-- Database schema
| mountain : id [ INT ] primary_key , name [ TEXT ] , Height [ INT ] , Prominence [ INT ] , Range [ TEXT ] , Country [ TEXT ] | camera_lens : id [ INT ] primary_key , brand [ TEXT ] , name [ TEXT ] , focal_length_mm [ INT ] , max_aperture [ INT ] | photos : id [ INT ] primary_key , camera_lens_id [ INT ] photos.camera_lens_id = camera_lens.id , mountain_id [ INT ] photos.mountain_id = mountain.id , color [ TEXT ] , name [ TEXT ] |
-- -- What are the names of photos taken with the lens brand 'Sigma' or 'Olympus'?

SELECT T1.name FROM camera_lens AS T1 JOIN photos AS T2 ON T2.camera_lens_id  =  T1.id WHERE T1.brand  =  'Sigma' OR T1.brand  =  'Olympus';