Pentax 6x7- If tripped without a battery, or with a dead battery, the mirror will hang up in mid travel. To reset, press the Safety Device Release Button (located below the left strap lug) with a pointed object, and press the shutter button for one blank exposure. Insert a new battery after the mirror has been reset.
Pentax 6x7 TTL Prism- The meter prism must be attached to the camera body before the lens is attached to ensure proper meter coupling. Motor will appear to be inoperative if not done in proper sequence.
Mamiya RZ- The dots around the shutter release button are for the following: Red = release lock, orange = manual/emergency 1/125th sec., white = regular/on.
Mamiya M645- If this camera is fired without a battery and locks up, hit the battery check button to release the mirror.
Bronica- This camera likes silver oxide batteries best (rather than alkaline) for the most reliable functionality.
Lenses with push/pull focus ring- This lens has a push-pull focus selector. Simply push or pull the entire focus ring to switch between auto focus and manual focus. (For more info. on this topic, see "the locking collar" on this post)
Nikon (FM, FM2(N), FE, FE2)- The advance lever must be in the “stand out” position to expose the red dot on the top plate of the camera body in order to function. If using the camera with a motor drive however, the advance lever must be in “flush position” (against the camera body) to work correctly.
Leica R (R3 and up)- Leica R cameras (models R3 and up) require a 3 cam or 3rd cam (R-only cam) lens for proper meter function. 1 or 2 cam lenses are for the standard and SL series cameras respectively, and will give inaccurate meter readings on the later R cameras. 3rd cam (R only) will not mount on early (non-R) Leicaflexes.
Rollei S and T series cameras- The shutter must be cocked before collapsing the lens. Attempting to collapse the lens before cocking can cause damage.
Rollei Twin Lens Cameras (later models)- In order the activate the film counter and engage the camera, the film must be placed under the sensing roller (the silver roller at the bottom of the camera closest to the film spool) before being put into the take-up (empty) spool at the top.
Mamiya 6 and 7- To fire the camera you must advance the shutter, attach the lens, and then pull the textured button on the bottom of the camera down to open the curtain. In order to remove the lens from the body, you must first cock the shutter, then close the curtain by turning the crank on the bottom of the camera counter-clockwise. Then you can push the lens release button.
Fuji GS645- To close the camera, you must set the lens on infinity, advance the shutter, and then push the “closing” bar. (This is also true for many other folding cameras)
Pentax K2- To change the film speed, first set the exposure factor control dial at “1x”. While depressing the ASA ring lever, turn the ASA ring until the ASA number of your film is opposite the orange index mark.
Nikon AF 35mm Cameras- If you see an “FEE” error code flash on the camera's LCD screen, you must set the aperture ring all the way to the minimum aperture (the number on the aperture dial that is red or orange) in order for the camera to read the minimum aperture on the lens. (For more info. on this topic, read "The Top 2 Camera Error Codes")