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JPEG Tone Curves / dynamic range

Our Dynamic Range measurement system involves shooting a calibrated Stouffer Step Wedge (13 stops total range) which is backlit using a daylight balanced lamp (98 CRI). A single shot of this produces a gray scale wedge from the camera's clipped white point down to black (example below). Each step of the scale is equivalent to 1/3 EV (a third of a stop), we select one step as 'middle gray' (defined as 50% luminance) and measure outwards to define the dynamic range. Hence there are 'two sides' to our results, the amount of shadow range (below middle gray) and the amount of highlight range (above middle gray).

To most people highlight range is the first thing they think about when talking about dynamic range, that is the amount of highlight detail above middle gray the camera can capture before it clips to white. Shadow range is more complicated; in our test the line on the graph stops as soon as the luminance value drops below our defined 'black point' (about 2% luminance) or the signal-to-noise ratio drops below a predefined value (where shadow detail would be swamped by noise), whichever comes first.

Note: this page features our new interactive dynamic range comparison widget. The wedges below the graph are created by our measurement system from the values read from the step wedge, the red lines indicate approximate shadow and highlight range (the dotted line indicating middle gray).

Cameras compared

As expected, the SLT-A99 has a tone curve that is virtually identical to previous Sony Alpha models. Absent any DRO enhancements, this yields almost nine stops of dynamic range, placing it comfortably among its full frame peers. The roll-off from clipped whites to highlight detail on the A99 is just a touch steeper than we see from the Canon EOS 5D Mark III.

The effect of Sony's 'DRO+' settings differs depending on the scene, so this test, performed using our 18 step wedge, isn't necessarily an accurate indication of 'typical' performance with a real-world subject. It does clearly show, however, the way in which DRO+ is designed to work, extending incrementally the amount of mid tones by lifting the shadow areas, to get the most detail out of these areas from a single exposure.

The A99 offers no fewer than 13 different 'Creative Styles', which are essentially color response presets applied to in-camera JPEGs. Each style can be adjusted for contrast, sharpness and saturation. The Deep and Light presets darken and brighten the image by about 1/3 stop EV, respectively. The Vivid, Landscape, Sunset and Black and White presets all boost contrast, primarily by way of heavier shadow tones.

As is the case with Nikon and Canon DSLRs, the A99's ISO 50 mode is an 'extension' ISO sensitivity setting, which gives roughly 0.7 EV less highlight dynamic range than ISO settings of 100 and higher. The likelihood of highlight clipping then, should serve as a caution against enabling ISO 50 when shooting in very bright situations - precisely the conditions that are at great risk for blown highlights.

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Comments

Total comments: 13
fotokram
By fotokram (1 day ago)

I just don't understand the point, that the A99 empties its buffer twice as fast as Canon's EOS 5D III at Continuous Hi? Both cameras allow 6 fps, but the 5D III can shoot JPEG Large/Fine until the card is full while the Sony stops after 20 frames. When shooting RAW the 5D III can take 17 frames (like the Sony), before the frame rate switches to 2.7 fps (A99: "only" 1.7 fps). The 5D III then needs 4 seconds to empty the buffer, while the A99 needs 7.5 seconds. From my point of view, the 5D III is the faster camera. Or did I get something wrong?

0 upvotes
Gangstar
By Gangstar (2 weeks ago)

I have owned previously the a55 a77 and for the last 12 months the A99 I paid £1750 new inc tax the a99 paired with the Zeiss 24-70 it a fantastic combo in fact the sony 28-75 2.8 produced stunning results but I would tell lies if i said it was on parr with the Zeiss which really pops the subject although has softness at corner edges @ 24mm is evident...Low light for my use has been great never has any problems...The flash/system shoe is the only annoyance and slight over exposure easily fixed in light room. what would I change upgrade faster AF..sensor 24mp ff is more than ample.In all I am a very happy with my a99 well done sony engineers...

Comment edited 2 times, last edit 3 minutes after posting
0 upvotes
Lassoni
By Lassoni (2 months ago)

There's really no way around it. This is hands down sony's best camera to date. They really should revisit this, maybe give it a sensor and/or mount of their A7s , aim to make it better @ low light than Canon 5d3 (much more cleaner than 5d3, almost 1DX spec), and get rid of the translucent mirror maybe. Keep the body as is, make it mirrorless with around 15-18 megapixel and give it FPS of 8-11.

0 upvotes
Scottelly
By Scottelly (8 months ago)

Something that amazes me about the A99 is the fact that it handles high ISO better than the new Nikon D600 and D610 cameras. I just found this out by looking at the ISO 6400 samples here on DPreveiw in their studio shot comparison tool: http://www.dpreview.com/reviews/studio-compare#baseDir=%2Freviews_data&cameraDataSubdir=boxshot&indexFileName=boxshotindex.xml&presetsFileName=boxshotpresets.xml&showDescriptions=false&headerTitle=Studio%20scene&headerSubTitle=Standard%20studio%20scene%20comparison&masterCamera=nikon_d600&masterSample=dsc_4526_03&slotsCount=4&slot0Camera=nikon_d600&slot0Sample=dsc_4526_03&slot0DisableCameraSelection=true&slot0DisableSampleSelection=true&slot0LinkWithMaster=true&slot1Camera=sony_slta99&slot1Sample=dsc00049&x=-0.378464142966364&y=0.34409159041539195

Make sure you look at the playing card, after you pick which cameras you want to compare and set the ISO selection box to ISO 6400 (or whatever ISO you want to compare).

1 upvote
HowaboutRAW
By HowaboutRAW (6 months ago)

It doesn't handle high ISOs better than the Nikon D600.

Though one way to help with high ISOs is to use good Zeiss lenses and those are more readily available for this Sony.

0 upvotes
J Shen
By J Shen (9 months ago)

Continued post: During burst shooting, SLT cameras can see a live image preview or can not see ? Thanks for advice !

0 upvotes
J Shen
By J Shen (9 months ago)

About SLT & SLR cameras, If following two comments (from dpreview) are conflicting each other ? During bursts shooting SLT cameras can see the frames or can not see ? maybe I'm misunderstood. Thanks !
1, Unlike ordinary DSLR cameras, SLT cameras by Sony use Translucent Mirror technology that directs light onto the main image sensor as well as a separate autofocus sensor. This means that subjects stay sharply focused at all times as you compose scenes with the tilt-angle LCD or through the high-resolution, high-contrast OLED Tru-Finder. And with no moving mirror to slow you down, you’ll enjoy non-stop live image preview during speedy burst shooting or while you’re recording Full HD video.
2, One distinct disadvantage to current EVF technology is that when shooting bursts at higher frame rates, you are not seeing a live preview, rather the frames you have just captured. This can make camera panning (to follow a fast moving subject) virtually impossible to do with any accuracy.

0 upvotes
Scottelly
By Scottelly (8 months ago)

Well, my A55 worked just fine for following fast-moving subjects, while shooting at 10 fps, and I believe the A99 is an improvement over the A55. (also can shoot at 10 fps)

0 upvotes
Thomas Karlmann
By Thomas Karlmann (11 months ago)

It may be only the a99 RAW for ISO 25600 that is broken. Thanks.

0 upvotes
Thomas Karlmann
By Thomas Karlmann (11 months ago)

beomagi: Thanks, I overlooked it.

0 upvotes
Thomas Karlmann
By Thomas Karlmann (11 months ago)

DPR Raw Link for a99 Studio Scene appears to be broken. Please fix.

0 upvotes
beomagi
By beomagi (11 months ago)

Connectors under flaps here
http://www.dpreview.com/reviews/sony-alpha-slt-a99/18

0 upvotes
Thomas Karlmann
By Thomas Karlmann (11 months ago)

This review fails to show the I/O connectors! What is under those flaps? Most importantly where is the PC-sync terminal???? If there isn't one, I'll keep looking for a different camera. Please clarify.

1 upvote
Total comments: 13