Dpi for ixus 500?

[andylepki]

Hi

I take all my pictures at superfine 2592 x 1944 on my Canon Ixus 500.
Could anybody tell me what this translates to in terms of size in mm and DPI ?


Thanks in advance
Andy

[Poco]

It all depends on how big you want it? If you want to print it 150mm wide then that translates into 150mm. Now, of course, DPI or PPI (pixels per inch) and mm don't make any sense together.

If you know how big you want it, then the dots (pixels) per inch is easy to calculate. DPI = dots/inches so at 6" wide it would be 2502/6 or 432 DPI on the horizontal.

Why are you asking? Are you are asking what is the maximum size you can print the photos? There is no maximum. You can print them any size you want. However, you will find that the larger they get the worse it will look up close. But if you were going to paste it on the side of a building 20 stories above the ground then you could print it pretty big without anyone noticing the quality difference. There are a few factors that affect how big you might want to print it including the distance at which you will be looking at it. The best thing you can do is try it. People will give lots of opinions about how it can't be printed larger than a certain size, but it is very subjective you may really like a 40"x60" print from your camera, you may not.

[andylepki]

Thank you very much for your help.
I was recently approached by an ad agency who wanted to use an image of mine for a full page A4 colour magazine ad.
Unfortunately, it was an old image that I only had as 1024*768 - so by your equation, for a 12" page ( approx 297 mm ) the best resolution I could offer was 85.3 DPI which would clearly not be good enough for full colour reproduction.
I'd obviously like to make sure that for any further requests I could provide at least the minimum requirement, so it's better to know now if I need to upgrade my camera to something a bit more 'professional'.

Murphy's law is I'll upgrade, but never get another call again!

Regards,
Andy

http://www.lepki.com

[Poco]

Ya, 1024x768 is a bit small. Then again, I've printed some amazing 8x10 photos from my old 2.1MP camera. It seems to depend a lot on the content (some things scale up well). Your Ixus 500 (Is that the same as the s500 in North America?) should be able to print that large without any trouble at full resolution. I have a lot of great 8x12 prints from my s400.

Just out of curiosity, what DPI did they ask for? You could always try upsampling your original with some of the available software out there and see how it looks. I don't know much about them, but I've heard they can do a better job at guessing the missing data than the defaults in Photoshop.

[andylepki]

They didn't ask for a specific DPI, they just asked for the best resolution I had. I was tempted to resample in photoshop, but thought a creative agency would be able to tell straight away.
I'll take a look for some software and see what it can do - thanks for the tips.

Incidentally, in my 'real job' I'm doing some marketing research around a photography competition. I can't enter it myself. They're asking for food related images - 200mm wide at 300 DPI. I now know what that means!

http://observer.guardian.co.uk/seedsofchange