Sony SLT Alpha 99 review: New full-frame sensor is Sony’s best yet

By Janice Chen - Friday, December 21, 2012

Camera Review
Introduction | Measurement | Comparisons | Conclusion

The new Sony SLT Alpha 99, Sony’s first full-frame DSLR equivalent in three years, combines the company’s latest and greatest 24.3-megapixel Exmor CMOS sensor with its SLT (Single Lens Translucent) technology to deliver impressive image quality combined with fast and continuous autofocus while shooting still images and videos.

When Sony released its first full-frame DSLR, the Sony Alpha 900, back in 2008, it was the highest-resolution DSLR to date and held its own when compared with competitors such as the Nikon D700 and Canon EOS 5D Mark II from the more established DSLR vendors. In 2009, Sony followed up with a lower-end full-frame model (the Sony Alpha 850) but since then has been focusing its efforts on cameras with smaller sensors, including its popular NEX line of compact interchangeable-lens hybrid cameras as well as its SLT line of cameras that utilize a stationary semi-transparent mirror rather than the flip-up mirrors in conventional SLRs.

Because there’s no need for the mirror to move up and down between shots as there is with a traditional SLR, the Alpha 99 and other SLT cameras can display live-view images constantly and autofocus works quickly and continuously while images are shot rather than needing to focus between frames.

 This not only helps the A99 achieve continuous shooting speeds of up to 10 fps, but it also means that the camera can produce smoother results when using autofocus while shooting video, a feature that also benefits from the A99’s new dual phase-detect AF system (which combines a 19-point AF system with 11 cross sensors and a 102-point focal plane phase-detection AF sensor overlaying the main image sensor). It also means you can’t have an optical viewfinder, but the A99 compensates with an impressive 2.4-million-dot OLED electronic viewfinder with 100-percent coverage. (You can read more about the Sony SLT Alpha 99’s new features here.)

Measurement

Comparisons

Conclusion

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Comments
Added by LeCoq |  January 22

A99 and D600

Hi I have a quick question. Does the d600 has built-in body image stabilization when shooting video? I am getting either the d600 or the a99 primarily to shoot field video for documentaries, then the body image stabilization is very important to me, but it disappoints me the price and the loss of light that the a99 has, any one knows if the d600 has any type of body image stabilization when shooting video? thanks in advance!

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Added by drummerpcr |  January 24

Re: A99 and D600

The Sony a99 has in-body stabilization whereas the Nikon d600 does not. Nikon does not provide image stabilization in any of its camera bodies, while Sony does use image stabilization in every SLT camera body. Hope that helps!

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Added by ferrera |  January 08

Sony A99

What is the source to mention that in A99, 50 to 60% of light is spent to drive the dual AF system ?

If so, why doesn't it affect the color depth & dynmanic range (both scores same as D600) ? after the tranmission of light is reduced by half ?


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Added by Preter |  January 16

Re: Sony A99

To avoid embarrassing yourself, at least get your facts right? Where did you find the ridiculous 50-60% figure?

The light loss is a rather negligible 1/3 loss of light only, a difference most people can't even tell with their naked eyes.

However, in-body image stabilisation of up to 4.5 stops with ANY LENS and the total elimination of mirror vibration shake at ANY SHUTTER SPEED is completely conspicuous to the naked eye. Its a mind blowing massive leg up over your D600.
DXO can never take that into consideration.

Suck it up.

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Added by lapero |  February 22

Re: Sony A99

and here we have the biggest sony fan boy directly from sar ;-)

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Added by digiman69 |  January 05

A99 vs A850

Checking to compare A99 vs A850, I noticed the real iso measured on the A99  are vastly inferior to the nominal one and inferior to those of the A850.
If you take this in the right account even considering the iso 50 setting not available on the A850/900 the noise performance of the A850 equals the one of the A99 up to the 6400iso barrier (with reference to raw files only).
The only real advantage is the greater dynamic range of the A99 since the gain in colour depth is less than marginal. The above just refers to sensors comparisons done by DxO obviously the A99 adds many feat. vs the previous generations of Sony DSLR FF. Anyway since I'm interested on the photo side only, I don't see this new camera as a real step up from my trusty A850 which raw files are a pleasure to work with DxO.
SW.
I will buy tomorrow an updated version of the A850 with an integrated grip plus live view for photo only, multi frame noise reduction, in camera HDR, peak focus and the panoramic capture. Such features are a joy to use on my second body the A65

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Added by evilthought |  December 29, 2012

databsae

Why A99 scores are not in database yet, two weeks after this review was posted?

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Added by Nicolas |  January 02

Re: databsae

Hello,

I just checked, the A99 is now in the database.

Enjoy the review!

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Added by randybenter |  January 02

Re: databsae

No, It still shows as "PREVIEW" in "Compare Camera Sensors"

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Added by Nicolas |  January 03

Re: databsae

Yes indeed.

I am going to see what's wrong with it.

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Added by M7 |  December 24, 2012

Semi Pro camera?

Come on now DXO. How's that the 5D III that scored lower by your own admittance, is a pro camera and the Sony A99 is a semi-pro camera?

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Added by lpef |  December 26, 2012

Re: Semi Pro camera?

I think it's a mistake: 5D mark III is the only "classic full frame dslr" pro camera without an integrated grip
and 5D mark II was a semi-pro..

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Added by alzurzin |  December 23, 2012

this seems incorrect

Well, high ISO may be important to some, but the difference in DR is not significant: in fact, to my eyes, the A99 has better DR at the lower ISOs I prefer to use.  Other features of the A99 are more important.  DxO is very subjective, and overly biased for ISO. 

2 factors are very important to me: chromatic aberration and clipping.  The A99 produces the least of these flaws than any other camera. DxO completely ignores these factors, yet they are the most important for photography.  The D800 has a great amount of noise, CA, and clipping.  The D600 has less than the D800, but still much more than the A99.

The A99 may be the first digital camera to capture all the nuances of the Zeiss lenses (maybe Leitz too, if a mount adapter can be found).  This is a great advancement.


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Added by Revenant |  December 24, 2012

Re: this seems incorrect

Chromatic aberration is not caused by the sensor, but by the lens. Seems odd to complain about a sensor test (not a camera test, mind you) not taking account of CA.

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Added by lightdreamer |  December 22, 2012

Please recheck your Low Light ISO Result for A99

I have compared the A99 against the A900 and the A99 is for sure 1 EV better in this regard. I made my comparisons in M-Mode and used dcraw without any sharpening or noise reduction. The A99 should reach the 2000+ level easily.

Regards

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Added by a odd guy |  December 23, 2012

Re: Please recheck your Low Light ISO Result for A99

I can't understand what you mean.

All of DxOMark score is based on RAW data comparison.

It doesn't have relevance to sharpening and noise reduction.

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Added by Revenant |  December 24, 2012

Re: Please recheck your Low Light ISO Result for A99

DXOMarks definition of the Low-light score: "Thus low-light ISO is the highest ISO setting for a camera that allows it to achieve an SNR of 30dB while keeping a good dynamic range of 9 EVs and a color depth of 18bits."

In other words, it's not just about the visible noise in the image, but also about DR and color depth. When the SNR goes below 30dB, or DR goes below 9 EV, or color depth goes below 18 bits, whichever happens first, then the image quality is no longer excellent according to DXO's definition. Obviously, at least one of these three things happens at a much lower ISO on the A99 than on its full-frame rivals, which explains the low-light score.

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Added by Bobo_SAN |  May 19

Re: Please recheck your Low Light ISO Result for A99

Yes it will, and I see it as well and may very well be easily compared because the database studio samples (http://www.dpreview.com) with other cameras that not are SLT.
DXOmark SLT disadvantage precisely because it leads to a slight loss of light and measurement settings that the DXO are performed against a very tight although the differences are micro small but measurable laboratory.

Low-Light-ISO is actually somewhere in the 1950's až 2050. It can be deduced from the databases studio samples (http://www.dpreview.com) in comparison to other cameras that Low-Light ISO-2000 were around.

For example:
Nikon D3X has a low-light-iso 1992 in stiodio but the results are compared to the 3200 and 6400 very much alike. The ISO 3200 seems to A99 x places better and D3X one in a watch or I would even say that the A99 has ISO a tad better.

Second example:
Nikon wrote in 7100 that the ISO is very similar to the A99 but it is not true, A99 is hell somewhere else but in 7100 measured in 1256 Low-light-A99 and ISO 1550 but realistically it is somewhere around 2000, and why it's so very much to know in comparative study of still pictures at ISO 3200/6400 in the raw Nikon 7100 vs Sony A99 (large differences in favor of A99).

DXOmark SLT can not properly assess the reality is somewhere else then.

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Added by thalas |  December 22, 2012

I still wonder about ISO score

I still wonder about ISO score,
Every one know that a99 and d600 are using same sensor.
Even dpreview still proved these two got same ISO score which are better than D800E and 5D MK III.
Why A99 on DXO got ISO score only half of D600?
This gap is too big. Could you let readers know?

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Added by a odd guy |  December 22, 2012

Re: I still wonder about ISO score

It's just effective ISO sensitivity magic!

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Added by podchong |  December 24, 2012

Re: I still wonder about ISO score

Because of the SLT effect.
Please read about SLT technology and you will known why.

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Added by thalas |  December 26, 2012

Re: I still wonder about ISO score

I knew about SLT technology.
Only thing I want to know is Dpreview gave same iso score for a99 and d600, but DXO gave it totally different.
who is better accurate ? which one i should believe? why its so different?
I didnt meant to begin some conflict, everyone knew DXO and dpreview are best of the best camera measurement. I was expecting these two website give similar iso score. That's all.


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Added by fashaoding |  December 22, 2012

I still can't see the mearement ofa99

I guess dr in high iso is to low so  it's only 1555

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Added by ferrera |  December 22, 2012

DXO mark score of Sony a99

A900 – ISO scores 1431
A99 – ISO only scores 1555 ???

But the real ISO performance of A99 is obviously much better in ….

It expects A99 to score over 2K but under D600 & MKIII

I really doubt the accuracy of the test

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Added by a odd guy |  December 22, 2012

Re: DXO mark score of Sony a99

A99 is  equipped with a dual AF system.

And it needs much amount of light to drive the dual AF system than A77's AF system and any other Alpha.

I mean,A99 can't generate a picture with amount of light as much as D600.

and also,It is said that A77 needs 20~30% amount of light to drive AF.

but, A99 is not only equipped with basically phase detection AF system.
A99 has "on board" Phase detection AF system additionally.

As it see the NEX-5R's DxOmark score which is said to be equipped with on board phase detection AF system and NEX-5N which has same sensor as NEX-5R without on board phase detection AF system.

It indicates that on board phase detection AF system would need about 20% amount of light.

And then,considering all of these things,,That dual AF system would need about 40~50% amount of light to drive AF.

I heard that A99 has same sensor as D600.

D600's Low-Light ISO score is 2979.

A99's sensor can receive about only 60~50% amount of light,because of affection of light reduction from that AF system,

2979*(60~50%)= 1787 to 1490

Do you get it,guys?

A99's Low-Light ISO score is not doubtable score,I think.

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Added by a odd guy |  December 22, 2012

Re: DXO mark score of Sony a99


>I mean,A99 can't generate a picture with amount of light as much as D600.

Ignore this statement,please.

I can't even figure this out.


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Added by fashaoding |  December 27, 2012

Re: DXO mark score of Sony a99

Quote:

<div id="linkdxomark">This a comment for <a href="http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Sony/SLT-Alpha-99">this page on the website</a></div>A900 – ISO scores 1431
A99 – ISO only scores 1555 ???

But the real ISO performance of A99 is obviously much better in ….

It expects A99 to score over 2K but under D600 & MKIII

I really doubt the accuracy of the test

I can't see detail about a99 review...

I don't know why.

Isnt it reviewed now?

Reply

Further readings for the Sony SLT Alpha 99 review: New full-frame sensor is Sony’s best yet

To provide photographers with a broader perspective about mobiles, lenses and cameras, here are links to articles, reviews, and analyses of photographic equipment produced by DxOMark, renown websites, magazines or blogs.

Camera Review  |  October 30, 2012
SLT-A99: Sony is back in full-frame fight

Finally, a Sony full-frame DSLR: the last one was the Alpha 850. But though the new full-format 24Mpix camera shines with all of its new technology and features, it now belongs to the family of cameras with electronic viewfinders instead of with the Alpha 900 and its traditional DSLR viewfinder. With this new positioning, Sony stands out from among the leading lights in this market segment.

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Tests and reviews for Nikon D700


Tests and reviews for Sony Alpha 900


Tests and reviews for Sony SLT Alpha 99