The Importance Of Megapixels?

[JamieR]

Hi all, I'm a little confused on the importance of megapixels, I've read that megapixels aren't all that important.

Ill give an example. A 15MP camera will give the same result as a 10MP camera.

Now i don't understand this. Am i missing something?

Am i right in saying that if a camera has 15MP, you can print larger prints at an excellent quality, and the result in that size print would be better of a 10MP cameras image at the same size?

If anyone can clear it up for me then thanks in advance.

Regards,
Jamie.

 

[Josh66]

Well, it's not that they're the same - but the difference isn't as big as it sounds.

For example - a 10MP image, 3872x2584 pixels, will give you approximately a 13x8.5 print at 300ppi. A 15MP image, 4744x3160 pixels, will give you approximately a 16x10.5 print at the same resolution.

That's not 33% bigger.


Someone (I can't remember who) said in another thread that if you have enough resolution to print an 8x10, you can print as large as you want. The bigger the print gets, the farther away you have to stand.

That being said - more megapixels will get you a larger image, it's just not going to be as much of a step up as you might think.

 

[JamieR]

I understand now.

So the megapixels only really apply to how big a print you can get?

It won't make a difference to the image quality on a computer screen?

Thanks,
Jamie.

 

[ShotGunNik]

I would agree with that statement ^^^

I took a pic using my girlfriend's 8 megapixel Point and Shoot that came out damn near as clear and crisp as my XSi shots lol, especially when I uploaded them on to my laptop.

 

[Dwig]

...It won't make a difference to the image quality on a computer screen?

Not until the MP number drops below about 2mp. Many screens won't show any lower quality until the image drops to 1mp or lower.

 

[GeneralBenson]

Well, it's not that they're the same - but the difference isn't as big as it sounds.

For example - a 10MP image, 3872x2584 pixels, will give you approximately a 13x8.5 print at 300ppi. A 15MP image, 4744x3160 pixels, will give you approximately a 16x10.5 print at the same resolution.

That's not 33% bigger.

Um, it's exactly 33% bigger. Actually, I take that back, it's 50% bigger. 10mp would be 33% smaller than 15mp. We're talking about area here, and it has diminishing returns. It basically works like the inverse square law. If you take 16x10.5, it equals an area of 168. If you take 13x8.5, it equals an area of 110.5. 168 is 50% larger than 110.5, 110.5 is 33% smaller than 168. by the time you're dealing with 10 million pixels, going up to 15 million is just adding some extra rows of pixels around the edges. Just to add one more row of pixels around the 3872x2584 10mp sensor will already be 12,916 more pixels. And all that did was add 2 pixels' height and 2 pixels' width to your image. The next row would be 12,920 more, then 12,924 more, then 12,928 more. Now you've added 51,688 pixels and your image has only gotten 8 pixels taller and 8 pixels wider. So the higher megapixel the sensors get, the less difference each new bunch of MP's make.

 

[Josh66]

We're talking about area here, and it has diminishing returns. It basically works like the inverse square law.

I know, I was talking about linear dimensions - 13 is not 33% (or 50%) of 16.
I guess I wasn't very clear. I think everyone knew what I meant though.

 

[ANDS!]

I know, I was talking about linear dimensions - 13 is not 33% (or 50%) of 16.
I guess I wasn't very clear. I think everyone knew what I meant though.

Everyone did. But "Mr. Internet" revels in taking the opportunity to correct someone.

As to the OP - every new camera out there that you buy will have a resolution of 8MP or more; 10 is really the new "low end" of camera resolution. A 6MP image will make great 8X10 prints. If you want to go larger than that (13X19 for example), a 6MP can still make great prints up to that size (which is currently the maximum size for consumer larger format printers).

So essentially - worrying about megapixels at this stage of camera technology, is like worrying about whether or not you will remember to breathe - pointless.

 

[dhilberg]

Megapixels are important, but the industry greatly over exaggerates it for marketing purposes, just like the PC world focuses on CPU clock speed as a performance indicator. Camera manufacturers have taken advantage of people's assumption that more == better, which is why they focus on megapixels when trying to sell you a camera. Almost all newer cameras have more megapixels than really needed, so I wouldn't even worry about it.

If--like many people--all you are ever going to print is 4x6 or 5x7 @ 300ppi (true photo quality), then mathematically speaking you only need a 3 megapixel camera (yes, it's true). For on-screen photos, 72 ppi is all you need, which means that you can get away with even less megapixels.

Here's some links on the subject:

The Megapixel Myth
The Truth About Digital Cameras - Pogue’s Posts Blog - NYTimes.com
Breaking the Myth of Megapixels
Design215 megapixels comparison and maximum print size charts

 

[B Kennedy]

I agree with dhilberg that the camera industry is using more MP as an advertising scheme. So many people ask me about which camera to get and they want to push to get the most MP possible. You can only give advise so many times and then you just start chuckling. But anyways, its great that everyone is talking about print sizes etc., but what's really interesting is what you can do post-op with the pictures having many more pixels to work with. Like people were saying about print sizes, sure a 3mp camera can print a 5x7 just as well as a 20mp if exposed/focused properly. But say you don't expose properly and you have to edit/enhance later on. Especially say if you underexpose a picture, yet you really liked it for whatever reason, when you try and lighten it up a bit (choosing whichever tool you like) you intevitably will get more noise from a lower end lower MP camera. I think the more MP as well gives you more freedom in the editting/alteration process and then ultimately in the printing process. Let me know what you guys think about the post-op processing vs MP

 

[hankejp]

Not to Hijack this thread, but has anyone printed a poster size (20x30) from a D90 size file? Just wondering how the quality looked.

Thanks

 

[dcclark]

Hankejp -- I have printed a 20x30 from my 10 MP D40x -- I forget if the D90 is 10 or 12 MP, but either way, my results will apply. It looks great. The image quality is good enough that you won't notice any problems, as long as you're not trying to smell the photo. Technically speaking, you'll get around 130 dpi, which (at the distances that you should be viewing a 20x30 from) will look great. Notice that 12 or 15 MP will NOT increase the dpi in any noticeable way.

 

[GeneralBenson]

Everyone did. But "Mr. Internet" revels in taking the opportunity to correct someone.

Sorry, sorry, sorry. I idn't mean to play the part of Mr. Intardwebs. What I was meaning to point out was that is is in fact 50% larger, and still barely makes a difference.

I think megapixels are stupid at this point. The only things that mater are IQ, high ISO performance and all of that stuff. I have a 10mp camera and a 15mp camera, and I pretty much can't tell them apart except for at high ISOs. I would be happy with a 12mp camera that has amazing IQ for the rest of my life, even if the new hot stuff is 120mp.

 

[skieur]

Irrespective of the math and rhetoric, I can see the difference between a 5 mp, a 8mp, 14mp and 21 mp camera in terms of sharpness on the screen.

skieur

 

[B Kennedy]

I'm a little confused, whats IQ in camera terms again? LOL

Sorry, sorry, sorry. I idn't mean to play the part of Mr. Intardwebs. What I was meaning to point out was that is is in fact 50% larger, and still barely makes a difference.

I think megapixels are stupid at this point. The only things that mater are IQ, high ISO performance and all of that stuff. I have a 10mp camera and a 15mp camera, and I pretty much can't tell them apart except for at high ISOs. I would be happy with a 12mp camera that has amazing IQ for the rest of my life, even if the new hot stuff is 120mp.