Canon 1Ds Mark II Resolution DPI Question, Please Help

[magjipro]

Hi I just got a Canon 1Ds Mark II and I have a question about the DPI Resolution. I shot some pictures at the Highest/Largest JPEG setting and the image is 4992x3328, however as I view the image in Photoshop and I look under image size, the dimentions are correct put the resolution is only 72dpi????? My 10D was 180 or 240 dpi, I can't remember exactly off hand but I know its one of the two for sure. Anyways my question is that is this Normal for the 1Ds Mark II? Isn't 72 DPI a little low? I mean I still did a great 8.5x11 print at 300dpi (I cut and pasted the image). I don't know the exact math conversions with the dpi in relation to pixel dimentions so I can't see how accurately the relation is. Basically I want to know is that if this is normal or is there a setting in camera that I have to adjust. Please let me know. Thanks

Silton

[Longwatcher]

The 10D default setting was 240, but the jpeg was usually embedded in the CRW file. With the 1DsMkII, the jpeg is produced separately so they may have set the default differently.

Not sure though as I shoot Raw + M2 Jpeg, but really only care about the DPI setting of the CR2 file, so never paid attention to jpeg, I will have to check when I get home out of curiosity.

[SSonnentag]

The dpi setting in Photoshop is nothing more than a number. It has absolutely nothing to do with your camera or image quality, size or anything else. The default 72 dpi value is what is arbitrarily chosen for your screen (pixels per inch). Basically 72 dpi is what you use for web images. If you bring up the image resize dialog and turn off resample you can set your dpi to any number you wish and the only thing that will change is your printed output dimensions. Or you can change your print dimensions and watch the dpi value change.

[prime80]

It does the same thing on the 350D. Most P&S cameras I've used default to 180dpi, but my 350D always comes in at 72dpi. Is this in the EXIF data? It's no big deal, as it's easily changeable in PS, but it would be nice if there was some way to set it to default to 300dpi in PS.

[Jim_T]

The dpi setting in Photoshop is nothing more than a number. It has absolutely nothing to do with your camera or image quality, size or anything else. The default 72 dpi value is what is arbitrarily chosen for your screen (pixels per inch). Basically 72 dpi is what you use for web images. If you bring up the image resize dialog and turn off resample you can set your dpi to any number you wish and the only thing that will change is your printed output dimensions. Or you can change your print dimensions and watch the dpi value change.

Exactly..

Just to add.. There's absolutely NO need to change the DPI unless you intend to print the image.. If you aren't printing it (or sizing it for the web), then the DPI is number you can competely ignore. As SSonnentag says.. it has NOTHING to do with the quality of the image.

[magjipro]

Thanks all for the information, I was a little curious about this. As I've been doing it in the past is I've been creating a canvas the size I plan to print (example 8X10 at 300dpi) I do know in conversion the higher the DPI the smaller the image will be when cut and repasted to the image with the higher print resolution. For example copying a 4992x3328 at 72dpi image and pasting it on a 8X10 image at 300 dpi versus and 8X10 image at 200dpi. Meaning that the pasted image will be bigger on the 200 dpi canvas.

Now the most confusing issue to me is that the 1DS Mark II is a 16.7 megapixel camera versus the 10D which is a 6.5 megapixel camera. The 10D has a pixel resolution of 3072 x 2048 at 240dpi. Now in comparision the 1DS MII has a mega pixel imager that is 2.569 times larger then that of the 10D. Therefor that would mean the pixel resolution should in theory be 7897X5261 (but is not its only 4992x3328) Now from this Math, ok the increase in size isn't adding up already, and on top of that the DPI if off which yields a smaller print size all together. I mean is there something I am not getting here. As far as maximum print size is concerned.

I did some math and size comparisons on Photoshop. I created 2 seperate solid colored canvas with the orginal DPI and pixel resolutions of both cameras and pasted together on a 20X30 canvas at 300dpi then cropped for the bigger image (1DS M II) The 1Ds has a maximum 300dpi print resolution of about 16.64 x 11.09. The 10D at 300 dpi is about 10.64 X 7.09. Now judging from this the 1Ds is only about 1.5 times bigger (close estimate)in printable image size compared to the 10D, Shouldn't it be more like 2.569 times bigger (due to to bigger image sensor) ? Again this all comes back to the DPI rating, and thats in my theory is whats causing that math problem.

So is that it?, its just 72dpi? I don't understand why they wouldn't make it at least comparable to the 10D, I mean most of us that uses these kinds of camera take pictures to eventually print them, so a bigger print size does still make the difference and in this case if you look at all the math, DPI does matter and make a difference in printable image quality. I don't understand why the 72dpi though or if this can be change?

Any comments?

[tim]

In PS CS choose Image -> Resize, turn off the "resample" check box, then type in the new resolution/size you want. Nothing changes except the ruler on the side of the picture - if you have it turned on. Even when printing, that size is usually ignored.

[magjipro]

Hi thanks for your reply. I understand what you are saying about the resize, but you do lose print size when you do that.

My whole point to this tread is why 72dpi? In comparison to the 10D and other cameras the other cameras are getting more print size per mega pixel. Thats what I am saying. If things were equal the 1Ds MII should have a 2.56 times bigger print size then the 10D which it does not.

My point is why have so many MegaPixel if its not using it to its full advantage? A pixel is a pixel right, so the more pixel you have it should offer a higher resolution?

Or maybe its to much data for the camera to handle. If the resolution were 240, the file would be about 3 times larger then the 72 dpi image, maybe to much to process?

Maybe they are using the larger image sensor not so much for image resolution but more for dynamic range, light sensitivity and less noise and higher ISOs? I am just curious to the reasoning behind this. Thanks for your input.

[radar-eclipse]

Shoot in RAW and work it from there.

[tim]

Hi thanks for your reply. I understand what you are saying about the resize, but you do lose print size when you do that.

You don't lose anything if you turn off the resample check box. Just ignore the ppi number until you work out what's going on, it's almost never used.

Only shoot RAW if you know what you're doing, otherwise shoot JPG or if you're really keen RAW+JPG. To learn, buy this book (http://www.amazon.com/exec/obidos/tg/detail/-/032127878X/qid=1113466778/sr=8-1/ref=sr_8_xs_ap_i1_xgl14/002-3047575-5896047?v=glance&s=books&n=507846).

[cecilc]

In comparison to the 10D and other cameras the other cameras are getting more print size per mega pixel. Thats what I am saying. If things were equal the 1Ds MII should have a 2.56 times bigger print size then the 10D which it does not.

No ....

Man, you're comparing apples and oranges here.

You're trying to equate a 2.56 increase in OVERALL AREA to an equivalent 2.56 increase in LENGTH/WIDTH - and it ain't gonna work that way. And I'm going to let you work your way through that yourself ..... but I'll tell you that the TOTAL AREA of the print size between the 10D and the MII at 300 dpi IS about 2.56 .... which would meet with your expectations.

I will also re-iterate what's been said above - the 72 dpi that you see when you open the image in PS means nothing ..... it's just a number. And you've found that you can change it to meet your needs .....

Hope that helps take away some of your anxiety .....

[sugar_babygirli]

dpi= dots per inch

Affects how the printer uses ink and the quality etc. (which you all already know this, but just saying what the actual "dpi" stands for. ;)

[cecilc]

The 10D has a pixel resolution of 3072 x 2048 at 240dpi.

That's true .... and that 3072x2048 is a constant - it will not change no matter what dpi setting you put in the "Resolution" box (as long as you have "Resample Image" unchecked).

Now in comparision the 1DS MII has a mega pixel imager that is 2.569 times larger then that of the 10D. Therefor that would mean the pixel resolution should in theory be 7897X5261 (but is not its only 4992x3328).

Again, man, you're trying to equate TOTAL AREA with DIMENSIONS ...... can't do that.....

I mean is there something I am not getting here.

Yea,....I think so ..... but I have every confidence that you WILL get it ....

[Jim_T]

dpi= dots per inch

Affects how the printer uses ink and the quality etc. (which you all already know this, but just saying what the actual "dpi" stands for. ;)

I always thought dots per inch was a measure of a scanner's resolution. Don't scanners scan at various DPI settings. What does that have to do with printer ink ? :)

While it is confusing... The term 'Dot' has to be taken in context. It can mean scanner samples, printer ink dots.. It can mean phosphor points on a monitor and it can mean pixels as well.. It's completely interchangable.

Just as a point.. Photoshop uses the term pixels per inch (PPI) in the image size dialog box.

[magjipro]

Thanks for the input. By the way I thought the 1Ds has 16.7 effective Mega Pixels? Thats what the specs say, overall I believe its about 17 MP.