CREATE TABLE mountain (id DECIMAL, name TEXT, height DECIMAL, prominence DECIMAL, range TEXT, country TEXT)
CREATE TABLE photos (id DECIMAL, camera_lens_id DECIMAL, mountain_id DECIMAL, color TEXT, name TEXT)
CREATE TABLE camera_lens (id DECIMAL, brand TEXT, name TEXT, focal_length_mm DECIMAL, max_aperture DECIMAL)

How many distinct kinds of camera lenses are used to take photos of mountains in the country 'Ethiopia'?
SELECT COUNT(DISTINCT T2.camera_lens_id) FROM mountain AS T1 JOIN photos AS T2 ON T1.id = T2.mountain_id WHERE T1.country = 'Ethiopia'
SELECT COUNT(DISTINCT "T2"."camera_lens_id") FROM "mountain" AS "T1" JOIN "photos" AS "T2" ON "T1"."id" = "T2"."mountain_id" WHERE "T1"."country" = 'Ethiopia'