice.

No sharpening or noise reduction has been applied. Raw files were processed in Adobe Lightroom 5.5. (I did not test out of camera JPGs, because I find that the A7s' look over-sharpened).

One final note – the shots were done in a very dimly lit room. Dim enough that if one was standing at the book shelf it would be impossible to read a printed page without additional illumination. Aperture priority mode was used, and the cameras raised the shutter speed automatically as the ISO was increased.

Sony A7s Vs. A7r


Sony A7s

Sony A7r

ISO 100

   

ISO 200

 
 

ISO 400

   
 

ISO 800

   
 

ISO 1600

   
 

ISO 3200

   
 

ISO 6400

   
 

ISO 12,800

   
 

ISO 25,600

   

ISO 51,200

NA 

ISO 102,400

 

NA

ISO 204,800

NA

 

ISO 409,600

NA

 

Observation

You should, of course, draw your own conclusions. Based on what I see here, and also on prints made from the original raw files, what I see is as follows...

Dynamic Range

– Based on these tests as well as my day-to-day shooting I do not see any obvious difference in dynamic range between the two camera. Many people had speculated that the larger pixels of the A7s would produce wider dynamic range capability. Not that I can detect. It will take someone with a full testing lab to determine if there is any gain in DR or not, but I don't see it.

ISO Test

– Up to and including ISO 1,600 there is little to differentiate between the two cameras in terms of visible noise.

– At ISO 3,200 and 6,400 the A7s remains very clean, while the A7r starts to show visible noise. At ISO 6,400 I would add a bit of NR to A7r files, and usually do.

– At 12,800 the A7s starts to show a bit of noise, but nothing of concern. The A7r is at the limit of its usefulness for anything except emergency use.

– At ISO 25,600 the A7s can use a bit of NR, but not much. The A7r is not usable for anything except documentary purposes, and then with NR applied.

– At ISO 51,200 the A7s is quite usable with some moderate noise reduction.

– ISO 102,400 is the limit at which I would use the A7s. It needs some NR, but would be usable for non-critical applications.

– ISO 204,800 is a bridge to far for me, and 409,600 is for bragging rights, not real world imaging.

On the basis of these tests I would judge the A7s to have almost a three stop advantage over the A7r between ISO 6,400 (which is as high as I would use on the A7r)  and ISO 51,200 where the A7s reaches its useful limit (for my type of shooting).

If you look closely you may decided that the difference is more like 2.5 stops, rather than 3 stops, but since I tested in whole stop increments to make the quantity of images generated in the test manageable, the point is open to debate. Remember as well that ressing the A7r files down to match the image size of those from the A7s reduced the visible noise at any given ISO.


Other Features

Electronic Shutter (Edited)

A significant addition to the A7s over its earlier siblings is an electronic shutter. This makes the camera completely silent, and for those who think that the A7 series has shutter vibration (which I have never seen in 8 months of using an A7r, even with extensive testing) this would be one way to mitigate it.

This feature makes the A7s the world's only full-frame camera with a truly silent shutter. Along with its high ISO capability, wedding photographers, among others, will find this very appealing.

My only complaint is that the interface team at Sony forgot to add this feature to the twelve position Function menu. It simply isn't able to be loaded into one of these slots. This means that to turn off the mechanical shutter, and to make the A7s silent, you need to go into the Menu, select the Gear option and then tab #4. What a pain! On the Panasonic GH4, which also has an electronic front curtain shutter it's as simple as programming one of several custom function buttons. Firmware update please Sony.

Cable Guide Attachment

Found inside the A7s' box is a small piece of plastic with numerous holes in it. Since my sample has no user manual, it took a few moments to realize that this is a cable guide, which attaches securely to the left side of the camera and is designed to prevent the accidental dislodging of audio, video or data cables. Nicely done. Just don't lose it, though it's my guess that videographers will leave it attached full time.

Video

Video has a lot of jargon associated with it. If this topic is new for you there is a Primer on Video Jargon contained in my recent GH4 review.

4K

The Sony A7s offers 4K (3840 X 2160) video recording capability. But, it can not record 4K to an SD card within the camera itself. It will only record 4K video in 8 bit 4:2:2 to an external recorder. Sony has worked with Atomos, who make the new Shogun recorder, which will record 4K from the A7s' HDMI port. The Shogun will apparently ship in Q4, 2014 at a price of $1,995. Until then the only video available from the A7s is in HD. (There are other 4K recorders available, but none at anything as low as the Shogun's price, or ability to record from HDMI).

The reason for this limitation is apparently that the A7 series body is not capable of the heat dissipation needed when 4K is recorded, especially because its being output from a large Full Frame sensor. This of course begs the question of what will be the future of 4K video from the A7 line? Just about every image recording device that comes to market these days, from cell phones to superzooms, to smaller sensor CSCs offers 4K. Will Sony have to reengineer the A7 series to be able to handle 4K without an external recorder? Prices on the older A7 and A7r are dropping, and Photokina is just around the corner, so we'll know soon.

The elephant in the room also needs to be mentioned, and that's the Panasonic GH4. Unlike the A7s it records 4K internally to an SD card at up to 100Mbps. It to can record to an external recorder like the Shogun via HDMI, but it trumps the A7s by outputting in 10 bit 4:2:2, rather than 8 bit. Furthermore, the GH4 can record Cinema HD format of 4096 X 2160 as well as consumer 4K with 3840 X 2160; the A7s only the latter.

And given that the GH4 retails for less than $1,700 while the A7s is at $2,500, it will cost a total of  $4,500 configured to record 4K video on the Sony. No wonder some people are looking askance at the A7s when it comes to video.

Of course the A7s' 4K video advantage is that with its 12MP sensor the 4K image is recorded on a one-to-one pixel basis. This means, no line skipping or binning is needed, just as with the GH4. But, while the GH4 has a Micro Four Thirds sensor, the A7s has a Full Frame sensor, and thus offers more cinematic depth of field, which has been the calling card of other Full Frame DSLRs like the Canon 5D MKII and III.

Until the Atomos Shogun external recorder is available some time later this year there is no way for me to report on the A7s' 4K video capability. The rest of this section will deal with the camera's HD video recording capability.


HD Video

The A7s records video with three different codec, XAVC S, AVCHD, MPEG-4, and AVC/H.264. The highest quality is obtained from XAVC S, which can record full HD in 1920 x 1080  at 60p, 30p, and 24p at 50Mbps).  The camera can also record 1280 x 720 at 120p/50Mbps. 

XAVC-S is a modern codec and performs very well. At 50 Mbps performance should be sufficient for broadcast use. It is a Long-GOP version of Sony's pro XAVC codec and thus more sparing on recording speed needed and space on a card. It is now supported by Final Cut Pro X and likely most other pro-grade NLEs. Sadly, Sony persists on placing the files in a Private folder, as if it was AVCHD, and that can be problematic when loading files into many NLEs.

I did not have time to explore the camera's HD video capabilities in depth. Two areas that I looked briefly at are high ISO performance and S-Log 2. What I found is that video high ISO performance pretty much matches that of stills, with ISO 51,200 being the highest usable speed.

I also compared Picture Profile off with S-Log 2 activated and these are both shown at the head of the brief clips below.

Click on the Full Screen Control in the Lower Right of the Image

Once 4K capability is available via an Atomos Shogun recorder (which I have on order), I hope to re-explore the A7s' video capability in more depth, and also do a comprehensive shoot-out with the Panasonic GH4.


Picture Profile (PP)

Do not confuse Picture Profile with Picture Effect, which are those silly effects such as Toy Camera, Retro, etc. Picture Profiles come from Sony pro video cameras, and on the A7s are found under the Camera menu item, Tab #5. But, only when the camera is in Movie Mode on the main mode dial.

There are seven PP positions, including one marked OFF, and each one contains a wide range of customizable settings, including....

Black Level, Gamma, Black Gamma, Knee, Color Mode, Saturation, Color Phase, Color Depth, Detail and also a Copy mode (to copy settings to another PP, and Reset.

Many have further deep menu selections. For example Color Mode has...

Movie, Still, Cinema, Pro, ITU709 Matrix, Black and White, and S-Gamut

While Gamma has.....

Movie, Still, Cine1, Cine2, Cine3, Cine4, ITU709, ITU709(800%), and S-Log 2

There are also Time Code Settings, found under the Tool Box menu.

All-in-all the number of settings will be a dream for knowledgeable videographers, but likely a settings nightmare for those less adept at the arcania of video. I have not yet seen the User Manual, but if history is any teacher Sony's manual will be sorely lacking in really useful advise on how best to set these for a given purpose. It will take someone with a waveform monitor and experience to set these properly.

I therefore expect that there will be a large secondary market (as there is with other high-end video cameras) for PP settings, so if you get an A7s check out the web sites of some of the Sony video camera gurus for their recommendations.

Dandylion & Swing. Clearview, Ontario. June, 2014
Sony A7s with 24-70mm f/4 Zeiss Sonnar @ ISO 100

First Impressions and Closing Thoughts

Because I've been using a Sony A7r since October, 2013 I am well familiar with the basic camera, so there was little in the way of learning curve, other than the new video capabilities. The first thing that I did was to set up the A7s so that the custom buttons and functions matched those on my A7r. This immediately make the A7s feel like an old friend. Because of the new video functions there are a few menu selections that have moved, but nothing of consequence. My biggest beef, already mentioned, is that Sony forgot to allow Silent Mode / Electronic Shutter to be available as a custom function.

Otherwise, the A7s has all of the goodness as well as minor flaws of its predecessors. It still takes far too many seconds for the camera to start-up when a new battery is inserted. Many. I assume that what it's doing is calibrating the battery, but it should be doing that on its time, not mine. The camera still can not use auto-bracketing and self timer at the same time, which really should be addressed sooner rather than later in a firmware upgrade. 

Otherwise, I am a huge fan of the A7 series, especially the A7r. It packs the highest resolution 35mm Full Frame sensor available (without an AA filter) into a body that is actually smaller than many Micro Four Thirds cameras. There is focus peaking, settable live Zebras, a great EVF, and the ability to use the widest range of third party full-frame lenses of any camera on the market.

The A7s plays a somewhat different song, but one that's equally as sweet. High quality video, the promise of 4K (though only with a pricey external recorder), and fantastic low light capability. The camera comes with a separate battery charger (BC-TRW) rather than using USB charging, and two (count them) two batteries. 

I did notice that the A7s goes though batteries faster than the A7r, but with only a few days to shoot and do tests I am unable to quantify this. Video on the A7s seems to be particularly battery intensive.

While the ability exists to use an almost unlimited array of legacy lenses on A7 series cameras, the number of native FE mount Full-Frame lenses is still rather sparse. The following, according to Sansmirror.com is Sony's lens roadmap from now (mid-2014) through end 2015.

      • 16-35mm f/4 Zeiss OSS (2014) (announced May 1, 2014)
      • 85mm f/1.8 Zeiss OSS (2014)
      • 100mm f/2.8 Macro G (2014)
      • 35mm f/1.4 Zeiss (2014)
      • 24mm f/2 Zeiss (2014)
      • 28-135mm f/4 G OSS (2015) (announced May 1, 2014)
      • 135mm f/2 Zeiss (2015)
      • 21mm f/2.8 Zeiss (2015)
      • 35mm f/2 G OSS (2015)
      • 50mm f/1.2 Zeiss (2015)

 Add to this the already shipping...

Vario-Tessar T* FE 24-70mm F4 ZA OSS

Sonnar T* FE 55mm F1.8 ZA

FE 28-70mm F3.5-5.6 OSS (kit lens with the A7)

Sonnar T* FE 35mm F2.8 ZA

 FE 70-200mm F4 G OSS

...and the lens future for the FE line looks very good.

And, if a bit of extra bulk isn't of concern, Sony's large array of Alpha Full Frame lenses can all be used on the A7 series via a LAEA4 adaptor, with full phase detection autofocus.

Who is it For?

This then only leaves the most important question of all – what constituency is this camera intended for? Clearly, its low light sensitivity is remarkable. Two and a half to three stops more of usable sensitivity than just about any other camera would not be an indefensible claim. But, the trade-off is its use of a 12 Megapixel sensor. This is at the low end of the scale by 2014 standards. Anyone who crops a lot, or who wants to make large prints will find the sensor's low resolution constraining. 

But, as I noted earlier in this report, individual images from the A7s have what I can only call the medium format look, which might be a curious thing to say given that the sensor is only 12 Megapixels, but nevertheless is what I see. Large pixels are simply different in the "look" that they create.

Videographers and film makers will welcome the low light ability, full frame shallow DOF lenses, and 4K ability. But 4K won't be available until Q4 of 2014 when the Atomos Shogun ships. Then the price equation will need to be considered, because at $4,500 for camera plus recorder numerous alternatives present themselves.

I have to hand it to Sony. Releasing a specialized camera such as the A7s certainly presents a technological challenge to its competitors, and gives photographers yet another fascinating choice. And releasing it months ahead of a third party recorder that can take advantage of the camera's 4K capability is certainly indicative of Sony's aggressiveness when it comes to new product introductions, especially in a Photokina year.

My parting thought is that the A7s is neither the holy grail of cameras, nor a whimsical outlier. It's going to take a special photographer with keen image perception to appreciate what the A7s has to offer. Thanks Sony, for catering to more than the lowest common denominator.

June, 2014

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