Is A 12 Mp Camera Good

The Megapixel Myth
© 2008 KenRockwell.com. All rights reserved.

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Resolution Comparisons amid 6, 8 and 10 MP DSLRs.

Pixel Dumping

Introduction

For normal 4x6" (10x15cm) prints, fifty-fifty VGA (640 10 480 or 0.3MP) resolution is just fine. Digital cameras did this back in 1991!

In 1999 when digital cameras were merely 1.2 or 2 MP, each megapixel mattered if you were making bigger prints.

Today, fifty-fifty the cheapest cameras have at least 5 or 6 MP, which enough for any size print. How? Uncomplicated: when you print three-anxiety (1m) wide, you stand further back. Print a billboard, and you stand 100 feet back. 6MP is plenty.

Sharpness depends more on your photographic skill than the number of megapixels, because well-nigh people's sloppy technique or subject motion blurs the image more than the width of a microscopic pixel.

Even when megapixels mattered, in that location was little visible difference betwixt cameras with seemingly different ratings. For instance, a 3 MP camera pretty much looks the same as a vi MP photographic camera, fifty-fifty when blown up to 12 x xviii" (30x50cm)! I know because I've washed this. Have you? NY Times tech writer David Pogue did this here and hither and saw the aforementioned thing — nothing!

Joe Holmes' limited-edition 13 ten 19" prints of his American Museum of Natural History serial sell at Manhattan'due south Jen Bekman Gallery for $650 each. They're made on a 6MP D70.

There are plenty of shows selling shots from fuzzy Holgas for a lot more money, simply that those folks don't tell me about it. Holgas sell for $24.95, make new, here. You lot tin meet an award-winning shot made with a Holga hanging in Washington, D.C.'southward Hemicycle Gallery of the Corcoran Museum of Art in their 2006 Eyes of History contest of the White Firm News Photographers Association hither.

Sharpness has very footling to do with image quality, and resolution has picayune to practice with sharpness. Resolution (pixel count) has nothing to do with moving picture quality. Color and tone are far more of import technically. Even Consumer Reports in their November 2002 issue noted some lower resolution digital cameras made better images than some college resolution ones. That was a long time ago!

Explanation of Terms

Pixels

Pictures are made up of little dots called pixels. Pixel stands for PICture ELement. Put plenty of them together and y'all have a picture. They are arranged horizontally and vertically. Go close plenty to your figurer screen (or employ a magnifier) and you lot'll run into them.

Resolution (Linear Resolution)

Image Resolution

Resolution is how many pixels you have counted horizontally or vertically when used to describe a stored image. Digital cameras today have between 2,048 and four,500 pixels horizontally. three MP cameras have 2,048 pixels horizontally and 14 MP cameras take four,500 pixels. They have fewer pixels vertically since the images aren't as tall as they are broad.

That's not much of a difference, is it? That's the whole point of this article. I'll explain that a little further down.

Print Resolution

Resolution is also how many pixels y'all have per inch or other linear unit when y'all print on paper. Most prints are fabricated at 200 - 300 pixels per inch (PPI or DPI, dots per inch). This is the image resolution and has nothing to do with the engineering by which the print is made. (For instance, inkjet printers' nozzle sizes are the silly 2880 DPI or other numbers you see. These printer numbers are often used by hucksters to hoodwink and distract you when talking well-nigh resolution. These only refer to how the ink is spat out on the paper.)

Screen Resolution

About figurer screens today are near 100 DPI, dots per inch. There isn't much variation from screen to screen and so we rarely hash out this. It's easy to figure out: most computer screens are about 1,024 x 768 pixels. If your screen is 10" wide and so divides one,024 by x and yous have a 102.4 DPI screen. Bigger screens tend to take more than pixels, for instance, my 22" CRT has 1,600 x 1,200 pixels and has a viewing surface area of 16 x 12."

Yep, laptops with bigger screens tend to have lower linear resolution. No big deal.

Pixel Count, expressed as Megapixels

Pixel Count, expressed as Megapixels, is but multiplying the number of horizontal pixels by the number of vertical pixels. Information technology's exactly like calculating surface area. A three MP photographic camera has 2,048 (horizontal) x one,536 (vertical) pixels, or 3,145,728 pixels. We phone call this simply iii MP.

Small differences in pixel count, between say 5 MP and 8MP, are unimportant because pixel counts are a square function. It'southward exactly similar calculating area or foursquare footage. It but takes a twoscore% increment in linear dimensions to double the pixel count! Doubling pixel count simply increases the real, linear resolution by xl%, which is pretty much invisible.

The Myth

The megapixel myth was started by camera makers and swallowed hook, line and sinker by camera measurebators. Camera makers use the number of megapixels a camera has to hoodwink you lot into thinking it has something to do with camera quality. They use it because even a tiny linear resolution increase results in a huge total pixel increase, since the total pixel count varies as the full surface area of the image, which varies as the square of the linear resolution. In other words, an almost invisible 40% increment in the number of pixels in whatsoever i management results in a doubling of the total number of pixels in the prototype. Therefore camera makers tin can always brag about how much improve this calendar week's photographic camera is, with even negligible improvements.

This gimmick is used by salespeople and manufacturers to you feel equally if your current photographic camera is inadequate and needs to be replaced even if the new cameras each year are just slightly better.

1 needs at to the lowest degree a doubling of linear resolution or film size to make an obvious improvement. This is the same as quadrupling the megapixels. A simple doubling of megapixels, even if all else remained the aforementioned, is very subtle. The factors that matter, like color and sharpening algorithms, are far more meaning.

The megapixel myth is as well prevalent because men always want a unmarried number past which something's goodness can exist judged.

Unfortunately, it'south all a myth because the number of megapixels (MP) a camera has has very little to do with how the image looks. Even worse, plenty of lower MP cameras tin make ameliorate images than poorer cameras with more MP.

The Hype

Here'due south a complete fabrication past a visitor who is trying to spread the myth to get you lot to purchase too much camera. There's a similar page here. That folio is brilliantly done, all the same it's done with completely fraudulent data to exaggerate the differences. At the low magnifications shown on the screen whatever and all of those examples should expect perfect. Instead the two lower resolution examples have been deliberately degraded to brand them look worse. Their folio displaying results for a 5 10 vii" print really show how the 4 MP camera would look diddled upwards to 12 past 9 feet, not 5 x seven inches!

How exercise we know their 4MP case is what you'd see blown up twelve feet wide, not 5 x vii inches? Easy: for the 4 MP example at maximum ingather I see pixels diddled upwardly to picayune squares measuring 16 pixels per inch on my screen. (Just get out your ruler and measure for yourself.) Yous divide the number of pixels past the PPI (DPI) to get how many inches you get in impress at that resolution. Thus printing a 2,289 x one,712 pixel (4MP) image at 16 PPI gives (2289/16)" x (1712/16)" or 143" 10 107" or, dividing inches by 12 to get anxiety, 12' x 9.'

I'thou sure the designer of that page would feign ignorance of the engineering science involved if fabricated to ain upward to it. Page designers don't have Ph.D.due south in digital paradigm processing, either. Most likely the designer worked on it till their managing director made sure that they showed a clear difference. Their manager, if fabricated to come up clean, would probably explicate that the page was put up to illustrate the differences as an educational service, non as actual science or a legitimate example. They had to make certain "adjustments" to make the differences clear, namely, to make the 4 MP and 5 MP cameras look much worse than they are.

I taught yous above how to calculate the differences among different resolution cameras. The deviation betwixt the 6 MP and 4 MP cameras should be (square root (6/4)) or SQR(1.5) or 22.four%. In other words, the size of the pixels or number per inch should be less than 25% different between the four MP and 6 MP cameras. They've made the lower resolution cameras wait much, much worse by comparison on that page.

Honest Results for Comparison

three MP uncropped	Cropped every bit per red rectangle

Hither's the aforementioned percentage crop as that other store-sponsored website shows. I gave them an advantage by showing my images in a higher place at twice the size as they did (requiring 4 times the number of pixels) and then starting with only a three MP camera, not the 4 MP every bit shown in their worst example.

Looks fine, eh? I actually had to throw many pixels away. These sizes are easy to do with a 3 MP photographic camera. Even if they are calculation in some unstated magnification to try to accost other problems in rendering prints vs. screen images the differences between 4 MP and 6 MP are nowhere nearly every bit exaggerated as that store site shows. They show at to the lowest degree a 4x departure in the size of the pixels betwixt iv MP and 6 MP. Equally you know the size difference between four MP and 6 MP is just l% in pixel count, and since pixels are foursquare that means less than 25% in pixel size or pitch! Since that part of that retailer's site isn't an advert for whatsoever item product I doubt and truth in advertising rules utilise. Caveat emptor!

Impress Sizes

Image clarity is more dependant on how you shot the photo than on the number of megapixels. A clean shot from a 3MP photographic camera is much better than a slightly out-of focus shot from a $5,000 12 MP camera.

A clear image can be printed any size from any modernistic digital camera. Sure, if you lot print landscape size and look at it from inches away you won't have the sharpness you'd get from iv x five" film, simply if you lot shot it properly, it will be abrupt enough to look neat when viewed from a distance appropriate to the size of the print.

So long equally you lot accept 100 to 150 DPI (dots or pixels per inch), you have plenty for a sharp print viewed at arm'due south length. This means a 6 MP camera tin make prints 30" (75cm) wide and still look bang-up. When was the last time you printed that big?

Ideally you'd similar to print at 300 DPI to expect super-precipitous even when viewed too close with a magnifier. You lot can figure this by:

Long print dimension in inches = 4 ten (square root of megapixels)

Long print dimension in centimeters = 10 x (square root of megapixels)

For case, the square root of iv (megapixels) is two. 4 x (2) is viii. Thus the biggest print you can make without losing sharpness equally seen through a magnifier from a 4MP camera is 6 10 viii" (15x20cm). From a 16 MP photographic camera also yous could get to 12 ten 16" (30x45cm), and still await at the print through a magnifier.

The resolution issue is one of scale and viewing altitude.

Sure, more than resolution is better at bigger sizes, only how sharp your prototype is has trivial to do with how good it is. Far more important technically is whether or non the colors are right and whether or not any sharpening was done tastefully. Many digital cameras add nasty looking sharpening that puts very artificial halos effectually sharp lines, making the image wait obviously digital to those of usa who recognize these things. Sloppy sharpening is washed to impress the innocent by overemphasizing the lines around things if existent sharpness and resolution is lacking.

Of course you tin can print much bigger, since sharpness isn't equally of import in color as nigh people worry. You can get great results from a 6MP camera at 20 x xxx" if you desire, since normal people view large images from further abroad. This is all art and in the eye of the beholder; I adopt huge prints made from my 4 x v" film camera, and for portraits I prefer the smoothing of digital cameras.

Don't worry too much about this, since sharpness is not as important in color as it is in B/W. I make 12 x 18" color prints all the time from three to 6 MP cameras and they look great, since I only print images that are good to begin with.

Replace Film?

What size film?

Film, like digital files, comes in many resolutions. 35mm is an amateur format, medium format (120 or 6x7) is for head shots, and large format (4x5" and upwardly) is for landscapes.

Arizona Highways prefers 4x5" picture show. As of 2008, they now accept digital images, only with a catch: they have to be at least 300 DPI at 12x18," or xx MP. They say an 8MP photographic camera is OK, simply y'all'll notice that you have to supply 12x18" at 300 DPI, which is iii,600 x 5,400 pixels, or xx MP.

If you lot do fret the pixel counts, I find that it takes well-nigh 25 megapixels to simulate 35mm film, which is yet far more than than any practical digital camera. At the 6 megapixel level digital gives about the same sharpness as a duplicate slide, which is plenty for about things. Honestly, I have actually had digital files written back out onto film to see this. See also my film vs. digital page here.

Of course I use much bigger motion-picture show than 35mm for all the pretty pictures you run into at my website, so digital would need about 100 megapixels to simulate medium format film, or 500 megapixels to simulate 4x5" film. This is all invisible at Internet resolutions, but obvious in gallery-size prints.

PLUG

If you lot observe this as helpful equally a book you might have had to purchase or a workshop yous may have had to take, feel gratis to assistance me continue helping everyone.

Thanks for reading!

Ken

Source: https://www.kenrockwell.com/tech/mpmyth.htm

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