Image quality stinks

[swisherphotography]

HELP! If anyone could answer this 3 questions it would be greatly appreciated.

Up until about 1 year ago I have always used medium format and my canon E0S A2E. I took a leap into the digital world not having a clue as to what I was doing. I thought It wouldn't be that difficult since I have run photoshop before. Here are all the facts:

I scan images and enlarge them to 11x14 16x20. No problem
I use a Kodak easyshare. (5mp) and can produce 11x14 images. No problem

When I use my Canon 10D, I sometimes get horrible results. When I photograph, the image is the same size in the camera. Since photoshop 7 doesn't do RAW I convert to a Tiff file. HOWEVER when i open them in photoshop, the resolutions are so different I can't get accurate results. For example. I photographed a bride at the altar. The shots were 2 minutes apart. Same location. Same lighting. Let's say print A opened to a small size with 250 resolution. Print B was a 30x40 650 resolution. So now I can't produce a quality 8x10 out of "A" but can produce a quality 11x14 out "B" WHY is this happening?

I also photographed a wedding where the natural 2 pm daylight 400 spd produced a quality 5x7 image. The reception was in a dark facilty (dark walls, no window, all lights off) I used on camera flash and 800 spd. I produced 8x10. WHY is this happening?

Realistically, what is the largest size image I should be able to produce from this 6mp camera? Quality enough that a customer won't notice any pixilation.?

If anybody can help me please post back or email at stephlong@charter.net

Thank you
Stephanie

[Toogy]

What program are you using to convert raw files to tiff?

[Bodog]

Stephanie, welcome to the forum! I'm a little confused by your question, but it sounds like you are confusing the ppi/dpi "resolution" of an image with image quality. The pixel count is the determining factor, not the ppi/dpi setting.
I believe the 10D has the same sensor as my DRebel, which gives me a 6.3 mpixel image. The image dimensions are 3076 X 2052. Depending on which converter I use to convert the raw file, Photoshop will show a "resolution" between 72 ppi and 300 ppi. As long as I leave the "resample image" box unchecked, I can change that to any number I wish, without affecting the quality of the image. Try it. You'll notice that when the ppi count changes, the printed document size changes also. The lower the ppi, the larger the print. You can also change the width or height of the print. Notice that when you do, the ppi will change to match the new print dimensions. You will also notice that changes to these number does not affect the actual image size (as long as the re-sample box is not checked). As long as you have enough total pixels to keep the ppi above 150 at the size you need to print, you should get a decent print. Generally, the smaller the print you are making, more ppi you need. (big prints are usually viewed from a farther distance) At some point you may need to re-sample the image to increase the pixel count, but that is another issue, and to my mind last resort. I'm quite happy with the 11 X 19 prints I'm getting from my Drebel, printed at 150 ppi...

So, if you want an 11 X14 print from the 10D you just need to set the ppi to somewhere around 220. Unfortunately the aspect ratio of the 10d's image quite doesn't fit the 11 X 14 aspect, ( you can see this by entering a width of 14 or a height of 11) so you are going to have to do some cropping to get a good fit.

Hope I didn't misunderstand your problem and this helps...

[tim]

I think bodog answered your question. If you do a little search around here on ppi and/or dpi that should help you understand things a little better. If it doesn't answer your question just clarify it and we'll have another go :)

Print size: I printed this picture (http://www.mrwild.co.nz/PhotoGallery/2004/NewYears/slides/CRW_4701.html) taken with my old 300D at A1 size, about 30*20, and it looks great! If you stand closer than a meter you can see it's not perfectly detailed, but you can't see pixels. I probably wouldn't print pictures of people that size, but A2 should be acceptable for most people.

[scottbergerphoto]

I suggest using Qimage from www.ddisoftware.com for resizing and printing. It has its own algorithyms for doing this and does a wonderful job. It even sharpens the image for printing.
Scott