Glossary of Photo Terms



P mode – Program Mode
Auto everything. The camera controls all settings based on built-in algorithms to provide the best exposure. Often P modes come in flavors favoring sports, portrait, night scenes, etc.. The flavors will favor certain settings like increasing the shutter speed for sports or opening the aperture on portraits to blur the background.

PDAF – Phase Detect Autofocus
Phase detection autofocus works by comparing two versions of the focus area it is assigned to and using a method similar in function to a rangefinder to determine if the area is in focus, focused too far or too near. Because it knows whether an out of focus image is focused too close or too far, it can tell the focusing processor which way the lens element has to move to bring it into focus. In an SLR (DSLR) the image pairs are reflected off of the reflex mirror into the phase-detection sensors. On mirrorless cameras with phase detection uses sensors integrated into the surface of the sensor to perform the evaluation.

Peaking – Focus Peaking
On advanced video and still cameras, focus peaking superimposes a dense pattern of bright dots over areas of high contrast corresponding to areas of the image that are in sharp focus. This is especially helpful when focusing manually.

PF  – Purple Fringing

An aspect of Chromatic Aberration that appears as a purple fringe  most often on the edges of high contrast areas between blue sky and darker objects like tree branches of the edges of buildings.

Pincushion Distorsion – Compressed distortion
Lenses that aren’t properly corrected will cause straight lines in a scene to bow inwards (pincushion distortion) or outwards (barrel distortion). Most common in telephoto lenses, pincushion distortion isn’t usually an issue unless it is extreme. It is most noticeable in photos with straight edged objects at the edge of the frame and can be distracting is it is too pronounced. Typically less severe that the barrel distortion in wide-angle lenses. The name comes from the dimpling and pulling in of the fabric as a pin is pushed into a pincushion. If you’re under 50, you might need to Google “pincushion”.

PNG – Portable Network Graphics (.png)
A “lossless” compressed file format created to be a replacement for the GIF (Graphics Interchange Format). PNG files can support up to 32bit color with minimal loss during compression. Like a GIF, it supports transparent areas but does not support animated images.

PP – Post-Processing
Common forum abbreviation for Post Processing which refers to a wide range of adjustments, editing, format conversion, tagging, categorizing and other actions performed on images after they are downloaded from the camera.

PPI – Pixels Per Inch
Sometimes used interchangeably with DPI (Dots Per Inch) which is a printing standard. PPI is a display standard that refers to the number of pixels per diagonal inch of a display. A higher PPI means the display will appear “clearer” or “sharper”. The not-so-sharp 72 PPI “standard” baked into a lot of image output is based on a 14″ 800×600 monitor. A 27 ” QHD (2560×1440) monitor has 109 PPI and a 32″ UHD (3860×2160) monitor has about 138 PPI. Some of the newer high end phones hav over 400 PPI making the individual pixels too small for the human eye to discern. PPI is a relative measurement since monitors of different sizes that have the same resolution will have different PPI values.

PS – Photoshop
Common forum abbreviation for Adobe’s Photoshop image editor

RAW – Raw file
Not an acronym. It refers to the unprocessed image format available in many digital cameras and some phones. Sort of a digital “negative”. The RAW format contains the basic image data that the sensor records before it is processed by the camera into a JPEG. A RAW file can be manipulated after-the-fact for exposure compensation, white-balance, noise-reduction, sharpness, contrast, color settings and almost any other adjustment options that the camera offers. Because each camera maker uses it’s own RAW format, applying the adjustments requires either the proprietary software from the camera manufacturer or an editing program like the ones available from Adobe or Corel. RAW is used by photographers where critical adjustments may be needed in post-production to correct for difficult lighting or incorrect settings.

RF  – Rear Focus
A lens that moves the rear element group to focus. Usually found in a larger telephoto where moving the huge front element to focus would be impractical.

RF  – Range Finder (e.g. Leica’s M8) 
A camera that uses a dual image parallax rangefinder system to focus.

RP  – Release Priority
A camera setting in an autofocus camera that allows the shutter to be released even if the focusing system does not confirm that focus has been achieved.

S Mode – Shutter Priority Mode
Setting the camera to shutter-priority makes the shutter speed the primary setting and forces the camera’s metering system to adjust the Aperture (f/stop) and ISO (if it is set to Auto-ISO) to set the proper exposure. This mode gives you excellent control over controlling motion blur.

SAM  – Smooth Autofocus Motor
Sony term for their silent in-lens motor technology used in lower-cost lenses instead of the faster SSM motors.

SD – Secure Digital
A memory card format that is widely used in compact cameras and increasingly, in consumer camcorders and DSLR cameras because of the large capacities and high transfer speeds available.

SDHC – Secure Digital – High Capacity
A memory card format that is physically identical to Secure Digital. They are available in capacities from 4 GB up to 32GB with higher transfer speeds than SD.

SDXC – Secure Digital – Extended Capacity -A memory card format that is physically identical to Secure Digital and SDHC. They are available in capacities from 64 GB up to a theoretical limit of 2TB with extremely high transfer speeds.

Shutter-lag – Shutter delay -The delay between pressing the shutter release and the actual recording of the image.

SLR – Single-Lens Reflex -An Interchangeable Lens Camera where the viewfinder uses an optical path from the primary lens that provides the image to the film or digital sensor (DSLR). The image is reflected to the viewfinder by a mirror that swings out of the light path during the actual exposure and swings back afterwards (hence, “reflex”). Usually refers to a camera that offers interchangeable lenses but a few models were made that used an optical SLR design with a fixed zoom lens.

SMC – Super Multi-Coated
Hoya designation for filters with advanced anti-reflection coatings

SP  – Superior Performance
Tamron term for their high-performance series of lenses

Spot-Metering – Center-spot metering
A metering mode that measures only a small central area of the frame (usually indicated by a circle in the viewfinder). This is a useful mode when the subject is illuminated very differently than the rest of the scene or when you need the subject to be exposed as correctly as possible, but the rest of the scene can be sacrificed. It is also used when you want to expose the subject as a silhouette by spot-metering on the bright background and recomposing before shooting.

SSD  – Super-sonic Drive Motor
Pentax term for their in-lens motor technology

SSD  – Solid State Drive
Refers to a computer or external hard drive that uses solid state memory to store data instead of magnetic coatings on spinning platters.

SSM  – Super Sonic Motor -Sony term for their in-lens motor technology

SSS  – Super Steady Shot
Sony term for their sensor-based image-stabilization technology. Replaces AS – Anti Shake