Opening RAW photos in Photoshop

I think it's useful to distinguish between two terms: processor and editor.

Photos is a processor. Technically it's a parametric editor. It never changes the file. It records your decisions in the database and creates a JPEG representation if it. But what you're processing is the Raw. Other apps that work like this: Lightroom Classic, CaptureOne and so on.

Photoshop is a pixel editor. It literally changes the pixels in the image. So, for instance if you load a 6k x 4k image into Photoshop and then crop it to 5k x 3k then the unwanted pixels are actually removed. The file is changed. Those pixels are deleted, gone. Affinity Photo is similar.

The largest impact on quality of an image is, imho, the quality of then lens. Then the sensor and after that, the processing. If you're going to continually edit an image, create different versions and so on, then using a paramedic editor or using Tiff is advisable. If you're finished editing then storing the image in a high quality Jpeg is perfectly acceptable.

Viewed on screen or in print, the output of a tiff and a high quality Jpeg are indistinguishable.

If you want the best quality processing of your Raws then you're not using a give-away app like Photos, frankly. You're looking at DXO PhotoLab, Lightroom Classic, CaptureOne and other pro-level apps. Not that there's anything wrong with Photos as such, just that these apps are more capable, and more capable of more subtle adjustments.

Hi

Yes, go into the Apple Photos editor (select then hit enter). Then click the circle with the three dots in it top right. Then select Photoshop (Or ACR).

At least this is how I do it for affinity photo.

Note this process will bring back the edits into Photos as the edited version of your raw file.

If you don't want this, then you need to export the unmodified original from photos and just open the file in ACR as you would any other raw file.

You would need to export the unmodified original to the Finder and send that to Photoshop. In fact, It won't go to Photoshop, it will go to ACR.

When you send an image to an external editor Photos creates a duplicate to send and then the external sends it back after the editing, in the act of saving. It's important that Photos creates the file as otherwise it has no way of knowing it exists. Hence, if you use Save As, for instance in the external editor, Photos has no knowledge of the resulting file, as Save As creates a new file.

The problem with Raws is there is on way to edit and save a Raw in the same format. A processed Raw must be saved as some other format - DNG, TIFF, JPEG - and so, if Photos sent the Raw to an external editor, it would have no knowledge of the resulting image, and so be unable to manage it, because it did not create that file.

The work around is that Photos sends a tiff of a raw. If that's not what you want then you need to export the Raw first. It's interesting that Lightroom Classic has to resort to some clever plug-ins to save the same issue.