How to transfer photos/videos from Mac to external hard drive

Hi

I don't know where you got the information that TIFF takes up less space. Tiff takes up much more space than Jpeg. Jpeg takes more space than HEIC (Which is probably what your phone is storing). You will need to export in jpeg, or get a much bigger drive.

Depending on what you want to do with the exported images (for example - if you just want to make a backup), you could export unmodified originals, which should take the same space as on the phone (assuming you don't have optimised storage turned on on the phone). But bear in mind unmodified originals won't retain any edits, and exported heic files will not be usable in many applications.

Tiff files are uncompressed, whereas JPEG use lossy compression - hence why they are far more popular. TIFF files can be very large. I just exported a 192kb photo as a TIFF and it turned it into 3.9MB file!

Stick to exporting in JPEG unless you really need to use TIFF and you should be fine.

Here are three exports of the same image. One HEIC as stored in the library (unmodified original). One max quality TIFF and one max quality JPEG to demonstrate the difference in file size.