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Author Topic: Do More Mega Pixels translate in a richer photo?  (Read 31227 times)

pcdebb

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #30 on: March 06, 2015, 02:22:04 AM »
Interesting lesson for me here.  I've battled with this question for ages, and battling it now as to if I am going to upgrade from a T3.  Truthfully i want more glass  ::)

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #30 on: March 06, 2015, 02:22:04 AM »

Ryan_

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #31 on: March 06, 2015, 09:45:08 PM »
i think downsampling can give really good results. here is a downsampled d800 to match d3 image. and a downsampled one of mine shown next to the full rez one taken on a 70d. i think for downsampling to be really effective you need to use the bicubic sharper algorithm and go 50% in both directions.
I'm confused about the buzzard image, do you mean you uprezed and then down rezed the buzzard image to get the one on the right(sharper image)? Because they look like exact same photo but that one on the right looks way more detailed. Just wondering how?

candc

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #32 on: March 07, 2015, 08:31:32 PM »
The one on the right is just downsampled with dxo using the bicubic sharper algorithm shown at 100% The one on the left is full res viewed at 50%. Remember that sensors use a bayer array and each pixel only records either red green or blue. Then Bayer interpolation tries to combine that info into an image with the same resolution. Downsampling with the bicubic sharper algorithm basically combines 4 adjacent pixel which each contain separate color information into 1 pixel. In effect it's like having pixels that are twice the size that record all the color information. So if you start with a 50mpx sensor image and downsample it then it is better than one that uses that same starting resolution as the downsampled image.
« Last Edit: March 07, 2015, 08:37:24 PM by candc »

privatebydesign

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #33 on: March 07, 2015, 08:54:31 PM »
The one on the right is just downsampled with dxo using the bicubic sharper algorithm shown at 100% The one on the left is full res viewed at 50%. Remember that sensors use a bayer array and each pixel only records either red green or blue. Then Bayer interpolation tries to combine that info into an image with the same resolution. Downsampling with the bicubic sharper algorithm basically combines 4 adjacent pixel which each contain separate color information into 1 pixel. In effect it's like having pixels that are twice the size that record all the color information. So if you start with a 50mpx sensor image and downsample it then it is better than one that uses that same starting resolution as the downsampled image.

All you are doing there is demonstrating your video cards bad interpolation of a 50% view. You can only judge sharpness on a monitor at 100%, that is it. The reason your downsampled buzzard looks so sharp by comparison is because your graphics card is just passing the 100% signal through, it isn't dynamically resizing it like it is to the 50% view one.

Bayer arrays don't mess with detail or luminance of a pixel, they just, potentially, mess with the colour of a pixel. The AA filter messes with the detail, which is why all images from any one model camera (if it has an AA filter) all require the same level of input/capture sharpening.
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

candc

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #34 on: March 07, 2015, 09:09:51 PM »
Right, and when you look at the two images we are really talking about Acutance. The cheetah images are really better at demonstrating what I am getting at which is that an image captured with a higher resolution sensor and downsampled is better than one captured with a sensor of same size as the downsampled image.

privatebydesign

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #35 on: March 07, 2015, 09:44:30 PM »
Right, and when you look at the two images we are really talking about Acutance. The cheetah images are really better at demonstrating what I am getting at which is that an image captured with a higher resolution sensor and downsampled is better than one captured with a sensor of same size as the downsampled image.

I wouldn't necessarily disagree with that, just your buzzard illustration. But there are lots of caveats to 'better' and any relevant comparisons.

Here is a 1Ds MkIII and a 7D, both cropped to the same area, the 1Ds MkIII is at 100% the 7D is down sampled to match the resolution. Ignore the slight difference in focus and the dof is, actually, the same, they are both reproduced the same size so there is no dof difference between crop and ff in this specific situation. Same lens, same manual exposure and flash, heavy tripod, mirror up cable release, 10X manual Live View focus on both. The important bit about this comparison is that they are the same sensor area, the same generation sensor tech, just one has over twice the pixels as the other that have been downsampled.

The 7D crop is a downsampled 722,000px, the 1Ds MkIII is a native 323,000px, I cant see the differences at well over twice the pixels, can you?

The other thing with this comparison, I deliberately set it up to favour the crop camera, i'e 200iso (the 7D's optimal iso) and f5.6, again optimal for the 7D with a 300mm f2.8. At more taxing iso levels the differences could be quite different.
« Last Edit: March 07, 2015, 09:47:32 PM by privatebydesign »
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

candc

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #36 on: March 07, 2015, 10:00:39 PM »
they both look about the same but #1 seems to be a bit sharper and more contrasty. which one is which?

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #36 on: March 07, 2015, 10:00:39 PM »

privatebydesign

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #37 on: March 07, 2015, 10:11:56 PM »
they both look about the same but #1 seems to be a bit sharper and more contrasty. which one is which?

That is because the bottom one is back focused slightly, ignore the ruler and look at the paper towel and the bottom one is sharper with more contrast. When doing stuff like this focus is everything, and way beyond AF capabilities.
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

candc

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #38 on: March 07, 2015, 10:27:14 PM »
I guess your right then. It seems this "more megapixels" business is over the top and reached its useful real world limit. If you have to look that hard then its not worth dealing with the huge files.

privatebydesign

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #39 on: March 07, 2015, 10:39:12 PM »
I have been saying that for a long time  :)

There are a few people who need or want these new sensors and fewer who will actually get the best out of them, but even me who is a full time pro and who's work often gets printed big and glossy will rarely see the difference when downsampled. Like I say, noise will be a different test, but the new sensors have been capped low anyway.

There are some very good uses for the new sensors, and I'd still get one if my work goes that way, but getting 'better' IQ from down sampling isn't a good enough reason.
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

takesome1

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #40 on: March 07, 2015, 10:47:17 PM »
they both look about the same but #1 seems to be a bit sharper and more contrasty. which one is which?

That is because the bottom one is back focused slightly, ignore the ruler and look at the paper towel and the bottom one is sharper with more contrast. When doing stuff like this focus is everything, and way beyond AF capabilities.

Impossible comparison since they are focused at two different points. Second not all firmware is created equal, for instance the original 7D had quite a bit of head room for sharpening. For a proper comparison they need to be PP for quality to there maximum level then compared. All things need to be equal for an equal comparison.

Now is it beyond AF capabilities? No it is not. I have done the same comparison with birds and paper using the 7D II, 5D II and 1D IV. You can see the difference in MF on paper and you can see it in real world when you hit the critical focus point of the birds eye. When talking AF capabilities, the 1D body in the sample would be far more likely to hit the critical point of focus than the 7D would have.

takesome1

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #41 on: March 07, 2015, 10:50:22 PM »
I have been saying that for a long time  :)

There are a few people who need or want these new sensors and fewer who will actually get the best out of them, but even me who is a full time pro and who's work often gets printed big and glossy will rarely see the difference when downsampled. Like I say, noise will be a different test, but the new sensors have been capped low anyway.

There are some very good uses for the new sensors, and I'd still get one if my work goes that way, but getting 'better' IQ from down sampling isn't a good enough reason.

I would say it pays to know why you need the additional mp and how it will benefit what you do.
Many types of photography will see no benefit and actually loose quality in their work going that way.

privatebydesign

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #42 on: March 07, 2015, 11:06:01 PM »
they both look about the same but #1 seems to be a bit sharper and more contrasty. which one is which?

That is because the bottom one is back focused slightly, ignore the ruler and look at the paper towel and the bottom one is sharper with more contrast. When doing stuff like this focus is everything, and way beyond AF capabilities.

Impossible comparison since they are focused at two different points. Second not all firmware is created equal, for instance the original 7D had quite a bit of head room for sharpening. For a proper comparison they need to be PP for quality to there maximum level then compared. All things need to be equal for an equal comparison.

Now is it beyond AF capabilities? No it is not. I have done the same comparison with birds and paper using the 7D II, 5D II and 1D IV. You can see the difference in MF on paper and you can see it in real world when you hit the critical focus point of the birds eye. When talking AF capabilities, the 1D body in the sample would be far more likely to hit the critical point of focus than the 7D would have.

The difference between my opinion and yours is, mine is backedup with actual images that illustrate my point. You are just blowing hot air.

Why do you assume I processed them both the same? I didn't, I processed them both optimally in the software I had (Adobe), that was the point for me, I didn't do these tests for you or the forum, I did them for me to see what advantages buying a 7D would have for me. Turns out I have pretty conclusive empirical results that show that going from 21 MP to a theoretical 46 MP FF sensor wouldn't do much for me if I was thinking downsampling would give me any additional IQ.

As for your AF comments, dream on, I did the same tests with AF and 10x Live View manual focus, AF is nowhere near as accurate and the differences in the above examples equate to around 2" of focus difference at 30' at f5.6 with a 300mm lens, so well within DOF limits and any normal reproduction size. Yes the 1Ds MkIII AF has a much better accuracy rate than the 7D, so what when neither of them is as accurate as live view when we are looking at resolution?
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #42 on: March 07, 2015, 11:06:01 PM »

privatebydesign

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #43 on: March 07, 2015, 11:07:31 PM »
I have been saying that for a long time  :)

There are a few people who need or want these new sensors and fewer who will actually get the best out of them, but even me who is a full time pro and who's work often gets printed big and glossy will rarely see the difference when downsampled. Like I say, noise will be a different test, but the new sensors have been capped low anyway.

There are some very good uses for the new sensors, and I'd still get one if my work goes that way, but getting 'better' IQ from down sampling isn't a good enough reason.

I would say it pays to know why you need the additional mp and how it will benefit what you do.
Many types of photography will see no benefit and actually loose quality in their work going that way.

Nobody should lose quality, why do you think they would? More MP won't hurt (other than file size) it just won't often give much more.
Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, DR, MP's or AF, it is about the light.

takesome1

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #44 on: March 07, 2015, 11:23:39 PM »
I have been saying that for a long time  :)

There are a few people who need or want these new sensors and fewer who will actually get the best out of them, but even me who is a full time pro and who's work often gets printed big and glossy will rarely see the difference when downsampled. Like I say, noise will be a different test, but the new sensors have been capped low anyway.

There are some very good uses for the new sensors, and I'd still get one if my work goes that way, but getting 'better' IQ from down sampling isn't a good enough reason.

I would say it pays to know why you need the additional mp and how it will benefit what you do.
Many types of photography will see no benefit and actually loose quality in their work going that way.

Nobody should lose quality, why do you think they would? More MP won't hurt (other than file size) it just won't often give much more.

High ISO noise, for those of us who like to shoot in the evening without flash. Lower ISO, lower shutter speed, more camera shake....

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Re: Do More Mega Pixels translate in a richer photo?
« Reply #44 on: March 07, 2015, 11:23:39 PM »