7D Sensor...

[Kernuak]

The default for long exposure noise reduction is on. Likewise for high ISO noise reduction it is standard. I always switch both to off, so that I have more control and have the maximum frame rate possible. I've never checked to see if noise reduction also affects focus speed/accuracy, but low light focusing is one of the achilles heels of the 7D. One shot is also often more accurate than servo in low light. I have my 5D MkII set to one shot the majority of the time, while on the 7D I have it on AI Servo by default, so that probably increases the difference between the two in low light. The 5D MkII is far superior in terms of accuracy then, so it could be that the less sophisticated focus of the 550D is working to its advantage. Simple is sometimes best,

[KeithR]

Does anyone else agree?

Uuuummmm...

No.

[briansquibb]

The 7D came out in 2009, so its a bit old.  You seem to be thinking it should have been better back then?  At the time, it was the best sensor.

Best APS-C maybe ....

[KeithR]

Best APS-C maybe...

And it's better at the image level than quite a few FF sensors too - it's certainly better than the original 5D, and better than the 1Ds bodies, up to and including the Mk III.

[briansquibb]

Best APS-C maybe...

And it's better at the image level than quite a few FF sensors too - it's certainly better than the original 5D, and better than the 1Ds bodies, up to and including the Mk III.

I guess that will debatable them - have you compared a 7D image with a 5DII, 1D4 or a 1Ds3 image?

[pdirestajr]

It's a great camera and will continue to be. Just because newer tech comes out doesn't mean this camera will stop bring able to capture beautiful images.

If your thing is shooting test charts in the dark, then perhaps a "better" sensor is on the horizon... But I'd wait for the 7D mark III or IV. They are going to be awesome at iso 1,000,000!

[Jim K]

I disagree.

The 7D has the best APS-C sensor currently offered by Canon.  The features that differentiate it from the lower models are build, AF, fps, etc. 

If the 7D had a larger sensor - even slightly larger - the image circle of EF-S lenses would not cover it. So...bad idea.

neuroanatomist: I recently went out shooting for a week with my brother inlaw. He has a 7d and a 24-70. I have a 550d and Tamron 17-50. Over the week we exchanged cameras several times for hours at a time. I expected his 7d+24-70 to blow the 550d away. Well, I was in for a surprise. Overall, the 550d + Tammy where at least as good as the 7d. I would even dare that in some cases they where better. When shooting at night in low light on a tripod, the 7d took quite a few seconds to digest each shot - the 550d was much quicker?

Bottom line is (my impression) that placing aside all of the 7d's pro qualities as far as AF, body, etc. from a pure IQ point of view - I saw no large advantage - and even seem to feel a certain annoying softness in the images.

Strange ? Can you comment?

Has your brother-in-law micro-adjusted the AF on his 7D with the 24-70? That should have gotten the focus right on.
Have you micro-adjusted the AF on your 550D with your Tamron 17-50? Oh, I dont think the 550D can microadjust. I know the 60D does not. That is something that was dropped during the "upgrade" from the 50D to the 60D 

[neuroanatomist]

That is a fantastic subject and shot.

Thanks!

Bottom line is (my impression) that placing aside all of the 7d's pro qualities as far as AF, body, etc. from a pure IQ point of view - I saw no large advantage - and even seem to feel a certain annoying softness in the images.

Agreed - from a pure IQ standpoint, the 7D has basically no advantage over the 550D.  The softness probably results from two factors - one may be the NR settings, more NR means softer images.  The second is that the 7D apparently has a slightly stronger AA filter than the newer cameras with the same sensor, and as a result, 7D images require a bit more sharpening in post.

[jrista]

Best APS-C maybe...

And it's better at the image level than quite a few FF sensors too - it's certainly better than the original 5D, and better than the 1Ds bodies, up to and including the Mk III.

I'm not sure I would go quite so far as that. The 7D has a great sensor...for APS-C. But comparing it to FF sensors, even those a few years old, at best its comparable, but I would say the Mk III sensor was definitely better. At least, the full-size images I've seen taken with them have visibly less noise than the 7D.

When comparing scaled down samples, everything on the market for the last several years is pretty much comparable, downscaling eats noise for breakfast and is the great normalizer.