Glossary

Anti-aliasing filter (low-pass filter): A low-pass filter, also known as anti-aliasing filter, was added in front of the imaging sensors of high-resolution digital cameras to eliminate the problem of moiré. Moiré is a type of artifact that occurs in cameras where subjects with repetitive elements exceed the camera sensor’s overall resolution. The filter effectively reduces the high frequency content to allow it to be captured and effectively introduces a small amount of blurring of the image. This blurring can be counteracted by sharpening of the image post-capture.

Aperture and “stopping down”: “stopping down” refers to increasing the numerical f-stop number which decreases the size (diameter) of the aperture of a lens, resulting in reducing the amount of light entering the iris of a lens. The f-number of a camera lens is the ratio of the focal length to the diameter of the entrance pupil. Reducing the aperture size increases the depth of field (DOF) of the image

Camera JPG: The highest quality jpg format stored on a Nikon camera is JPG fine which is compressed approximately 1:4. Nikon have lens-specific data pre-loaded in camera firmware to reduce vignetting, chromatic aberration and distortion. Images saved in this format will have these corrections.

Camera TIFF: This uncompressed format and causes only a small loss in image data compared with RAW. The downside is that TIFF files are comparatively large. Nikon have lens-specific data pre-loaded in camera firmware to reduce vignetting, chromatic aberration and distortion which saving in this format.

Chromatic Aberration (CA): Lateral chromatic aberration also called “colour fringing” is a lens aberration that causes colours to focus at different distances from the image centre. It is most visible near corners of images. CA was once a major issue with lens at the extremes of focal length with film cameras. Digital cameras allow on camera correction with firmware (in the case of most Nikon digital camera) or with software using RAW files. It is better to have lenses with low CA as software may not totally remove this artifact when it is very pronounced.

Cycles/mm: Another way of expressing spacial frequency. This is the same a line pairs. There are two line widths per line pair. For detail see here

Diffraction Limit: Often called the DLA (Diffraction Limited Aperture). This aperture value is the point at which diffraction begins to negatively affect image resolution as the lens is stopped down.

Distortion

Barrel distortion: Magnification decreases with distance from the axis

Pincushion distortion: Magnification increases with distance from the axis.

Mustache distortion: Complex form of distortion that has elements of both barrel and pincushion distortion

Figure from here