Lens mountA bayonet ring: the lens turns and locks into place.
Mirror (reflex mirror)Flips up at the moment of exposure, clearing the way.
Lens release buttonUnlocks the lens so it can be turned off.
Self-timer lamp (AF-assist lamp)Blinks during the self-timer countdown; also lights dim scenes.
Strap mount (strap eyelet)One on each side of the body.
Back 8
Viewfinder eyepieceShows the scene through the lens, via mirror and prism.
EyecupRubber that shades the eyepiece and cushions your eye.
Diopter adjustmentSharpens the viewfinder for your own eyesight.
Screen (monitor)Shows menus, the live view and the pictures taken.
Menu buttonOpens the camera's settings menus.
Playback buttonShows the pictures already taken.
Info buttonShows or hides the shooting information.
Memory card slot coverOpens to the slot for the memory card.
Top and bottom 9
LensGlass elements that focus the picture onto the sensor.
Shutter button (shutter-release button)Half-press to focus, press fully to take the picture.
Power switchTurns the camera on and off.
Mode dialPicks the shooting mode: auto, program, priority or manual.
Command dial (main dial)Changes the setting for the chosen mode, such as shutter speed.
Hot shoe (accessory shoe)Takes a flash; its contacts carry the firing signal.
Focal plane markShows where the sensor lies, for measuring focus distance.
Tripod socketScrews onto a tripod or other support.
Battery compartment coverOpens to the battery, which sits inside the grip.
Inside: the light path 4
Focusing screenA matte screen the viewfinder picture forms on.
PentaprismTurns the picture the right way round for the eyepiece.
ShutterOpens for a set time to let light reach the sensor.
Image sensorTurns the light into the digital picture.
How this list was compiled: Read 2026-09-26. (1) A camera maker's online manual for an entry-level digital SLR, Getting to Know the Camera, https://onlinemanual.nikonimglib.com/d3500/en/02_introduction_01.html : power switch, shutter-release button, mode dial, lens release button, mirror, lens mount, AF-assist illuminator and self-timer lamp, accessory shoe, command dial, eyelets for camera strap, focal plane mark, rubber eyecup, viewfinder eyepiece, diopter adjustment control, playback, menu and information buttons, memory card slot cover, battery-chamber cover, tripod socket, monitor. (2) A second maker's online manuals, Part Names, for two mirrorless cameras, https://cam.start.canon/en/C003/manual/html/UG-00_Before_0090.html and https://cam.start.canon/en/C005/manual/html/UG-00_Before_0090.html : shutter button, main dial, self-timer lamp/AF-assist beam, grip (battery compartment), lens mount, hot shoe, lens release button, power switch, strap mount, focal plane mark, shutter curtain/image sensor, eyecup, viewfinder eyepiece, menu button, info button, playback button, dioptric adjustment knob, screen, tripod socket, card slot cover, battery compartment cover, mode dial. (3) Wikipedia, Digital single-lens reflex camera, https://en.wikipedia.org/wiki/Digital_single-lens_reflex_camera : the mirror at 45 degrees sends light over a matte focusing screen and a pentaprism or pentamirror to the viewfinder eyepiece, and to the image sensor when the shutter release is pressed. (4) Britannica, Viewfinder, https://www.britannica.com/technology/viewfinder : in a single-lens reflex the mirror reflects the image to a ground-glass focusing screen, seen through a pentaprism that corrects its reversal; the mirror moves out of the way at the moment of exposure. Licence: own work
The drawing: Drawn for this site by script, 2026-09-26. Licence: own work
How it works
This camera anatomy quiz names one part of a digital SLR at a time, and you tap it on the drawing. The last three are inside the body: the focusing screen, the pentaprism and the shutter.
Read the full guide
Names that get swapped
The shutter button is on top of the grip; the shutter is the blind inside, just in front of the image sensor. The screen is the big panel on the back; the focusing screen is the matte plate under the pentaprism. The mode dial is the large one on the left of the top view; the command dial is the thumb wheel behind the grip.
The viewfinder eyepiece is the glass window. The eyecup is the rubber frame round it, and the diopter adjustment is the tiny wheel beside it.
Two doors: the memory card slot cover is on the side of the grip, the battery compartment cover underneath.
The front view is drawn with the lens off: the mirror is the pale shape inside the lens mount.
Questions and answers
What does DSLR stand for?
Digital single-lens reflex. Light comes in through a single lens, and a mirror reflects it up to the viewfinder, so what you see is what the lens sees. An image sensor records the picture digitally.
What does PASM stand for on a camera?
Program, aperture priority, shutter priority and manual: four shooting modes on the mode dial, which is sometimes called a PASM dial for that reason.
Is it a pentaprism or a pentamirror?
Either, depending on the camera. Entry-level digital SLRs mostly have a pentamirror, where the traditional design has a pentaprism. Both sit over the focusing screen and send the picture to the eyepiece. This quiz calls the part a pentaprism.