picture quality - DPChallenge Forums

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

04/20/2005 04:41:40 PM · #1

i was speaking to a consumer about quality versus pixels, and she exclaimed that it was her idea that the more mega pixels the better the quality and i told her thats not always the case especially in hers trying to print a 4x6 with 12MP the pictures will look really digital and nastey unless she crops and in larges and it wouldnt have made to much difference if she used 3 or 2 MP its also my understanding that pixels cause a picture to become more sharp and punch when blown up for a example 8x10 which would then correlate to quality but with a 4x6 it doesnt really matter she could have used 0.3 MP and got pretty much the same results ladies and gentlemen DPC please tell me iam right or am i *****?

GeneralE

Canon PowerShot S3 IS

04/20/2005 05:01:56 PM · #2

For excellent quality prints for a 4x6 you need 1200x1800 pixels -- about 2-1/2 megapixels. More than that may be "overkill" but making a small print from a large file will NOT usually cause much of a problem. However, making a pring from too small a file WILL cause problems; a 0.9MP camera is only 640x480 pixels, and will give a barely-acceptable print.

Some of this is dependent on which printer/method you use as well.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

04/20/2005 05:07:14 PM · #3

Originally posted by GeneralE:

lets say you do 0.3 and print at a walmart minilab? what would happen then?

GeneralE

Canon PowerShot S3 IS

04/20/2005 05:14:25 PM · #4

Originally posted by LEONJR:

lets say you do 0.3 and print at a walmart minilab? what would happen then?

That's like 200 x 150 pixels or about 50 dpi -- it will probably look look "pixellated" or blocky/chunky up close. From a couple of feet away it will probably look OK -- you'll recognize the picture -- but probably some detail will be lost.

Also, it's cheap enough -- why don't you try it (take them the same image at low- and high-resolution) and report your findings?

Message edited by author 2005-04-20 17:15:59.

04/20/2005 05:22:06 PM · #5

OK good idea

Canon EF 70-300mm f/4.5-5.6 DO IS USM

04/20/2005 05:25:45 PM · #6

Is there a detectable difference between 300 dpi and 512 dpi (uncropped 4x6 from 300D)? Whatabout 512 and 1024 dpi?

I don't expect a difference between 250 and anything higher can be detected on matte paper, but I'm not so sure about high gloss paper.

cpanaioti

Canon EOS-40D

04/20/2005 05:59:33 PM · #7

If your printing at home you may see deterioration when you go above 250 dpi. If you're sending out to print once you go past the dpi setting for the printer used you will see deterioration as well.

Gil P

Canon EOS-1Ds Mark II

04/20/2005 06:04:16 PM · #8

[quote=Plexxoid] Is there a detectable difference between 300 dpi and 512 dpi (uncropped 4x6 from 300D)? Whatabout 512 and 1024 dpi?

I don't expect a difference between 250 and anything higher can be detected on matte paper, but I'm not so sure about high gloss paper. [/quote

Message edited by author 2005-04-20 18:05:42.

04/20/2005 06:14:16 PM · #9

Um, yeah, that's what I said :D

04/20/2005 06:16:31 PM · #10

Originally posted by cpanaioti:

If your printing at home you may see deterioration when you go above 250 dpi. If you're sending out to print once you go past the dpi setting for the printer used you will see deterioration as well.

Most home printers support well over 1000 dpi, don't they?

04/20/2005 06:22:35 PM · #11

Listen i wish i could anwser that dpi question but to bad iam not that familiar with dpi BUT i want to though for some odd reason i feel like i might learn better here peer to peer versus reading on the internet its to confusing all i know is that it means dot per inch and thats about it now you might think thats sad lol BUT i only used FUJI cameras and to FUJI everything is about PIXELS. So unlike like the canons and nikons that have swtiches i dont so my question is what is dpi? how does it correlate into image quality? In photoshop CS why all my pictures come out under image size as 72 but could be 3040x4080 (12 MP) if dpi renders size? like i said its confusing and why if i change it to 300 dpi everything looks like blocks at 100percent ? i know its alot to chew but if you can help me please do thanks!

Sony 24-70mm F4 Vario-Tessar T* FE OSS

04/20/2005 06:31:28 PM · #12

DPI refers to how many pixels are in an inch when printing.

Bear_Music

Samsung Galaxy S24 Ultra

04/20/2005 06:41:13 PM · #13

DPI (dots per inch) is a measurement of printer resolution. PPI (pixels per inch) is a measurement of image resolution. To a certain extent they correlate, but not precisely. If your ppi is significantly greater than your printer's dpi capabilities, you will have a problem; the computer is trying to send to the computer more than one set of instructions for each location the printer is capable of mapping, and this can actually cost a LOSS of detail compared to an image printed to the same size with ppi reduced to match printer's target dpi. There's never anything to be gained by having a ppi (at the actual printed dimensions) greater than the printer's dpi capabilities.

This is not something I'm truly expert at however. I expect there are a number of frequenters of this site that can explain this in greater detail. I believe some of the better printers also have software built in that downsamples as needed to match resolutions, but I'm not sure.

Robt.