Return of Interesting article on DxO about 5D III and D800...

Started Apr 10, 2013 | Discussions
qianp2k
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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to Steen Bay, Apr 14, 2013

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:/

We can also see that the 7D actually has a higher resolution. The 5D's MTF curve stops at app. 61 lp/mm because it runs out of vertical pixels (app. 61 lp/mm represents the 5D's Nyquist frequency), while the 7D's MTF curve continues to app. 72 lp/mm (on 24 x36mm). The contrast is rather low, but the 7D's resolution is nevertheless higher.

I'd suggest everyone reads these articles to understand these concepts first and understand what that means in real world photos.

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

http://www.imatest.com/docs/sharpness/

From above two DXOMark MTF tests, we can see 7D only extends at MTF 15% or below that virtually invisible by eyes in real world photos even at base ISO when 7D photos buried by higher noises/grains. So that 7D higher resolution (18mp vs 12.8mp from 5D) is only on paper or reflected in larger CR2 file size but unless you have an eagle eye, you just cannot see it

A bit of sharpening makes it easier to see. It's clearly visible if comparing the resolution test chart shots in DPR's 5D and 7D reviews.

a) that depends from shooting distance.  A meaningful test should be done from at least 50x focus-length distance; b) depends on which lens. 7D needs a really good prime such as 100L (85/1.8 is also very nice lens) under perfect neutral gray and grainless/noiseless light condition at base ISO 100; c) doesn't reflect in real-world photos in outdoor harsh light or indoor poor light.

Not 100% sure, but think that DPR uses EF 85/1.8 on Canon FF and EF 50/1.4 on Canon APS-C. Agree that the 5D has better sharpness/contrast/acutance, but the 7D's higher MP count will most often also give it a higher 'resolution' (at least at low ISOs).

As shown in the two snapshots of old MTF charts between 5D and 7D, even with two excellent prime lenses, 100L and 85/1.8, 7D still only outresolves 5D around MTF 15% and below that virtually invisible by normal human eyes, and likely only in center not in edges/corners (on average MTF resolution).  You need to realize DXOMark tested in "perfect" ideal environment at base ISO on neutral gray resolution card virtually noiseless/grainless). I am sure with inferior lenses especially with zoom (such as 14-105L vs EF-S 15-85 or 17-55), then 7D will not be extended much more (that means at even lower MTF such as 5-10%).  Then in real world photos (outside "clean" lab), 7D/60D will be further impacted by higher noises/grains at pixel level (DXOMark SNR test confirms that), so that further will push 7D/60D advantage into lower MTF percentage that will be completely invisible by human eyes as above two articles said.

Therefore DXOMark tests likely use at least 20% MTF as someone suggested to test lenses on respective sensors (systems) to represent what human eyes can resolve (or perceive), and they changed to Perceptual Sharpness for easier understanding.  Ultimately what we can see in eyes only matters.  That should also answer your earlier scenario regarding smaller-sensor sport/wildlife cameras.  That's the reason Olympus FT DSLRs never succeeded in sport venues because Canon and Nikon have 300-600mm super-tele lenses. Then 2.0x crop has no chance, that's the reason why top wildlife photog are willing to lug around big super-tele lenses to achieve the best possible photos not only in IQ but in resolving fine details.  Sure 2.0x crop or even smaller sensor cameras do have "reach" (or pixel density) advantage in small birding that sometime even 600mm is not long enough.  However FF/APS-H owners could add 1.4x, 1.7x and 2.0x TCs, and can bring out 800mm and with 1.4x TC that still can AF at F8.0, that effectively overcome "reach" shortage and will result better IQ photos.

Anyway in theory I don't disagree with you but that has not been reflected in reality, not yet.  The main reason is lens not sensor.  I'm sure smaller sensors can involve better and better, so do larger sensors.  But the point is glass-based lenses.  It's either impossible or actually no longer smaller/lighter for 2.0x crop manufacturers for example to manufacture 300mm/F2.0 prime, or 400mm/F2.8 or 150mm/F1.4 lenses, in order to overcome 2.0x more crop penalties.

As another person said, crop penalty is real and amount of pixels is also real.  But crop format has much larger impact than amount of pixels that vividly confirmed by DXOMark tests.  We all remember in camcorder optical zoom vs digital zoom, that actually is very similar between crop format (digital zoom) vs longer lens (optical zoom).

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From DPR's 5D and 7D reviews - horisontal/vertical resolution (extinction resolution) :

5D - 2300/2000 (2500/2500) LPH

7D - 2500/2450 (3100/3050) LPH

I am not sure how DPR calculated into above data?  From the same AOV?  Using the same lens? Under that MTF percentage? 5D is 8-yr-old and DPR Lab has changed its test environment between when they reviewed 5D and 7D.  I wish DPR can add some old cameras such as 5D into new standard lab samples

That's the problem here.. according to DxO's P-Mpix scxore the 5D beats the 7D, but if looking at DPR's resolution test chart shots, then it's rather clear that the 7D has a higher resolution.

The key is that if those paper resolution actually can be seen by normal human eyes?  In those two DXOMark test charts with very nice prime lenses 100L and 85/1.8 (no mention inferior lenses), we can see 7D is only better at MTR 15% and below (even lower with inferior lenses) that are very low contrast and virtually invisible by human eyes even under grainless/noiseless lab environment (no mention in imperfect real-world environment .  5D is better above 15% MTF that is more meaningful and matter to human eyes.  It's all about perceptual sharpness or perceptual resolution as DXOmark uses two words interchangeably.

5D vs. 7D is just an example. Think that we'll have a similar 'problem' (acutance/sharpness vs. resolution) if comparing for example 5D3 vs. D800, or if looking at the effect of diffraction when stopping down.

I am sure 41mp Nokia 808 is 41mp on paper. In lab test, it may has 1% MTF data higher than 36mp D800 or 2% higher than 22mp 5D3.  The only matter is whether you eyes can actually see that?    If you eyes unable to tell, then those paper resolution is meaningless that you can think but you cannot see, heeh.

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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to qianp2k, Apr 14, 2013

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:/

We can also see that the 7D actually has a higher resolution. The 5D's MTF curve stops at app. 61 lp/mm because it runs out of vertical pixels (app. 61 lp/mm represents the 5D's Nyquist frequency), while the 7D's MTF curve continues to app. 72 lp/mm (on 24 x36mm). The contrast is rather low, but the 7D's resolution is nevertheless higher.

I'd suggest everyone reads these articles to understand these concepts first and understand what that means in real world photos.

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

http://www.imatest.com/docs/sharpness/

From above two DXOMark MTF tests, we can see 7D only extends at MTF 15% or below that virtually invisible by eyes in real world photos even at base ISO when 7D photos buried by higher noises/grains. So that 7D higher resolution (18mp vs 12.8mp from 5D) is only on paper or reflected in larger CR2 file size but unless you have an eagle eye, you just cannot see it

A bit of sharpening makes it easier to see. It's clearly visible if comparing the resolution test chart shots in DPR's 5D and 7D reviews.

a) that depends from shooting distance.  A meaningful test should be done from at least 50x focus-length distance; b) depends on which lens. 7D needs a really good prime such as 100L (85/1.8 is also very nice lens) under perfect neutral gray and grainless/noiseless light condition at base ISO 100; c) doesn't reflect in real-world photos in outdoor harsh light or indoor poor light.

Not 100% sure, but think that DPR uses EF 85/1.8 on Canon FF and EF 50/1.4 on Canon APS-C. Agree that the 5D has better sharpness/contrast/acutance, but the 7D's higher MP count will most often also give it a higher 'resolution' (at least at low ISOs).

As shown in the two snapshots of old MTF charts between 5D and 7D, even with two excellent prime lenses, 100L and 85/1.8, 7D still only outresolves 5D around MTF 15% and below that virtually invisible by normal human eyes, and likely only in center not in edges/corners (on average MTF resolution).  You need to realize DXOMark tested in "perfect" ideal environment at base ISO on neutral gray resolution card virtually noiseless/grainless). I am sure with inferior lenses especially with zoom (such as 14-105L vs EF-S 15-85 or 17-55), then 7D will not be extended much more (that means at even lower MTF such as 5-10%).  Then in real world photos (outside "clean" lab), 7D/60D will be further impacted by higher noises/grains at pixel level (DXOMark SNR test confirms that), so that further will push 7D/60D advantage into lower MTF percentage that will be completely invisible by human eyes as above two articles said.

Therefore DXOMark tests likely use at least 20% MTF as someone suggested to test lenses on respective sensors (systems) to represent what human eyes can resolve (or perceive), and they changed to Perceptual Sharpness for easier understanding.  Ultimately what we can see in eyes only matters.  That should also answer your earlier scenario regarding smaller-sensor sport/wildlife cameras.  That's the reason Olympus FT DSLRs never succeeded in sport venues because Canon and Nikon have 300-600mm super-tele lenses. Then 2.0x crop has no chance, that's the reason why top wildlife photog are willing to lug around big super-tele lenses to achieve the best possible photos not only in IQ but in resolving fine details.  Sure 2.0x crop or even smaller sensor cameras do have "reach" (or pixel density) advantage in small birding that sometime even 600mm is not long enough.  However FF/APS-H owners could add 1.4x, 1.7x and 2.0x TCs, and can bring out 800mm and with 1.4x TC that still can AF at F8.0, that effectively overcome "reach" shortage and will result better IQ photos.

Anyway in theory I don't disagree with you but that has not been reflected in reality, not yet.  The main reason is lens not sensor.  I'm sure smaller sensors can involve better and better, so do larger sensors.  But the point is glass-based lenses.  It's either impossible or actually no longer smaller/lighter for 2.0x crop manufacturers for example to manufacture 300mm/F2.0 prime, or 400mm/F2.8 or 150mm/F1.4 lenses, in order to overcome 2.0x more crop penalties.

As another person said, crop penalty is real and amount of pixels is also real.  But crop format has much larger impact than amount of pixels that vividly confirmed by DXOMark tests.  We all remember in camcorder optical zoom vs digital zoom, that actually is very similar between crop format (digital zoom) vs longer lens (optical zoom).

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From DPR's 5D and 7D reviews - horisontal/vertical resolution (extinction resolution) :

5D - 2300/2000 (2500/2500) LPH

7D - 2500/2450 (3100/3050) LPH

I am not sure how DPR calculated into above data?  From the same AOV?  Using the same lens? 5D is 8-yr-old and DPR Lab has changed its test environment between when they reviewed 5D and 7D.  I wish DPR can add some old cameras such as 5D into new standard lab samples

They followed standard resolution chart measures.

That's the problem here.. according to DxO's P-Mpix scxore the 5D beats the 7D, but if looking at DPR's resolution test chart shots, then it's rather clear that the 7D has a higher resolution.

The key is that if those paper resolution actually can be seen by normal human eyes?  In those two DXOMark test charts, we can see 7D is only better at MTR 15% and below that are very low contrast and virtually invisible by human eyes.  5D is better above 15% MTF that is more meaningful and matter to human eyes.  It's all about perceptual sharpness (or resolution as DXOmark uses two words interchangeably).

The DxO chart is showing acutance Differences.  Simply looks where the resolution measure on the chart points to. It also shows the extension of resolution beyond 60 lp out to 70lp in advantage to the 7D.  This has been pointed out to you...but you choose to ignore the correction to your misinterpretation because it goes against your bias.

5D vs. 7D is just an example. Think that we'll have a similar 'problem' (acutance/sharpness vs. resolution) if comparing for example 5D3 vs. D800, or if looking at the effect of diffraction when stopping down.

I am sure 41mp Nokia 808 is 41mp on paper or in lab test, it may have 0.5% MTF data higher than 36mp D800 or 2% higher than 22mp 5D3.  The only matter is whether you eyes can see that?  

You keep throwing out this Nokia phone as a red herring to divert attention away from the fact that every chart and photo produced by others and you clearly show the 60D/7D sensor to outresolve the 5D

just to be clear Peter.....the 18mp aps-c sensor offers more resolution than the 5D.  It appears it's only you who refuses to accept it.

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qianp2k
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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to jayrandomer, Apr 14, 2013

jayrandomer wrote:

schmegg wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:/

We can also see that the 7D actually has a higher resolution. The 5D's MTF curve stops at app. 61 lp/mm because it runs out of vertical pixels (app. 61 lp/mm represents the 5D's Nyquist frequency), while the 7D's MTF curve continues to app. 72 lp/mm (on 24 x36mm). The contrast is rather low, but the 7D's resolution is nevertheless higher.

I'd suggest everyone reads these articles to understand these concepts first and understand what that means in real world photos.

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

http://www.imatest.com/docs/sharpness/

From above two DXOMark MTF tests, we can see 7D only extends at MTF 15% or below that virtually invisible by eyes in real world photos even at base ISO when 7D photos buried by higher noises/grains. So that 7D higher resolution (18mp vs 12.8mp from 5D) is only on paper or reflected in larger CR2 file size but unless you have an eagle eye, you just cannot see it

A bit of sharpening makes it easier to see. It's clearly visible if comparing the resolution test chart shots in DPR's 5D and 7D reviews.

a) that depends from shooting distance.  A meaningful test should be done from at least 50x focus-length distance; b) depends on which lens. 7D needs a really good prime such as 100L (85/1.8 is also very nice lens) under perfect neutral gray and grainless/noiseless light condition at base ISO 100; c) doesn't reflect in real-world photos in outdoor harsh light or indoor poor light.

Not 100% sure, but think that DPR uses EF 85/1.8 on Canon FF and EF 50/1.4 on Canon APS-C. Agree that the 5D has better sharpness/contrast/acutance, but the 7D's higher MP count will most often also give it a higher 'resolution' (at least at low ISOs).

As shown in the two snapshots of old MTF charts between 5D and 7D, even with two excellent prime lenses, 100L and 85/1.8, 7D still only outresolves 5D around MTF 15% and below ....

Fail.

It doesn't show that at all. You have a fundamental misunderstanding of what these graphs represent it seems.

It simply shows that the 5D has higher acutance down to around MTF 15% (where it runs out of resolving ability all together and the 7D keeps going) - not that it resolves more! And this is from a raw image that has not been adjusted in post processing at all - it has only a passing bearing on the obtainable final image detail and the test is simply designed to compare lenses on a given camera.

What's unacceptable about comparing two curves at fixed ordinate value?  That is certainly a standard way of using graphical information.  It may not be the way the data were generated, which is typically by measuring (or calculating) the acutance at a given resolution, but the ability to compare curves at fixed ordinate values is one of the reasons scientists and engineers employ graphs in the first place.

Agreed.

In other words, if one asks the question, "what is the maximum resolution which has a minimum MTF of 15%?" the value assigned for the 5d would indeed be larger than the value assigned for the 7d.  What he says is correct given his caveat of 15% MTF.  If he had said, "the 5D has higher resolution than the 5D" without such a caveat he would have failed, but we already know that the absolute resolution of the 7D is higher than the 5D simply from the number of pixels.

To me it's only matter if my eyes actually can see (resolve) otherwise "paper" resolution (if merely judged by amount of pixels) is meaningless.  I am the one think DXOMark Perceptual Sharpness (or Resolution) makes sense.

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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to qianp2k, Apr 14, 2013

qianp2k wrote:

Steen Bay wrote:

From DPR's 5D and 7D reviews - horisontal/vertical resolution (extinction resolution) :

5D - 2300/2000 (2500/2500) LPH

7D - 2500/2450 (3100/3050) LPH

I am not sure how DPR calculated into above data?  From the same AOV?  Using the same lens? Under that MTF percentage? 5D is 8-yr-old and DPR Lab has changed its test environment between when they reviewed 5D and 7D.  I wish DPR can add some old cameras such as 5D into new standard lab samples

Like I said, then I think that DPR uses the EF 85/1.8 on Canon FF and the 50/1.4 on Canon APS-C. The studio scene has changed since the 5D review, but think that the same resolution test chart was used for 5D and 7D. The AoV (or rather the framing) was of course the same, and they 'calculated' (or rather 'estimated') the resolution figures by simply looking at the testshots (at least 100% view on the monitor, I suppose). You can take a look at the resolution test shots yourself. They are available for download (Page 31 in the 5D review and page 28-29 in the 7D review).

That's the problem here.. according to DxO's P-Mpix scxore the 5D beats the 7D, but if looking at DPR's resolution test chart shots, then it's rather clear that the 7D has a higher resolution.

The key is that if those paper resolution actually can be seen by normal human eyes?  In those two DXOMark test charts with very nice prime lenses 100L and 85/1.8 (no mention inferior lenses), we can see 7D is only better at MTR 15% and below (even lower with inferior lenses) that are very low contrast and virtually invisible by human eyes even under grainless/noiseless lab environment (no mention in imperfect real-world environment .  5D is better above 15% MTF that is more meaningful and matter to human eyes.  It's all about perceptual sharpness or perceptual resolution as DXOmark uses two words interchangeably.

5D vs. 7D is just an example. Think that we'll have a similar 'problem' (acutance/sharpness vs. resolution) if comparing for example 5D3 vs. D800, or if looking at the effect of diffraction when stopping down.

I am sure 41mp Nokia 808 is 41mp on paper. In lab test, it may has 1% MTF data higher than 36mp D800 or 2% higher than 22mp 5D3.  The only matter is whether you eyes can actually see that?    If you eyes unable to tell, then those paper resolution is meaningless that you can think but you cannot see, heeh.

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qianp2k
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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to Steen Bay, Apr 14, 2013

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

From DPR's 5D and 7D reviews - horisontal/vertical resolution (extinction resolution) :

5D - 2300/2000 (2500/2500) LPH

7D - 2500/2450 (3100/3050) LPH

I am not sure how DPR calculated into above data?  From the same AOV?  Using the same lens? Under that MTF percentage? 5D is 8-yr-old and DPR Lab has changed its test environment between when they reviewed 5D and 7D.  I wish DPR can add some old cameras such as 5D into new standard lab samples

Like I said, then I think that DPR uses the EF 85/1.8 on Canon FF and the 50/1.4 on Canon APS-C. The studio scene has changed since the 5D review, but think that the same resolution test chart was used for 5D and 7D. The AoV (or rather the framing) was of course the same, and they 'calculated' (or rather 'estimated') the resolution figures by simply looking at the testshots (at least 100% view on the monitor, I suppose). You can take a look at the resolution test shots yourself. They are available for download (Page 31 in the 5D review and page 28-29 in the 7D review).

Sure.  I downloaded both JPEG (if original RAWs are available?), and then compare them side by side.  Honestly my eyes don't see much difference except 7D one is bigger and darker.  As I said we need to compare them side by side at the same size either by upsampling 5D to 7D file szie or downamping 7D file to 5D size otherwise different sizes will cause delusion.   Here is one of snapshots comparing them side by side at their respective full size, and I don't see much difference.  My eyes can count same numbers of lines or cannot count the same fine details that unable to figure out

No mention DPR used different lenses and their AOV are not exact the same if they shoot from the same distance.  From what I see, 5D file is a bit sharper and 7D file shows noticeable purple CA.

That's the problem here.. according to DxO's P-Mpix scxore the 5D beats the 7D, but if looking at DPR's resolution test chart shots, then it's rather clear that the 7D has a higher resolution.

The key is that if those paper resolution actually can be seen by normal human eyes?  In those two DXOMark test charts with very nice prime lenses 100L and 85/1.8 (no mention inferior lenses), we can see 7D is only better at MTR 15% and below (even lower with inferior lenses) that are very low contrast and virtually invisible by human eyes even under grainless/noiseless lab environment (no mention in imperfect real-world environment .  5D is better above 15% MTF that is more meaningful and matter to human eyes.  It's all about perceptual sharpness or perceptual resolution as DXOmark uses two words interchangeably.

5D vs. 7D is just an example. Think that we'll have a similar 'problem' (acutance/sharpness vs. resolution) if comparing for example 5D3 vs. D800, or if looking at the effect of diffraction when stopping down.

I am sure 41mp Nokia 808 is 41mp on paper. In lab test, it may has 1% MTF data higher than 36mp D800 or 2% higher than 22mp 5D3.  The only matter is whether you eyes can actually see that?    If you eyes unable to tell, then those paper resolution is meaningless that you can think but you cannot see, heeh.

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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to qianp2k, Apr 14, 2013

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

From DPR's 5D and 7D reviews - horisontal/vertical resolution (extinction resolution) :

5D - 2300/2000 (2500/2500) LPH

7D - 2500/2450 (3100/3050) LPH

I am not sure how DPR calculated into above data?  From the same AOV?  Using the same lens? Under that MTF percentage? 5D is 8-yr-old and DPR Lab has changed its test environment between when they reviewed 5D and 7D.  I wish DPR can add some old cameras such as 5D into new standard lab samples

Like I said, then I think that DPR uses the EF 85/1.8 on Canon FF and the 50/1.4 on Canon APS-C. The studio scene has changed since the 5D review, but think that the same resolution test chart was used for 5D and 7D. The AoV (or rather the framing) was of course the same, and they 'calculated' (or rather 'estimated') the resolution figures by simply looking at the testshots (at least 100% view on the monitor, I suppose). You can take a look at the resolution test shots yourself. They are available for download (Page 31 in the 5D review and page 28-29 in the 7D review).

Sure.  I downloaded both JPEG (if original RAWs are available?), and then compare them side by side.  Honestly my eyes don't see much difference except 7D one is bigger and darker.  As I said we need to compare them side by side at the same size either by upsampling 5D to 7D file szie or downamping 7D file to 5D size otherwise different sizes will cause delusion.   Here is one of snapshots comparing them side by side at their respective full size, and I don't see much difference.  My eyes can count same numbers of lines or cannot count the same fine details that unable to figure out

Well, you'll have to look at the finer lines where the difference will be rather clear (see for example around '24', which represents 2400 LPH).

No mention DPR used different lenses and their AOV are not exact the same if they shoot from the same distance.  From what I see, 5D file is a bit sharper and 7D file shows noticeable purple CA.

That's the problem here.. according to DxO's P-Mpix scxore the 5D beats the 7D, but if looking at DPR's resolution test chart shots, then it's rather clear that the 7D has a higher resolution.

The key is that if those paper resolution actually can be seen by normal human eyes?  In those two DXOMark test charts with very nice prime lenses 100L and 85/1.8 (no mention inferior lenses), we can see 7D is only better at MTR 15% and below (even lower with inferior lenses) that are very low contrast and virtually invisible by human eyes even under grainless/noiseless lab environment (no mention in imperfect real-world environment .  5D is better above 15% MTF that is more meaningful and matter to human eyes.  It's all about perceptual sharpness or perceptual resolution as DXOmark uses two words interchangeably.

5D vs. 7D is just an example. Think that we'll have a similar 'problem' (acutance/sharpness vs. resolution) if comparing for example 5D3 vs. D800, or if looking at the effect of diffraction when stopping down.

I am sure 41mp Nokia 808 is 41mp on paper. In lab test, it may has 1% MTF data higher than 36mp D800 or 2% higher than 22mp 5D3.  The only matter is whether you eyes can actually see that?    If you eyes unable to tell, then those paper resolution is meaningless that you can think but you cannot see, heeh.

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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to Steen Bay, Apr 14, 2013

Their final rez figures show a higher resolving power for the 7D.  Keep in mind, no matter how many tests and photos you produce, Peter will argue anyway.

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Re: true and 14-24 on d800 only scores 17
In reply to MAC, Apr 14, 2013

MAC wrote:

Mako2011 wrote:

Just another Canon shooter wrote:

BTW, the real test should be at equivalent FL and equivalent f-stops with common lenses.

When comparing resolution across formats you have to keep the subject distance constant. DxO apparently doesn't do that. Might be a source of some of their inconsistencies

true !

Wrong, actually. They have one chart. When they test equivalent FL's they shoot from the same distance. There is a reason equivalence is call that way.

BTW the slanted edge test does not feel the distance differences too much.

I do not see any inconsistencies. Their MTF data perfectly confirm what the theory predicts. It is funny how some people (not you) dismiss both the theory and the experimental data.

Too bad they replaced the MTF charts with the meaningless one number tells it all metric.

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True that
In reply to Just another Canon shooter, Apr 14, 2013

Just another Canon shooter wrote:

MAC wrote:

Mako2011 wrote:

Just another Canon shooter wrote:

BTW, the real test should be at equivalent FL and equivalent f-stops with common lenses.

When comparing resolution across formats you have to keep the subject distance constant. DxO apparently doesn't do that. Might be a source of some of their inconsistencies

true !

Wrong, actually. They have one chart. When they test equivalent FL's they shoot from the same distance.

Actually not the case at all when they test lens. They do shoot from different distances depending on format. Strange of them. Might be why the no longer publish the charts as well.  Hard to explain their methodology of late.


Too bad they replaced the MTF charts with the meaningless one number tells it all metric.

True that.

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Re: Return of Interesting article on DxO about 5D III and D800...
In reply to Steen Bay, Apr 14, 2013

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

From DPR's 5D and 7D reviews - horisontal/vertical resolution (extinction resolution) :

5D - 2300/2000 (2500/2500) LPH

7D - 2500/2450 (3100/3050) LPH

I am not sure how DPR calculated into above data?  From the same AOV?  Using the same lens? Under that MTF percentage? 5D is 8-yr-old and DPR Lab has changed its test environment between when they reviewed 5D and 7D.  I wish DPR can add some old cameras such as 5D into new standard lab samples

Like I said, then I think that DPR uses the EF 85/1.8 on Canon FF and the 50/1.4 on Canon APS-C. The studio scene has changed since the 5D review, but think that the same resolution test chart was used for 5D and 7D. The AoV (or rather the framing) was of course the same, and they 'calculated' (or rather 'estimated') the resolution figures by simply looking at the testshots (at least 100% view on the monitor, I suppose). You can take a look at the resolution test shots yourself. They are available for download (Page 31 in the 5D review and page 28-29 in the 7D review).

Sure.  I downloaded both JPEG (if original RAWs are available?), and then compare them side by side.  Honestly my eyes don't see much difference except 7D one is bigger and darker.  As I said we need to compare them side by side at the same size either by upsampling 5D to 7D file szie or downamping 7D file to 5D size otherwise different sizes will cause delusion.   Here is one of snapshots comparing them side by side at their respective full size, and I don't see much difference.  My eyes can count same numbers of lines or cannot count the same fine details that unable to figure out

Well, you'll have to look at the finer lines where the difference will be rather clear (see for example around '24', which represents 2400 LPH).

I am sorry but that not clear to me.  As I said they need to compare at the same size.

No mention DPR used different lenses and their AOV are not exact the same if they shoot from the same distance.  From what I see, 5D file is a bit sharper and 7D file shows noticeable purple CA.

And use the same lens in the exact same AOV.  I believe DXOMark tests are more controlled and more accurately.  DPR used two different lenses to make their tests largely irrelevant.

According to DXOMark by checking Measurement | Sharpness | FieldMap, to my eyes 50/1.4 performs noticeably better than 85/1.8 between 5D vs 7D.  So that shows DPR gave a favor to 7D with 50/1.4 over 5D with 85/1.4!  Therefore DPR tests with two different lenses are really invalid.

DXOMark 5D vs 7D with the same 85/1.8 lens

DXOMark 5D vs 7D with the same 50/1.4 lens

DXOMark 5D+85/1.8 vs 7D+50/1.4

In my real-world tests especially outdoor, I simply don't see my 60D has an advantage in resolving fine details than 5D in shots of the school building.  Honestly please download and check these original CR2 files and analysis by yourself and compare them at the same sizes by either upsampling 5D files to 60D sizes or downsampling 60D files to 5D sizes thru Photoshop Bicubic enlargement/reduction.  They need to be compared at the same sizes, period.

https://drive.google.com/folderview?id=0B3MrYp_nWjPGMW9pS050UVhCZzQ&usp=sharing

You can see whatever you want to see.  But I have to follow my eyes honestly.

That's the problem here.. according to DxO's P-Mpix scxore the 5D beats the 7D, but if looking at DPR's resolution test chart shots, then it's rather clear that the 7D has a higher resolution.

The key is that if those paper resolution actually can be seen by normal human eyes?  In those two DXOMark test charts with very nice prime lenses 100L and 85/1.8 (no mention inferior lenses), we can see 7D is only better at MTR 15% and below (even lower with inferior lenses) that are very low contrast and virtually invisible by human eyes even under grainless/noiseless lab environment (no mention in imperfect real-world environment .  5D is better above 15% MTF that is more meaningful and matter to human eyes.  It's all about perceptual sharpness or perceptual resolution as DXOmark uses two words interchangeably.

5D vs. 7D is just an example. Think that we'll have a similar 'problem' (acutance/sharpness vs. resolution) if comparing for example 5D3 vs. D800, or if looking at the effect of diffraction when stopping down.

I am sure 41mp Nokia 808 is 41mp on paper. In lab test, it may has 1% MTF data higher than 36mp D800 or 2% higher than 22mp 5D3.  The only matter is whether you eyes can actually see that?    If you eyes unable to tell, then those paper resolution is meaningless that you can think but you cannot see, heeh.

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Just another Canon shooter
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Re: True that
In reply to Mako2011, Apr 14, 2013

Mako2011 wrote:

Just another Canon shooter wrote:

MAC wrote:

Mako2011 wrote:

Just another Canon shooter wrote:

BTW, the real test should be at equivalent FL and equivalent f-stops with common lenses.

When comparing resolution across formats you have to keep the subject distance constant. DxO apparently doesn't do that. Might be a source of some of their inconsistencies

true !

Wrong, actually. They have one chart. When they test equivalent FL's they shoot from the same distance.

Actually not the case at all when they test lens. They do shoot from different distances depending on format. Strange of them. Might be why the no longer publish the charts as well.  Hard to explain their methodology of late.

The distance depends on the FOV, not on the format. Equivalent FL = same FOV = same distance to the same target.

Note that I am talking about equivalent lenses, not about the same lens.

DXO

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Re: True that
In reply to Mako2011, Apr 14, 2013

Mako2011 wrote:

Just another Canon shooter wrote:

MAC wrote:

Mako2011 wrote:

Just another Canon shooter wrote:

BTW, the real test should be at equivalent FL and equivalent f-stops with common lenses.

When comparing resolution across formats you have to keep the subject distance constant. DxO apparently doesn't do that. Might be a source of some of their inconsistencies

true !

Wrong, actually. They have one chart. When they test equivalent FL's they shoot from the same distance.

Actually not the case at all when they test lens. They do shoot from different distances depending on format. Strange of them. Might be why the no longer publish the charts as well.  Hard to explain their methodology of late.

They also shoot from different distances depending on the FL when testing lenses on FF. Is that unfair? What else should they do? The 300/2.8L II doesn't seem to suffer much from the greater distance.


Too bad they replaced the MTF charts with the meaningless one number tells it all metric.

True that.

Fortunately, in sharpness/profiles we can also see the "Acutance for use case in %" (whatever that's supposed to mean..) across the frame at different FLs and f-stops.

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Mako2011
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resolution
In reply to Just another Canon shooter, Apr 14, 2013

Just another Canon shooter wrote:

The distance depends on the FOV, not on the format. Equivalent FL = same FOV = same distance to the same target.

Note that I am talking about equivalent lenses, not about the same lens.

We were discussing resolution. To compare resolution across different sensor formats accurately...you have to maintain the same distance to target or your resolution results will not be comparable.

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unfortunately...
In reply to qianp2k, Apr 14, 2013

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

From DPR's 5D and 7D reviews - horisontal/vertical resolution (extinction resolution) :

5D - 2300/2000 (2500/2500) LPH

7D - 2500/2450 (3100/3050) LPH

I am not sure how DPR calculated into above data?  From the same AOV?  Using the same lens? Under that MTF percentage? 5D is 8-yr-old and DPR Lab has changed its test environment between when they reviewed 5D and 7D.  I wish DPR can add some old cameras such as 5D into new standard lab samples

Like I said, then I think that DPR uses the EF 85/1.8 on Canon FF and the 50/1.4 on Canon APS-C. The studio scene has changed since the 5D review, but think that the same resolution test chart was used for 5D and 7D. The AoV (or rather the framing) was of course the same, and they 'calculated' (or rather 'estimated') the resolution figures by simply looking at the testshots (at least 100% view on the monitor, I suppose). You can take a look at the resolution test shots yourself. They are available for download (Page 31 in the 5D review and page 28-29 in the 7D review).

Sure.  I downloaded both JPEG (if original RAWs are available?), and then compare them side by side.  Honestly my eyes don't see much difference except 7D one is bigger and darker.  As I said we need to compare them side by side at the same size either by upsampling 5D to 7D file szie or downamping 7D file to 5D size otherwise different sizes will cause delusion.   Here is one of snapshots comparing them side by side at their respective full size, and I don't see much difference.  My eyes can count same numbers of lines or cannot count the same fine details that unable to figure out

Well, you'll have to look at the finer lines where the difference will be rather clear (see for example around '24', which represents 2400 LPH).

I am sorry but that not clear to me.

...never a more accurate and descriptive statement has been written. If you can't understand or see the difference at 2400 LPH in the examples...then the rest may be just out of reach. Are you viewing on a very low resolution monitor? That may be part of the issue or barrier to understanding. I wish real high quality CRT's would make a comeback.

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I'm still not understanding what he's said that's wrong
In reply to schmegg, Apr 14, 2013

schmegg wrote:

Nothing at all wrong with graphing data and comparing it.

When he said .. "7D still only outresolves 5D around MTF 15% and below", I take that to ipso-facto imply that he believes the graphs show that the 5D out-resolves the 7D above MTF15.

So, what is wrong though is that those graphs don't show what he claims. What they show is that the 5D, at almost all levels of detail it is capable of resolving, will have higher acutance than a 7D at the same level of detail. They do not, however, show that the 5D out-resolves the 7D - as he claimed.

I took his statement to mean, given a minimum value of acutance (presumably what he deems as acceptable), the resolution at which the 5d reaches that value is higher in resolution than the 7d.  In other words, if I were to draw a line from at a constant 15%, I would intersect the 7d curve before the 5d curve.  One would say that, given the constraint of at least 15% MTF, the 5d achieves higher resolution (in this particular test).

In other words, if I took a test shot, made everything within 15% of middle grey grey, everything above white, and everything below black, and then tried to find the highest resolution lines, I would find more on the 5d image than the 7d image.  A contrived situation, for sure, but given the evidence from those MTF charts that statement seems correct.  Is that not the case?

From those graphs it can be seen that the 5D runs out of resolving capability at just above 60 lp/mm, whereas the 7D continues to record detail up to and beyond 70 lp/mm. The acutance is lower, but the detail is still recorded on the 7D whereas it isn't on the 5D. So, in fact, the graphs show the opposite to his claims - that the 7D out-resolves the 5D, albeit with lower acutance as lens quality drops. (It'd be interesting to see the 300/2.8L II, for instance, as even the 100 macro is very close in terms of acutance).

I think everyone agrees the resolution of the 7d will be higher than the 5d, because it has more pixels.  That's not the statement I was confirming.  Perhaps not everyone does, in which case I'm sorry.

However, acutance is not fixed at capture time like resolution is. It can be, and usually is, modified in post processing. And this is not considered at all in the MTF data because it is concerned with showing the relative sharpness of different lenses on a given camera - and changing acuity in post processing is of no relevance for the purpose of comparing lens sharpness. So not only do the graphs not tell the whole story, but they also show the opposite of what he claimed they show.

Are you saying restricting acutance to a certain threshold to determine "maximum resolution" is not appropriate?  That somewhat subtler argument is not one I can disagree with.

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Re: unfortunately...
In reply to Mako2011, Apr 14, 2013

Mako2011 wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

qianp2k wrote:

Steen Bay wrote:

From DPR's 5D and 7D reviews - horisontal/vertical resolution (extinction resolution) :

5D - 2300/2000 (2500/2500) LPH

7D - 2500/2450 (3100/3050) LPH

I am not sure how DPR calculated into above data?  From the same AOV?  Using the same lens? Under that MTF percentage? 5D is 8-yr-old and DPR Lab has changed its test environment between when they reviewed 5D and 7D.  I wish DPR can add some old cameras such as 5D into new standard lab samples

Like I said, then I think that DPR uses the EF 85/1.8 on Canon FF and the 50/1.4 on Canon APS-C. The studio scene has changed since the 5D review, but think that the same resolution test chart was used for 5D and 7D. The AoV (or rather the framing) was of course the same, and they 'calculated' (or rather 'estimated') the resolution figures by simply looking at the testshots (at least 100% view on the monitor, I suppose). You can take a look at the resolution test shots yourself. They are available for download (Page 31 in the 5D review and page 28-29 in the 7D review).

Sure.  I downloaded both JPEG (if original RAWs are available?), and then compare them side by side.  Honestly my eyes don't see much difference except 7D one is bigger and darker.  As I said we need to compare them side by side at the same size either by upsampling 5D to 7D file szie or downamping 7D file to 5D size otherwise different sizes will cause delusion.   Here is one of snapshots comparing them side by side at their respective full size, and I don't see much difference.  My eyes can count same numbers of lines or cannot count the same fine details that unable to figure out

Well, you'll have to look at the finer lines where the difference will be rather clear (see for example around '24', which represents 2400 LPH).

I am sorry but that not clear to me.

...never a more accurate and descriptive statement has been written. If you can't understand or see the difference at 2400 LPH in the examples...then the rest may be just out of reach. Are you viewing on a very low resolution monitor? That may be part of the issue or barrier to understanding. I wish real high quality CRT's would make a comeback.

You obviously didn't answer on my points:

a) DPR used different lenses so two "resolution" they tested ONLY can be read independently but not link them together for a comparison.  You cannot compare apple to orange;

b) According to DxOmark tests, 7D performs noticeably better with 50/1.4 than with 85/1.8.  DPR gave 7D a favor with 50/1.4 over 5D with 85/1.8, hope that is clear to you;

c) DPR didn't test from the same AOV (when they shoot from the same distance  and didn't publish CR2 files so I can either upsampling 5D to 7D size or downsmapling 7D to 5D size thru PS bicubic enlargement/reduction.  You cannot compare them at different sizes.  Do you compare 30x20" to 26x18" prints?

Although I don't doubt DPR tests on those setup separately but simply you cannot link them for a comparison on the reasons I said above, period.

Again you see whatever you want to see but not everyone shares your vision, however

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In reply to qianp2k, Apr 14, 2013

qianp2k wrote:

Mako2011 wrote:

qianp2k wrote:

Steen Bay wrote:

Well, you'll have to look at the finer lines where the difference will be rather clear (see for example around '24', which represents 2400 LPH).

I am sorry but that not clear to me.

...never a more accurate and descriptive statement has been written. If you can't understand or see the difference at 2400 LPH in the examples...then the rest may be just out of reach. Are you viewing on a very low resolution monitor? That may be part of the issue or barrier to understanding. I wish real high quality CRT's would make a comeback.

You obviously didn't answer on my points:

No need/value. The problem was already clear/obvious so that would have to be addressed first before anything else could move forward. No point in giving directions to the nearest pizza joint if we don't know where you are. Have to first figure out why your having clarity issues before things can clear up. You have to first get to a point where you understand the "example around '24', which represents 2400 LPH" .

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Re: I'm still not understanding what he's said that's wrong
In reply to jayrandomer, Apr 14, 2013

jayrandomer wrote:

schmegg wrote:

Nothing at all wrong with graphing data and comparing it.

When he said .. "7D still only outresolves 5D around MTF 15% and below", I take that to ipso-facto imply that he believes the graphs show that the 5D out-resolves the 7D above MTF15.

So, what is wrong though is that those graphs don't show what he claims. What they show is that the 5D, at almost all levels of detail it is capable of resolving, will have higher acutance than a 7D at the same level of detail. They do not, however, show that the 5D out-resolves the 7D - as he claimed.

I took his statement to mean, given a minimum value of acutance (presumably what he deems as acceptable), the resolution at which the 5d reaches that value is higher in resolution than the 7d.  In other words, if I were to draw a line from at a constant 15%, I would intersect the 7d curve before the 5d curve.  One would say that, given the constraint of at least 15% MTF, the 5d achieves higher resolution (in this particular test).

Yes.

In other words, if I took a test shot, made everything within 15% of middle grey grey, everything above white, and everything below black, and then tried to find the highest resolution lines, I would find more on the 5d image than the 7d image.  A contrived situation, for sure, but given the evidence from those MTF charts that statement seems correct.  Is that not the case?

That is correct. However, both cameras are still resolving detail at 60lp/mm, the only difference being acutance. By 70lp/mm the 5D is no longer resolving but the 7D is still resolving - therefore the graphs show the 7D out-resolves the 5D.

From those graphs it can be seen that the 5D runs out of resolving capability at just above 60 lp/mm, whereas the 7D continues to record detail up to and beyond 70 lp/mm. The acutance is lower, but the detail is still recorded on the 7D whereas it isn't on the 5D. So, in fact, the graphs show the opposite to his claims - that the 7D out-resolves the 5D, albeit with lower acutance as lens quality drops. (It'd be interesting to see the 300/2.8L II, for instance, as even the 100 macro is very close in terms of acutance).

I think everyone agrees the resolution of the 7d will be higher than the 5d, because it has more pixels.  That's not the statement I was confirming.  Perhaps not everyone does, in which case I'm sorry.

That's fine - no problem. I didn't take it that you were 'having a go' at me.

I'm pretty sure most people in this discussion, including yourself, already understand what I was attempting to explain. It was really meant for the benefit of people who are reading this thread and don't yet understand what MTF graphs are - as some of the claims made by one person in particular seem to be based upon a misunderstanding.

However, acutance is not fixed at capture time like resolution is. It can be, and usually is, modified in post processing. And this is not considered at all in the MTF data because it is concerned with showing the relative sharpness of different lenses on a given camera - and changing acuity in post processing is of no relevance for the purpose of comparing lens sharpness. So not only do the graphs not tell the whole story, but they also show the opposite of what he claimed they show.

Are you saying restricting acutance to a certain threshold to determine "maximum resolution" is not appropriate?  That somewhat subtler argument is not one I can disagree with.

Well, in terms of which of two sensors will resolve more, yes I am. If, for instance, you are interested in particular in detail at around the 70lp/mm frequency, then choosing a 5D would be futile, whereas a 7D will still give you some hope of recovering that detail as at least it will have been recorded, albeit at very low acutance. (remember, acutance is not fixed at capture time - the MTF graphs are for comparing sharpness delivered by different lenses on a given body, not for determining final image sharpness).

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Just another Canon shooter
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Re: resolution
In reply to Mako2011, Apr 14, 2013

Mako2011 wrote:

Just another Canon shooter wrote:

The distance depends on the FOV, not on the format. Equivalent FL = same FOV = same distance to the same target.

Note that I am talking about equivalent lenses, not about the same lens.

We were discussing resolution. To compare resolution across different sensor formats accurately...you have to maintain the same distance to target or your resolution results will not be comparable.

When you shoot with equivalent FL's, you do shoot from the same distance.

BTW, even if you don't, the results will be comparable. Read the Imatest explanations. But this is off topic anyway.

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In reply to Just another Canon shooter, Apr 14, 2013

Just another Canon shooter wrote:

Mako2011 wrote:

Just another Canon shooter wrote:

The distance depends on the FOV, not on the format. Equivalent FL = same FOV = same distance to the same target.

Note that I am talking about equivalent lenses, not about the same lens.

We were discussing resolution. To compare resolution across different sensor formats accurately...you have to maintain the same distance to target or your resolution results will not be comparable.

When you shoot with equivalent FL's, you do shoot from the same distance.

Yes...for example... 40mm f/4 1/100 ISO 200 on 4/3 is equivalent to 50mm f/5 1/100 ISO 320 on 1.6x which is equivalent to 80mm f/8 1/100 ISO 800 on FF when the photos of the same scene are taken from the same position and displayed at the same size.

Not sure our friends at DxO are so picky

BTW, even if you don't, the results will be comparable.

Not when comparing resolution across different formats.

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