camera dpi question

[guitarkid]

I was wondering if there is a way to adjust the dpi in the camera as the photo is shot....original in the camera? I don't know if this is possible but my Canon 20D shots are 240 dpi? and my Canon 30D is 300 dpi. maybe it's just how it is out of the box. I heard that is just how it is and if I need shots with a minimum of 300 dpi then i need to use the 30D? Yes I know you can change the dpi in photoshop but that is pixel stretching, etc. I'm talking right out of the camera.

thanks,
steve

 

[coastietech]

Good question! I am interested in the answer to this question as well.

 

[darich]

it's amazing what you can find using the search function on this forum!!

 

[guitarkid]

Saw that thread before in the past, thanks. It discusses printer and photoshop dpi whereas my questions is, can you adjust this right in the camera? There is always the difference between the 20D and 30D regardless of photoshop and printers used as if it's hard-coded on the cameras processor / chip.

thanks,
Steve

 

[darich]

it can't be adjusted in the camera.
And the 20D produces jpegs at 72dpi - mine did for 18months before i upgraded.

The point is it doesn't matter what the camera shoots in - the important thing is the printing quality.

 

[The_Traveler]

The resolution coming out of your camera i.e 72ppi/240ppi etc., matters not a jot until you come to printing. The only thing that matters is the number of pixels.

My 20D produces a 3504x2336 pixel image. Whether it comes of my camera at 1ppi or 1000ppi the image is still a 3504 x 2336 image.

Here's a pretty good link

http://www.steves-digicams.com/techc...uary_2005.html

Cheers
Jim

Lew

 

[BoblyBill]

Yay!!! I can actually answer this one in a educated way... OK... lets start with this. No you can't change the DPI of the camera (unless you change the size of picture you are making but disregard this for a second). Let's say I have a camera that takes a 3000x2000 (6 MP) pixel picture. If I put this picture on my computer, it will be the computer that places the default DPI on the picture... (In fact my computer asigns my pictures from my 3.1 MP (2160x1440) camera to 8x12 at 180dpi). What you should be able to do is to calculate the size of the file (i.e. pixels) by multiplying the dpi by one of the sides (i.e. 8x180 = 1440 and 12x180 = 2160). You can kind of think that the computer automatically asigns a size to the picture. So... If you have a camera that produces a 3000x2000 pixel picture you could print:
20x30 at 100 DPI
12x18 at 166.6666 DPI
8x12 at 250 DPI
4x6 at 500 DPI

Most software will probably automatically assume you will want to print an 8x12 so it will pick the DPI that would be apropriate for that size file. I hope that makes sense.

 

[guitarkid]

thanks, it kind of does but it's too much thinking for me since i don't know what sizes the bride and groom want to print. i just take the photos in raw, edit in CS2, export to tiff, crop if need be, usually not, then rename and export to jpg. anyway, when it is in RAW form i noticed in the lower right that every time the 20D says 240dpi and the 30D says 300dpi. this was in the bridge part of CS2...when editing RAW files. i don't care about printing, or any of that stuff. just wanted to know if the 20D will ever show 300dpi like the 30D does in RAW files. i'm sure i can't and i'm cool with that since both cameras take very nice photos and never had complaints on photos that came from the lab.

the main reason i ask this is because the lab i work with prefers 300 dpi images when working with wedding albums....digital wedding albums where the photos are part of the page...so if the 20D does 240dpi, you know what i'm saying here. i guess i don't care.

thanks,
steve

 

[THORHAMMER]

if your shooting raw then dpi pretty much meaningless for your purposes..
edit the raw files to show proofs...

export them as 4x6

when they have picked out what they want just pull up the allready edited raw file of those shots, re crop based on what they want and re export at the appropriate size.

 

[Alex_B]

simple answer .. the DPI which comes with a digital file is totally meaningless. hence it does not matter if in your jpeg it says 72 or 300 dpi or whatever.
just always chose highest resolution and don't delete the files.

 

[Alex_B]

if your shooting raw then dpi pretty much meaningless for your purposes..

dpi is meaningless for any kind of digital format.

 

[guitarkid]

thanks Alex, i will just ignore the differences then. i shoot in RAW, make my changes and color corrections in RAW, export to tiff, crop if i need to, then export the hi rez tiff to hi rez jpg. from there they are about 4 or 5mb in size, the jpegs.....i then copy all jpgs to a DVD and mail off to the lab. they use these hi rez jpgs for when people order prints.

on my end i import all the same photos in the software supplied by the lab and they are automatically resized to thumbnail resolution, and they are uploaded to the lab's servers. users can go to my proofs link and view the photos instantly. that is how i do it. the photos are automatically resized for thumbnails.

i don't mess with proof books or anything like that. if users want proofs i can order them but i don't offer them. i do offer an entire proof book where the photos are printed on pages and bound with a leather bound folder front and back. that is also from the lab. i just need to click a button and say MAKE PROOF BOOK and the software uploads my order to their servers and i get a nice book in about 2 weeks.

steve

 

[EOS_JD]

Thanks for noting my previous post nice to see people getting this.

First thing I usually correct is that you are NOT talking about DPI here. THat is a printer/scanner term for output.

What we are discussing here is pixels per inch (ppi). THink about that term. Pixels per inch....

If the 20d = 3504 x 2336 pixels (same as 30D) then the printed image at 240ppi would be the number of pixels divided by the ppi setting (done once per axis)

3504/240 = 14.6"
2336/240 = 9.73333"

So your printed image would be 14.6" x 9.7"

The 30D has the same number of pixels in its image 3504x2336 and to print at 300ppi you would end up with a smaller print

3504/300 = 11.68"
2336/300 = 7.786"

All that matters is the number of pixels in the image - forget about ppi (dpi) setting.

 

[guitarkid]

thanks for the advice and i understand the pixels per inch thing but i don't understand why in adobe CS2, bridge, photos shot with the 20D show up as 240dpi and the 30D photos show up as 300 dpi. i don't get it. and as far as printing and dividing by some number 3000 X whatever, i'm just lost. i have a mental block with it. my biggest thing was...why do the 20D and 30D show up as different dpi, ppi, whatever, in adobe bridge?
steve

 

[darich]

Forget that the 2 cameras show up in adobe bridge with different dpi numbers - it's already been said here - it's meaningless. It doesn't matter. It doesn't make a difference.
To prove it to yourself, import an image from each camera and change that number to 72 - each image will look identical on the screen.

The printing and "dividing by 3000x some number" is quite simple

Standard prints are printed at 300 dots per inch (different term from pixels per inch). Dots per inch makes a big difference to the final print - pixels per inch doesn't.
You want a 12 x 8 inch print. So if standard printing is 300 dpi (note dpi when talking about printing) then you'll need 12 (x300) x 8 (x300) to achieve a nice print. In other words your original image would have to be 3600 x 2400.

This is probably where the confusion lies.

You'd need to adjust your jpeg image to 3600 x 2400 using photoshop. So you'd be changing the resolution or "image size" as PS calls it.
This may mean you're making your image larger or smaller depending on the camera you used to shoot the original image.
But that stil makes no difference to the dpi that Adobe Bridge showed at the start 72, 240, 300, - no matter.

The important thing is that the image you send to the lab is suitable for printing at the size you specify and simply multiplying both dimensions by 300 and adjusting to that size is the quickest and easiest way to do it.

Hope that clears things up a bit for you