eseavey7
Canon vs Pentax IR UV
Using a glass prism and a halogen light, I tested the spectral response of a Pentax K10D and a Canon XTi, with a Hoya R72 IR filter, no filter and a B+W 403 UV filter. The sensor sizes of Pentax and Canon are different and have been scaled for comparison purposes. Both cameras had the sigma 18-50mm lens.
From left to right: Pentax IR, Pentax no filter, Pentax UV, Canon IR, Canon no filter and Canon UV. The cut-off in sensitivity around 370nm is caused by the multi coatings on the lens. To measure beyond 370nm would require quartz prisms and lenses.
Note the heavy IR contamination with a Canon when using a UV filter...
Canon vs Pentax IR UV
Using a glass prism and a halogen light, I tested the spectral response of a Pentax K10D and a Canon XTi, with a Hoya R72 IR filter, no filter and a B+W 403 UV filter. The sensor sizes of Pentax and Canon are different and have been scaled for comparison purposes. Both cameras had the sigma 18-50mm lens.
From left to right: Pentax IR, Pentax no filter, Pentax UV, Canon IR, Canon no filter and Canon UV. The cut-off in sensitivity around 370nm is caused by the multi coatings on the lens. To measure beyond 370nm would require quartz prisms and lenses.
Note the heavy IR contamination with a Canon when using a UV filter...