Sony DSC-H5 picture resolution [Archive] - Digital Camera Resource Page Forums

barrylawrence

11-02-2007, 04:56 AM

I have my DSC-H5 set to fine pictures.. with the largest image size possible 7 mg...
and yet.. when I download my pictures to my computer and open them in Photoshop.. it always has a resolution of 72 dpi...
The image size is huge.. that's fine.. but the resolution is ALWAYS listed at 72 dpi...

now in Photoshop I suppose I could change it back up to a high resolution, but it's not a real resolution change.. a bit of a cheat and not real...

so... what am I doing wrong with my settings? why can't I get a high resolution picture, or am I thinking wrong here? thanks

Sintares

11-02-2007, 11:43 AM

Sigh..

The 72dpi means nothing, its just a number and does not affect the number of pixels the camera takes a photo with.

Some cameras set the dpi flag at 72, others at 96, 120 etc etc

Its just a software flag..

When you import the photo into an editor the size in inches is displayed by dividing the pixels by the dpi flag.

Except a digital picture file does not have a size in inches.. it has a size in pixels, until you print it has no physical size..

The H5 has a resolution in pixels of 3072 x 2304

Have a look at the "size" in photoshop.

If you where to print that file at 72pixels per inch you would get an actual print at 42.667 x 32 inches

Now change the 72ppi to 300ppi and make sure resample is not ticked.. there photoshop reports the same number of pixels and magically the document size is now 10.24 x 7.68inches.

You see ? Same number of pixels and the image has not been changed at all, just (when saved) a flag is reset from 72 to 300.

So what I am saying, the 72 or 96 or whatever is just a number not affecting the image.

If for example you where to not change the image from 72 to 300 ppi and tell photoshop to print at exactly 10.24 x 7.68 inches, then the pixels are divided automatically out and you get roughly 300ppi, even though the flag is set at 72ppi.

Summing up

Ignore the dpi/ppi figure, that is only calculated when you print and tell photoshop and the printer what actual size to print at, until then you have a file with pixels and no set physical dimensions.

The human eye is typically for a hand held and inspected print unable to tell the difference much beyound 300 pixels or so , ie a 300ppi print looks the same hand held as a 600ppi, and in actual use a hand held print will typically look ok down to 150-200 or so, and for a wall mounted print where you are standing well back you can get away with even less pixels per inch.

Indeed stand fifty yards back and you could print that file at billboard size no problem.