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ISO Accuracy

The actual sensitivity of each indicated ISO is measured using the same shots as are used to measure ISO noise levels, we simply compare the exposure for each shot to the metered light level (using a calibrated Sekonic L-358), middle gray matched. We estimate the accuracy of these results to be +/- 1/6 EV (the margin of error given in the ISO specifications). We found that measured ISO from the Sony SLT-A57 is within +/- 1/6 EV of indicated ISO across its entire ISO range.

Noise and Noise Reduction (JPEG)

This is our standard studio scene comparison shot taken from exactly the same tripod position. Lighting: daylight simulation, >98% CRI. Crops are 100%. Ambient temperature was approximately 22°C (~72°F).

Note: this page features our new interactive noise comparison widget. By default, we show you the default noise reduction settings of the camera tested, and three other models of the same class. You can select from all available NR options, and from other cameras. The 'tricolor' patches beneath the familiar gray/black/portrait images are taken from the same test chart, and show how noise impacts upon blue, green and red areas of a scene.

As with Sony's current Alpha models, the A57 has three levels of noise reduction (high, normal and low), as opposed to the more limited choice between 'Auto' and 'Weak' that was found on the SLT-A55. Looking at the crops, all three settings give visually the same results up to ISO 1600.

Default noise performance of the A57 is nearly identical to that of the Sony NEX-5N from base ISO to ISO 3200. The A57 does a slightly better job of balancing noise suppression and image detail compared to its predecessor, the A55. As you can see in both the samples and the graph, the A57 performs very well in comparison to its peers, providing usable detail up to ISO 6400, and in a pinch, at ISO 12800.

ISO 25600 is only available as a multiple shot NR setting, in which the camera merges six separate exposures, averaging out the noise. This feature that requires you to be in JPEG-only mode. As you can see in the samples above, choosing this option minimizes noise without losing much detail compared to ISO 16000. For a look at this multi shot NR feature in a real-world example see our Sony SLT-A55 review.

RAW noise (ACR 7.2 Beta, noise reduction set to zero)

 

Looking at the raw file samples above, highlights just how much noise reduction is applied during JPEG processing, as chroma noise is visible even at base ISO. It is still well-controlled, however, and does not begin to obscure fine detail until ISO 1600. As you can see from the graph, the A57's noise performance is virtually identical to that of the A55 up through ISO 3200. This performance places it among the best of the A57's APS-C and Micro Four Thirds rivals.

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Comments

Total comments: 4
atoal

recently got a sony a57 when shooting with a minulta lens the image on the display is crystal clear for about 2 seconds and then goes blurry. does anybody know how to stop this?

0 upvotes
BobFoster

As I know a lesser lens might introduce coloured fringing around sharp, fine contrasts in an image such as this -- particularly in the upper-left corner where the branches overlay the sky -- but the SAL1855 passed with flying colours

1 upvote
m Anthony

My friend has a Sony A 57, he uses the Fast frame mode, I think the "T" setting to take pictures of his daugher's sports activities, but the images are blulrred, I advised him to set a shutter speed of 1/800 or even higher, but I do not see how to do that with the "T" setting. Can this be done?
Sorry I do not own a Sony camera, this seems like a nice feature and I'm just trying to help a friend.

Thanks Much
m Anthony

Comment edited 3 times, last edit 1 minute after posting
0 upvotes
tohydrom

Tell your friend to force the camera to shoot at higher shutter speed by raising the ISO, which you can control while in the T mode :)
good luck,

0 upvotes
Total comments: 4