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Old Jan 27, 2013, 9:10 PM   #1
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Default Reviews and lab test on the Canon EOS Rebel T4i

I just finished reading all the reviews and the DXO-mark lab test on the new Canon EOS Rebel T4i. I don't understand why DXO-mark labs gave the older model Canon T3i a higher overall score rating than the newer Canon T4i. 65 for the T3i and only 62 for the T4i. Many of the reviews were rather negative as well in reference to overall still image quality. To make matters worst, they compaired the Canon T4i with the Nikon D5100. The Nikon D5100 had an overall score of 80. They claim the Nikon D5100 beat both the Canon T4i and the T3i in all test categories by a wide margin. These categories were color depth, dynamic range, low light ISO and overall still image quality. Please tell me how this is possible, the Nikon only has a 16 megapixel sensor as compared to the 18 megapixel sensor of both the Canon T4i and the T3i. I can't help but wonder if DXO-mark labs and all the reviewers are biased and prejudice and just like Nikon's over Canon's. I was thinking about buying a new Canon T4i but after reading all these reviews, I am having second thoughts. What do you guys and gals think ? Are all these reviews and lab test lies ? I just don't see how it's possible for the Nikon D5100 to be better than the Canon T4i with it's lower rated megapixel sensor. I need your thoughts and advice. Thanks.
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Old Jan 28, 2013, 6:48 AM   #2
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The DxOMark Scores are subjective, presuming that the only thing that matters for Portrait Photography is Color Depth, the only thing that matters for Landscape Photography is Dynamic Range and the only thing that matters for Sports Photography is High ISO performance.

Of course, none of these is true.

But DxOMark does provide the raw data they collect, and that is sufficient for someone to make their own judgement. Click on the Measurements tab, and look at the SNR 18% and Dynamic Range charts for the T3i, T4i and D5100. You'll see that the signal-to-noise ratio for the D5100 is slightly better than for the Canons, and at low ISO settings, the dynamic range of the D5100 is much better than for the Canons.
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Old Jan 28, 2013, 7:45 AM   #3
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The 600d,650D,D5100 etc... are all fine camera's- capable of very good results in the right hands- and although there may be small differences in the lab,I suspect out there in the real world the differences would be negligible.
DP Reviews Noise comparison-
http://www.dpreview.com/reviews/cano...d-rebel-t4i/17

DP reviews DR comparison- (note Canon's HTP option...)
http://www.dpreview.com/reviews/cano...d-rebel-t4i/18

I think features/handling etc might be more significant than the above when determining which of the above to purchase...
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Old Jan 28, 2013, 11:10 AM   #4
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Hey "TCav" and "SIMON40", thank you both for your replies to my question. Even though the Nikon D5100 tested slightly better than the Canon EOS Rebel T4i (650D), I would have to agree with SIMON40 that in the real world the differences would be negligible unless you blew the pictures up to the size of a house. I don't understand how they do these test. I can't help but wonder if maybe some of the differences is a result of the lenses that were used for the test. Maybe they picked one of Nikons better lenses for the test and the lens on the Canon was just so so. I looked at numerous examples where they blew the pictures up 100% and you could then clearly see that the Nikon had better resolution. I still don't understand how this could be possible. How can the 16 megapixel sensor in the Nikon D5100 have better resolution than that of the Canon's T4i 18 megapixel sensor ? This does not make sense. I have always been told that the higher the megapixel number is, this will always result in better resolution and better overall still image quality. I'm sorry, but I still think these test and reviews are biased and unfairly favor Nikon.
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Old Jan 28, 2013, 11:35 AM   #5
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My guess is that, for these kinds of tests, they use the same lens on whatever the body might be. Somthing like the Sigma 70mm f/2.8 macro would be a good choice for anything they can mount it on.


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Originally Posted by surplusshooter View Post
... I looked at numerous examples where they blew the pictures up 100% and you could then clearly see that the Nikon had better resolution. I still don't understand how this could be possible. How can the 16 megapixel sensor in the Nikon D5100 have better resolution than that of the Canon's T4i 18 megapixel sensor ? ...
I don't buy that either. Where did you read that?
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Old Jan 28, 2013, 2:55 PM   #6
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"TCav", I read this at; digitalreviewcanada.com (Nikon D5100 versus Canon Rebel T3i side by side comparison review). This review was of great interest to me due to the higher rating that DXO-mark labs gave to the T3i over the T4i. I originally stated that the crop was 100%, this is not correct, it was only a 50% crop comparison. As you will see, the comparison pictures between the Canon and Nikon clearly show significant blown highlights and consideerable loss of detail in resolution and over all poor image quality in the Canon. Both cameras used their 18-55mm kit lenses for the test. I can't help but think that the reason the Canon did so poorly was due to the lens and not because of an inferior sensor or in camera processor. Please let me know what you think. Thanks.
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Old Jan 28, 2013, 3:26 PM   #7
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It's actually quite a difficult comparison to do accurately- for example,if using kit lenses,then differences may be in part down to the lens.
Then you have to assume that a given iso reading is actually accurate- which occasionally is not the case. You may have selected say iso 800,but the camera's actual sensitivity may be slightly higher or lower.
Different cameras invariably meter differently- with some more accurate than others.
You can select similar iso,"f" numbers,shutter speeds etc on two or more camera's and you can be sure they'll all produce different results.
Take the use of Canon's highlight tone priority,for example- do you test with this function on or off... which would give a different dynamic range either way.
Do you compare the camera's at their best possible output,regardless of settings- or do you compare them at default settings...?
I'd suggest the former- which brings the user into the equation- which for me is the most important factor here.
As I stated earlier- all of the aforementioned cameras are competent and in the right hands are capable of very good and comparable results...

Just my ten pence worth... I'm fully aware of the various tests and results that have been floating around on the web etc... and whenever I've taken the time to download other peoples images taken with various cameras, I always seem to be more impressed with Canon's results... which would seem to be contrary to the tests.
Perhaps Canon users are more competent...???
And of the various DSLR camera's I've owned (Sony,Olympus,Pentax,Canon,Nikon), I still prefer the look of Canon DSLR images...
Perhaps it's just my own personal taste...?
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Old Jan 28, 2013, 4:57 PM   #8
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You can't compare a 50% crop of a 16MP image to a 50% crop of an 18MP image. Plus, the angle of view of the Canon is slightly narrower than that of the Nikon.

Thanks for passing this on. I now know not to take anything seriously that comes from digitalreviewcanada.com.
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Old Jan 28, 2013, 7:37 PM   #9
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"TCav", you have me confused in your statement about comparing crops at 50% on a 16MP image against a 18 MP image. The 18 MP image should win hands down. It's only logical that the 16 MP image will fall apart first, it had fewer MP to start with. However, this was not the case with the Canon 18 MP image. If you seen the review pictures, it is very clear to see that the 18 MP images from the Canon were really bad as compared to the Nikons 16 MP images when they were both cropped at 50%. I still don't understand why the Canom T3i and the T4i rate so poorly againt the Nikon D5100 in still image quality. One reviewer stated that the reason that the Nikon D5100 had better still image quality than that of the Canon was do to the fact that the Nikon has the same Sony sensor and image processor that is in the semi-pro Nikon D7000 and he thought that Nikon had slightly better glass. I don't know about that, but I will still say this, the 18 MP sensor in Canon's T3I and T4i should not have be beaten by Nikon's 16 MP sensor. It's technologically impossible ! I believe these reviews and lab test are rigged and totally biased in the favor of Nikon and I find this to be very dishonest and distasteful. Do you not agree ?
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Old Jan 28, 2013, 9:48 PM   #10
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Yes, the D5100 has the same 16MP Sony sensor as the D7000, but the T3i has the same 18MP Canon sensor as the 60D, so the argument doesn't stand up. And, no, Nikon doesn't have slightly better lenses.

The Canon has 5% greater horizontal resolution and a 6% narrower angle of view. As a result, a 50% crop of a Canon image would contain 12% more detail than the same size crop of an image from a Nikon image. So you could not make a direct comparison between the two, and the only way to do so would be to scale one or both to compensate for the differences which would certainly muddy the results, even if you didn't intend for your favorite to look better than the competition.
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