Pentax 40 MZ-3i operating instructions Technical Data, Exposure corrections in auto mode

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15. Exposure corrections

The automatic exposure systems are adjusted to a subject reflection factor of 25%, this being the average reflection factor for subjects shot with flash.

Dark backgrounds that absorb a lot of light, or bright backgrounds that reflect a great deal of light (e.g. backlit scenes), can result in overexposure or under- exposure of the subject, as the case may be.

Exposure corrections in auto mode

To compensate the above described effect, exposure can be corrected by opening or stopping down the camera’s aperture. If the background is mainly bright, the flashgun’s sensor will cut off the flash too soon with the result that the subject will be underexposed. With a dark background the flash is cut off too late so that the subject looks too light.

☞Bright background:

open the aperture 1/2 to 1 f-stop (e.g. from f/5.6 to f/4)

Dark background:

close the aperture 1/2 to 1 f-stop (e.g. from f/8 to f/11)

Exposure corrections in TTL mode

Many cameras have an adjusting facility for exposure correction which can also be used in TTL flash mode.

☞Note: Please observe the corresponding explanations in the Operating Instructions for the camera or SCA adapter.

Here, exposure correction by changing the aperture on the lens is not possible. This is because the camera’s automatic exposure system will regard the changed f-stop as a normal working aperture.

16. Technical Data

Partial light output

Flash duration

LC-display

Guide number

 

P=Flash Power

in seconds

 

at ISO 100

 

 

 

 

50 mm zoom

 

1

1/200

1

40

 

1 - 1/3

 

1_

 

 

1/2 + 1/3

 

2¯¯

 

 

1/2

1/600

2

28

 

1/2 - 1/3

 

2_

 

 

1/4 + 1/3

 

4¯¯

 

 

1/4

1/1500

4

20

 

1/4 - 1/3

 

4_

 

 

1/8 + 1/3

 

8¯¯

 

 

1/8

1/3000

8

14

 

1/8 - 1/3

 

8_

 

 

1/16 + 1/3

 

16¯¯

 

 

1/16

1/5000

16

10

 

1/16 - 1/3

 

16_

 

 

1/32 + 1/3

 

32¯¯

 

 

1/32

1/8000

32

7

 

1/32 - 1/3

 

32_

 

 

1/64 + 1/3

 

64¯¯

 

 

1/64

1/13000

64

5

 

1/64 - 1/3

 

64_

 

 

1/128 + 1/3

 

128¯¯

 

 

1/128

1/20000

128

3,5

 

1/128 - 1/3

 

128_

 

 

1/256 + 1/3

 

256¯¯

 

 

1/256

1/26000

256

2,5

 

 

 

 

 

 

Table 1: Flash durations at the individual partial light output levels

54

55

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Contents Mecablitz 40 MZ-3i Main switch LC display lighting / Modelling light NomenclatureSensor LC display Acoustic exposure verification on Film speedContents Brief survey of the operating functions ForewordPlease also open the back cover page with the illustrations Stroboscopic mode, ch , pSafety Instructions Never fire a flash in the immediate vicinity of the eyesBattery warning indicator Close the battery compartment coverPreparations Removing the Standard Foot or SCA adapter Switching the flashgun on and offMounting the flashgun on the camera Mounting the Standard Foot or SCA adapterTTL flash mode Setting procedure for TTL modeDirect way to good flash shots Easy Mode Automatic flash modeSetting procedure for TTL Easy Mode To EM„ + or „ button See ch , p Setting procedure for auto flash modeTo a Also be set on the camera lensManual flash mode Setting procedure for manual flash modeBounce flash Lock-in positions of reflector and headBouncing the flash in the auto and TTL modes Bouncing the flash in the manual modeMounting the light reducing filter With secondary reflectorTTL remote operation Setting procedure for Metz TTL remote operationMetz cordless TTL remote operation ControllerSwitching off the Metz TTL remote operation Checking the slave addressRemote-Operation Setting procedure for Metz a remote operationMetz cordless auto remote operation Distance values on the LC display disappearWinder mode Using the winder in the manual modeUsing the winder in auto and TTL modes Partial light output levels in the auto mode Partial light output levels in the manual modeSetting procedure for manual mode with partial light output Flash durations Stroboscopic modeWorking with partial light output levels Macrophotography close-upsSetting procedure for stroboscopic mode Use the „+ or „- buttonFill-in flash in daylight Fill-in flash in auto modeFill-in flash in manual mode Complete illumination of shadow areasFill-in flash in TTL mode Working with user programsProcedure for storing a program Calling a stored programProg. flashes Zoom reflector main reflector Setting procedure for the Ex-Zoom modeZoom reflector Ex-Zoom-modeOr was, correctly exposed in the auto and TTL mode Special functionsPull-out/push-in wide-angle diffuser AF measuring beam AF measuring beamML function Modelling Light ML-functionsSwitching on with the controls locked An intermittent beep signalling alarm soundsSwitching on the „Beep function Locking the controls key functionTesting the display segments Calling the Service ModeAdjusting the dimensional units Rapid functionExposure corrections in TTL mode Technical DataExposure corrections in auto mode Exposure correctionsRemarks ModeFreq. fHz 105Example ProcedureFlashes per second = fHz Partial light output PIncluded Optional extras Flashing operating mode symbols Troubleshooting hintsNo display in on switch position Meaningless informationAlphabetical index Fill-in flash
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