# Resolving Power on the 5D Mk II / III



## azraelot (Mar 12, 2011)

Hi everyone,

First post! w00t 8)

A little about myself: I'm a college student studying photojournalism, and I shoot video stories like this one with the school's 5D Mark II and 24-105 f/4.

I don't have any of my own gear, but I'm planning on taking out loans to buy a camera and lenses in the next year while I can still qualify for student loans. Which camera I get, we shall see. Lotsa factors in play, but right now I'd be eyeing the 5DIII when it comes out (or the 5DII if there's a major drop in price).

I have a question about resolving power, because I've seen it pop in conversations around the 5DIII. If the MP boost is as big as people think it will be, is that actually going to affect image quality significantly? Or is it going to actually create more problems, like not being able to use a 24-105 on such a high MP camera?

If you were in my position as a student, what would you do? Would you get a 5DII body today and some lenses, or would you hold out for a 5DIII?


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## olav (Mar 12, 2011)

If its no problem for you getting a camera for enough time now, i'd suggest to wait as you have access to a pretty good camera. if its not enough time, get one as soon as possible!
And have fun with it!


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## motorhead (Mar 12, 2011)

azraelot,

Resolution is really a lens issue. A poor lens will never produce images that are good, even if mounted on the worlds best camera. That lesson took me years to learn!

I'd therefore suggest that you don't wait for the 5D3, but instead buy a used mk2 (at a bargain price if the mk3 has appeared by the time you are in a position to buy).

Canon make excellent optics, being traditionally very good at long lenses. But so do others, sometimes at considerably better prices. I admit that since moving to Canon from Nikon I have become an "L" fan, but I've read good things about Sigma. Again, the used market can offer some amazing kit - I bought an almost unused EF100-400L only a few months old at half the new price a few years ago and have been very pleased with it.


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## Admin US West (Mar 12, 2011)

First, do not wait for a rumor to happen. Some of them have been circulating for years.

Second, a newer and higher resolution body will make the combination of lens and body look sharper.

The measure of sharpness is MTF.

Modulation Transfer function or MTF of the camera lens-body combination is equal to the product of the MTF of the lens and Camera body.

If both equal 0.8, the final mtf is o.64. If either improves, the product increases, so if the body becomes .85, the system MTF improves to 0.68.

Add in a monitor, printer, and paper, and the final MTF is lower yet.

Start here to learn about MTF. There are good references at the end of the article.

http://www.normankoren.com/Tutorials/MTF.html


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## azraelot (Mar 25, 2011)

Hey, sorry for the late reply, but just wanted to say thanks for the help, everybody!


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## prestonpalmer (Mar 26, 2011)

azraelot,

It could be sometime before the 5DIII is out. Do yourself a favor, get a 5DII and some Canon L series lenses. You will not be disappointed even when you upgrade the camera body sometime in the future. Don't worry about camera resolution or resolving power. The mega pixel war is over, all of us pro's want better sensor performance rather than more megapixels. Invest in good glass and you won't need to worry about it.

Cheers!


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## iPrevailed (Mar 26, 2011)

im personally waiting for thr 5DMkIII. i am in no rush and i can wait. more time to save up since i only have 2k.


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## bvukich (Mar 26, 2011)

iPrevailed said:


> im personally waiting for thr 5DMkIII. i am in no rush and i can wait. more time to save up since i only have 2k.



I am/was also waiting for the 5D3 to be released; but with all the uncertainty with what's going on in Japan, on top of the uncertainty inherent to trying to make decisions based on rumors, I gave up waiting.

Ok, I didn't exactly give up. I just came to the realization that it will probably be a year before the 5D3 comes out, and acted accordingly. So last night I ordered a 60D, and with the difference I'll get a lens or two. Then next year, or whenever the 5D3 comes out, I'll pick one up.


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## iPrevailed (Mar 26, 2011)

yeah at least thats an upgrade im still with my XTi since uh 2007? haha i have no clue. I opened up a savings account last week. put 2,000 in it and just throwing money in it every week so by the time the 5D3 comes out i will have that and the kit lens with possibly an alien bee or another L series lens. gotta sell two other since theyre EF-S and ill for sure keep my 50mm 1.4


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## neuroanatomist (Mar 26, 2011)

bvukich said:


> I am/was also waiting for the 5D3 to be released; but with all the uncertainty with what's going on in Japan, on top of the uncertainty inherent to trying to make decisions based on rumors, I gave up waiting.



I, too, was waiting/hoping for a 5DIII, but I 'gave up' last October and bought a 5DII. It's a great camera, and every month that goes by with no announcement and yet more delays makes me even happier I stopped waiting. I'll get a 5DIII when it comes, and by then I think I'll have more than gotten my value from the depreciation on the 5DII.


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## foobar (Mar 26, 2011)

azraelot said:


> If the MP boost is as big as people think it will be, is that actually going to affect image quality significantly? Or is it going to actually create more problems, like not being able to use a 24-105 on such a high MP camera?


- A higher resolution camera will not make a lens perform worse. The image-level quality will still be as good or better than with a lower resolution camera. Only pixel-level quality may be worse
- Even if the 5D3 would be a 32mp camera, the pixel density would still be less than that of Canon's current APS-C cameras, and last time I checked, people were quite happy using the 24-105 on those.
- Going from 21mp to 32mp isn't as huge of a jump as at seems. It's about the same as the jump from the 40D to the 50D and much less than the jump from the 5D to the 5D2

Compared to the 5D2's resolution (5616x3744), you would gain ~1350 pixels in width and ~900 pixels in height. That's not world's apart.


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## azraelot (Mar 26, 2011)

foobar said:


> azraelot said:
> 
> 
> > If the MP boost is as big as people think it will be, is that actually going to affect image quality significantly? Or is it going to actually create more problems, like not being able to use a 24-105 on such a high MP camera?
> ...



Ahh, I think I understand. So, I'm going to take a stab at this and see if I get marginally close to the facts 

Resolving power is the lens' ability to "resolve" as much image information as possible per pixel? A lens with superior optics would be able to resolve more information per pixel, so if you zoomed in to the pixel level, you'd have more information = sharper image = more ability to crop in. Basically, the image quality won't get worse with a higher MP sensor. BUT the individual pixels will. BUT there will be more of them, so it won't matter too much in most situations.

Am I understanding that correctly?


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## foobar (Mar 26, 2011)

azraelot said:


> so if you zoomed in to the pixel level, you'd have more information = sharper image = more ability to crop in. Basically, the image quality won't get worse with a higher MP sensor. BUT the individual pixels will. BUT there will be more of them, so it won't matter too much in most situations.


Correct.


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## WarStreet (Mar 26, 2011)

azraelot said:


> Basically, the image quality won't get worse with a higher MP sensor. BUT the individual pixels will. BUT there will be more of them, so it won't matter too much in most situations.
> 
> Am I understanding that correctly?



Keep in mind that this is true if you are comparing same sensor size. 

Rather than 'won't matter too much', the result will be higher resolution for the higher pixel count sensor if the sensor size is the same, and compared with the same lens.


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## armando (Mar 28, 2011)

neuroanatomist said:


> bvukich said:
> 
> 
> > I am/was also waiting for the 5D3 to be released; but with all the uncertainty with what's going on in Japan, on top of the uncertainty inherent to trying to make decisions based on rumors, I gave up waiting.
> ...



want to throw my ticket in the hat, I too gave up and bought one.


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## Caring (Mar 28, 2011)

I asked myself the same question earlier this month, and a quick Google found this:

http://www.luminous-landscape.com/tutorials/resolution.shtml


It is a bit scientific, but Table 3 clearly states for a high performance lens (eg. f/2.8 L glass) on a full frame camera, the optimal megapixels is ~151-463 MP. So whilst the 5D Mk ii sensor resolution benefits may have hit the "ceiling effect" for some conditions at f/8.0 and more narrow apertures, for the most part there is still so much sensor resolution benefit to be reaped!

Thanks,
Caring


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## torger (Mar 28, 2011)

When discussing resolution limits in a camera system (which we landscape photographers like  ) you should *not* see it as a chain where the resolution cannot be higher than the weakest link allows. Instead, the total resolving power is the weighted sum of all parts in the system.

The reason for this is that most limitations are soft limits, take diffraction for example - it is not 100% contrast, reaching airy disc diameter and then 0% contrast. Instead a limit leads to graceful fine detail contrast degradation. This means that if you improve the resolving power of one component in the system, you will in practice most likely see some improvement even though you have "passed the limit" on some other component/factor. Of course, it will pay off less to improve a strong link than a weak, but sometimes it can be worth it anyway.

A typical example when it can be useful is outresolving the diffraction since it really is a soft onset limit.

When it comes to bayer array sensor you have the whole anti-aliasing filter and demosaicing factor to take into account, making the actual resolution limit of the sensor itself fuzzy. Pixel peep a foveon sensor (no AA filter, RGB for each pixel) and compare to a unsharpened output from a bayer sensor in Canon or Nikon and you'll see clearly that you don't get 100% contrast down to the pixel level.

(Actually, I tend to think that it can be an advantage to have slight contrast loss at the pixel level that bayer/aa has, this makes jaggies and other pixel artifacts less likely to become visible in a cropped image, even after sharpening has been applied)


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## Admin US West (Mar 28, 2011)

torger said:


> When discussing resolution limits in a camera system (which we landscape photographers like  ) you should *not* see it as a chain where the resolution cannot be higher than the weakest link allows. Instead, the total resolving power is the weighted sum of all parts in the system.



Like it or not, the science behind MTF says that the final MTF is the product of the MTF of all the components. Since MTF is always less than one, the product is always smaller than the weakest link.

I've never heard that MTF is the sum of all the parts. MTF is basically resolving power.

http://www.normankoren.com/Tutorials/MTF.html


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## torger (Mar 29, 2011)

scalesusa said:


> torger said:
> 
> 
> > When discussing resolution limits in a camera system (which we landscape photographers like  ) you should *not* see it as a chain where the resolution cannot be higher than the weakest link allows. Instead, the total resolving power is the weighted sum of all parts in the system.
> ...



Sure. The saying "weighted sum of all parts in the system" is not scientific, it is just a way to think which relate better to what you see in practice than the thinking "not sharper than the weakest link" which is more common.

MTF is measured or probably more often estimated by theoretical calculations. Airy disc diameter is based on some subjective criterion on where the response is "low enough" compared to the peak. And on it goes -- that is no limit is on/off sharp, what you see as you stress the system with finer and finer detail is gradual reduction of contrast.

When you chain together several systems all which have soft limits, soft limits that also behave differently and are differently defined, it is hard to predict the end result. You cannot say that diffraction airy disc diameter defines a resolution limit the same way a sensor sensel diameter does. Still I see people make those assumptions all the time, that is if the airy disc is 6 microns, then 4 micron sensels give no better fine detail contrast than 6 micron sensels, which is not true since those both limits are soft and behave differently.

Since limits are soft (gradual reduction in contrast, where some subjective definition puts a "limit" at some place along that gradual reduction), you most often see improvements in the end result if you improve one part in the system, even if another part is past its "limit". Of course, if a part in the system is very far past its limit then you will see no gain, but you cannot really theoretically calculate exactly when "no visible gain" happens, you need to test in practice and see what happens.


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