November 26, 2014, 09:01:31 PM

Author Topic: A7 / A7R Reviewed by Thom Hogan  (Read 1104 times)

J.R.

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A7 / A7R Reviewed by Thom Hogan
« on: March 11, 2014, 06:41:42 AM »
Thom Hogan has completed his review of the A7 / A7R. This bit of his review stands out for me -

Quote
Image Quality: Okay, we are now in one area where I know I’m going to get a lot of blowback: image quality. The number one thing I heard the fanboys all rejoicing about when the A7r was announced was this: “Yes! D800E quality in a smaller, lighter, less expensive body.” No, the A7r produces less than D800E quality in a less expensive body. If you want a free lunch, I suggest you try the local rescue mission.

The difference isn’t actually easy to describe because it involves what’s going on behind the covers. But let me lay out the basics: the D800E will shoot 14-bit raw files with no underlying artifacts and fully recoverable data. The A7r will shoot 11-bit raw files with potential posterization issues in the data. The same is true of the A7 versus a D610, too.

Let’s start with the 11-bit thing. Sony always uses compression in storing raw files. The way they do that is quite clever. They slice each pixel row into 32 pixel blocks. In a Bayer sensor, that means two colors, each with 16 data points). For each 16 pixels of a color, Sony looks at the minimum and maximum pixel values for each and stores that. For the other 14 pixels they store a 7-bit value that is offset from the minimum value. In essence, they get 32 pixel values stored in 16 bytes, when normally 11-bit storage for that data should take 44 bytes.

This is not lossless compression. It is highly lossy. Nor is it visually lossless. That’s because when you have an extreme set of values in the 32-pixel block (e.g. sun peaking out from behind tree edge), you get posterization of data. Don’t believe me? See this article, which describes it better than I can in the limited space of a review. Indeed, every A7/A7r owner should probably have a copy of RawDigger so that they can understand exactly where the issues in their raw files lay. Even Nikon’s optional visually lossless compression scheme does a better job at this, as it hides its posterization only in very bright values that our eyes just don’t resolve.

This factor alone means that the A7r is not equivalent to a D800E. Sorry fanboys, but those of us who want high performance cameras actually want real performance, not a simulation. (I should point out that this compression scheme is used in most Sony cameras now, including the RX1, which is where I first noticed it.)

Coupled with other issues (see Shutter Slap, below), the A7r simply doesn’t match my D800E in optimal collection of raw data. Remember, I used to write a column called Optimal Data, and that’s my mantra when shooting: collect optimal data.


Full review here ... http://www.sansmirror.com/cameras/a-note-about-camera-reviews/sony-nex-camera-reviews/sony-a7-and-a7r-review.html

So basically ... no, I'm not considering the A7R any longer.  8)
« Last Edit: March 11, 2014, 06:43:50 AM by J.R. »
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A7 / A7R Reviewed by Thom Hogan
« on: March 11, 2014, 06:41:42 AM »

neuroanatomist

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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #1 on: March 11, 2014, 09:37:43 AM »
But...but...it has oodles and oodles of DR.  And DxO gave it a very high score.  It simply must be a better camera than anything made by Canon.  You se , it is  really about  QE, FWC, and  noise.  All this lossy RAW file compression and posterization can kiss my posterior.   :P

Plus, the D800E is just an antiquated mirrorslapper anyway.  :P :P
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J.R.

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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #2 on: March 11, 2014, 10:48:56 AM »
But...but...it has oodles and oodles of DR.  And DxO gave it a very high score.  It simply must be a better camera than anything made by Canon.  You se , it is  really about  QE, FWC, and  noise.  All this lossy RAW file compression and posterization can kiss my posterior.   :P

Plus, the D800E is just an antiquated mirrorslapper anyway.  :P :P

Indeed ... another reason why DxO scores are plain simple bull which needs to be ignored. They only take into account the sensor regardless of what the camera does to what is captured!

But then you've made my day with your post above ;D The ABC brigade does exactly that!
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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #3 on: March 11, 2014, 12:52:06 PM »
It's a nice review to balance against the initial head-over-heels reviews, but to me, he is writing as a Nikon D800E devotee, trying his best to pick at the A7r (and by doing so, everything else including Canon).  His conclusion is:

"The D800E, after two years on the market, still clearly produces the highest quality images I’ve seen out of camera other than Medium Format ones, and it does so clearly. It’s the best all-around camera I know of at the moment."

I might give D800E kudos as the best landscape-on-tripod camera but best "all-around camera"?   ???

 

neuroanatomist

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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #4 on: March 11, 2014, 12:56:40 PM »
I might give D800E kudos as the best landscape-on-tripod camera but best "all-around camera"?   ???

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J.R.

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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #5 on: March 11, 2014, 12:59:59 PM »
It's a nice review to balance against the initial head-over-heels reviews, but to me, he is writing as a Nikon D800E devotee, trying his best to pick at the A7r (and by doing so, everything else including Canon).  His conclusion is:

"The D800E, after two years on the market, still clearly produces the highest quality images I’ve seen out of camera other than Medium Format ones, and it does so clearly. It’s the best all-around camera I know of at the moment."

I might give D800E kudos as the best landscape-on-tripod camera but best "all-around camera"?   ???

Yup ... Thom Hogan is a Nikon devotee and I couldn't get my head around the "best all-around camera" either.
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sagittariansrock

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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #6 on: March 11, 2014, 03:52:55 PM »
It's a nice review to balance against the initial head-over-heels reviews, but to me, he is writing as a Nikon D800E devotee, trying his best to pick at the A7r (and by doing so, everything else including Canon).  His conclusion is:

"The D800E, after two years on the market, still clearly produces the highest quality images I’ve seen out of camera other than Medium Format ones, and it does so clearly. It’s the best all-around camera I know of at the moment."

I might give D800E kudos as the best landscape-on-tripod camera but best "all-around camera"?   ???

Yup ... Thom Hogan is a Nikon devotee and I couldn't get my head around the "best all-around camera" either.

I had read part of his Df review earlier and was about defend him here on its basis. Then I decided to finish reading the whole Df review. Not much to defend, unfortunately.
While he complains about the ergonomics, a lot, he ends up giving a 'recommended' rating. So, yeah...
It is unfortunate when people with the power to influence lose credibility due to bias or other conflicts of interest.
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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #6 on: March 11, 2014, 03:52:55 PM »

sdsr

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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #7 on: March 11, 2014, 03:53:28 PM »
I'm sure I haven't tested my A7r as thoroughly as Mr. Hogan did his, and my experience with the D800e is limited to a week's rental with a couple of (high end) lenses (mostly the latest Nikon 85mm 1.4), and thus perhaps doesn't count, but I'm tempted to suggest that one reason why he finds it hard to describe the differences in image quality between the two is that the flaws he singles out in the A7r are either trivial or simply don't show up in most "normal" use (though I probably shouldn't use that term - for all I know, my use isn't "normal").  This is merely anecdotal and doesn't prove anything, but speaking just personally, after I returned the Nikon and looked at the images I took with it I sensed no camera/lens envy/remorse, but after trying both Sony A7s I promptly bought an A7r (it doesn't hurt that, as Hogan concedes, the two Sony FE primes are "stunningly good," but at the time I made my decision I had used nothing but adapted Canon lenses).

Aside from that, it seems a bit odd that he decided to evaluate the A7s in terms of whether they could be considered "the best all-around" camera, surpassing his beloved D800e (itself an odd choice for the title, as others have pointed out).  The structure of his review suggests he's rather missing the point.  I haven't read any of Sony's publicity stuff, but I wonder how many people genuinely interested in these cameras in the first place, or who know and like these cameras, would suggest that they are contenders for such a title in the first place?  No-one would recommend them for very fast performance, let alone herons-catching-fish, for instance, and whether they would be a good recommendation to anyone at all as the only camera they need own would depend entirely on how they like to use their cameras; for a lot of people they would be a terrible choice.  (I'm surprised that Mr. Hogan doesn't seem to acknowledge that some people prefer EVFs.)

As we all know, nothing's perfect, so you compromise.  If you really care about noise, you get a 6D and forego the AF etc. advantages of a 5DIII; if you really care about herons-catching-fish you forego a degree of resolution; if you want maximum versatility in a small, light system, you buy into Micro 4/3 and accept the (decreasing) disadvantages of a smaller sensor.  And so on.  For my part, while the A7s aren't as versatile as any of the cameras I've mentioned, I greatly appreciate the ability to get images of such high quality and detail so easily out of body/lens combinations this small/light. 

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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #8 on: March 11, 2014, 10:33:55 PM »
Yeah this seems to be a blind nikon fanboy. Rogers reviews are for the most part unbiased and I think that his take on this contradicts the other gentleman's opinions with fact. Sony may use all those compression but it's not affecting sharpness. I still am considering the a7r. Just want canon to release their version. 

http://www.lensrentals.com/blog/2013/12/sony-a7r-a-rising-tide-lifts-all-the-boats

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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #9 on: March 12, 2014, 12:39:35 AM »
So basically ... no, I'm not considering the A7R any longer.  8)

For me...I'll stand by for Zeiss FE UWA for my A7R ;)

It small to carry around and produces HIGH quality images.
« Last Edit: March 12, 2014, 12:50:14 AM by Dylan777 »
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Re: A7 / A7R Reviewed by Thom Hogan
« Reply #9 on: March 12, 2014, 12:39:35 AM »