Areas in focus and quality of focus

[pedz]

Lightroom Version Number

Latest as of today (LR Classic 9.3)

Operating System

1. macOS 10.15 Catalina

If Adobe is listening, here is what I want for Christmas Maybe we already have it and I just don't know about it.

I read very quickly about "focus stacking" that Photoshop can do, which is much like HDR it seems but Photoshop has some buttons to look at focus. This implies that somehow, Mr. Computer can figure out which areas are in focus and which ones are not. Utopia would be if Mr. Computer could figure out the degree to which an area is in focus.

If this is true, then what would be mega super duper cool is if Lightroom could give me a few tips when I am reviewing an image. It would be nice if it could give me where it thinks the in focus areas are at perhaps by making the out of focus areas dim or draw a red line around the in focus areas. It would also be nice if it could give me a range say from 0 to 10 of what amount of the image is in focus. Indeed, this might be -10 to 10 with 0 through -10 if nothing is in sharp focus with -1 being just slightly out of focus and -10 being way out of focus.

What I'm going after is a quicker way to review batches of photos of the same subject, order them by the focus rating, and then go through them in that order until one has the focus area over the intended target.

Shamefully, I'm a computer geek / programmer but I don't have a clue how one would go about determining what areas are in focus. I'm assuming that Photoshop can do it somehow based on its focus stacking ability.

Note, I'm not talking about digging out the metadata that tells me where the camera put the focus point. That would be nice to have too but I realize that its not a universal EXIF data so Adobe would need to customize it for each camera.

 

[clee01l]

There are some Lightroom Plugins that map the in focus points for an image as determined by the camera and stored in the manufacturer reserved metadata structure. Where this information resides in this "blob" data varies from Manufacturer to manufacturer and proprietary RAW format. These fields have to be parsed individually by manufacturer. The Lightroom plugins work for most Canon and Nikon cameras I had not noticed this in PS but I suspect they do the same and I know they do more than that with the {Select}{Focus Area} function.

As I see it, add on features like Panoramas, HDR, Focus Stacking only increase the bloat in Lightroom. Adobe provides this additional functionality in the full featured product Photoshop.

 

[prbimages]

That's an interesting idea. My thoughts: To use Photoshop's focus-stacking, you need more than one image and they have to be aligned first (as I'm sure you know). So really it is not exactly finding what is "in focus", but rather doing a comparison of two or more images to decide which is "most in focus" in any given area. I think that would be a different kind of problem. I am guessing that, to decide what is "most in focus", it would be looking at how narrow are the boundaries between areas of different tone and colour. If Photo A has a narrow gradation from blue to red (say) in a given area, and Photo B has a wider gradation, Photoshop decides that Photo A is the most in focus at that point, and builds a mask to hide Photo B. However, it is not deciding that Photo A is "acceptably" sharp, only that it is sharper than B. I wouldn't think that it could apply the same logic to a single photo.

 

[Johan Elzenga]

Photoshop has its 'Select - Focus Area' menu, which supposedly selects those parts of the image that are in focus. You will get a dialog that allows you to fine tune it before it makes it final selection. I never use it because I'm not impressed by the results. The technology behind it and behind focus stacking is simple. Sharpness is edge contrast (that is how contrast auto focus in cameras works as well), so Photoshop simply looks for the layer with the most contrast in a certain area.

 

[prbimages]

Photoshop has its 'Select - Focus Area' menu ...

I did not know that!