metadata - Is there any software which will set the EXIF Dates based on the file's modification date?

I have been using Exifer for many years to re-date and re-name my photos based on the EXIF dates from the camera(s).

I have now started using some alternative camera apps available on the iPhone (specifically Plastiq Camera and Hipstamatic) but these do not save any EXIF information in the images.

What I would like to do then is to insert the Date Digitised, Date Taken and Date Modified EXIF values based on the JPG file's Modified Date (which is correct to the time of taking the photo) and to also set the Make to Apple and Model to iPhone 3GS (although the process would apply to any JPG image which has no EXIF data, regardless of the source)

I have looked at Exifer, IrfanView, ExifTool, Picasa and others and they either cannot set the dates at all or can only set them to a specific date/time.

So, is there any software available which will automatically set the EXIF Dates based on the file's Modified date property?

Or, is there some switch in ExifTool that I have missed possibly?

I would like to be able to do this as a batch on a folder of images.

Answer

I think you can do it with ExifTool:

exiftool -v "-FileModifyDate>DateTimeOriginal" *

Tried on some copies of jpegs and it seems to have worked.