MidOpt Introduces Three New NIR Imaging Filters

Three new imaging filters have been made available by MidOpt.

The primary use is for the blocking of unwanted near-infrared light.

The filters are: SP635 Absorptive Visible Shortpass/Near-IR Block Filter; SP644 Near-IR/Mid-Red Dichroic Block Shortpass Filter; and, AB555 Acrylic Absorptive Near-IR/UV-Block Visible Bandpass Filter.

A number of mounting options are available, including Standard Threaded Mounts, Slip Mounts that easily adapt to lenses without filter threads, the 25.4 C-Mount for easy installation into cameras, and custom fabrication of unmounted shapes and sizes.

The SP635 filter is mostly used inside cameras to block infrared light. The SP635, when working with any camera that has been modified and its internal IR cut filter has been removed can return function once again like the unmodified camera. An absorptive infrared rejection filter, it is also recommended for protecting a camera’s sensor from stray light emitted by lasers, or other high power near-IR light sources. These filters are A/R coated on both sides to maximize visible band transmission while offering superior out-of-band blocking. Peak transmission is 90%.

The SP644 is one of several dichroic filters offered mainly for use as an internal infrared blocking filter in colour cameras. It achieves uniform blocking of near-infrared wavelengths out to 1100nm, uniformly high transmission across the visible range and a 50% point in the middle of the red portion of the spectrum. This, says MidOpt, makes it an ideal choice for cameras with typical CMOS sensor responsivity. It can achieve natural colour rendition with superior response in the blue channel. Its useful range is 395-638nm with a peak transmission ?90%.

The AB555 passes light in the visible range and blocks all near-infrared, ultraviolet and violet wavelengths. It offers excellent laser protection at 1064nm (O.D. 6) and additionally, optical density exceeds 5.0 in the UV (190-375nm), near-IR (760-1070nm) and at 10,600nm. The standard thickness is 3.5mm and the material is a light greenish colour in transmission. Sheet stock can be quickly laser cut to a wide variety of custom sizes and shapes, particularly when used as a cover for an enclosure, or a laser protective window.

Find out more about MidOpt filters

In the meantime, if you have any questions about these lenses please contact our dedicated sales team.