Lightroom - Focus point / length data?

Question

I am building a visualization using Lightroom data (the catalog file) to extract information of my pictures.

My Question: In Lightroom, how do i know what my focus length is (that dial which you turn ad some cameras will tell you if you are infinity or not) , Or even if the picture was taken in auto focus or Manual focus.

I did come across the question: Can I filter by autofocus in Lightroom? , but i haven't been able to find that information within the catalog file itself. Please correct me if I am wrong: a. The data for Auto/Manual Focus is not stored in lightroom, and plugins exist to extract the information from the RAW file b. The focus length (I'm assuming the there is only one focal plane that can be focused) is either not recorded by cameras (i have a Nikon D7000) or not recorded in Lightroom.

Answer 1

Most cameras that record the focus distance in the EXIF data attached to a photo store that information in the "maker notes" section of the EXIF info. The maker notes section allows manufacturers to place any information they wish inside a file without having to worry about a common standardized protocol for designating this information. Unfortunately, most Adobe products ignore the information contained in the maker notes section of the EXIF info. They often also strip this information from the EXIF info when converting and exporting an image file that contains maker notes in the EXIF info. At the very least they don't display any of the information contained in the maker notes section when displaying EXIF info from within Adobe applications. For example, when converting raw .cr2 files from a Canon camera to .dng files using the adobe file converter all maker notes info in the EXIF info is gone from the converted .dng file.

That being the case, you'll probably need to use an application other than Lightroom, or any other Adobe product, to accomplish what you wish to do.

Answer 2

This might point you in the right direction rather than being a direct answer:

The information you're after is stored in each image file rather than the catalog file.

You say you're writing a "visualisation" but I'm unsure what that is. Perhaps you mean a plugin or perhaps you mean you're parsing the catalog file to create new information? Using a plugin, it'll be possible to extract the info as it's been done before. Sorry I'm not sure what the attribute name would be within lightroom however....

I found "approximate focus distance" is stored in the EXIF data. I examined the raw exif info using Photoshop once I'd realised LR wouldnt tell me.

In PS, open your image and select File->File Info then choose "Raw Data". Scroll down until you find a mention of distance. For my .NEF file, the tag is

<aux:ApproximateFocusDistance>4294967295/1</aux:ApproximateFocusDistance>

I believe it might be different for other file types. (I've heard Subject Distance mentioned)

I'm also sure there are other exif viewers out there which would give you this info but PS worked for me.

HTH. Good luck