Camera Labs

Hi guys!

I was wandering the other day; if I change the resolution on my camera from 12MP to 6 or even 3MP does the camera give to each pixel more area of the sensor? That would be just fantastic, at least from a low-light-performance point of view. But I suspect that would too good to be true. I am going to try it with my D5000, but I'm asking this here in case someone wants to have a go or already knows. Maybe other brands do, or same pro cameras...

Well, thanks for your answers.

Ivan Manko

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It is my deauty to capture beauty.

You'll just end up with a low quality image

try and see

Does resolution=quality, Phil?

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It is my deauty to capture beauty.

There's no direct correlation between resolution and quality. There's not just the size/area of the pixel to take into account but also its sensitivity to light and the latter tends to improve with time. In my view the resolution increases because there's a common misconception among consumers that higher resolution automatically means higher quality so if they find a camera doesn't have a higher pixel count, they will wonder if why.

You should also take into account that your lens has a profound effect on the image quality. It's arguably more apparent than the difference you'd notice if you compared similar bodies.

However if the absolute low light performance was required, I'd most likely look at one of the full-frame bodies from Canikon.

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Bodies: Canon EOS 550D w/ Magic Lantern
Lenses: Tokina AT-X 116 Pro DX f/2.8, Canon EF-S 15-85mm f/3.5-5.6 IS USM, Canon EF-S 18-55mm f/3.5-5.6 IS, Canon EF 50mm f/1.8 II, Canon EF 70-300mm f/4-5.6 IS USM
Accessories: YongNuo Speedlite YN-468 Flash, Neewer Macro LED Ring Light, Meike Battery Grip, YongNuo RF-602 Wireless Flash Trigger & Receiver YongNuo WR-128 Wireless Remote Control

Thanks, Rorschach, I really appreciate your effort.

With my second question I was being a bit ironic. It is obvious that the size of the photo has nothing to do with its quality.
But I think you misunderstood my original question as well. A part from that we all know that big sensors are appreciated because they, well, they are bigger, and therefore gather more light, and more precisely, into every pixel.(And wide angle is easier to archive, and the bokeh is better, and so on) So, theoretically, a full frame camera with more pixels could have the same performance, as far as noise concerned, as a camera with a cropped sensor. But my original question was about how the camera works. Most cameras allow you to take photos without using the full resolution available, generally to save memory cards, but I was wondering, if the camera just converts the file digitally into a smaller sized file or does it actually rearrange the sensor so it gives a lower resolution photo but with the advantages this would mean.
And again, I think if this was true we would know, because it should be a big deal. But maybe same manufacture does… I am begging for your knowledge.

Ivan Manko

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It is my deauty to capture beauty.

First one. Sadly. So saving the pictures in a lower resolution doesn't affect low light performance but only the size. But on resized pictures noise may become less "aggressive". But that's the case if you resize them afterwards, too.

A full frame camera with the "same resolution" as a 7D would have a 46MP sensor. Still with a newer technology (the 7D isn't the newest camera out there) the low light performance could be a bit better.

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Canon EOS 500D + Canon EOS 5D Mark III
Canon EF 24-105mm 4L IS USM + EF 100-400mm 4.5-5.6L IS USM + EF 100mm 2.8L Macro IS USM + Sigma 12-24mm 4.5-5.6 EX DG HSM + Canon Speedlite 580 EX II + Nissin Speedlite Di 466

I was thinking the same thing today, I wish that the noise performance on my D7000 would improve if I saved as a lower resolution. However, saving it as a lower resolution just decreases the file size, compressing it. It doesn't make the physical pixels on the sensor itself larger, but if the pixels did become larger (however that would be achieved) you would get a better signal to noise ratio in theory. The only thing that occurs with a smaller resolution is a smaller file, so you can squeeze more images onto a card. Unless you're desperate for space or know that you'll only be posting the images online, I wouldn't recommend it.

I personally wish that Nikon or Canon would release a 4 or 5 megapixel camera, with superb low light performance. I mean, really, how often do I use the full 16 MP of my D7000? Never, I haven't once made pictures so large that I needed more than 5 megapixels.

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-Evan

Gear: 7 Nikon Nikkor AI-S and AF-S lenses, SB-700 flash, Nikon D7000, Nikon FM, variety of accessories

"There are no rules for good photographs, there are only good photographs."
- Ansel Adams

Very simple answer: Noise depends on the size of the projected/printed image, not the number of pixels on your sensor! (provided you compare sensors of the same size and technology)
Look at you monitor: If you fit an image full-size on it, there is clever some algorithm in your computer binning all the pixels from your sensor on only 1920x1200 = 2.3MP. So if you own a 12MP D300 this piece of software just lumps approx 5 pixels into one averaging out the brightness and color values. And averaging reduces noise. If you do this with a 16MP image from a D7000, the algorithm just averages 7 pixels to set one pixel on the screen. More averaging = more noise reduction.
Conclusion: The more pixels a sensor has the more pixels will be averaged when viewing the image on your monitor or in a print which reduces any increase in noise that the smaller photosites produce.
This is called pixel-binning and is best been done in post-processing - not be reducing the size in-camera!
So, no need to guy a 3MP camera for low-light photography

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses