Dumb question

[metoo]

I was looking at my Exif data on flikr and it says

X-Resolution 72 dpi
Y-Resolution 72 dpi

What is this? These numbers don't seem very high is this right? Are these pictures going to print ok? I haven't figured out RAW yet so I'm shooting in JPEG Fine and large. AM I doing something wrong?

Sorry for the really dumb question .

[corvus2606]

That means that you image is being saved at 72 dots per inch. for professional printing, they prefer to see 300 odd dpi.

Your best bet is to start shooting raw, It gives you much greater control over the final image. and allows you to export your jpegs at whatever resolution you need.

[metoo]

Ok here is the whole EXif data. This was SOOC.

Camera Canon EOS Digital Rebel XS
Exposure 0.008 sec (1/125)
Aperture f/2.2
Focal Length 50 mm
ISO Speed 200
Exposure Bias 0 EV
Flash Off, Did not fire
Orientation Horizontal (normal)
X-Resolution 72 dpi
Y-Resolution 72 dpi
Date and Time (Modified) 2010:12:15 11:42:26
YCbCr Positioning Co-sited
Exposure Program Manual
Date and Time (Original) 2010:12:15 11:42:26
Date and Time (Digitized) 2010:12:15 11:42:26
Metering Mode Partial
Sub Sec Time 35
Sub Sec Time Original 35
Sub Sec Time Digitized 35
Color Space sRGB
Focal Plane X-Resolution 4438.356164 dpi
Focal Plane Y-Resolution 4445.969125 dpi
Custom Rendered Normal
Exposure Mode Manual
White Balance Auto
Scene Capture Type Standard
Macro Mode Normal
Self Timer Off
Quality Fine
Canon Flash Mode Off
Continuous Drive Continuous
Focus Mode One-shot AF
Record Mode JPEG
Canon Image Size Large

What is the difference between those two? I was looking back at images i took with my P+S and it was like 180 dpi vs the 72 dpi. I'm not quite understanding how this works. Is this something that happened when I uploaded to flikr or do I have something set wrong in my camera? Is there any way to change these numbers with out shooting in raw? I'm not a professional so does it matter at this point? At what size print will this be a problem?

[corvus2606]

I dont think he focal plane resolution is overly important for printing, but If you are wanting anything larger than an 8"x5" print, 72 dpi is a little low.

I'm not a canon user, so i cant tell you what settings you need to change, but if you are shooting jpeg, then it is doing it there, not when you upload to flickr. your camera's manual should be able to tell you how to change the settings.

I think you are possibly letting yourself get intimidated by the concept of shooting raw. It shouldnt change your shooting method at all. but it will allow you to get much nicer looking images because you have control over things like clarity and contrast. I'm not a pro, but I have shot raw from day 1, I will never consider only shooting jpeg simply because I feel it limits me. But to each their own.

What I would suggest, is that you try shooting RAW+jpeg, that way you have both types, you arent out of your comfort zone, but you will have a chance to play with the raw images, and see exactly how much more you can do with it in post production.

[metoo]

Originally Posted by corvus2606

I dont think he focal plane resolution is overly important for printing, but If you are wanting anything larger than an 8"x5" print, 72 dpi is a little low.

I'm not a canon user, so i cant tell you what settings you need to change, but if you are shooting jpeg, then it is doing it there, not when you upload to flickr. your camera's manual should be able to tell you how to change the settings.
.

WOW that is crappy! I don't understand because I have it set to the highest setting it goes.... It is set to large and fine. It seems like i should be able to get usable prints out of it even in JPEG. Could something be wrong with my camera?

[Mr Guy]

Simply put, it's extra information that SOME programs and SOME printers will use. You're missing the information that will tell us if you can print the pictures ok, but my gut level reaction is yes.

Your ACTUAL resolution is more critical, as most printers and (all?) print shops will correct the print dpi to whatever it needs to be to match what you request.

Basically, think of it this way. When the image is created, it has a certain number of pixels wide and a certain number long. To know how big to display it, you take the number of pixels and divide it by the dpi. However, it works the other way too. If you know how big you want to print it, you take the resolution and divide it by the size, and get the dpi you have to print it at. 180 dpi is sufficient, although higher is generally better, and 300 is considered "standard".

Help?

*Edit* Incidentally, RAW doesn't have much to do with it. Yes, it's true your program will set the desired print size if you want, and use the resolution to figure out the DPI for the image. Default is usually 72 DPI because that's native for most monitors. When they print it, they'll figure it out.

As I said above, the reverse calculation is more important for figuring out the actual resolution:

Size in inches to print X 150 (minimum for "photo quality") dpi = necessary resolution

so like an 8x10 needs to be 1200 x 1500 MINIMUM to get a photo quality print.

The differences in DPI and it's perception on quality is also strongly influenced by the distance you intend to view the image from. For example, billboards are massive, but crappy DPI, because you view them from far away so your brain resolves the difference. Newspapers look fine, but when you look closely, it's easy to see the colored dots making up the image.

[metoo]

Ok so your saying the 72 DPI is because I'm viewing it on a monitor? I have my camera (canon XS) set to Fine and Large in the camera body is says my pics should be 3888x2592 . Which I thought would be PLENTY large enough for my uses even with a crop. I rarely print a picture larger than 8x10 or 11x14(and that one is rarer). I thought I was fine, but i haven't printed a picture in a long time. Seeing the 72 DPI made me nervous. Paticularly when i looked back and I had a 180 DPI wiht my old point and shoot camera...... It just didn't make sense to me. I just went and reread my manual and triple checked all my in camera settings and I don't see how I can set a picture to larger (other than RAW??). If something is off it can't be with my in camera settings....

Thanks for your help. I kinda feel stupid posting about this.

[corvus2606]

Sorry, I did give a bit of bad info there, Mr Guy is right, it is also relating to your image size.

listen to him, I'll go back into my corner

[Mr Guy]

Originally Posted by metoo

Ok so your saying the 72 DPI is because I'm viewing it on a monitor? I have my camera (canon XS) set to Fine and Large in the camera body is says my pics should be 3888x2592 . Which I thought would be PLENTY large enough for my uses even with a crop. I rarely print a picture larger than 8x10 or 11x14(and that one is rarer). I thought I was fine, but i haven't printed a picture in a long time. Seeing the 72 DPI made me nervous. Paticularly when i looked back and I had a 180 DPI wiht my old point and shoot camera...... It just didn't make sense to me. I just went and reread my manual and triple checked all my in camera settings and I don't see how I can set a picture to larger (other than RAW??). If something is off it can't be with my in camera settings....

Thanks for your help. I kinda feel stupid posting about this.

I'm saying your software sets it to 72 by default, so that when you hit "actual size" on your photoviewing program, you a reasonable size. It's definitely not a dumb question, and it's easy to get confused. It's both simple and confusing all at once.

Try and think of it this way:

The resolution is the number of total dots you HAVE

The DPI is how close together you display them

The display size or print size is the end result

If you know any two of those, you can figure out what the other needs to be. You can throw away as many dots of resolution as you need to, but you can't add any. The only time you ever need to care about the DPI is specifically for that math that helps you determine if your resolution is high enough, as mentioned above.

3888 x 2592 will start to look blocky if it's printed any larger than (3888 x 2592 / 150 x 150) = 25.9 inches x 17.2 inches

but it will look BEST printed no larger than

(3888x2592 / 300dpix300dpi) = 12.9 inches x 8.6 inches

Anywhere in between those two sizes will look good, it's just that the higher the dpi the closer you can look to the image before you can see the dots.

[Jim Bryant]

I use the Canon EOS MKII's and shoot RAW. My capture resolution say's 72 dpi, but the actual size of the captured image is width 48.667 inches, height 32.444 inches @ 72dpi. You can change the resolution when post processing the image. When I do, it then say's 300 dpi, width 11.6, height 7.787. In other words, doesn't matter...you control the dpi in post processing.