Thursday, August 15, 2013

I wanted to do an evaluation of my Sony Nex-6 camera when using high ISO - up to its ISO 25,600 maximum setting. I decided to follow some magazine reviews of high-ISO cameras by using an 8x10
image for judging the quality of the image (instead of viewing the image at 100%), except that I used 8x12 so I can use the aspect ratio of the sensor, without cropping. My monitor has a resolution of 95 pixels per inch, so 8x12 is 760 pixels x 1140 pixels, or 1140x760 as in the format used for describing images on computer monitors.

The DSC00373 image was recorded with an ISO 6400 setting; the DSC00374 image was recorded with an ISO 12800 setting; and the DSC00375 image was recorded with an ISO 25600 setting. All three of these images are straight out of the Nex-6 camera, with no post processing, so it is obvious that the camera is doing a lot of noise reduction to the jpg files. The DSC00375-ACR-0 image is the RAW file process through ACR with NO changes, so the noise is evident is this image. The DSC00375-ACR-80 image is the same RAW file processed in ACR with a noise reduction of 80%. This image is roughly equivalent to the unprocessed jpg image out of the camera.

The DSC00408 image was taken at a telephoto zoom of 64mm (35mm equivalent), so I could concentrate on the band shell. The exposure was set for the bandshell and no attempt was made to lighten the shadows, because I wanted to show JPG images "as-is" except for noise reduction. One post processing of the image was: jpg format, into Photoshop CS6, and applied the Topaz DeNoise filter using the "JPEG-strongest" preset.

The other post processing of the image took the RAW file into Adobe Camera Raw (ACR) and used its noise reduction. I tried several levels of noise reduction in ACR using the DSC00408 image. At an ACR noise reduction of 60%, the image has more noise and less detail than the image using the Topaz DeNoise filter. Higher levels of ACR noise reduction removed more noise, but as expected, also reduced the level of detail even more. This is the same as my previous experience of getting better noise reduction results when using Topaz DeNoise filter. I like the Topaz DeNoise filter post processing better (than ACR) because of the higher level of detail while still reducing the noise.

The DSC00398-w and DSC00399-w images are provided to show the max telephoto and max wide angle images.

I have two conclusions as a result of my testing:
1. Even at an ISO setting of 25600, the Sony Nex-6 camera creates acceptable images for viewing on a monitor, without post processing. The 8x10 print is remarkable for the ISO level, but is not perfect, of course.
2. The Topaz DeNoise filter produces better images than using ACR noise reduction.

DSC00373, ISO 6400

 DSC00374, ISO 12800 

 DSC00375, ISO 25600

DSC00375-ACR-0, ISO 25600 

 DSC00375-ACR-80, ISO 25600

 DSC00408, ISO 25600 Topaz DeNoise

DSC00408, ISO 25600, ACR 80

DSC00398, max telephoto, 300mm (35mm equivalent)

DSC00399, max wide angle, 27mm (35mm equivalent)

Tuesday, August 13, 2013

Butterflies on the bush outside a window of our house. More butterfly photos are on my website: