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Author Topic: Canon 50D review out  (Read 23541 times)
The View
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« on: October 30, 2008, 04:53:31 PM »
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Dpreview has the review of the 50D out.

http://www.dpreview.com/reviews/canoneos50d/

Main points: no real detail advantage over the 10MP 40D, but 50% larger files.

Worse high ISO performance than the 40D.

The 50D seems to be a victory of the marketing idiots over the photographers and the engineers by pumping unnecessary 15MP into an APS-C sensor.
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DarkPenguin
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« Reply #1 on: October 30, 2008, 05:03:55 PM »
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They've made a few changes to the review since this morning.  (ACR 4.6 instead of ACR 4.6 RC.)  People are still fighting over it.  One claim is that DPP is much better with 50D files than ACR.  I dunno.  I've seen samples where the 50D is markedly better than the 40D but those weren't controlled tests.  So I think I'm hanging on to the 40D for a while.  I would like the better LCD and the improved seals.
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The View
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« Reply #2 on: October 30, 2008, 05:09:28 PM »
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Quote from: DarkPenguin
They've made a few changes to the review since this morning.  (ACR 4.6 instead of ACR 4.6 RC.)  People are still fighting over it.  One claim is that DPP is much better with 50D files than ACR.  I dunno.  I've seen samples where the 50D is markedly better than the 40D but those weren't controlled tests.  So I think I'm hanging on to the 40D for a while.  I would like the better LCD and the improved seals.

Oh yes, every Canon SLR performs much better in DPP than in ACR.

There might be something true about that.

Maybe dpreview should not use ONE  RAW converter for every camera but the best suited RAW converter. For Canon SLRs it's nonsense not to at least include DPP processing (I completely stopped using ACR as DPP results are so much superior).


Anyway, the basic truth of the review might be that engineers and photographers need to have more power than the marketing people.

Marketing people should market what's there in products, not have the power to get products that are easy to market, as it defeats the purpose of marketing: winning customers.


I love Canon SLRs, the character of their images, the colors, the high ISO performance. I hope they'll get back on track and reduce marketing people back to what they are: hired help. And if they can't market good products, they should get the hell out of the business and have smarter people do their job.
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Guillermo Luijk
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« Reply #3 on: October 30, 2008, 05:51:24 PM »
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hehe, dynamic range (Section 19): ISO100: 8.3 EV  ISO1600: 8.5 EV
One day the DPreview guys will find out that the Earth is flat.

The RAW noise comparision 40D vs 50D (Section 18) seems strange. Despite the higher resolution of the 50D sensor, if the test was done properly the results for the 50D are very disappointing.

BR
« Last Edit: October 30, 2008, 05:54:41 PM by GLuijk » Logged

The View
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« Reply #4 on: October 30, 2008, 07:09:26 PM »
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Quote from: GLuijk
One day the DPreview guys will find out that the Earth is flat.

BR

If they step too close to the edge, they'll find out there's no railing.
« Last Edit: October 30, 2008, 07:09:49 PM by The View » Logged

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Panopeeper
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« Reply #5 on: October 30, 2008, 07:16:36 PM »
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The DPReview crew have proven again, that they don't have even a rudimentary understanding of "dynamic range".

At ISO 200 = 400 = 800 = 1600 = 8.5 EV. The three stop loss in the highlights is totally made up by higher ISO gain - is that not great? (forget about the rest)

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Gabor
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« Reply #6 on: October 30, 2008, 07:36:39 PM »
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Quote from: Panopeeper
The DPReview crew have proven again, that they don't have even a rudimentary understanding of "dynamic range".

At ISO 200 = 400 = 800 = 1600 = 8.5 EV. The three stop loss in the highlights is totally made up by higher ISO gain - is that not great? (forget about the rest)
hey Gabor, and they managed to accurately quantify the DR improvement with HTP, not just 1EV, but a fantastic 1.1EV! perhaps you should start using HTP in your panos to prevent the skies from blowing  
« Last Edit: October 30, 2008, 07:36:51 PM by GLuijk » Logged

Graeme Nattress
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« Reply #7 on: October 30, 2008, 07:52:29 PM »
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You can't properly measure dynamic range without looking at the raw sensor data in linear light. To try and do it off a JPEG will lead to vastly misleading results, and doing it of RAW in ACR trying to get a "best curve" is nearly as bad. At least they use a test wedge.

Graeme
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Panopeeper
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« Reply #8 on: October 30, 2008, 08:12:06 PM »
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Quote from: Graeme Nattress
You can't properly measure dynamic range without looking at the raw sensor data in linear light. To try and do it off a JPEG will lead to vastly misleading results, and doing it of RAW in ACR trying to get a "best curve" is nearly as bad. At least they use a test wedge.
That's right; it needs to be measured on the pure raw data (even if the light happens to be curved :-).

The result is, that the noise characteristics is the same as that of the 40D.
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Daniel Browning
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« Reply #9 on: October 31, 2008, 12:14:05 AM »
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I really appreciate the camera reviews completed by dpreview.com. They are very comprehensive and informational. There are several issues with the measurement systems and conclusions, however.

First, the use of 100% crops to compare with other cameras and draw conclusions about resolution and noise is a mistake, as it magnifies each camera to a different degree, like holding one print under a loupe and another at arm's length. If the reviewer were to resample images from both cameras to the same resolution (or just print them), the conclusions about noise and resolution would be far different.

The other issue is the software and settings used for RAW conversion. All the popular converters apply vastly different conversion styles, behind the scenes, to different camera models, even from the same manufacturer. Therefore the only fair way to analyze what the camera is capable of is to use the un-popular software that treats RAW data the same, and to measure that RAW data. Using dcraw and IRIS would allow authoritative measurement of the true noise performance.

If dpreview were to correct these two mistakes, I believe they would quickly realize how their crusade against pixel density is based entirely on a false premise.
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« Reply #10 on: October 31, 2008, 01:01:04 AM »
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Quote from: The View
Dpreview has the review of the 50D out. ...
Main points: no real detail advantage over the 10MP 40D, but 50% larger files.
Yes, it does seem that the 50D would have been a "better" camera had it also used an updated version of the 10 MP sensor in the 40D, rather than jumping to a 15 MP sensor. Cleaner 10 MP files that can be interpolated if need be, and are inherently able to be sharpened more smoothly, would seem to be preferable to me. I wonder how sales for Canon would go if it ever released a 10 MP edition of the 50D? However, I estimate that that's rather unlikely.
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Ray
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« Reply #11 on: October 31, 2008, 01:06:15 AM »
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Quote from: Graeme Nattress
You can't properly measure dynamic range without looking at the raw sensor data in linear light. To try and do it off a JPEG will lead to vastly misleading results, and doing it of RAW in ACR trying to get a "best curve" is nearly as bad. At least they use a test wedge.

Graeme

There is an over emphasis on jpeg comparisons at dpreview, from my perspective because I don't use jpeg mode. However, it's probably true that most users of DSLRs do shoot jpegs, and therefore it is only sensible for Dpreview to cater to those people.

For the same reasons, most people who shoot RAW probably also use ACR to convert their RAW images, therefore does it not seem sensible that Dpreview should use ACR to compare the DR of different cameras?

It's quite likely that there are more objective methods of measuring and comparing DR, using, for example, DCRAW, IRIS, Rawnalize etc, but how do results from such 'possibly more objective' analyses help users of ACR? If you are a user of ACR, you want to know what the DR of your new camera will be like in ACR. If you think DPP does a better job, then that's reason enough to use DPP instead of ACR. However, why should there be any reason for a DCRAW based analysis to be any more relevant to DPP users than ACR users?

You can't satisfy all of the people all of the time, ya know!
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Daniel Browning
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« Reply #12 on: October 31, 2008, 02:00:39 AM »
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Quote from: Ray
It's quite likely that there are more objective methods of measuring and comparing DR, using, for example, DCRAW, IRIS, Rawnalize etc, but how do results from such 'possibly more objective' analyses help users of ACR?

By showing the difference between the capability of the camera and the limitations of the software. It's one thing to say "the camera stinks" and another to say "the camera is good, but Adobe's raw processor does a poor job on this one."
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The View
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« Reply #13 on: October 31, 2008, 03:12:37 AM »
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Quote from: witwald
Yes, it does seem that the 50D would have been a "better" camera had it also used an updated version of the 10 MP sensor in the 40D, rather than jumping to a 15 MP sensor. Cleaner 10 MP files that can be interpolated if need be, and are inherently able to be sharpened more smoothly, would seem to be preferable to me. I wonder how sales for Canon would go if it ever released a 10 MP edition of the 50D? However, I estimate that that's rather unlikely.

I actually expected something like 12 MP, which is considered as the limit for the APS-S sensor.

But I agree, 10MP would even have been better.


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The View
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« Reply #14 on: October 31, 2008, 03:30:23 AM »
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Quote from: Ray
most people who shoot RAW probably also use ACR to convert their RAW images, therefore does it not seem sensible that Dpreview should use ACR to compare the DR of different cameras?

I don't think that "most people" use ACR. Many, yes, but most?

A camera can't be tested with what "most people" use, but what the most knowledgeable people use. And that's often not ACR.


The best test is done in a way that is best for a certain camera.

The best tests are done in a way that matches actual shooting situations.



And do the box shots of dpreview match those?

Of course not.



Also: those close crops often hide how a sensor represents light quality. How colors are represented.



Test sites have a big influence on camera manufacturers.

In a worst case scenario it could give us cameras that perform well under those test conditions - not in real shooting situations.


This is why I personally prefer subjective reviews of photographers, that do their work and give reasons what the strengths and weaknesses of a certain camera are.

Then I don't need any charts.

That said, the results of this dpreview test don't seem to sustain our knowledge, that pixel packed sensors are not something we really want. They seem to have gotten the right results with the wrong methods.
« Last Edit: October 31, 2008, 03:32:12 AM by The View » Logged

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ErikKaffehr
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« Reply #15 on: October 31, 2008, 03:33:57 AM »
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So you think that interpolating sparse data is more correct that sampling denser data?

I don't think that interpolation ever is a replacement for real data. I definitively would suggest that there are advantages in increasing resolution, but it is well possible that the limits for diminishing returns have been reached. The resolution needed is dependent on the size of the enlargement. There is some advantage to having higher resolution than the resolution of the lens, namely that a much weaker anti aliasing filter can be used.

The advantage of higher pixel density would only be visible in:

- Large prints (or pixel peeping)
- With the very best optics
- At the best aperture

So if not all of the above are fulfilled no or little advantage would be seen.

Best regards
Erik


Quote from: witwald
Yes, it does seem that the 50D would have been a "better" camera had it also used an updated version of the 10 MP sensor in the 40D, rather than jumping to a 15 MP sensor. Cleaner 10 MP files that can be interpolated if need be, and are inherently able to be sharpened more smoothly, would seem to be preferable to me. I wonder how sales for Canon would go if it ever released a 10 MP edition of the 50D? However, I estimate that that's rather unlikely.
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ErikKaffehr
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« Reply #16 on: October 31, 2008, 03:45:49 AM »
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Hi,

There is no real good reason to talk about a 10, 12 or 15 MPixel limit. The linear difference between 15 and 12.5 MPixels is 9.5%. In terms of resolution if a 12.5 MPixel sensor needs 50 lp/mm a 15 MPxel sensor would require 55 lp/mm, that is a small difference. Also I'm pretty sure that DR will not be reduced more than half a stop and I cannot see that the speed advantage of a 10 MP sensor over a 15 MP sensor would be more than a half stop.

Essentially, I don't think that there is a limit but we have diminishing returns when increasing MPixels if other factors are kept fixed.

Erik

Note: the 50 lp/mm example is contrived. A 12.5 MPixel sensor has a pitch of 5.5 microns and has an inherent resolution of 91 lp/mm. Resolution on it's own is a meaningless figure, however. The only way resolution makes sense is in the combination with the MTF. So we could say an MTF of 50% at 50 lp/mm or an MTF of 20% at 90 lp/mm. Very few lenses for 135 format would achieve something like 20% at 90 lp/mm but it is definitively possible to design a lens having that capability.

Quote from: The View
I actually expected something like 12 MP, which is considered as the limit for the APS-S sensor.

But I agree, 10MP would even have been better.
« Last Edit: October 31, 2008, 06:26:04 AM by ErikKaffehr » Logged

Ray
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« Reply #17 on: October 31, 2008, 04:54:39 AM »
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Quote from: The View
I don't think that "most people" use ACR. Many, yes, but most?

A camera can't be tested with what "most people" use, but what the most knowledgeable people use. And that's often not ACR.


The best test is done in a way that is best for a certain camera.

The best tests are done in a way that matches actual shooting situations.

Sorry! Can't agree with your statements. Perhaps my statement, "Most people use ACR', should be modified to 'Most people who are concerned about good image quality, use ACR.' Photoshop is not the only image processor, but it appears to be the best, if you can afford it.

A camera can be tested with what most people use. Dpreview do it.

Quote
The best test is done in a way that is best for a certain camera.

Such a test is not always feasible. If a reviewer had the time and resources, he/she could compare all available converters that could handle the new camera's RAW files. How many converters are there, currently, that can convert 50D RAW files? If there were an obscure converter available that somehow could drag more DR out of the RAW files, people who are concerned about image quality would of course be interested.

If anyone knows about such a converter, please speak up now. Show us the results so we can see how much better 50D DR is with this new or obscure converter.


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barryfitzgerald
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« Reply #18 on: October 31, 2008, 06:28:24 AM »
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I was rather pleased DP called for an end to the megapixel race.

Please repeat after me:

"There is more to image quality than megapixels alone"

;-)

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Guillermo Luijk
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« Reply #19 on: October 31, 2008, 06:55:05 AM »
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Quote from: barryfitzgerald
I was rather pleased DP called for an end to the megapixel race.
I have a question here: if we assume the Canon 50D with a 4.5 MP/cm² pixel density has reached the limits of the Mpx race as DP tests seem to demonstrate, how are there people around (including Ken Rockwell) managing to take nice pictures even at 100% crops with their Canon G10 and 34 MP/cm² pixel density?

If I see a limit for Mpx not to go to 20Mpx or above, is more related to the practical usefulness and the storage and processing power requirements of such huge resolutions, than to physical limits.
« Last Edit: October 31, 2008, 06:57:54 AM by GLuijk » Logged

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