Megapixel Count

swiram

I primarily shoot wildlife with my Nikon D3200 and have been wanting to get the most out of my camera. I have been wondering if there is an advantage to scaling down my pixel count, say to 13.5 mp or so. Thanks!

ohyeahar

Short answer: No.

There are 2 potential advantages to shooting at a lower resolution:
1. You get smaller files, but when memory cards are so cheap today, this is a non-issue.
2. High-ISO image noise is more tolerable. This is highly subjective. What happens when you shoot at a lower resolution is your camera just down-samples your image. In doing so, it throws away a lot of image noise, but it also throws away a lot of details of your images. As a result, your image noise is less defined, but then so is everything else. Noise reduction in Nikon cameras are so good now that this is really moot.

The point is, it’s not worth it to shoot at lower resolution. This is especially true if you shoot wildlife where cropping is essential.

bruto

If you downsample in the camera you cannot shoot RAW, and every resave of a JPG image adds a level of compression and potential loss. I've experimented a bit with cropping. Although the difference is very small at the highest quality, you may see some difference between a raw to raw crop and a JPG to JPG crop, even if the quality of the JPG is high, and even if the resulting crop is saved then as a JPG.

Just for grins, I just tried a set of shots, at ISO 6400, aimed at a green houseplant with a dark background. Because I had to do this a couple of times and did not bother with a tripod, the result is not perfectly scientific. I took the shot first in highest resolution JPG, then lowest, then RAW. I also made an in-computer downsampling of the first. For this exercise I worked entirely in Irfanview, which does not do the absolute best job of converting RAW to JPG. In terms of noise, the downsized JPG slightly edged the natively small JPG, the RAW close to these, the large JPG last. In terms of sharpness, the RAW is the best by a small margin. All are a little grainy, as expected from ISO 6400, but surprisingly free of random noise.

I had the in-camera noise reduction turned on. The difference here is very slight, but there is a small reduction of random noise in the darkest areas with it on. It doubles the length of time of every exposure, so it is not recommended for time exposures, sky shots, etc., but costs little for normal use.

I think that unless you are shooting at high ISO there is little reason to downsample in the camera. If you plan to crop, you should stick to the highest resolution. Given how easy it is to convert RAW files to JPG, the only reasons I would bother with in-camera JPG is if one expects to transmit files without a computer to process them, if you are running short of space or power, or perhaps if a combination of slow memory card and multiple shots is causing you to overrun the buffer.

Moose

I agree with everything @ohyeahar and @bruto said and recommended. If you want to get rid of noise, use a program like Adobe Lightroom, which has dedicated sliders for removing noise. Happy shooting!