The Truth About Mega Pixels?

[Dirk W]

All things being equal, at what point can the human eye start to see the differences between a 6,8, or 10 mp camera in, say, a 12x16 photo? I read different opinions ranging from "you can't tell the difference" to "the photo still looks good but you can see the difference between 6mp and 10mp." I'm going to take the jump into DSLR soon and tryng to decide where to put the $$. Here's a link that I'm sure many of you have read. It would lead one to believe 6mp would be plenty even with cropping.

http://pogue.blogs.nytimes.com/2006/11/21/21pogues-posts-2/

[Dbl]

Dirk, many variables apply here. Consumer digital cameras always have small sensor chips in them, about the size of your little finger's fingernail. A 5D has a sensor that is roughly 4 times that size. Why does all this matter? What this means is that the signal-to-noise ratio of bigger sensors is better. All other things being equal, bigger sensors give a less noisy, "grainy" image.

Lower noise, in turn, means you can get more sensitivity out of the sensor for the same amount of image grain. Cheap consumer cameras today often deliver noticeably noisy, grainy looking images at ISO 400. Large-sensored DSLRs today can easily make cleaner images than this at ISO 1600, or even 3200.

Now if you are shooting wildlife with a 300mm lens and are constantly cropping the file to get "closer" more mp's would certainly help, but obviously that is not the solution you want, longer glass will get you closer without sacrificing lost pixels.

There really is no easy way to explain all of this without spending some time reading, which you already have done, but any of the DSLR's on the market these days will adequately do what you are asking, give you a usable 12 x 16 print. I regularly make 24" x 30" posters for clients out a file that is shot using the large jpeg mode in my 20D.

Good luck in your search.

[mcary]

I don't have any real insight into this question, but I do know of another photo forum where this debate became a little bit heated and the topic was pretty well covered. I don't know if I'm allowed to refer you to that forum (as far as rules are concerned). So, if anyone knows if it's allowable - let me know and I'll post a link.

[Steve Foss]

Mike, the rule is if that site sells anything at all, then it is a commercial site, and we can't link to it unless they are FM sponsors or staff.

However, you certainly can identify the site without using quite everything. I mean, I've referred people to tutorials at the Luminous Landscape, which we cannot post a link for, but people can figure it out.

Dirk, let me weigh in briefly on Mp count. I won't discuss the all-in-ones because, as Dbl said, they have very small sensors, and the more pixels you pack onto a sensor, the more digital noise you get.

The smallest megapixel count I know of in a DSLR on the market today is a bit more than 6 Mp. The largest I know of is 16.7 Mp. And don't worry if there's one or two I've missed at either end of that spectrum, because the point I want to make is that, unless you are making truly large fine art prints, 6 Mp is plenty if you aren't needing to crop, as Dbl said, to get your images.

I have shot images with a 6.3 Mp sensor and enlarged them to 20x30. They were excellent, and the client was very happy. I've made prints to that size with images from an 8.2 Mp sensor, too. Those are both Canon sensors, but Nikon or Olympus or any number of other DSLR sensors will do as well.

Realistically, jumping from 6 to 10 Mp will give you some boost in final image size, but not as much as you might think. Not, say, a 67 percent increase, even though the straight math indicates you have 67 percent more pixels. It just doesn't work that way.

Also, the image itself will dictate how large you can make it before it falls apart to the eye. Vast sweeps of color and such things can go much larger, for example, than an image that depends on small, intricate detail. If 12x16 is as big as you want to take it, there's virtually no circumstance, determined by Mp count, anyway, where an uncropped 6 Mp image won't give you an excellent print.

That's especially true if you shoot RAW instead of jpeg. Now I'm not going to revisit the old "which is better?" dump. But in my experience in the last four years with digital, I'm able to make bigger enlargements that hold together better from RAW images than jpeg, and I've done some experiments using them side-by-side on the same capture, in which I selected RAW+large jpeg on the camera so the exact same image would be rendered in both formats.

So I recommend getting a DSLR you can afford and that fits your hand well, not one based on pixel count. Anyway, whatever you get with it, have a blast and share your work with us.

[Dirk W]

Thanks for the info guys, Mcary, I'm interested in that link if you've got the directions.

[mnteacher]

I would be interested also.

[carlcmc]

I have a Nikon D80 10mp. One of the biggest things that more megapixels seems to get you is the ability to crop the image to include just what you want and have good results left over.

Nikon with their line and Canon with their line seem to be top bets for quality and longevity (support etc and the line continuing).

[deathmatch782]

I have a Nikon D50. It's 6.1 mega pixels. Works fine for everything I need.

For whatever camera you decide to get, a good lens goes a long way for picture quality.