topic Re: 300 DPI photos for Canon 6D in EOS DSLR & Mirrorless Cameras

300 DPI photos for Canon 6D

parklandphotos — Wed, 27 Jul 2016 12:29:54 GMT

How do I program my Canon 6D camera to get 300 dpi photos?

Re: 300 DPI photos for Canon 6D

Waddizzle — Wed, 27 Jul 2016 12:46:51 GMT

@parklandphotos wrote:
How do I program my Canon 6D camera to get 300 dpi photos?

You do not. It is best performed in post processing. The Canon DPP4 software can do it for you through the Batch process module.

Re: 300 DPI photos for Canon 6D

kvbarkley — Wed, 27 Jul 2016 13:31:26 GMT

That exif field is really for scanners. When you scan a 4x6 print it is good to know the DPI so you know the size of the original. Cameras need to put something there so Canon puts 72. You can use software to change it later, but it is best to just ignore it and not worry about it.

If someone *requires* you to submit a 300 dpi image, laugh at them and run away since they do not know what they are doing unless it is your printer telling you how much resolutiion you need for a certain print.

Re: 300 DPI photos for Canon 6D

ebiggs1 — Wed, 27 Jul 2016 14:08:54 GMT

300 dpi is a printing spec, not a camera spec.

Re: 300 DPI photos for Canon 6D

RobertTheFat — Wed, 27 Jul 2016 15:49:54 GMT

@kvbarkley wrote:

If someone *requires* you to submit a 300 dpi image, laugh at them and run away since they do not know what they are doing unless it is your printer telling you how much resolution you need for a certain print.

Well, you may say that, but if the "someone" is running a juried show in which you and several hundred others hope to have pictures displayed, you will not laugh, but will smile and do as you're told. Fortunately it costs you nothing (but your pride) to comply, since the restrictions that really matter are the size of the JPEG file and the actual size of the framed print (if you're lucky enough to be chosen to submit one).

Re: 300 DPI photos for Canon 6D

ebiggs1 — Thu, 28 Jul 2016 13:45:45 GMT

B from B,

"... but if the "someone" is running a juried show... but will smile and do as you're told."

Or laugh it off as that has to be a amateurish uninformed 'show'! Not worth submitting even if you win it.

Re: 300 DPI photos for Canon 6D

Waddizzle — Thu, 28 Jul 2016 16:07:44 GMT

@ebiggs1 wrote:
B from B,
"... but if the "someone" is running a juried show... but will smile and do as you're told."

Or laugh it off as that has to be a amateurish uninformed 'show'! Not worth submitting even if you win it.

Hmmp. I would have thought requiring digital image files to conform to a size specification would "level the playing field", so to speak.

Re: 300 DPI photos for Canon 6D

kvbarkley — Thu, 28 Jul 2016 16:13:19 GMT

Size specifications are fine, and probably necessary so you dont get GB sized files. But 300 dpi is not a "size spec" it is a printing spec.

Why say submit a "4x6 photo at 300 dpi" when you can say an "image with 1200 x 1800 pixels."

And why would you reject an image that conformed to the 1200 x 1800 pixels but happened to have the dpi field set to 72 dpi.

Re: 300 DPI photos for Canon 6D

Waddizzle — Thu, 28 Jul 2016 16:50:23 GMT

@kvbarkley wrote:
Size specifications are fine, and probably necessary so you dont get GB sized files. But 300 dpi is not a "size spec" it is a printing spec.

Why say submit a "4x6 photo at 300 dpi" when you can say an "image with 1200 x 1800 pixels."

And why would you reject an image that conformed to the 1200 x 1800 pixels but happened to have the dpi field set to 72 dpi.

Uh, yeah. It is a print size specification, in this case for viewing. You know, like characters per inch? Quit while you're ahead.

Re: 300 DPI photos for Canon 6D

ebiggs1 — Thu, 28 Jul 2016 16:59:26 GMT

" it is a printing spec." Absolutely.

This is quite correct. A photo has no dpi. "Quit while you're ahead.", or in your case quit before you get further behind.

Re: 300 DPI photos for Canon 6D

Waddizzle — Thu, 28 Jul 2016 17:24:47 GMT

@ebiggs1 wrote:
" it is a printing spec." Absolutely.

This is quite correct. A photo has no dpi. "Quit while you're ahead.", or in your case quit before you get further behind.

Absolutely. When images are displayed on your computer monitor, they are printed to the screen. That's how it works.

Re: 300 DPI photos for Canon 6D

ebiggs1 — Thu, 28 Jul 2016 17:46:21 GMT

A photo on your screen is shown as picture pixels. A photo on a screen has only a 'size' in pixels. So forget the dpi as it has no relevance here.

"... in your case quit before you get further behind." Now see what happened? You got further behind!

Re: 300 DPI photos for Canon 6D

Waddizzle — Thu, 28 Jul 2016 18:29:18 GMT

@ebiggs1 wrote:
A photo on your screen is shown as picture pixels. A photo on a screen has only a 'size' in pixels. So forget the dpi as it has no relevance here.

"... in your case quit before you get further behind." Now see what happened? You got further behind!

Obviously, you do not know how JPEG [not RAW] images are actually reproduced on your screeen. Like I said, JPEG images are literally printed on your screen at the resolution specified by the metadata in the file.

Re: 300 DPI photos for Canon 6D

kvbarkley — Thu, 28 Jul 2016 18:46:48 GMT

No wonder I have all these jpegs sticking to my screen! They are *literally* printed there!

What you said is really software dependent. Since jpeg and Exif are two different standards, they really don't have anything to do with each other.

Re: 300 DPI photos for Canon 6D

jrhoffman75 — Thu, 28 Jul 2016 20:19:27 GMT

Perhaps the organization is also creating a printed document as a record of the event/competition and they want to be sure they can reproduce quality images?

Re: 300 DPI photos for Canon 6D

kvbarkley — Thu, 28 Jul 2016 20:24:30 GMT

I would not want my images printed without my involvement. And again, it is easy enough to overide the dpi and print whatever size you want.

But the display thing is obviously untrue. with the exception of paint, all the programs I use on the PC open the images at a reasonable size, certainly not the default 72dpi that Canon has in its images!

Re: 300 DPI photos for Canon 6D

ebiggs1 — Thu, 28 Jul 2016 20:38:52 GMT

"But the display thing is obviously untrue."

It must be a hard concept to understand.

Re: 300 DPI photos for Canon 6D

ebiggs1 — Thu, 28 Jul 2016 20:41:06 GMT

"Obviously, you do not know how JPEG [not RAW] images are actually reproduced on your screeen."

"... in your case quit before you get further behind."

You are going to get so far behind we won't be able to tell if it is you.

It's OK because you are not the only one that gets confused with dpi.

Re: 300 DPI photos for Canon 6D

Waddizzle — Thu, 28 Jul 2016 22:54:46 GMT

@ebiggs1 wrote:
"Obviously, you do not know how JPEG [not RAW] images are actually reproduced on your screeen."

"... in your case quit before you get further behind."
You are going to get so far behind we won't be able to tell if it is you.
It's OK because you are not the only one that gets confused with dpi.

I am not confused about DPI. I'm talking about scaling images for display at actual size on your monitor. None of you seem to understand understand how software actually produces an image on your screen.

The above comment about MS Paint proves my point. And, he came so close to the truth, too.

Re: 300 DPI photos for Canon 6D

Waddizzle — Thu, 28 Jul 2016 23:28:44 GMT

"But the display thing is obviously untrue. with the exception of paint, all the programs I use on the PC open the images at a reasonable size, certainly not the default 72dpi that Canon has in its images!"

Do you actually think Canon picked 72 DPI? Let me tell you where it came from. It is also currently the resolution standard used for displaying images on web pages, for historical reasons.

Once upon a time when PCs were first invented, text used to produced as an 8x8 dot matrix, both on your screen and on your dot matrix printer. A single dot was used to separate adjacent characters. This meant that each character occupied 9 pixels, and if you wanted to display 8 characters per inch, then you required 72 DPI to reproduce 8 characters per inch.

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"Full size" images are displayed on your screen at a lower resolution than what is actually saved in many files. So, how do they go from X megapixels to your screen resolution? As noted, MS Paint displays images without scaling the pixels to fit the screen. Obviously, the images are rescaled in some fashion. Depending upon the desired result, the scaling can be done in different ways.

To make a long story short, groups of pixels in the image file are averaged to produce one pixel that you see on your display. At 300 DPI, that is approximately a 4x4 matrix [for a 72 DPI display] of pixels are processed to produce a single pixel of a given color. A larger matrix, 8x8, would be capable of yielding higher color resolution per pixel. A smaller matrix, 2x2, would have less color resolution.

So, the "playing field is leveled" by requiring everyone to produce images at a specific DPI, and canvas size, so that everyone's images are scaled for viewing equally.