The importance of optical filters. A) Experimental condition 3 (Table 1), with NB filter only. Without Blue but with ND filters: F#: 56. B) Experimental condition 6 (Table 1), no filters. Without either Blue or ND filters F#: 50. C) Experimental condition 2 (Table 1), Blue filter only. With Blue, without ND filter F#:60. D) Experimental condition 1 (Table 1), both ND and Blue filters. Software enhancement, camera correction are the same in all four images. Higher value of F# indicates a higher effective resolution. With Blue, without ND filter F#:60.