6mp on a k10d

pdxbmw · 10-10-2008, 01:03 PM

This is my first post.

This may be a stupid question, but I keep hearing that the 6mp DSLR's produce better photos in low light than the higher mp count DSLR's. My questions is, if you change the mp settings in the k10d to 6mp's, should/would it produce sharper images in low lighting situations?

Gooshin · 10-10-2008, 01:13 PM

Originally Posted by pdxbmw

This is my first post.

This may be a stupid question, but I keep hearing that the 6mp DSLR's produce better photos in low light than the higher mp count DSLR's. My questions is, if you change the mp settings in the k10d to 6mp's, should/would it produce sharper images in low lighting situations?

the reason that low MP count cameras produce better images in the dark (if you compare similar era technologies), is because the physical size of the pixel is bigger, remember that the total surface area remains the same.

without getting into all the physics of it, the blanket statement is that larger pixels will produce cleaner signals at higher ISO's, and therefore better images.

the setting in your camera to change the megapixels is not what you think it is.

you have 10 physical megapixles on your sensor, you cannot change this. This is the hardware that is used to take pictures.

what you CAN change, is the output format, RAW or JPEG. and within the JPEG format, you can further choose the quality level, with 10 megapixels being the highest, 6 in the middle and the rest i dont even know...

the only thing you get by shooting 6MP "jpegs" are smaller images, and they will most definetly be lower quality.

rfortson · 10-10-2008, 02:49 PM

I've never used a smaller mode because I want to use all the pixels I pay for. :P

However, I seem to remember some people saying that the noise was better on a 6mp shot from the K10D than a 10mp shot from the K10D. I understand the physics of what Gooshin says, and generally agree. However, I could imagine some sort of averaging of pixels going on internally to downsize a 10mp shot to 6mp (after all, the field of view/framing is the same - only the size changes). In doing this downsizing, it's possible it could have an affect on the image noise.

Of course, I don't own the K10D anymore so I can't test this theory. Someone else will have to do it. You should also search "that other site" to see if you can find the threads addressing this.

*sewebster* · 10-10-2008, 03:15 PM

Originally Posted by rfortson

However, I seem to remember some people saying that the noise was better on a 6mp shot from the K10D than a 10mp shot from the K10D. I understand the physics of what Gooshin says, and generally agree. However, I could imagine some sort of averaging of pixels going on internally to downsize a 10mp shot to 6mp (after all, the field of view/framing is the same - only the size changes). In doing this downsizing, it's possible it could have an affect on the image noise.

You could presumably do this in post then as well, which would likely be a better idea. I guess if it worked, you'd need the algorithm.

Marc Sabatella · 10-10-2008, 07:06 PM

Originally Posted by sewebster

You could presumably do this in post then as well, which would likely be a better idea.

It is definitely true that when you downsize a 10MP image to 6MP, you end up with an image in which the overall amount of noise is not noticeably worse than a 6MP image. Or, looked at another way, when viewing a 10MP image and a 6MP image at the same size (either on screen or printed), noise levels are comparable. Assuming we are talking about otherwise comparable sensors - and the K10D/K200D sensor is indeed comparable to the K100D one in this respect.

So if one can resize a 10MP to 6MP and get an image with no more noise overall than the 6MP image in PP, it is possible in theory for the camera to do this too. Meaning that *maybe* setting the camera to 6MP mode would indeed yield a less noisy image. But you're almost certainly better off doing it in PP. Or, not bothering doing the PP, but just taking advantage the fact that as long as you view/print the images the same size, the 10MP image will *not* look worse than the 6MP one.

res3567 · 10-12-2008, 10:22 PM

What is "that other site?

Marc Sabatella · 10-12-2008, 11:58 PM

Originally Posted by res3567

What is "that other site?

The Pentax SLR Talk forum on dpreview.com. The forum software there doesn't allow posting the name of *this* forum for some reason, so people are in the habit of calling this "the other Pentax forum", and even though it isn't actually necessary, that goes both ways.

audiobomber · 10-13-2008, 11:15 AM

Originally Posted by pdxbmw

I keep hearing that the 6mp DSLR's produce better photos in low light than the higher mp count DSLR's.

Not necessarily. The K20D has 14.6 megapixels but has lower noise than the 6mp Pentaxes because of it uses a different (CMOS) sensor.

Originally Posted by pdxbmw

My questions is, if you change the mp settings in the k10d to 6mp's, should/would it produce sharper images in low lighting situations?

I don't think that's a stupid question at all. I've heard it argued a few times on these boards. My opinion is the same as Gooshin's, I believe the camera takes the shot using the entire sensor and simply edits out more pixels in the jpeg processing.

This should be an easy thing to test for though. Take a high ISO photo at full jpeg resolution and then the same photo with the jpeg setting reduced to 6mp. Downsize both in post-processing to some value below 6mp for a direct comparison.