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Rhobes
Oct 11, 2005, 09:07 PM
I really don't understand the ever increasing megapixels in new cameras. It seems to be a war between the camera manufacturers to sell more, because more is better, and people generally thing that has to be better.

My basic thought was your printer resolution basically determines the final outcome. If my 3.2 megapixel camera can print photographic quality 8x10's with my Epson set to max in all modes & printing at 300 dpi what is my gain with a 10 megapixel camera printing at those same settings on the same printer?

I understand that I could print a photo quality 5 foot x 5 foot poster with some of these cameras where-as mine could only do the 8x10 but who of all those buying these 10-12 megapixel camers have $20K dollar industrial printers to do this? Hey, what am I missing here? :cool: Whats the gain with snapshot prints or even 8x10"s?



homerjward
Oct 11, 2005, 09:11 PM
I really don't understand the ever increasing megapixels in new cameras. It seems to be a war between the camera manufacturers to sell more, because more is better, and people generally thing that has to be better.

My basic thought was your printer resolution basically determines the final outcome. If my 3.2 megapixel camera can print photographic quality 8x10's with my Epson set to max in all modes & printing at 300 dpi what is my gain with a 10 megapixel camera printing at those same settings on the same printer?

I understand that I could print a photo quality 5 foot x 5 foot poster with some of these cameras where-as mine could only do the 8x10 but who of all those buying these 10-12 megapixel camers have $20K dollar industrial printers to do this? Hey, what am I missing here? :cool: Whats the gain with snapshot prints or even 8x10"s?
well, 8x10 at 300dpi is actually 7.2mp so a print from your 3.2mp camera will have to be enlarged or something to print like that. but an issue especially in point and shoot/all-in-one cameras is noise. if a 10mp camera and a 3mp camera have about the same amount of noise, when printed at, say 4x6 at 150dpi the 10mp will look better because the noise is less visible. i think...(correct me if im wrong)

Mac_Freak
Oct 11, 2005, 10:03 PM
You might want to read a bit long article on Megapixel Myth on Ken Rockwell (http://www.kenrockwell.com/tech/mpmyth.htm)

It is really good at explaining image pixels and print pixels as well as image quality and gains or losses with higher MegaPixel cameras

MistDragonCA
Oct 30, 2005, 12:26 AM
to convert from scanning resolution to line screen where line screen is measured in dots per inch and scanning resolution is measured in pixels per inch...

SR=LS*(2(delta))

where delta=size_0/size_final

so basically, say you have a picture that you want to be printed out at 150LS. (this is the base resolution for things like pamphlets and most things printed on offset presses.) the scanning resolution is 150*2=300 pixels per inch. this means that the document needs to be scanned or converted to at least 300 ppi.

BrandonSi
Nov 23, 2005, 01:46 PM
This is always a source of confusion for some people, and honestly this is only of concern if your planning on using your photos in print. If you don't, don't concern yourself with dpi or ppi, or even megapixels. Any decent consumer camera (5mp+) today should be capable of taking a high enough resolution for viewing on a CRT or LCD in most circumstances.

If you are using photos in print, then it's not as difficult as it's made out to be. Keep in mind the normal human eye can only resolve around 267dpi. Most prefer photos to be printed at 300dpi, and this is set as a standard.. a sort of "perfect" print resolution. If I had a photo that I shot from my camera, and wanted to print an 8x10 of it at 300dpi, it would need to be at a resolution of 2400x3000. 8 * 300 = 2400 and 10 * 300 = 3000.

If I wanted the same photo in 8x10 at 267dpi, the resolution would need to be 2136x2670.

The big thing to keep in mind is that most cameras use a 3:2 image ratio, so you need to crop photos to fit stanard print sizes, like 8x10. A 3:2 image would produce an 8x12 print natively.

kgarner
Nov 23, 2005, 03:02 PM
The other benefit of high MP is the ability to crop your images and still having enough resolution to get good prints.

-hh
Nov 23, 2005, 03:49 PM
The other benefit of high MP is the ability to crop your images and still having enough resolution to get good prints.

Agreed. Roughly speaking, the 15% increase in pixels for 6-->8MP means that you could crop the 8MP by 15% and end up with the 6MP's worth of pixels.

Since this cropping results in a reduction in the field of view, it is effectively an increase in a telephoto's length.

I'm not sure exactly how to calcuate this theoretically, but if we assume that its as simple as the 15% change, then the new effective focal length would be simply increased by 15%. FWIW, this approach makes sense to me, since the rule of thumb to double the effective focal length is to crop to half of the original height & width (1/4 of original frame).

By this means, a 300mm telephoto would effectively become a ~350mm lens. Considering how expensive big glass gets, so long as all other factors remain relatively equal, it is certainly worth considering as another option to "reaching out" while maintaining image quality.


-hh

seenew
Dec 1, 2005, 07:09 PM
The other benefit of high MP is the ability to crop your images and still having enough resolution to get good prints.

That's a major factor in some of those pocket cams that have no optical zoom, but 8MP.

iGary
Dec 1, 2005, 07:11 PM
Like I said earlier, that is why everyone needs one of these:

http://img.engadget.com/common/images/7828362158325683.JPG?0.6086941179428317

22MP

seenew
Dec 1, 2005, 08:15 PM
^holy crap, what is that?!

iGary
Dec 1, 2005, 08:18 PM
^holy crap, what is that?!

I hope your credit card has a big limit.

http://www.bhphotovideo.com/bnh/controller/home?A=details&kw=HAH2D&is=REG&Q=&O=productlist&sku=398349

mkrishnan
Dec 1, 2005, 09:04 PM
For me, the MPs are important for the cropping reason to some extent (I don't always personally care for standard aspect ratios) and for large prints. At 16x10, a 6MP camera like my 300D only gets about 200DPI full crop. Which is still actually quite good enough. In fact, my wall prints are at 150 or 180, I think.

And yes, Gary, I know what I need to go get. But unless you wanna be my sugar daddy, I don't think I'm gonna get it. *sobs*

steveedge
Dec 10, 2005, 11:19 PM
The bottom line is that pixels do matter and more of them make sharper images. As for printing differences, it is largely a matter of scale as to whether you can tell any difference in the sharpness of an image. If you print at larger sizes and resolutions then you can tell a difference, the higher pixel camera will produce a sharper image if you are measuring apples to apples and oranges to oranges, so to speak.
so bottom line is, how large do you want to print and is it large enough that the number of pixels come into play ?
I read the ken Rockwell article someone posted and while he starts out talking about (dispelling) the megapixel myth, near the end of the "print size" section he clearly states (contradicts) that photographs from 4 mega pixel cameras are NOT as sharp as photographs from 6 megapixel cameras.
His logic seems to be that a fuzzy image is as good as a sharp image because it looks ok to him and he therefore thinks it will look ok to everyone else.
That is fine as a personal preference but it doesn't do much for his argument.

I do agree though that on a desktop printer you may not be able to tell a difference..but that doesn't mean there isn't one. ;)

skidknee
Dec 11, 2005, 04:05 PM
Like I said earlier, that is why everyone needs one of these:

http://img.engadget.com/common/images/7828362158325683.JPG?0.6086941179428317

22MP


Digital back.... *drools*



Anyway, MP isn't really too important. Alas the megapixel myth, where every company is using MP to advertise for their latest and greatest, to make it seem that much more amazing.

I own a 20D, which is 8.2 MP roughly, and I've printed 32 x 54 inches with a RAW file, and it looks pretty damn crisp. I could probably blow it up even larger, using an Epson 9600. So in terms of size, you can do a lot, it's really the wide format prints that MP start to affect what scale you want to print at.