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Author Topic: Interesting Comparison  (Read 18849 times)
fike
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« Reply #20 on: December 15, 2008, 12:29:42 PM »
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Quote from: ErikKaffehr
;-) (Re. permanence)

I like to print big, and I like to print detailed.  I typically think of a scenario where the person views the image from a meter or two and then walks in close to inspect it more closely...perhaps from 6 inches.

LCDs and Plasmas are beautiful but don't hold up to this kind of close inspection.  I have a mosaic stitched print that is made in three 24" wide strips. The overall print is 6 feet wide by 4 feet tall.  You can see people in the image that are less than 3mm high.

As for permanence, I am not sold on the temporary LCD/Plasma displays.  I guess I am just old fashioned.  

so, for long-lens detail capture, I think the 50D may be superior to the 5DMkII under ideal conditions or on a tripod.
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« Reply #21 on: December 15, 2008, 02:35:45 PM »
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Good observation, Ray!

On the whole the 5DII is probably better than the 20D, I'd guess, due to weaker antialiasing filter. Have you seen this page:

http://www.wlcastleman.com/equip/reviews/40D/index.htm ?

BTW, my Sony SAL 24-70/2.8 ZA is on the mail to my great surprise so I guess I can post some findings after the weekend on that lens on the Sony Alpha 900.

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Quote from: Ray
DXOmark has some interesting information comparing the 20D with the 5D2, which I understand is at the pixel level. According to their graphs, SNR of the 5D2 at ISO 1600 is just 1.4db better than the 20D. That doesn't sound much, especially when you consider that ISO 1600 on the 5D2 is actually ISO 1093 and on the 20D actually ISO 1333. In other words, I take a fully exposed shot with the 20D at ISO 1600, then take the same shot with the same lens on the 5D2, using the same exposure at ISO 1600, crop the 5D2 image to the same FoV as the 20D shot, and that 1.4db S/N advantage disappears because the 5D2 shot is slightly underexposed.
« Last Edit: December 15, 2008, 02:38:09 PM by ErikKaffehr » Logged

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« Reply #22 on: December 15, 2008, 07:15:13 PM »
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Quote from: fike
The 1.4x teleconverter is a decent idea, but again, that is a decrease in image quality and a loss of a single stop of light.  Will this cancel out the benefit of the improved body/sensor? Would there be unacceptable increased vignettingand distortion more obviously displayed by the full frame sensor and further exacerbated by the teleconverter.  

So an interesting hypothesis to test would be:

The 5dMkII with a 1.4x teleconverter has equivalent resolution and quality to a 20/30D without teleconverter???

Off thread topic but I have the Canon 1.4 txII and there is no evidence of reduced image quality when used with a quality lens such as the 500/4. Reduced IQ with the 1.4 and 2x tc on a quality lens has everything to do with long-lens technique and very little to do with glass.
« Last Edit: December 15, 2008, 07:15:35 PM by John Chardine » Logged

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« Reply #23 on: December 16, 2008, 08:01:45 AM »
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Quote from: John Chardine
Off thread topic but I have the Canon 1.4 txII and there is no evidence of reduced image quality when used with a quality lens such as the 500/4. Reduced IQ with the 1.4 and 2x tc on a quality lens has everything to do with long-lens technique and very little to do with glass.

I have observed some decrease in sharpness when using the teleconverter.  I think my bigger problem with the 1.4 tele is that with my 100-400 f/4.5-5.6 and my 30D, it doesn't have autofocus.  That is a big issue for me, particularly when I am shooting birds or something.  With the 5DMkII body I would be able to focus with the combo though.  

Again, as someone else mentioned, I think an interesting comparison would be 5dMkII with a 400mm lens and 1.4x teleconverter compared to the 50D with the same lens and no teleconverter.
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« Reply #24 on: December 16, 2008, 10:06:01 AM »
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if you have good light, the 100-400 will autofocus slowly with the last 3 pins taped on the lens and the 1.4x
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« Reply #25 on: December 16, 2008, 02:47:30 PM »
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Quote from: stever
if you have good light, the 100-400 will autofocus slowly with the last 3 pins taped on the lens and the 1.4x

Yes, I have messed with that.  Unfortunately, it isn't fast enough for birds.
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« Reply #26 on: December 16, 2008, 03:23:17 PM »
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Quote from: fike
Again, as someone else mentioned, I think an interesting comparison would be 5dMkII with a 400mm lens and 1.4x teleconverter compared to the 50D with the same lens and no teleconverter.

The 5D2 with 1.4x extender, after cropping the image in post processing, would have very similar resolution to a 50D without extender. I wouldn't like to predict which image, at the extreme pixel-peeping level, would be better, but I'm fairly confident that the differences would be too small to worry about.

The problem with the Canon 100-400 IS, is that it's not at its sharpest at F5.6. (It least my copy isn't, and I believe my copy is fairly typical and also not one of the early copies). This means, when the best resolution is a priority, one feels compelled to use F8 at 400mm. With a 1.4x extender, F8 becomes F11, so right away there is a penalty...no autofous and also the need for a slower shutter speed or a higher ISO. That also means that any noise advantage the 5D2 might have (compared with the 50D without extender) is wiped out.
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« Reply #27 on: December 16, 2008, 05:57:32 PM »
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Quote from: Ray
The 5D2 with 1.4x extender, after cropping the image in post processing, would have very similar resolution to a 50D without extender. I wouldn't like to predict which image, at the extreme pixel-peeping level, would be better, but I'm fairly confident that the differences would be too small to worry about.

The problem with the Canon 100-400 IS, is that it's not at its sharpest at F5.6. (It least my copy isn't, and I believe my copy is fairly typical and also not one of the early copies). This means, when the best resolution is a priority, one feels compelled to use F8 at 400mm. With a 1.4x extender, F8 becomes F11, so right away there is a penalty...no autofous and also the need for a slower shutter speed or a higher ISO. That also means that any noise advantage the 5D2 might have (compared with the 50D without extender) is wiped out.

I go a little farther. I tend to think that the 100-400 is sharpest at f/11.  Another reason why the 5dMkII quality improvements seem to be a wash when considering the use of long lenses.  But then again, f/11 is around the area where the 50D is considered diffraction limited.
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« Reply #28 on: December 16, 2008, 08:23:26 PM »
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I go a little farther. I tend to think that the 100-400 is sharpest at f/11.  Another reason why the 5dMkII quality improvements seem to be a wash when considering the use of long lenses.  But then again, f/11 is around the area where the 50D is considered diffraction limited.

I used to think my 100-400 was sharpest at F11, probably because any slight misfocussing was less apparent at F11. More careful testing revealed it was actually very marginally sharper at F8, but so close one could consider both F8 and F11 to be about equal. The real advantage of F8 is that it allows the use of a faster shutter speed which, with a telephoto lens, is often essential for a sharp result, even with IS enabled.

The fact is, the use of extenders seems to provide, at best, only marginally more detailed results. They are of dubious value in my opinion.

Here are a few 200% crops using the 100-400 with my 50D. Moving from left to right, (1) 400mm at F8 without extender, (2) F8 with extender, (3) F11 with extender, (4) F16 with extender.

The first image on the left, without extender, was cropped to the FoV of the other images and then interpolated to the same size. All images were sharpened in ACR to the same extent (amount 25, Detail 100%). As you can see, both the F11 and F16 shots with extender are about equal, but are both noticeably better than the F8 shots with and without extender.

I suppose if one were photographing an elephant at that distance, it might be worthwhile using an extender   .

[attachment=10330:Comparis...8_to_F16.jpg]
« Last Edit: December 16, 2008, 08:24:38 PM by Ray » Logged
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« Reply #29 on: December 17, 2008, 09:33:02 AM »
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Quote from: Ray
I used to think my 100-400 was sharpest at F11, probably because any slight misfocussing was less apparent at F11. More careful testing revealed it was actually very marginally sharper at F8, but so close one could consider both F8 and F11 to be about equal. The real advantage of F8 is that it allows the use of a faster shutter speed which, with a telephoto lens, is often essential for a sharp result, even with IS enabled.

The fact is, the use of extenders seems to provide, at best, only marginally more detailed results. They are of dubious value in my opinion.

Here are a few 200% crops using the 100-400 with my 50D. Moving from left to right, (1) 400mm at F8 without extender, (2) F8 with extender, (3) F11 with extender, (4) F16 with extender.

The first image on the left, without extender, was cropped to the FoV of the other images and then interpolated to the same size. All images were sharpened in ACR to the same extent (amount 25, Detail 100%). As you can see, both the F11 and F16 shots with extender are about equal, but are both noticeably better than the F8 shots with and without extender.

I suppose if one were photographing an elephant at that distance, it might be worthwhile using an extender   .

[attachment=10330:Comparis...8_to_F16.jpg]

This is some extreme pixel-peeping, but I will bite.  I thought the most detailed versions were the f/11 and f/16 with 1.4x teleconverter--particularly the f/11.  You are correct in saying that the difference is subtle, but if you focus on the leaves on the sapling tree, you can definitely see more information there.  When I shoot large expanses of leafy landscape, I don't like those leaves to dissolve into an amalgam of mush. I like some definition.  

Now, I still want to see the same comparison with the 5dMkII, 50D and 30D.  Does anyone have that series of cameras to work with.  Unfortunately all the online resolution samples that are done with these cameras are not applicable.  They always fill the frame with the target.  In this scenario, the 5DMkII needs to be moved farther away so that only the portion of the frame that is equivalent to the 1.6x crop factor will be visible.  This eliminates the step of resizing in photoshop or some other tool.
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« Reply #30 on: December 18, 2008, 07:01:57 PM »
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Now, I still want to see the same comparison with the 5dMkII, 50D and 30D.  Does anyone have that series of cameras to work with.  Unfortunately all the online resolution samples that are done with these cameras are not applicable.  They always fill the frame with the target.  In this scenario, the 5DMkII needs to be moved farther away so that only the portion of the frame that is equivalent to the 1.6x crop factor will be visible.  This eliminates the step of resizing in photoshop or some other tool.

It so happens that a 1.4x extender on a 5D2 produces very closely a pixel for pixel comparison with a 50D used without extender. Since the 20D pixel pitch is the same as that of the 5D2, and since the noise characteristics of the 5D2 pixel are very similar to those of the 20D, bearing in mind that at both cameras' nominated ISO values the 20D has an actual ISO which is higher, it becomes possible to simulate the performance of the 5D2 using the 20D.

Since there's a likelihood that I will eventually buy a 5D2 after the initial mad rush is over, I decided to do my own comparisons out of curiosity.

The following shots compare the 20D using a 400mm lens and 1.4x extender, with the 50D using the same 400mm lens without extender. I've used the same aperture of F11 for both shots since I didn't want to give a shutter speed advantage to either of the cameras. As it so happens, the 20D shot is at 1/800 sec as opposed to 1/640th for the 50D, despite the fact that ISO 800 was used for both shots and despite the fact that both shots are equally well exposed.

This confirms other results which indicate that the 20D is more sensitive than later Canon models, including the 5D2. However, that's all right for the purposes of these tests because a 560mm lens needs a faster shutter speed than a 400mm lens.

For those who don't want to bother looking at the following images, the deductions and conclusions are:

(1) When maximum telephoto reach is required, the 5D2 with 1.4x extender will produce detail and sharpness on a par with the 50D without extender, when images are viewd at 100%.

At an extreme pixel-peeping level, at 200% and 300% magnification, the 50D still has the edge, though, and this edge would have been slightly greater if I had used the 50D at F8.

(2) Despite the greater exposure given to the 50D shot at the same ISO, it appears to be noisier that the 20D shot, once again confirming that the smaller 50D pixel really is noisier than the 20D pixel and that total image noise is only equalled when the 50D image is downsampled to the 20D image size (or the 20D image is upsampled).

(3) At the lower edge of the 20D image, nearest the camera, it can be seen that the 20D shot is beginning to lose sharpness due to its shallower DoF. This is more apparent in the corners where the shallower DoF is combined with (I suspect) a fall-off in resolution due to the presence of the converter. In other words, the 560mm lens has poorer edge and corner resolution than the 400mm lens.

It should be noted that introducing an extender always reduces DoF, even when the main lens is at the same aperture. For example, a 400mm lens at F8 becomes a 560mm lens at F11 when a 1.4x extender is used. The DoF of a 560mm lens at F11 is still slightly shallower than a 400mm lens at F8.

[attachment=10394:Full_scene.jpg] [attachment=10395:Comparison_upper.jpg]  [attachment=10396:Comparison_middle.jpg]  [attachment=10397:Comparison_lower.jpg]  [attachment=10399:300__noi...mparison.jpg]  [attachment=10398:300__noi...midtones.jpg]
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« Reply #31 on: December 19, 2008, 06:31:22 AM »
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Quote from: Ray
It so happens that a 1.4x extender on a 5D2 produces very closely a pixel for pixel comparison with a 50D used without extender. Since the 20D pixel pitch is the same as that of the 5D2, and since the noise characteristics of the 5D2 pixel are very similar to those of the 20D, bearing in mind that at both cameras' nominated ISO values the 20D has an actual ISO which is higher, it becomes possible to simulate the performance of the 5D2 using the 20D.

Since there's a likelihood that I will eventually buy a 5D2 after the initial mad rush is over, I decided to do my own comparisons out of curiosity.

The following shots compare the 20D using a 400mm lens and 1.4x extender, with the 50D using the same 400mm lens without extender. I've used the same aperture of F11 for both shots since I didn't want to give a shutter speed advantage to either of the cameras. As it so happens, the 20D shot is at 1/800 sec as opposed to 1/640th for the 50D, despite the fact that ISO 800 was used for both shots and despite the fact that both shots are equally well exposed.

This confirms other results which indicate that the 20D is more sensitive than later Canon models, including the 5D2. However, that's all right for the purposes of these tests because a 560mm lens needs a faster shutter speed than a 400mm lens.

For those who don't want to bother looking at the following images, the deductions and conclusions are:

(1) When maximum telephoto reach is required, the 5D2 with 1.4x extender will produce detail and sharpness on a par with the 50D without extender, when images are viewd at 100%.

At an extreme pixel-peeping level, at 200% and 300% magnification, the 50D still has the edge, though, and this edge would have been slightly greater if I had used the 50D at F8.

(2) Despite the greater exposure given to the 50D shot at the same ISO, it appears to be noisier that the 20D shot, once again confirming that the smaller 50D pixel really is noisier than the 20D pixel and that total image noise is only equalled when the 50D image is downsampled to the 20D image size (or the 20D image is upsampled).

(3) At the lower edge of the 20D image, nearest the camera, it can be seen that the 20D shot is beginning to lose sharpness due to its shallower DoF. This is more apparent in the corners where the shallower DoF is combined with (I suspect) a fall-off in resolution due to the presence of the converter. In other words, the 560mm lens has poorer edge and corner resolution than the 400mm lens.

It should be noted that introducing an extender always reduces DoF, even when the main lens is at the same aperture. For example, a 400mm lens at F8 becomes a 560mm lens at F11 when a 1.4x extender is used. The DoF of a 560mm lens at F11 is still slightly shallower than a 400mm lens at F8.

[attachment=10394:Full_scene.jpg] [attachment=10395:Comparison_upper.jpg]  [attachment=10396:Comparison_middle.jpg]  [attachment=10397:Comparison_lower.jpg]  [attachment=10399:300__noi...mparison.jpg]  [attachment=10398:300__noi...midtones.jpg]


That is a fantastic analysis and a very creative way to compare the cameras without having the 5DMkII to look at.  As is so often the case with pixel-peeping, there is a gnats-@ss of difference when the marketing would have you believe that the difference is dramatic.  

What are you waiting for on that 5dMkII?    I want to see the comparison of it to 20D.  
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« Reply #32 on: December 19, 2008, 06:44:13 AM »
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Quote from: fike
What are you waiting for on that 5dMkII?    I want to see the comparison of it to 20D.  
Robert S. Blum
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« Reply #33 on: December 19, 2008, 08:10:16 AM »
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Quote from: jani
Robert S. Blum
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I've seen those.  They don't make the comparison we are discussing.  What we are discussing is a way to normalize the pixel pitch between the 20/30D generation and the newer 5DMkII generation.  To do this, you would need to have the resolution target on the 5dMkII samples appear smaller in the image so that it only covers the smaller area of the full frame 5dMkII sensor that is covered by an APS-C sensor.  Then, you can compare the quality of the pixels without debating the influence of pixel-pitch.  

This method of analysis is mostly important for people who are shooting telephoto.  If you care about wide angle, this analysis is less pertinent.  As you may be aware, a 400mm lens on an APS-C sensor has the same field of view as a 640mm lens would on a full frame camera.  Because we are trying to compare sensors and you can't easily compare a 400mm lens to a 640mm lens, the alternative way is to crop the 5dMkII image to have the same field of view achieved by the 20D.  This provides an elegant analysis because the pixel pitch and number of megapixels is the same at 8MP for the 20D and for the cropped 5dMkII.
« Last Edit: December 19, 2008, 08:18:22 AM by fike » Logged

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« Reply #34 on: December 19, 2008, 08:49:17 AM »
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Quote from: fike
What are you waiting for on that 5dMkII?    I want to see the comparison of it to 20D.  
 

I doubt whether I would get one before March 2009 if I put in an order today. Also, I'm not keen on being amongst the first to get a new product. There's already a 'black dots' problem which Canon are looking at, isn't there?

The fact is, I'd like a D700, an A900 and a 5D2. I can't afford all three and am totally paralysed   . (Er! with indecision).
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« Reply #35 on: December 19, 2008, 09:42:36 AM »
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Quote from: fike
I've seen those.  They don't make the comparison we are discussing.  What we are discussing is a way to normalize the pixel pitch between the 20/30D generation and the newer 5DMkII generation.  To do this, you would need to have the resolution target on the 5dMkII samples appear smaller in the image so that it only covers the smaller area of the full frame 5dMkII sensor that is covered by an APS-C sensor.  Then, you can compare the quality of the pixels without debating the influence of pixel-pitch.
Essentially, what you're saying could be compressed to:

You want the tester to use the same distance to the chart with both cameras.

So what you need to do, is to get someone with a 5D MkII to print the test chart used for the EOS 20D at imaging-resource.com and photograph it at the same distance as they did for the 20D, under similar lighting conditions.

That ought to be possible.

I only have the 20D and don't plan on buying the 5D MkII, so I can't really help.
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« Reply #36 on: December 19, 2008, 10:00:17 AM »
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Quote from: jani
Essentially, what you're saying could be compressed to:

You want the tester to use the same distance to the chart with both cameras.

So what you need to do, is to get someone with a 5D MkII to print the test chart used for the EOS 20D at imaging-resource.com and photograph it at the same distance as they did for the 20D, under similar lighting conditions.

That ought to be possible.

I only have the 20D and don't plan on buying the 5D MkII, so I can't really help.

Yes, same lens, same distance.  

Determine the distance using the 20/30D and then use the same distance and lens with the 5dMkII.  I am kind of surprised none of the reviewers have thought to do this analysis.  If you really appreciate the added reach that a cropped sensor provides, this really gives you an apples to apples comparison that includes lens range as a factor.
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« Reply #37 on: December 19, 2008, 10:08:12 AM »
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Quote from: jani
Essentially, what you're saying could be compressed to:

You want the tester to use the same distance to the chart with both cameras.

So what you need to do, is to get someone with a 5D MkII to print the test chart used for the EOS 20D at imaging-resource.com and photograph it at the same distance as they did for the 20D, under similar lighting conditions.

That ought to be possible.

I only have the 20D and don't plan on buying the 5D MkII, so I can't really help.

If you use the same lens on both cameras, shoot from the same distance and compare equal size crops, the crops will fairly exactly be comprised of the same number of pixels and you will, in fact, be able to compare noise and resolution at the pixel level without introducing interpolation effects.

However, the issue for me, and I think for fike also, is the possible advantage of carrying a 50D as a second camera for long telephoto work. Carrying a 1.4x extender with the 5D2 could be just as effective, except perhaps for the loss of autofocussing that use of an extender entails with a lens like the Canon 100-400 IS.

On the other hand, if you were to use the 1.4x extender with the 50D instead of the 5D2, you could expect to get a marginally sharper and more detailed result. But just how significant that extra detail would be in practice, or on print, is another matter. I wish I owned a top notch telephoto prime to carry out such comparisons, but unfortunately I don't.
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