How many pixels is really needed?

For those of us who dont need to make or never make enlargements larger than 20x24 inches, how many pixes is really needed? Canon came out w/ a 16MP camera. I recently printed a 8.5x11 from my D70 (6mp) in high jepg straight from the camera and the quality was just as good as from 35mm using the same equivalent film.

So do I need or want such a high pixel count? This will also force me to need a very large storage card as w/ my D70 I can get almost 300 images on one 1GB card in high jepg.

Also if any of you super informed photogs have any inside scoop, do you think that some day cameras (mainly DSLRs) will come w/ internal storage so cards are not needed? I would think that would be a smart move and an economical one as well. You buy your new 16 mp camera and it comes w/ internal 6 GB storage! And a slot for added if needed! Only a high school drop out would think of that!

Fat Boy

ps: every one have a Merry Christmas!

From a somewhat (subjective) technical point of view, a good image needs about 3lp/mm when viewed at 10 inches. This is a reasonable viewing distance for most prints.

Now it takes 2 pixels to make a line pair. In practice it takes about 2.5 because cameras aren't designed to take pictures of lines. Thus it takes 7.5 pixels to meet 3lp/mm. Converting to inches this becomes about 191 pixels per inch. In practice a finely detailed print will need about 250 ppi.

Extrapolating this out to a viewing distance of driving by a billboard in your car you can see why you don't need that much resolution and how 35mm/digital works fine.

BTW, most cameras have built in memory. It's called a buffer.

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Originally Posted by darkman

BTW, most cameras have built in memory. It's called a buffer.

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While true, that's hardly what Fat Boy was talking about.

Fat boy, it's really better to use external flash cards for two reasons.

1) Your total number of pictures on a shoot is limited only by your batteries and budget.
2) Flash memory prices are continuously dropping. Therefore, if you just wait a bit you'll be able to snag a lot of memory for very little dough.

Your way you lose both of those advantages.

I can see internal storage being the "norm" at some point, the thing is it will be costly. The reason I can see the move towards a larger, internal storage is..... think iPod. The Flash players are going away, people want the 20-40-60 gig storage all in one, and are willing to pay for it (Apple's stock is up up up due to that goofy device).

How much storage is a reasonable limit to include though? Can you honestly fill up a 4GB card in one shooting session, for a casual enthusiast? Not to mention downloading that to your pc, ouch.

I'd welcome the idea, but would also like to either be able to upgrade the storage somehow with larger modules, and/or include a slot for CF cards for additional needs.

And, FWIW, I can print up to a 4x6 with an old 3 megapixel camera, and can't see a difference worth noting. I've gone up to 8x10, the edges were slightly "not sharp", but after cropping, it was fine.

Depends on your needs and your tastes.

10k

It's amazing how much the price of CF cards have fallen over the last year. I think it's a better idea to stick with removeable media like CF cards so that you don't have all images in one place. If you lose (one way or another) one 512mb or 1G card, you're better off than losing one 4G device with all your shots!

Back to your original question... It would be interesting to see prints that size side by side from 6mp and 16mp cameras. You'd have to shoot the same subject on the same day, same lens, same person doing the post work and prints. I'm sure you'd see a difference, but I'm pretty happy with the 16x24's from my 6mp Fuji S2. They're as detailed as MF.

The 16mp doesn't only help with making obscenely large prints or big prints from cropped images but is probably most usful for editing.