-- Retrieve the lens ID data
-- Called from the pre-formatted tag lua.lensID
-- Requires lua and extftool
-- Runs rather slow

n = 0
m = 0
lensID = ""
lensIDstring = ""

path = Image:get_path()

lensIDfile = io.popen("exiftool -Composite:LensID \"" .. path .. "\" 2>/dev/null ")
lensID = lensIDfile:read("*a")

if lensID ~= ""
then
	n = string.find(lensID, ":")
	if n > 2
	then
		n = n + 2
		lensIDstring = string.sub(lensID, n)
		m = string.find(lensIDstring, "Unknown")
		if m ~= nil
		then
			lensIDstring = ""
		else
			lensIDstring = string.gsub(lensIDstring, "\n", "")
		end
	end
end

lensIDfile:close()
return (lensIDstring)
