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02-24-2016, 01:49 PM   #1
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240 dpi

I noticed an odd thing today. My K-3 is outputting at 240 dpi from the camera. Previously, it output at 300 dpi. I have no idea what setting I would have changed to cause that. I'm shooting Raw+ with L*** jpgs, 100 ISO, with an FA Limited and original K (pre-M) lens today. 240 dpi is suitable for today's shoot, but I'm at a loss for what I did to change it off of 300 dpi. Any ideas?

02-24-2016, 02:05 PM - 1 Like   #2
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QuoteOriginally posted by K David Quote
I noticed an odd thing today. My K-3 is outputting at 240 dpi from the camera. Previously, it output at 300 dpi. I have no idea what setting I would have changed to cause that. I'm shooting Raw+ with L*** jpgs, 100 ISO, with an FA Limited and original K (pre-M) lens today. 240 dpi is suitable for today's shoot, but I'm at a loss for what I did to change it off of 300 dpi. Any ideas?
The camera does not output any dpi. Thats up to the software on your computer and your printer. The camera only outputs in pixels.
02-24-2016, 04:05 PM   #3
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I agree with #2. Most software when opening jpegs will default to 240 resolution. Did you change software, RAW to jpeg, or a preference in the image editor? 240 ppi is fine for Retina or even 4K monitors as well as B&W. But for printing, you do want 300 dpi for your resolution.
02-24-2016, 05:03 PM   #4
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I noticed this myself with my K7 but after going back and looking and working on some Jpegs, the Jpegs were 300 dpi while my RAW files are 240 dpi. My guess is it has something to do with the file types and the software management of said file types.

02-24-2016, 05:43 PM   #5
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QuoteOriginally posted by bigdavephoto Quote
the Jpegs were 300 dpi while my RAW files are 240 dpi
That makes sense. The jpegs in this case are outputs from raw (I went back and checked after deleting my source jpegs in favor of the jpegs from the edited raw and PSD files.) I'll do a test tonight to see if the jpegs in Raw+ are 300.
02-24-2016, 09:05 PM   #6
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This thread prompted me to view Properties > Details of a couple of images, and lo and behold, there is a DPI attribute, which I never noticed before.

As pointed out above, cameras put out pixels. DPI would become significant only when printing the image. I suppose the existing value would be used by default when printing with some simple software, if one doesn't specify any override. That would not be the usual MO when printing with software that has any "sophistication".
02-24-2016, 09:27 PM - 3 Likes   #7
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QuoteOriginally posted by Alex645 Quote
240 ppi is fine for Retina or even 4K monitors as well as B&W.
It's not fine - it's irrelevant.

The photo, RAW, JPG or any other format, could be in 1 or 100000 ppi/dpi, it doesn't matter as long as the file is for digital media.

It also doesn't matter when the ppi/dpi was changed, as long the photo wasn't re-sampled (had amount of pixels altered).

Bonus info: Changing sizes of images using ppi/dpi and re-sampling when the photo is for digital media is generally a bad idea, not the least because it's illogical and and cumbersome: How many inches and ppi/dpi is needed to make a Facebook cover with a 1:1 pixel ratio? You'll only find out by trial and error - mostly error.
02-24-2016, 10:12 PM   #8
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QuoteOriginally posted by Zafar Iqbal Quote
It's not fine - it's irrelevant.

The photo, RAW, JPG or any other format, could be in 1 or 100000 ppi/dpi, it doesn't matter as long as the file is for digital media.

It also doesn't matter when the ppi/dpi was changed, as long the photo wasn't re-sampled (had amount of pixels altered).
Yes, I agree that re-sampling, especially up, is begging for artifacts and should be avoided, but I don't follow your logic that regardless if it is compressed or uncompressed, a file can be any resolution as long as the file is for digital media.

What is your definition of digital media? Do you mean pixels on a screen vs. a digital print from ink or dye-sub from a digital printer? Resolution that is too high can be as problematic as low resolution, albeit not in the viewing, but in practical matters such as file size or streaming speed.

Although the future of photography may be purely online, I believe there is value in print media, both photo chemical and digital. And whether it is for a 200 lpi offset press or a 300 dpi giclee/inkjet or dye-sublimation printer, the resolution of the image is not irrelevant. Please explain further if I am not understanding your intent.

02-24-2016, 10:49 PM - 1 Like   #9
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QuoteOriginally posted by Alex645 Quote
Yes, I agree that re-sampling, especially up, is begging for artifacts and should be avoided, but I don't follow your logic that regardless if it is compressed or uncompressed, a file can be any resolution as long as the file is for digital media.

What is your definition of digital media? Do you mean pixels on a screen vs. a digital print from ink or dye-sub from a digital printer? Resolution that is too high can be as problematic as low resolution, albeit not in the viewing, but in practical matters such as file size or streaming speed.

Although the future of photography may be purely online, I believe there is value in print media, both photo chemical and digital. And whether it is for a 200 lpi offset press or a 300 dpi giclee/inkjet or dye-sublimation printer, the resolution of the image is not irrelevant. Please explain further if I am not understanding your intent.
I meant screens.

You can change the ppi with or without re-sampling. If you change it without re-sampling, the image will look no different on a screen, no matter what ppi you set it to. That was my main point.

However, those very same files will print differently if the printer/software is set to respect the ppi - and this in particular is where ppi comes into play. I'm not disputing print related use of ppi - with print you can't avoid ppi.

I'm also not saying an image shouldn't be changed in size for screen viewing purposes. It should (but with pixels, not ppi), not only for file size/streaming related reasons but also because an image is best view in 1:1 scale ratio, where 1 image pixel takes up exactly 1 screen pixel.

This means, for example, a 1920 pixels wide image will cover the full width and look at it's best on a 30" TV with a native resolution of 1920 - but so is the case if the screen is 5" and also has a 1920 pixels wide native resolution, so what is an inch really on screens? It's nothing, it's irrelevant.

I hope that made more sense.
02-24-2016, 11:01 PM   #10
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QuoteOriginally posted by Zafar Iqbal Quote
I meant screens.

I hope that made more sense.
Understood Thanks for explaining further...and yes, I agree.
02-25-2016, 01:15 AM   #11
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So I guess that part of why I'm confused relates to the dpi on the right click > properties > details page. With my Pentaxes, it's always been 300. With my Nikon and Canon DSLRs, it's always been 72 dpi. That's with the Nikons and Canons also set to the finest image quality setting.

I mean, ultimately, we're talking about a 24 megapixel image that's going to be used as an e-mail thumbnail, LinkedIn profile picture, and printed sales resume thumbnail at about 1"x1", nothing more. But the wedding I shot in January, which had all the same settings, is outputting to 300 dpi in the detail tab, and those are jpegs I edited from raw, too. So something is amiss.
02-25-2016, 10:48 AM - 1 Like   #12
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QuoteOriginally posted by K David Quote
So I guess that part of why I'm confused relates to the dpi on the right click > properties > details page. With my Pentaxes, it's always been 300. With my Nikon and Canon DSLRs, it's always been 72 dpi.
The dpi is dependent on your dimensions. For example, if I have 28.7MP image that would give me a pixel dimension of 3872 x 2592 pixels. At 300 ppi that comes out to a 12.9 x 8.6 inch document/print. IF I do not resample the image/pixels, at 72 ppi that turns the same file into a huge 53.8 x 36 inch image.

Cropping will reduce the pixels and file size and/or if I resampled the image larger or smaller. 72 ppi is considered the optimum viewing resolution for standard def monitor screens. 96 ppi for HD and 150-240 for Retina, 4K, or 5K. B&W gray scale prints are fine at 240 dpi and 300 dpi with 99% of all offset, inkjet, giclee, dye-sub, photographic, and digital printers is the standard. Just keep in mind that these numbers cannot be taken out of context with the dimensions of the document/image.
02-25-2016, 11:27 AM - 1 Like   #13
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QuoteOriginally posted by K David Quote
So I guess that part of why I'm confused relates to the dpi on the right click > properties > details page. With my Pentaxes, it's always been 300. With my Nikon and Canon DSLRs, it's always been 72 dpi. That's with the Nikons and Canons also set to the finest image quality setting.

I mean, ultimately, we're talking about a 24 megapixel image that's going to be used as an e-mail thumbnail, LinkedIn profile picture, and printed sales resume thumbnail at about 1"x1", nothing more. But the wedding I shot in January, which had all the same settings, is outputting to 300 dpi in the detail tab, and those are jpegs I edited from raw, too. So something is amiss.
I suspect it's down to your system software, or application software, not the file itself. Depending on what software I use on my Mac, the DPI shows as 72, 240, 300 on the same DNG or JPG. Exiftool shows 72 in the JPEGs. I would imagine in your image processing software you could set the default at anything you want; dpi is essentially irrelevant to the image itself. It's sorta like the instructions tag in IPTC.

In your use case it only becomes relevant in printing the sales resume.

I suppose you could change the exif info; on all my DNGs it's Xresolution and Yresolution in exif. But I think it's also stored in the JPEG header; not sure about DNG. In something like Photoshop you could save it; in Lr you'd use an export preset to change it, and then the Xresolution and Yresolution tags would be changed to whatever you set; or use exiftool to do it.
02-26-2016, 06:41 AM - 1 Like   #14
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QuoteOriginally posted by K David Quote
So I guess that part of why I'm confused relates to the dpi on the right click > properties > details page. With my Pentaxes, it's always been 300. With my Nikon and Canon DSLRs, it's always been 72 dpi. That's with the Nikons and Canons also set to the finest image quality setting.
You should trace through your workflow...specifically what the cameras are outputting and exactly what software you've been using and if its settings have changed.

Also make sure you understand how this setting in the exif is pretty much irrelevant for just about everything (with some odd printing software that might pay attention to it) and it's the actual pixel dimensions that matter.
02-29-2016, 06:46 PM - 1 Like   #15
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If you are using Adobe Camera RAW (ACR) to first load your DNG then click on the blue link at the bottom (shows image workflow settings) and change the resolution, colour space etc. to the size you want to work with. I use 300ppi, AdobeRGB and 16bit.

You should probably use sRGB if you are only printing from home or displaying on websites computers etc. and particularly if you don't have a wide gamut monitor and appropriate video card.

Also some of the Photoshop filters cannot work with 16bit colour but I change that in PS when required.

I have had the workflow settings change at one stage and I don't know why so it pays to check it every now and then and also when you buy a new camera.
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