Higher MP is bad?

I was reading reviews of the T2i and I came across this...

Now, I come from the film days, and this argument seems completely bogus to me. Back in the day, it was always a challenge for the lens manufacturers to produce lenses with the resolving power to get the most out of fine-grain film, whether Kodachrome 25, Pan-X B&W or even Tri-X. No one criticized the film because to get the most out of it, you may need to upgrade your lens. No one said that grainier film was better because it did not expose the flaws in the less expensive lenses people might own. They placed the criticism where it belonged... on the lens.

What has changed? Has the fact that we now depend on the camera / lens manufacturer to also produce the "film" (sensor) resulted the the manufacturers producing sub-standard lenses since the sensor can't see the difference anyway?

It is fair to criticize the technology trade-offs, for example, the same review stated this:

I don't know about the camera shake deal... this reviewer seemed unreasonably biased against Canon throughout, and this seems like a real reach for something to criticize. But, the points about dynamic range and high ISO performance may be correct, I don't know. I do know the same issues faced film manufacturers. Typically, fine-grained film did not perform well when pushed to high ISO (I still want to say ASA... so you know I'm old) ratings, resulting typically in contrasty and grainy images.

But, the initial point... a 12 MP sensor is better (and, hence, the Nikon D90's sensor is better) because it lets you get away with a cheaper lens compared with an 18 MP sensor... seems like the criticism is misplaced... that is the fault of the lens, not the sensor. And, in fact, what this really means is the camera's sensor is limiting the benefit you might get in the future should you choose to upgrade your lens.

Higher MP bad = internet BS.

Get a current Canon dSLR, feed it great glass, and prepare to be amazed at the detail in the resulting files. You can smile at the fact that Canon does this at equal noise levels to the lower res Noinks (save the D3s).

Lenses are not the place to save money, if you feel you need to scrimp bucks skip the filters. Acquire lenses equal to the sensors IQ to obtain the best results .

Everything it says is true, it is the conclusion that it means high MP = bad that is wrong. It is true that higher resolution sensors will show poor lenses, poor focus, poor camera holding technique, etc. more than low resolution sensors when magnified by the same amount. When printed to the same size it may not show it more but at 100% you'll see more shake and focus error at 18MP than 6MP.

Just like with fine grained film if your lens isn't up to the task then it is a waste, you might as well use low resolving film if your lens or technique are poor.

Actual pictures from a T2i as referenced in the review:

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Higher pixel counts do expose weaknesses in a number of areas, optics are just one. And thats why Canon and others are now engaged in updating their line up.

The more megapixels the better because it forces manufacturers to address the problems it exposes. The problem has been that in the race for more MP, other issues have been put to one side and are only now being taken seriously.

I am looking forward to seeing the first 100mp camera in the next year or so. May not be Canon but so what.

The big issue I see with high pixel density (ie. smaller sensor sites) is that diffraction shows itself at bigger apertures. That's physics and I don't see how they can get around that. Light's a wave. Sorry.

It's larger magnifications that causes "problems" with camera shake, faults in lenses and so on.
As long as we keep on magnifying our images more and more, they will of course look more blurred due to shake, for example. That is the same as using a longer focal length. More magnification = more impact from shake.

So why do we keep on magnifying more? Because an enormous amount of digital camera users seem to think that it's pixels that are interesting, not pictures. So wee keep on blowing up images to 100% matching between camera pixels and screen pixels, disregarding that the whole picture has grown out of the room we have our computers in. Except for some who frequently post at dpreview; they first sharpen the same image as much as possible three times in succession, then look at it at 400%.

This of course means that every fault there may be in the image is more and more visible to us. So we keep on complaining about the wind in our hair, disregarding that we are going 250 km/h now, not 50 km/h as we did a few years ago.

No matter what kind of lens you have, it will benefit from a sensor of higher resolution. An inferior lens will not benefit that much, but it will benefit. From a picture point of view, increased resolution is always good.
There may be limitations in the electronics used to implement this resolution, but it's there the compromise should be done, not because we use the EF-S 18-55 mm f/3.5-5.6 II on our 18 Megapixel 7D.

As mentioned, there are definitely disadvantages to having a high MP count on a similarly sized sensor.

But theoretically, that means there are also ADVANTAGES.

The sole advantage in a higher MP count is to obtain more DETAIL, for more enlargement and cropping options.

The problem is, most lenses are not capable of delivering the detail that these densely packed sensors want. So you basically get pictures that take up a lot more hard drive space, all while they don't give you any more detail than a smaller 12mp file.

I'm guessing THAT'S why he says more MP = bad.
There may be a new batch of lenses that come out that can deliver the detail the 7D/T2i is starving for.

"The big issue I see with high pixel density (ie. smaller sensor sites) is that diffraction shows itself at bigger apertures. That's physics and I don't see how they can get around that. Light's a wave. Sorry".

Thats what used to be said about the speed of light, now doubts are being openly aired. I believe that it will either be resolved, or the "problem" will be circumvented in some other way.

Science does not fully understand wave dynamics in water, never mind light. So any categoric statement saying something is impossible should be taken with a pinch of salt. What it really means is "we don't know how to do it right now".

District_History_Fan wrote in post #10890121
You can smile at the fact that Canon does this at equal noise levels to the lower res Noinks (save the D3s).

Absolutely. The fact that the 21MP Canon 5D2 has similar high-ISO noise to the 12MP D700 is hugely impressive. I'd really love to see Canon coming out with a couple versions of the 1DS4, say, 25+MP for the detailed landscapes, and a super-high-ISO beast with 18MP on a full frame for concerts etc. I know it's possible.

DC Fan wrote in post #10890156
...so there's no disadvantage there. (ISO 3200 example above.)

WOW, that made me smile.

Lowner wrote in post #10890177
Higher pixel counts do expose weaknesses in a number of areas, optics are just one. And thats why Canon and others are now engaged in updating their line up.

.... and a good thing it is too. I have the 70-200 mk I, but I now lust after the 70-200 mk II, and I can't wait to see the 24-70 mk II. I hope the improvement there is similar to the 70-200 update.

The only disadvantage I see with higher MP count is increased disk space requirements. All the other stuff is just internet posturing by people who don't actually take pictures.

As with all things there is no free lunch--higher MP sensors have advantages and disadvantages.

Putting them in consumer grade bodies is questionable marketing--the typical buyer is more likely to buy cheap lenses such as the 70-300III than a piece of high quality glass--and be disappoined with the results they get.

The comments above about low-class lenses and diffraction are both wrong. Well, the comments aren't, but the conclusions drawn from them.

All lenses benefit from higher resolution. Inferior lenses just not that much.

Images taken at all apertures benefit from higher resolution. Small apertures just not that much.

Diffraction is exactly the same with lower resolutions, you just don't know it. As long as the sensor size is the same, so is the effect of diffraction. A picture taken at f/32 with an 8 MP 30D suffers from the same degree of diffraction as if it was taken with a 7D. This doesn't make the picture from the 7D inferior, just not as superior as it would be if both pictures were taken at f/2.8.

The number of megapixels doesn't tell what kind of resolution the sensor is really capable of capturing. There are so many other factors. In compact cameras higher mp is definitely bad these days. It's only needed for marketing.