Sony a850 vs. Nikon d300 noise comparison with images.

Started Nov 6, 2009 | Discussions thread
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Ma55l Contributing Member • Posts: 805
Sony a850 vs. Nikon d300 noise comparison with images.

I read about people saying that the NikonD300 is the best APS camera for noise. But noise by itself can’t really be compared unless the playing field is first leveled.

One of the unlevelers is size. Looking at anything at a larger size will always show more noise/imperfections – use a telephoto lens and you will see more wrinkles in peoples faces. So I have included a composite photo below showing four partial 100% crops of the D300 and Sony a850, reduced to the same size. The two images on the left are at iso 100 and on the right are at iso 6400 for both. The Sony a850 is the upper set and the D300 is the lower set.

If you look at these 100% cropped images, taken under lab quality exposures, you will see things at high iso besides the noise that are quite intriguing. And you might not have considered in the past that they are important.

It has been stated that noise and resolution are interchangeable and inversely proportional. Reduce the amount of noise in an image by processing and you will loose resolution/detail. Let your eyes focus between the side by side images from the same camera. You will see those changes on a first hand basis and it is a dramatic change for each system.

So to say that one or another camera has more noise needs to have the resolution/detail factored in as well as the same size of the image.

But there is more. Check the photos for color saturation at high iso. The lower the color saturation in an image the less will be the chroma noise (all other items being the same). So that is a sliding scale as well.

Now look vertically in comparison and note in the iso 100 images that there is more detail in the Sony image than the D300 Nikon. That is expected due to the sensor size in MP. That extra resolution would not be seen on an 8 x 10 if you printed the whole image file. But cropping can be done at a greater level without loss of quality from the a850. The extra resolution basically gives you the benefit of a tele-extender without F stop loss. So a FF 50mm lens on a 24 MP sensor can be transverted into a 75 or 100 mm image by cropping. You could not effectively do that with a 12 MP sensor without lossing IQ in an 8x10. Imagine a 100 mm F 1.4 lens – doesn’t that make you drool.

Next look at the iso 6400 images (same size) and several things become immediately apparent. First is that there is more detail/resolution in the Sony image. Second is that there is about the same amount of noise in the wall above the napkins. Thirdly and most important, there is less saturation in the Nikon image in the green and red channels.

Some would say that the resolution/detail at iso 100 would not show up on an 8 x 10 print and I believe that is correct. However if you are heavy into cropping or enlarging (as mentioned above) the differences even at iso 100 would be easily seen.

Back to the two iso 6400 images. The loss of detail in the Nikon image is more dramatic in comparison to the Sony. If those were printed on an 8 x 10 the differences would be clearly seen with normal vision at 12 to 14 inches distance (Magazine reading distances.) The slight advantage of the noise in the D300 in the gray wall would be averaged out and would appear the same on a print vs. the a850. However and this is quite important the loss of color saturation in the green and red channels would be quite evident in the D300 print. Resolution and noise would be sort of melted in the downsizing that occurs when you make an 8x10, however the saturation which is quite lacking in the Nikon image would not benefit. In order to print the Nikon 6400 image you would have to increase the saturation. That will increase the chroma noise might now become visible on the Nikon print.

I believe maintaining saturation at high iso is better as there is less post processing work to get a print. However, Sony gets bad press as it shows up as more noise on test sites. A noise comparison without taking the other variables into account is not on a level playing field and is biased to the image with lowest saturation. Remember you can always reduce saturation later if needed.

If you have Photoshop – look at the image and reduce saturation in the a850 and see what happens to the noise. And conversely increase saturation in the Nikon image.

So image size, saturation and resolution need to be evaluated before one says this or that camera has less noise than any other.

In regard to the a850, I would take it any time over the Nikon d300 at low iso, as well as high iso - even at 6400. Remember these cameras are almost the same cost.

Two last points regarding noise: The Sony has image stabilization built in. If you wanted to use a 50mm F 1.4 lens, you would have the benefit of IS in the Sony but that would not hold true for the Nikon. There are no F 1.4, 1.7, or 1.8 VR/IS lenses made anywhere or by any manufacturer. Therefore the iso advantage would work out that you could use the a850 at an iso of 1600 (assuming a two stop advantage with IS) vs. the D300 at 6400. Given the degradation of the iso 6400 Nikon image that is clearly seen in the photo above, using 1600 to get the same photo via the a850 would show a spectacularly difference and far better image IQ.

The last or second item here is the effect of a larger sensor and camera on shooting speed. Because the a850 sensor is larger than the APS there is less comparative image movement when handheld on the sensor. I believe this factors adds another ½ stop of iso advantage under real life circumstances for the FF camera. That difference now totals 2.5 stops (two for IS and 1/2 for size). I invite you to go to the IR (Imaging-resource.com) site and compare the a850 at iso 1,000 (reduced in size from 6042 to 4272 pixels) against the D300 at iso 6,400 and see just what all this means in everyday situations.

In effect SIZE really does matter

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