The HC and HCD lens line consists of 11 high performance lenses with focal lengths from 28 to 300mm (the equivalent of 21 to 220 in 35mm).
All lenses feature a built-in lens shutter with shutter speeds up to a true 1/800 second.
All HC and HCD lenses can be ordered in a version where the focusing mechanism is calibrated for infinity focus and physically locked to prevent unintentional change due to aircraft vibration.
Every lens design – no matter how advanced – entails finding compromises between different lens characteristics such as distortion, chromatic aberration, and vignetting. Naturally, all high-end lens design attempts to minimize such lens errors, but in reality any lens represents a carefully selected balance of these negative factors – lens designers select the lesser of multiple evils while still trying to maintain the best possible design and one that will produce the best possible image quality.
With the HC and HCD lens line however, we have introduced a new tool for image refinement: Digital Lens Correction. This process allows certain lens errors to be corrected in post processing. For us, this means that we can focus more effort on minimizing other lens errors – errors that cannot be corrected in post processing. For you, this means that you get lenses which, combined with digital image corrections, will produce a superior image quality.
Images shot with an HC or HCD lens are automatically corrected for distortion, lateral chromatic aberration, and vignetting when processed in our Phocus™ software.
In fact, the corrections performed by Phocus are based on the theoretical lens design and are so accurate that they have actually revealed errors in traditional lens calibration methods.
Fixed lens and capture unit
The lens on the H4D Aerial camera is locked in place by 4 screws (1) inside the camera, which pushes the lens forward and secures a fixed position.
The digital capture unit is held by a single screw (2) from inside the camera and a rotation lock (3) at the bottom. This ensures a stable position even when external vibration occurs.
Digital lens corrections
Phocus, Hasselblad’s powerful proprietary processing software, enables advanced digital lens correction to be performed automatically on each image. These corrections are based on detailed data imported into Phocus and based on the theoretical design of each lens.
This means that any image can be tweaked to be perfectly correct, removing all distortion, for example, by taking the lens characteristics and actual subject distance into account.
Lenses used for aerial mapping photography are traditionally calibrated for distortion at a distance much closer than infinity. We know that lens errors are not the same and slightly change over distance and to be able to carry out automatic correction at all distances is a distinct advantage. One that significantly increases final image results.
The MTF graphs presented here show the improvement to the tangential MTF that is the result of our digital lens corrections. Simply put, you achieve a higher degree of overall image sharpness.