Tiffen IRND filters provide a true neutral density beyond the visible range into the near infrared. These innovative new filters are made from the finest optically pure glass and are ground and polished to the highest possible standards of flatness and perfect parallelism.
Why do you need IRND as opposed to regular ND?
Traditional NDs block visible spectrum light only. However, unlike photographic film stocks, the imaging devices in high-definition cameras are inherently sensitive to infrared light. A 10 stop “ND” filter would overwhelm your sensor with 1028x more infrared than visible light, causing nasty color shifts and artifacts. To combat this issue, Tiffen has developed a special Hot Mirror filter that completely blocks IR thru the entire spectrum. Just remember to install the filter with the mirror part facing outwards, away from the camera sensor.