20D - what's hi rez?

Pardon me but i've misplaced my 20D instruction book, and i'm in trouble ..... either my problem is user-caused, or else photo-editing program-caused, this is what i need to find out ... with some help from out there. Here's the problem ......

Had the camera 6 months, shot sports all fall, then skiing and ski-area-related stuff all winter, as a contributing photographer. I've shot everything at 'Large/hi quality' settings, or medium/hi ... and even RAW in the past couple of weeks. However, after running them through iPhoto (i've been using a new G4Mac since Xmas), it seems the end result images are all turning out to be 72 d.p.i. only. ..... whereas i thought the hi rez settings of the 20D, ensured the images would be 300 d.p.i.

I've started a thread on an iPhoto forum also, but i'm looking for opinions from knowledgeable 20D users also. Thanks!

dpi is proportional to image size. Lower the Image size and you raise the dpi.

Dont worrie about this.

You've still got 3500 pixels across right? So have a think about what the dpi means. A hint: the dpi recorded in the EXIF is as useful as tits on a bull.

Bloody aussie giving me an answer like that .... (watch out because i'm one too) ... but hey, my knowledge of dpi is it has to do with printing quality, right? But doesn't the "hi" setting of each image size ensure that there's enough, shall we say 'density' for lack of adequate techy wordage, to enable good printing?

See, I'm shooting the images as large files, but after burning the cd, they're coming out low dpi, and there's complaining at the other end that my images aren't 300 dpi ...... what am i doing wrong if i'm taking the photos at hi rez? I just don't understand .... yet.
Does it mean i should shoot in RAW only if recorded dpi is useless in EXIF?

dpi is the dots (pixels) in an image, divided by the inches. If you want more DPI, just reduce the inches.

(As MiG82 so eloquently put it The dpi your image editing program is showing you is pretty well meaningless).

Jim_T wrote:
dpi is the dots (pixels) in an image, divided by the inches. If you want more DPI, just reduce the inches.

(As MiG82 so eloquently put it The dpi your image editing program is showing you is pretty well meaningless).

thanks ... it's obvious there's a lot of gaps in my knowledge ... as far as my own image editing program is showing me, i can't see any dpi ... that info is coming from who i hand over the images to after putting them on CD ... and they say if they increase dpi, the image gets too small, as you say ... so how do i present them a large image with high enough quality to print large-sized images from? At the moment, all they can do with them is use them in the brochure only ... with no possibility for posters, etc.

Since DPI = Dots / inches, you must know how many pixels you have and how many inches you plan to spread them across in order to know the FINAL dpi when you print.

For example.. If you have an image that's 1000 pixels across and you spread those pixels across 10 inches of paper, then the DPI is 1000 pixels / 10 inches = 100 DPI.... You see if you spread 1000 pixels across 10 inches, you MUST have 100 DPI.. It's mathematically impossible to have anything else.

So.. If someone wants to print an image at 8 inches by 10 inches at 300 DPI, then the image MUST be:

8 inches X 300 dpi = 2400 pixels
10 inches X 300 dpi = 3000 pixels

If someone tells you they need so-many-dpi.. Then tell them they have to provide the inches so you can calculate the DPI.

The DPI that's provided by editing programs generally uses some default inch setting. (Unless they can read your mind, image editing programs have no idea how big you plan to print your images). In other words, the default DPI they give you is meaningless. The actual DPI doesn't happen until you actually spread your image pixels over inches of paper.

If it helps you, here is a link to download a pdf of the manual...

http://www.cleaningdig​italcameras.com/pdf/EO​S20DIM-EN.pdf

I often see them on ebay for sale as well.

EDIT: Just had a look, the ones on ebay seem to be some 'leech' selling a link to download the pdf!!

All of the above . You can download the manual from Canon.

kevin_c wrote:
If it helps you, here is a link to download a pdf of the manual...

http://www.cleaningdig​italcameras.com/pdf/EO​S20DIM-EN.pdf

I often see them on ebay for sale as well.

EDIT: Just had a look, the ones on ebay seem to be some 'leech' selling a link to download the pdf!!

thanks for the tip Kevin .... and for checking it out also!

Thanks ... couple more corners of the house to look for it in, then i might go the download route. thanks again.