rhadams824 Loc: Arkansas

I have a question about the DPI data on photographs. I notice that most of the time it varies from 360 to 300 DPI depending on the camera. If a camera produces photos with higher DPIs than other cameras is this one criteria for camera selection?
Do photos with higher DPIs contain more detail hence can be higher quality?

In looking at reviews, lines per inch at varying f stops is often stated as a measure of lens and camera quality but I have not seen DPIs mentioned.

oldtigger Loc: Roanoke Virginia-USA

DPI is a printer related term, not applicable to cameras/lenses

LarryFB Loc: Depends where our RV is parked

Outrigger is absolutely correct. I have never seen DPI information in a EXIF file and it doesn't not make sense to have it there. It always refers to how the photo is viewed on a device.

For high quality prints, you usually want something between 240 and 360. For computer screens or digital frames you would want something around 72.

EXIF usually has the photograph size listed in pixels. For example, my Nikon EXIF says a photo is 4928 pixels wide by 3264 pixels high. This is with a 16Mega Pixel sensor. I can save the file or export the file to a specific size (and I may have to crop the photo to get what I want), at a certain pixel density.

High quality prints are usually printed at about 300 DPI (although the 300 number might change, depending on who is doing the printing and what their recommendations are).

The only time you are concerned about DPI is when you are saving or exporting a specific image for a specific purpose (print, display on a computer, display on a digital frame, or whatever). You control DPI with your software, the camera only controls the pixels and that is a function of the sensor.

TheDman Loc: USA

It is absolutely meaningless.

TheDman Loc: USA

Actually for computer screens you shouldn't give it a second thought. It could be 1 dpi or 8,000. It doesn't matter.

Apaflo Loc: Anchorage, Alaska

Exif data is specified in the Standard of Japan Electronics and Information Technology Industries Association document "JEITA CP-3451" titled "Exchangeable image file format for digital still cameras: Exif Version 2.2". (It is worth noting just to start with that it is not EXIF, but rather Exif.)

A list of "Tags relating to image data structure" starts on page 17, and on page 19 it lists XResolution and YResolution tags. They are defined as DPI:

The point is that Exif data absolutely does have a tag for DPI. And DPI is not just for printing, it applies to any display device including monitors. The value of 72 is the Exif default if nothing is set! It is not correct for monitors, none of which display using 72 DPI.

However it also needs to be understood that display devices (including both monitors and printers) themselves will totally ignore the Exif tag, simply because they display at a fixed (in the hardware) resolution and cannot change. The DPI tag provided by Exif data is for information purposes. Some software editing packages use the Exif tag value to "help" users scale images to different sizes, though its use is almost universally confusing.

Simply put, if you change the Exif tag in an image file it does not change the image data. It can be set to 10 or it can be set to 10,000. Your image will display exactly the same on your monitor or print exactly the same on any printer regardless of which value the tag is set to.

TriX Loc: Raleigh, NC

Very interesting information.

TheDman Loc: USA

Half of it wrong.

TriX Loc: Raleigh, NC

Please elaborate.

oldtigger Loc: Roanoke Virginia-USA

what does "Exchangeable image file format for digital still cameras: Exif Version 2.2" have
to do with camera or lens quality?
Although many cameras have display devices attached to them, the device has
nothing to do with the captured image quality.

Apaflo Loc: Anchorage, Alaska

The OP did not ask about camera or lens quality.

All of the questions asked were about "DPI data on photographs". You may not have grasped that that is asking precisely, and uniquely, about Exif data.

In specific it is Exif Version 2.2.

Apaflo Loc: Anchorage, Alaska

And if it was you could have stated which part that is.

It isn't wrong though. You may not know that... if you want to discuss it in a civil manner, just ask about any part of that article. I can go into more detail, with history and with further authoritative quotes to add to those from the Exif Version 2.2 standards document.

oldtigger Loc: Roanoke Virginia-USA

my mistake.
When the OP said things like :"is this one criteria for camera selection?"
,"...hence can be higher quality?" and "...measure of lens and camera quality"
i just assumed he was interested in image quality.

BHC Loc: Strawberry Valley, JF, USA

Do you mean PPI?

Apaflo Loc: Anchorage, Alaska

You are using a predicate from the second paragraph as the subject of a sentence in the first paragraph. That is a mistake indeed...