topic Re: Image quality in EOS DSLR & Mirrorless Cameras

EOS Rebel T7 Image quality

Mark67 — Thu, 18 Aug 2022 12:40:26 GMT

Can anyone help? I am rather new to photography I have a rebel T7 and have been doing alot of nature, wildlife and astro photography. I have been shooting in RAW mode when I try to enlarge the pictures it tells me "low image quality" but it looks fantastic on the computer any suggestions on what I am doing wrong or how to fix it?

Re: Image quality

Tronhard — Wed, 17 Aug 2022 23:57:16 GMT

To be honest, we are lacking a lot of information.

Perhaps post a couple of images, along with the settings for them: such as lens, focal length, shutter speed, and ISO values.

What program are you using when you are getting this message about low quality? Are you viewing the RAW image or a JPG image within that program?

If you look at the first menu item on your camera's menu there is an item for Image quality, what settings is it showing?

Re: Image quality

Mark67 — Thu, 18 Aug 2022 00:16:00 GMT

I am shooting most everything in raw but it also takes a jpeg at the same time for my night shots I have been shooting in manual 20" F2.8 ISO 3200 photos look good on the computer but anything over 8x10 and I get a low image quality warning For my day shots I have mostly given up on trying to shoot in manual and have been using auto still get the low image quality on anything over 8x10 I kinda live in the middle of nowhere so the only place I can have photos printed is wallmart probably not the best place but my only option

Re: Image quality

Tronhard — Thu, 18 Aug 2022 00:36:59 GMT

OK, thanks for that. How about the resolutions settings for your camera? As mentioned, can you please advise what the resolution settings are on your camera: Menu, first tab, first page, first item. Thus:

Are you significantly cropping your images before printing?

What printer and printer settings are you using, particularly resolution?

Re: Image quality

Mark67 — Thu, 18 Aug 2022 00:37:47 GMT

I have been using the raw + L as that gives me 2 copies of each photo. As far a printer settings go I don't beleive those are adjustable as wallmart just has a kiosk you can plug a thumb drive I to also I have not been cropping any of my images. Thank you for your help

Re: Image quality

Tronhard — Thu, 18 Aug 2022 00:41:59 GMT

Thanks for that. Can you give me the pixel dimensions of a photo you are trying to print and its MP value please?

Re: Image quality

Mark67 — Thu, 18 Aug 2022 00:50:13 GMT

Sorry I don't know how to find that info and I don't currently have my laptop with me

Re: Image quality

Tronhard — Thu, 18 Aug 2022 01:06:33 GMT

OK, no worries... Perhaps this might help. It's a guide to the size of image file you need to print various prints outputs. To get an idea of this look at the dimensions of your image in pixels. For printing (as a guide), given the likely print output resolution is 300PPI you translate that to your file size as follows:

For an 8" x 10" => 8x300 x 10 x300 or if you will print Length x width x resolution(squared). So, applying that in this example, the resolution for an 8x10 would be around 7.2MP. If, on the other hand, the printer resolution was set at 600 DPI, then the file size would be 8x600 x 10x600 = 48MP! So printer resolution has a huge impact on the file size you need.

Check out this article: https://www.photoworkout.com/print-resolution/ , it views the relationship from the other direction, so to speak - check it all out first.

Re: Image quality

Mark67 — Thu, 18 Aug 2022 01:27:54 GMT

Thank you for the information the link was very helpful. Can't wait to get in front of my computer and play around with some photos.

Re: Image quality

Tronhard — Thu, 18 Aug 2022 01:30:39 GMT

Good luck with that. Come back to here if you need to explore this further.

Re: Image quality

jrhoffman75 — Thu, 18 Aug 2022 02:11:33 GMT

@Mark67 wrote:
I have been using the raw + L as that gives me 2 copies of each photo. As far a printer settings go I don't beleive those are adjustable as wallmart just has a kiosk you can plug a thumb drive I to also I have not been cropping any of my images. Thank you for your help

When you say you are bringing a thumb drive to WalMart are you copying images from the camera card to the thumb drive or have you done some processing them in software and exported a processed image from the software?

A L JPEG should print a quality 8x10, but if you have processed and saved an image in software you may have saved a smaller file size.

I also don’t think that Walmart kiosk will read a RAW file.

Re: Image quality

Tronhard — Thu, 18 Aug 2022 02:22:54 GMT

I agree John - that was why I was asking what program he was using to view the files. Something the MS Photo wouldn't alter the files without conscious effort, but other s/w might do some tweaking without it being obvious, especially if a RAW file was converted to a JPG for printing. We shall see...

Re: Image quality

Mark67 — Thu, 18 Aug 2022 23:04:41 GMT

I download directly from the camera to the computer and No the wallmart kiosk does not rea raw files I do do a very basic amount of processing lighten darken type stuff when done the photo automatically converts to JPEG

Re: Image quality

jrhoffman75 — Thu, 18 Aug 2022 23:21:32 GMT

What size JPEG is your software producing.

Re: Image quality

Mark67 — Thu, 18 Aug 2022 23:28:16 GMT

I dont know and I don't know how to find out. Would it be listed under properties? Or ??

Re: Image quality

Tronhard — Thu, 18 Aug 2022 23:38:45 GMT

Like John, I am suspicious of the possibility that your images are being downsized when saving in PP to JPG format. The size of the file, and preferably its pixel dimensions, as you give your files to Walmart, would be very helpful

Re: Image quality

Tronhard — Fri, 19 Aug 2022 00:12:45 GMT

I don't know what computer system you are working with, but on a Windows box, if you look at the file properties in File Manager you should see all the info we need. To do so, bring up the file in File Manager, Right Click on the file and select Properties. A dialogue box will appear, and on the first tab you will see the file size in MB, if you then click on the tab for Details and you can read the pixel dimensions and file size on the list displayed.

If you use Photoshop, once the image is displayed on screen, from the Menu, select FILE, then FILE INFO, and then Camera Data: from this screen you can read the pixel dimensions and also the pixels per inch of the image.

In Lightroom, open the file as if to edit, then go to the menu and select VIEW, then INFO. On a panel you should see details of the file there.

Re: Image quality

jrhoffman75 — Fri, 19 Aug 2022 02:21:55 GMT

I don't use Microsoft Photos, but I just tried an experiment.

I opened a .CR3 RAW file from my 1D X Mark III in MS Photos.

I selected edit, but did nothing to the file; I just selected "Save a copy"

It saved a JPEG of 2.42MB size; the original RAW file was 24.9MB.

I think that is your issue. I didn't have time to root around in MS Photos to see if the default settings can be changed.

Since you have a Rebel T7 maybe try using free Canon DPP4 for your editing.

Re: Image quality

Tronhard — Fri, 19 Aug 2022 02:30:34 GMT

Yes, if the OP is using MS Photos, it will definitely massively downgrade the images. I didn't really see a clear answer as to what IS being used. But your suggestion makes sense if that is the case...

Re: Image quality

Mark67 — Fri, 19 Aug 2022 04:13:10 GMT

So I just compared the RAW version to the JPEG they are the same dimensions but the JPEG is 33.8 MB and the RAW CR2 file is 31.8 I am using windows 11 and whatever program it comes with to view my photos the editing software I an using is Luminar Neo