Pentax K-3 Mark III Review

Exposure Modes

The Pentax K-3 III uses the same exposure modes as other recent Pentax cameras. Like on the K-1 and KP, there are 5 user modes. The large exposure mode dial made this possible. We applaud that the user modes are directly accessible on a dial rather than being accessed via a menu.

The mode dial has the following settings:

• Auto: The camera analyzes the scene and selects what it determines to be the optimal exposure. A number of advanced settings are disabled in green mode so that a novice user can safely use this mode without getting in trouble with the more complex settings and concepts. We like that Pentax has retained this setting even on a pro camera since this combined with the various other green settings allow users new to Pentax to get up and running quickly. The user can then gradually "graduate" to the more advanced modes and settings.
  
  
• P: Hyper Program mode. The camera sets shutter speed and aperture (and ISO if auto-ISO is engaged). Turning the front e-dial will set the shutter speed to a user selected value (and keep that value for subsequent shots) while the camera then adjusts aperture automatically; turning the rear e-dial will set the aperture (and keep that value for subsequent shots) and the camera will now adjust the shutter speed to match. The green button reverts both parameters to the program line and traditional program exposure mode where the camera sets aperture as well as shutter speed. The behavior of retaining the aperture value or shutter speed from shot to shot in P mode is called Hyper Program. It is possible to forego Hyper Program and customize the e-dials to shift the program line, set the ISO and/or adjust exposure compensation.
  
  
• Sv ("Sensitivity value" mode): This is an exclusive Pentax exposure mode. The user sets the ISO with the rear e-dial and the camera will set shutter speed and aperture to match.
  
  
• Tv ("Time value"): Shutter speed priority, the user sets the shutter speed with the front e-dial. The camera sets a matching aperture (and ISO if auto-ISO is engaged).
  
  
• Av ("Aperture value"): Aperture priority mode, the user sets the aperture with the rear e-dial, the camera sets a shutter speed to match (and ISO if auto-ISO is engaged).
  
  
• TAv ("Time and Aperture value"): This is another Pentax special. The user sets the shutter speed with the front e-dial and the aperture with the rear e-dial, and the camera adjusts the ISO to match.  Think of it as M mode with auto ISO.
  
  
• M: Metered manual exposure mode. The user sets shutter speed and aperture, the camera meter is active and indicates how much the exposure is off the metered value.  ISO cannot be set to auto in this mode.
  
  
• B ("Bulb"): Aperture is set with the rear e-dial. The shutter stays open for as long the shutter button is held down. What we particularly like is that a custom function can change this behavior so that the first press of the shutter release opens the shutter and the next press closes the shutter. The same behavior can be obtained when using the infrared remote control. This makes for much more convenient night shooting.
  
  
• X ("X-sync"): This setting is handy when using third party flash guns or when a flash is connected to the X-sync terminal rather than the hot shoe: The shutter is set to the flash sync speed and the aperture can be adjusted with the rear e-dial.
  
  
• U1 through U5: These are the customizable user modes. Not only will these settings recall the exposure mode the user as stored (like Av, Tv, etc.), but several other of the user's preferred settings can be stored in these user memory banks, hereunder:
  • Sensitivity (ISO)
  • EV compensation
  • Metering pattern 
  • AF mode and number of AF points
  • Drive mode
  • White balance
  • Custom image
  • And many more. Refer the Operations Manual for the complete list

The exposure lock dial can be operated in two ways:

1. It can be locked so that it can't accidentally be knocked of its setting. To lock it the lever must be pushed to the right so that the index park aligns with the lock setting. In order to turn the dial one must then press down on the center button. Turning the mode dial and holding down this button can easily be done with one hand.
2. Unlocked. The dial can be turned freely. To operate in the unlocked mode the lever must be set to the leftmost position. This is the position shown in the illustration. The click stops between the settings of the exposure mode dial are quite firm.

We like that Pentax offers the user both choices. Even though the click stops are firm one can still inadvertently change the setting when retrieving the camera from the camera bag in a rush. Pressing down on the button quickly becomes second nature.

The K-3 III's program line can be configured through the menu so that it matches your intended shooting style.  The program line selected affects which aperture and/or shutter speed the camera selects in the fully automatic (P, Sv) exposure modes. The following options are available:

• Auto: The camera selects what would be optimal based on some unpublished criteria
  
  
• Normal: All-around, middle-of-the-road mode
  
  
• High-Speed Priority: Sets the shutter speed as fast as reasonable possible for action photography
  
  
• DOF priority (deep): Intended for landscape photography. Sets a small aperture so as to maximize the depth of field (objects from near to far are rendered sharp)
  
  
• DOF priority (shallow): Intended for portraits and for when you want to isolate a subject from the background. Opens up the aperture to create a shallow depth of field
  
  
• MTF (with FA lenses and newer). When possible given the light and lens in use, the MTF program sets the aperture to or near the F-stop where the lens has the highest resolution. This program line is a Pentax invention back from the film days and it is still unique to Pentax

The exposure in the P automatic mode and in some of the semi-automatic modes (Av, Tv) is also affected by auto ISO, if set. Auto ISO has its own program line of sorts, refer below.

Comments on Manual Exposure Mode

Setting of the shutter speed and aperture is assisted by an easy to read exposure bar calibrated in on-third or half stops (customizable). The exposure meter bar is displayed in the viewfinder and on the status screen on the rear monitor. The scale can also be shown on the live view screen and on the top LCD.

Auto ISO is disabled in manual exposure mode so that one always has full manual control of the three exposure settings, shutter speed, aperture, and sensitivity. TAv mode is essentially Manual with Auto ISO.

Manual exposure mode is also the mode to use with legacy K-mount lenses with an aperture ring and no "A" setting: Hit the green button and the camera will stop down the lens, meter, set a shutter speed matching the chosen aperture, and open up the lens again. Av mode is the more convenient mode with screw-mount lenses (or other lenses that cannot be stopped down by the camera): Manually stop down to the desired aperture and hit the shutter button. The camera will select the appropriate shutter speed.

One significant improvement of the K-3 III is that, with manual lenses, the user can record the aperture value in the EXIF file simply by selecting the accurate aperture value on the camera by using the proper e-dial. Changing this value will have no impact on the lens's settings, but properly matching the lens's aperture and the displayed value will ensure proper recording.

Another improvement is that manual lenses can be used accurately in TAv mode, and that lenses which previously could only be used at their widest aperture can now be used stopped-down. These improvements show that, despite being a modern DSLR, the K-3 III is an excellent tool for anyone interested in using legacy K-mount glass.

Other Features that Affect Exposure

EV Compensation

The exposure value set by the camera's meter can be adjusted in the range from -5 EV to +5 EV. This can be set by using the EV compensation button with the rear e-dial, or by assigning a Smart Function to EV compensation.