stephenmold
newbie
Reged: 22/01/2010
Posts: 3
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Hi I have just bought a Pentax W80 camera primarily for it's ability to take pictures under water. When I download pictures to my computer and look at the jpegs in Photoshop Bridge it says they are 72 PPI - I have set the camera to 12 meg photo's at best quality so don't understand why they are comming out at only 72 PPI. My old Canon IXUS 800 IS with only 6 meg ability outputs jpegs at 180 PPI. Can anyone advise ?
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Fen
BAD WOLF
Reged: 12/03/2002
Posts: 25735
Loc: London'ish
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Don't panic...
That's the standard that most cameras set the JPEG files at.
You can easily change it in Elements (or similar software)
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Fen .......... My Fen's AP Galleries - My Blog - My Flickr
"Apologies to right-eyed shooters. You're screwed."
- Joe Mcnally
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El Sid
Going potty
Reged: 14/04/2003
Posts: 10755
Loc: Sussex-by-the-Sea
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Most compacts tend to output their files at 72ppi since it tends to be the standard resolution for most monitors.
As Fen says you can easily reset it in PS or Elements.
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Nigel
Completely BSRIPN 
ElSid Gallery
Terrorist?............or potential photographer?....... 
There are no people more opressed than those who willingly opress themselves
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MickLL
Too Grand, Man
Reged: 01/08/2004
Posts: 3935
Loc: SE England
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Quote:
Most compacts tend to output their files at 72ppi since it tends to be the standard resolution for most monitors.
As Fen says you can easily reset it in PS or Elements.
And to go with the 72dpi you will probably see that the picture is said to be of a huge physical size.My own camera (make irrelevant) also defaults to 72dpi but says that the picture is A3 size when the camera is set to the lowest quality and almost 1.5 metres by 1 metre when at the highest quality.
As the others have said you can trade dpi against physical size so by setting your photo editing software to a lower physical size you will see the dpi increase. When I talk size here I'm effectively talking print size. The size on screen is another kettle of fish!
MickLL
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stephenmold
newbie
Reged: 22/01/2010
Posts: 3
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Thanks Fen I guess you just change the reolution in Image size. Had a look at your website - very nice - and glad to hear the good news about your back. I too have a small offering at www.mold.me.uk
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LargeFormat
Pooh-Bah
Reged: 24/10/2006
Posts: 1912
Loc: Cumbria and Buckinghamshire
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Just to make it clear what is happening (and apologies if I'm telling you how to suck eggs)the pictures will have recorded the full 12.1MP. That is the resolution and you don't want to change that in your primary copy. You will want to change it on a copy if you want to post a picture on the forum and you will set the image size of the longest dimension at 600 pixels for that. The 72dpi is just how they are displayed. On screen 72dpi is about the resolution of the screen. For printing them you may want to use 300dpi. As stated you can switch around the dpi measure but your 12.1MP will always be there (unless you change the image size)
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ermintrude
Hinkypuff
Reged: 30/06/2003
Posts: 15143
Loc: London, UK
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Well while Im here waiting for my tea to cook Ive drawn ya a nice pretty diagram 
Basically your camera only records the exact same amount of pixels. eg this compact here records 2816 x 2212 = 6,228,922 pixels. If I displayed the whole thing at 72 pixels per inch it would occupy more space than if I displayed those exact same pixels at 300 pixels per inch, as Im cramming more into the same inch so less inches can be filled. 
Here's my pretty diagram:
Hope that helps
Now Im off to get my tea 
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(Ctrl A > Ctrl C  )
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stephenmold
newbie
Reged: 22/01/2010
Posts: 3
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Thank you to everyone who has responded - I am very impressed with the speed and detail in which my question has been answered - I have learnt a lot today - so thank you
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GlennH
stranger
Reged: 12/05/2005
Posts: 388
Loc: Paris
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72dpi is a Photoshop default as far as I know, and is not dictated by the camera. If you open the same image in a Windows application it'll be 96dpi (actually PS calls it ppi, when in reality it only has any relevance to the document size/print).
Most modern monitors have a resolution which is substantially above 72ppi, with pixel pitch being finer, and pictures looking sharper. This is particularly true of laptops, purely because they often combine smaller screens with HD resolutions.
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Glenn
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LargeFormat
Pooh-Bah
Reged: 24/10/2006
Posts: 1912
Loc: Cumbria and Buckinghamshire
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Quote:
Well while Im here waiting for my tea to cook Ive drawn ya a nice pretty diagram
Nicely explained Erm, I thought I was making it more complicated. However, I think dpi is dots per linear inch not dots per square inch. Thus your 1" square would be 7dpi, your 2" square would be 3.5dpi and your 4" square 1.75dpi.
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