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  • Nikon D3X vs. Sony A77 ISO Comparison

    Sony SLT-A77 and Nikon D3X Side-by-Side

    Sony A77 and Nikon D3X

    You might be wondering why we would want to compare the Sony A77 and Nikon D3X in terms of ISO performance. A better match might be to compare the Sony A900 to the Nikon D3X. After all, it is rumored the D3X uses a sensor manufactured by Sony. Considering that, and both the A900 and the D3X are 24 megapixel (plus some change) full-frame cameras, one might conclude those are the two cameras to compare. And, especially when you realize the A900 retails for $2700 and the D3X retails for $8000. So, you are probably still wondering, why the A77 and D3X?

    Well, the Sony A77, like the D3X for Nikon when it first came out, is the first camera of its kind. It has a 24 megapixel (plus some change) APS-C sized (1.5x crop) sensor. A lot of people are weary of packing more pixels into a sensor without increasing the sensor size at the same time. The idea is that if each pixel, or photosite, is smaller it will likely get bombarded with more photons of light than a larger photosite in a given amount of time. Oppositely, the smaller photosite is like a "net" and, being a smaller net, it is less likely to capture as many photons in a given instance. So, if you have a lot of light the smaller photosites will get saturated and turn white, and if you don't have much light the photosites will stay dark. Either way, you will have a loss of detail: blown out highlights, and blocked shadows. This may also translate into a noisier or "grainier" image at higher ISOs.

    Our fascination and the reason for comparing these two cameras is to see how the APS-C 24 megapixel sensor of the $1400 Sony A77 compares to the full-frame 24 megapixel sensor of the $8000 D3X. The full-frame size of the 24 megapixel D3X means each individual pixel is physically larger than the pixels of the A77. This means the D3X may likely have greater dynamic range in capturing scenes with more contrast than the A77, but that kind of comparison is not our goal here. We wanted to strictly take a look at the noise levels/sharpness of each.

    Please see the following comparison shots below. We set up a quick scene and shot both cameras with similar settings, changing only the ISO in between each shot. As we used Aperture Priority mode, the exposure evaluation was up to each individual camera. In addition, we shot both cameras at their highest-level JPG setting. How these cameras handle JPG processing may be very different, and seeing the RAW images from these cameras may be a lot different than what you see here. We have included 100% crops, side-by-side. We won't tell you which one was shot by the Sony A77 and which was shot by the Nikon D3x, until you get to the bottom. Which do you think are the A77 images, and which do you think are the D3X?

    Nikon D3X vs. Sony A77 ISO Comparison

    ISO 400

    Nikon D3X vs. Sony A77 ISO Comparison

    ISO 800

    Nikon D3X vs. Sony A77 ISO Comparison

    ISO 1600

    Nikon D3X vs. Sony A77 ISO Comparison

    ISO 3200

    Nikon D3X vs. Sony A77 ISO Comparison

    ISO 6400

    OK, so you are probably wondering which is which? Or, maybe you've already figured it out. The left side of each image is from the Nikon D3X, and the right side of each image is from the Sony A77. We noticed the D3X tends to look sharper (at least in the brush), but at the expense of more noise or "grain". The A77 images look less noisy/grainy at higher ISOs, but it looks like you can't pick out as many bristles in the brush. What do you notice? Which one do you think looks better overall?

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