topic Re: SL2 Image Resolution (PPI) in EOS DSLR & Mirrorless Cameras

SL2 Image Resolution (PPI)

wchettel — Sun, 22 Mar 2020 13:23:48 GMT

I have an EOS Rebel SL2 and the Image Quality is set to The saved images are 6000 px X 4000 px, but are only 72 PPI and HUGE in inches (83.33 inches x 55.56 inches).

Is there a setting that will let me save images at 300 PPI with a smaller size in inches?

Thanks,

Re: SL2 Image Resolution (PPI)

kvbarkley — Sat, 21 Mar 2020 19:36:06 GMT

Nope.

Re: SL2 Image Resolution (PPI)

rs-eos — Sat, 21 Mar 2020 19:43:17 GMT

I didn't see any settings in the camera manual for that. I think it really depends upon the manufacturer as to what DPI/PPI values are used.

If you use Adobe Lightroom, you can export your RAW to JPEG and specify all kinds of options to include PPI. Photoshop and other applications may also provide batch processing to do the same.

It's possible this may also exist as a plugin. e.g. macOS (at least 10.15 aka Catalina) offers third-party 'Quick Actions' that can run in Finder. The premise would be that you'd right-click on one or more of your JPEGs in Finder, select Quick Actions, then the particular plugin. I have no idea though if such a Quick Action exists to simply adjust the DPI/PPI while keeping the actual pixel count the same.

Re: SL2 Image Resolution (PPI)

RobertTheFat — Sat, 21 Mar 2020 20:12:54 GMT

@rs-eos wrote:
I didn't see any settings in the camera manual for that. I think it really depends upon the manufacturer as to what DPI/PPI values are used.

If you use Adobe Lightroom, you can export your RAW to JPEG and specify all kinds of options to include PPI. Photoshop and other applications may also provide batch processing to do the same.

It's possible this may also exist as a plugin. e.g. macOS (at least 10.15 aka Catalina) offers third-party 'Quick Actions' that can run in Finder. The premise would be that you'd right-click on one or more of your JPEGs in Finder, select Quick Actions, then the particular plugin. I have no idea though if such a Quick Action exists to simply adjust the DPI/PPI while keeping the actual pixel count the same.

Obviously you can make the adjustment on the RAW file using any decent photo editor. But when one uses RAW+JPEG. it's usually because the JPEG file has to be provided under some severe time constraint, usually to a newspaper. While the newspaper might well prefer to have the correct size and/or pixel density already specified, they should be able to edit it if necessary. While that might degrade the picture quality a little, a newspaper's picture quality is often so bad anyway that the extra edit shouldn't matter much.

Re: SL2 Image Resolution (PPI)

wchettel — Sun, 22 Mar 2020 13:24:28 GMT

Thanks for your feedback! I'm still learning how to use my camera and noticed that the images were the same PPI as my cell phone camera images. I use Photoshop Elements v18 (2020) and have resized several images with it but was wondering if there was a setting I missed that would do it in the camera.

Thanks again!

Re: SL2 Image Resolution (PPI)

RobertTheFat — Sun, 22 Mar 2020 05:24:09 GMT

@wchettel wrote:
Thanks for your feedback! I'm still learning how to use my camera and noticed that the images were the same PPI as my cell phone camera images. I use Photoshop Elements v18 (2020) and have resized several images with it but was wondering if there was a setting I missed that would do it in the camera.

Thanks again!
Walter

You have to understand that the PPI number is really just a prediction of the resolution at which the image will be printed. It has no physical significance until the image is passed on to the printer.

Re: SL2 Image Resolution (PPI)

rs-eos — Sun, 22 Mar 2020 12:18:16 GMT

While it's certainly true what Bob writes that DPI/PPI is used by the printer, these days it can also be used by displays.

For example, screenshots captured on Macs that use retina displays are marked as being 144 DPI. If you change that to be 72 DPI, the image will show four times larger (twice the width and twice the height) when viewed at 100% in the Preview application on such displays.

Re: SL2 Image Resolution (PPI)

ebiggs1 — Sun, 22 Mar 2020 15:46:35 GMT

Cameras do not have DPI. Neither do monitors. Printers are the only device that makes use of DPI. DPI is dots (as in ink)-per-inch.

You can not shoot at 300 DPI or any DPI number. Pixels is all you have. There are no inches, so there can not be DPI. Image size is dimensioned in pixels. You can assign any DPI number you want in post which controls the inch size it will print on paper. Inches are on paper. There are no inches in the camera. The max image size for the SL2 is 6,000 x 4,000 pixels. It will always be 6,000 x 4,000.

If you are getting confused in post editing about changing DPI, do the changing of DPI and do it without resizing or resampling. You want to change the DPI while retaining the original pixel dimensions (the real digital resolution) of the photo.

Re: SL2 Image Resolution (PPI)

RobertTheFat — Sun, 22 Mar 2020 16:29:48 GMT

@ebiggs1 wrote:
Cameras do not have DPI. Neither do monitors. Printers are the only device that makes use of DPI. DPI is dots (as in ink)-per-inch.
You can not shoot at 300 DPI or any DPI number. Pixels is all you have. There are no inches, so there can not be DPI. Image size is dimensioned in pixels. You can assign any DPI number you want in post which controls the inch size it will print on paper. Inches are on paper. There are no inches in the camera. The max image size for the SL2 is 6,000 x 4,000 pixels. It will always be 6,000 x 4,000.
If you are getting confused in post editing about changing DPI, do the changing of DPI and do it without resizing or resampling. You want to change the DPI while retaining the original pixel dimensions (the real digital resolution) of the photo.

OK, but note that any discussion of DPI is arguably a red herring in this thread. The OP's question referred only to PPI.

Re: SL2 Image Resolution (PPI)

ebiggs1 — Sun, 22 Mar 2020 20:58:05 GMT

Robert I didn't introduce DPI.

" I think it really depends upon the manufacturer as to what DPI/PPI values are used."

People use these two terms interchangeably which they are not.

The camera has neither since it doesn't have inches. A more clear definition is, DPI is the measure of how many printed dots a printer can put on a piece of paper within one inch. PPI is the amount of pixels a digital file contains when representing a certain height or width in inches.

If you pull up a photo in PS and look at it you will see it as 72 DPI. That is just a number that Adobe applies to the file as a beginning it has nothing to do with the actual resolution of the file since it has no DPI.

Regardless of the resolution of the image, a printer will lay down whatever number of DPI you specify. The closer the dots are placed to each other will result in a higher resolution image. Less DPI images will print with lower quality prints.

On the other hand, PPI is variable. An image can be represented in an number of sizes. Take a 4”x6” DSLR photo at 300 PPI. It is the same as a 8”x12” only at 150ppi. Using my arbitrary example the pixel dimensions are the same with both. This image is 1200px x 1800px. The important part is the actual pixel dimensions of the digital image 1200px x 1800px.

All cameras shoot at their full resolution. It is what is saved that changes. I know this is a confusing subject and I know some folks struggle with it. Mainly because some manufacturers and software companies use the terms interchangeably. They use them when they aren't relevant. Maybe there is some software issue that forces Adobe to assign 72 DPI to a file. Who know?

And, perhaps I am not explaining very clearly!

Re: SL2 Image Resolution (PPI)

kvbarkley — Sun, 22 Mar 2020 21:58:44 GMT

Which is exactly why I said "nope", but the can of worms got opened anyway.

Re: SL2 Image Resolution (PPI)

ebiggs1 — Sun, 22 Mar 2020 22:41:55 GMT

"...nope, but the can of worms got opened anyway."

Probably the best answer.

I think a lot of the blame for this confusion is on the manufacturers and software companies.