Thread: Megapixels needed?

I used an inexpensive digital camera at the office to take pix of my first restoration - they weren't worth posting

What is(are?) the mega-pixels of the cameras that some of you are using to post good pix? Garythepenman and urleebird post good, detailed pix.

Tom

Can't stay...bye bye, now...

I have a sony DSC-W7 (7.1MP). Any camera with 3.1MP should be just fine though. All the pix I've posted I scale down to about 1MP anyway.

It isn't the megapixels that make a good picture. It's the lens, lighting, focus, etc. Anything over 2mp will work fine for posting here. In fact, large MP cameras make it necessary for you to resize the pictures to convert them to a manageable size file for uploading to the site. Here's a good article on the [Megapixel Myth].

Can't stay...bye bye, now...

Just to stick my 2 cents in here. I sell quite a bit of watches on various forums and I have a Sony which is 3.something and the pics are 1200x1600 and they are xtl clear as a matter of fact when I upload them to my photo hosting site I always cut them down to 800x600 to make them more manageable.

But that old saying is true pixels aren't everything its lens quality and the lighting.

I picked up a basic camera, don't even know the pixel count, but it's got macro focus, so it will focus from about 1.8". If your camera has a regular focus, it may only start at around 18" or 24", which means you can't get a close, in focus pic no matter how much you try.

FWIW, my camera cost about $250c. Great for what it is.

Can't stay...bye bye, now...

Originally Posted by azjoe

It isn't the megapixels that make a good picture. It's the lens, lighting, focus, etc.

... and sometimes the photographer

Originally Posted by bill

We're down to 2 megapixels... do I hear 1?

I make my pics with my cellphone cam (still drooling over the Nikon D50) and it's 1.3 mega pixels. But I also do some post processing black magic on them

Nenad

Well, here's my mindset on the megapixel thing...

First, a word about digital cameras…

Digital cameras capture images electronically using a sensor device that is comprised of a grid of individual detectors, each detector representing a pixel. These sensors come in certain ratios… the ratio of the length to width is usually either 4:3 or 3:2. So, if you have a 6MP camera then it's either going to have a sensor that's about 2,800 x 2,100 or 3,000 x 2,000 pixels. When you take a picture, what ever image is projected onto the sensor grid is what is captured as the “picture”. Whether it’s in/out of focus, whether it’s bright/dim, etc. Let’s pretend it’s a “perfect” world, so we can ignore malfunctioning/noisy detectors, lens errors, focus errors, etc.

Next, what do we need to display the picture…

Well, let’s assume we want to display a picture that’s, say, 8”w x 6”h on our computer screen… that’s roughly the size of some recent pics posted by urleebird. And, let’s assume we’re using a 17” monitor… that’s roughly a display area that’s 13’w x 10”h. Lastly, the monitor is set at 1024x768 resolution… that means there are 1024 pixels across the width of the screen and 768 pixels vertically, which is approximately 78 pixels per inch across the width by 77 pixels per inch vertically… let’s use 80 for both just to make the math easy.

Thus, for our 8x6 displayed picture we’ll need a picture file that’s

(8x80) x (6x80) = 307,200 pixels.

Or .3 megapixels

So, how is this reconciled… how does the multi-megapixel sized picture produced by the digital camera get reduced to the size needed for displaying on the screen?

Well, damn near everything converts, resizes, and massages it… the software in the camera, the software you use to process what’s retrieved from the camera, the software which uploads/stores the picture, and the browser software that is displaying the picture. That this happens should not be unexpected. It’s always been a necessity in the photographic world… even in the days of film cameras we dealt with converting the 35mm image to 4x6 or 5x7 prints, concerning ourselves with the grain of the film, chemical processing technologies, the quality of the enlarger lens, the paper, etc.… all of which we knew made the picture better (or worse).

Hence, how many megapixels do we need in our camera?

Even Superfly’s phone camera produced higher resolution (1.3 megapixels) than we need if the world was perfect… if the lighting was perfect, if the lens and focus was perfect, if the detectors weren’t noisy, if the conversion software was accurate, etc.

So why does a 6mp camera produces better pics than a 3mp camera?

Well, it’s most likely because the camera is newer. It’s more technologically advanced… meaning that most likely the sensor is much higher quality and less noisy, the lens is better, the software in the camera is more sophisticated in focusing the image and massaging/converting the captured image file, etc. Add image stabilization and a host of other features and it should be no surprise that the picture quality increases. But it’s not strictly because there are more pixels… it’s because the pixels more accurately reflect the image they captured.