contents · 2019. 6. 13. · 1 quick start: instructions for measuring luminances...

Contents

1 Quick start: Instructions for measuring luminances 3

2 How to handle the LMK mobile advanced 72.1 Useful information about the camera . . . . . . . . . . . . . . . . . . . . . 8

2.1.1 Aperture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.1.2 Focal length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.1.3 Capture mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.1.4 Image compression . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.1.5 ISO-speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.1.6 HighDyn measurements . . . . . . . . . . . . . . . . . . . . . . . . 92.1.7 Live-View shooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 Further information on how to make luminance measurements 103.1 Selecting the exposure settings . . . . . . . . . . . . . . . . . . . . . . . . 103.2 Checking the exposure settings . . . . . . . . . . . . . . . . . . . . . . . . 123.3 HighDyn measurements with Auto Exposure Bracketing (AEB) . . . . . . 133.4 Manual exposure compensation . . . . . . . . . . . . . . . . . . . . . . . . 133.5 Setting the ISO speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143.6 Using optional neutral density filters . . . . . . . . . . . . . . . . . . . . . 143.7 Dirt and Dust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

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1 Quick start: Instructions for measuringluminances

Luminance captures should always be taken with the AEB function being activated (seeparagraph 3.3). Then, the image series captured will be processed to HighDyn luminanceshots by means of the LMK LabSoft luminance analysis software. Furthermore, fortaking exposure series, a tripod will always be necessary. To facilitate the capture ofserial images, the camera can be set to sequential captures (see Canon Manual page70).

Switch on the camera and activate themanual mode (M-mode) with the modedial:

Switching on evaluative metering:This menu item can be accessed using the Menubutton by selecting Menu 2 | Metering mode(see paragraph 3.1).

Selecting the exposure time:Choose the exposure time with the Main dialnear the shutter button. After that or meanwhilecheck the result of the exposure measurement inthe Viewfinder or on the LCD-Display withthe Exposure level indicator. On activatedLiveView shooting mode the visual control canalso be done on the LCD-Display (see para-graph 2.1.7).

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1 Quick start: Instructions for measuring luminances

Selecting the aperture:Choose the aperture (please select only the cali-brated F4 till F11) with theMain dial and by si-multaneously pressing the Exposure compen-sation button (see the picture). After that ormeanwhile check the result of the exposure mea-surement in the Viewfinder or on the LCD-Display with the Exposure level indicator.An aperture value selected once is stored, afterthat you only have to readjust the exposure timevalue if necessary.

Setting the RAW capture mode:This menu item can be accessed using the Menubutton by selectingMenu 1 | Quality (see para-graph 2.1.4). Selecting the option RAW+L al-lows simultaneous saving of compressed imagedata and as uncompressed RAW data.

Activating Auto-focus:Selecting the Auto-focus by using the Focusmode switch positioned at the lens support.

Deactivating the Image Stabilizer:Deactivating the optical stabilizer by using theImage Stabilizer switch positioned at the lenssupport.

Adjusting the Auto Exposure BracketingAEB with ±2 Exposure values (EV):This menu item can be accessed using the Menubutton by selecting Menu 2 | AEB. After press-ing the SET button the level of exposure com-pensation can be selected via theMain dial. Fi-nally pressing the SET button again to set it (seeparagraph 2.1.6 and paragraph 3.3.).

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Adjusting drive mode selection:You can enter via the Drive mode selectionbutton and than use the Arrow keys or theMain dial to choose the shooting mode. Youcan check with the LCD-Display (see CanonManual page 70).

Using tripod for stable camera stand:

Using Continous shooting:This allows the user the release of all images be part of an AEB, by one constant presson the Shutter button of the camera.

Using of Self-timer/Remote controlledshooting:This allows the usage of a IR-remote controller.After one-time pressing the Shutter button ofthe camera or the controller a 10-sec. delay ap-pears and then the AEB capturing follows (seeCanon Manual page 71).

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After capturing/photographing the images, done without PC connectivity, the image filesmust be copied to the hard drive on the PC:

• Switch off the camera and connect the camera via USB cable connector to the PC• Switch on the camera• Start the software EOS Utility (software starts automatically if the operating

system can associate the connected hardware with the program, normally with thesecond start)• Select a target folder and start downloading the images, all images on the SDHC

memory card will be copied to the local hard drive

Afterwards, choose the menu Capture | Canon files or use the icon Canon file in theLMK LabSoft software and the dialog for opening and conversion of Canon RAW-imagefiles appears.In this dialog you have firstly to select the folder on your local drive, where the images arestored (see paragraph 5.3 in the manual of the LMK LabSoft). The LMK LabSoft showsyou all pictures inside this folder and there exposure settings. For automatic exposurebracketing series (AEB) the start settings will be displayed. After the selection of thephotograph or the exposure bracketing series the LMK LabSoft software automaticallyloads associated files and calculates the luminance image. The monochromatic result willbe displayed in the ’Luminance image’ tab of the software in a pseudo-colouring scale.For ongoing support and instructions for the assessment and analysis of measuring dataplease do refer to the manual of the LMK LabSoft.

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Aperture/Exposurecompensation button Print/Transfer

White balance

Viewfinder

Exposurecompensation level

Cross keyWhite balance

Setting ´Enter´ button

Cross keyAF mode selection

Cross keyPicture Style

Cross keyDrive mode selection

Capturing mode

Erase buttonPlayback button

Menu button

Drive mode

Display/Imageinformation button

AF-Mode

Main dial

Mode dial

POWER - switch

Shutter buttonLens release button

Display-off-sensor

ISO speed button

Metering mode Image counter

Image recording quality

Exposure time

Aperture number

Zoom IN/OUT

Battery check

LiveView button

2 How to handle the LMK mobileadvanced

This chapter summarizes important rules and all needed control elements for employingthe camera to acquire luminance measuring data. The non-observance of some advicecould result in a considerably higher expenditure of time.

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2 How to handle the LMK mobile advanced

2.1 Useful information about the camera

2.1.1 Aperture

The camera is calibrated for luminance measurements with adjusted apertures betweenF4 ≤ Fx ≤ F11. This is valid for the standard lens configurations. For special lenssettings additional restrictions can occure.

2.1.2 Focal length

The camera can be used, if no other restrictions are given (special lens configuration),with all available zoom states (focal lengths) of the lens.

2.1.3 Capture mode

For making a measurement, the Mode dial will have to be set to the Manual capturemode ’M’. In this mode, the aperture value can be set manually between the numbersF4 ≤ Fx ≤ F11. After that you must select an exposure time which is suitable forthe brightness of the object to be captured. There are no restrictions for setting theexposure time. But it is not recommended to adjust the exposure time as ’bulb’. Thissetting makes no exact allocation of the exposure time and therefore a luminance imagecalculation is not possible.

2.1.4 Image compression

If capturing luminance iamges the image com-pression method ’RAW’ or ’RAW+L’ (captureof uncompressed images) must explicitly be ad-justed on the camera. Any type of compressedimages (i. e. JPG-images) can not be convertedto luminance measurements (see Canon manualpage 72).

2.1.5 ISO-speed

According to the factory settings, the ISO-speed shall not be changed and fix setted toan ISO value of 100. Modifying the ISO value modifies the amplification of the imagedetector and the sensitivity. On urgent demand the ISO-speed can be set manually (seeparagraph 3.5) to values between ISO 100 and 1600. For the utilisation as luminancemeter not all ISO-speed steps are calibrated.

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2 How to handle the LMK mobile advanced

The maximum available ISO-speed is limited to1600. For the adjustment press the ISO buttonand use the Main dial for selection (see Canonmanual page 62). Using the ISO-speed au-tomatic is not permitted for measuring lu-minances.

2.1.6 HighDyn measurements

The High-Dynamic function of the LMK LabSoft analysis software enlarges the dynamicrange by utilizing the AEB function of the camera. An exposure series of 3 captures isprocessed to form one HDR-image (high dynamic range).

The maximum dynamic range comprises ± 2 ex-posure values (EV). The starting exposure timesof the exposure series should suitably be chosenbetween 1/1250 sec. ≤ Ti ≤ 8 sec (see Canonmanual page 89). This AEB setting mustbe made each time the camera is started.

2.1.7 Live-View shooting

It is possible to shoot while viewing a real-time image on the camera’s LCD-display.This is called LiveView shooting. For using the Live-View function the Mode dialmust be set to ’M’.Additionally the automatic focus ’AF’ must beswitched off, because it is not available with thisfunction. By pressing the LiveView button, tothe right of the LCD-display, the LiveViewshooting mode is activated. The real time imagewith the current exposure settings is now shownon the LCD-display.

With the Main dial you can change the ex-posure time and by simultaneously pressing theAperture/Exposure button you change theaperture values as well. The result will be shownpromptly on the LCD-display. Exit the Live-View shooting by pressing the LiveView buttonagain (see Canon manual page 107).

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3 Further information on how to makeluminance measurements

In this chapter, all settings referring to a SinglePic-capture of luminance images areexplained.The capture of serial images and the use of these image series as MultiPic-captureor as HighDyn-capture(also known as HDR photography) will be dealt with in para-graph 3.3. However, series of continous shoots are liable to the same basic explanationsconcerning the exposure metering and there compensation as SinglePic-captures do.The aim is to adjust all settings influencing the image exposure to avoid the overflow ofimage pixel. Overflow means, that the affected pixel do not record valid measurementvalues.

3.1 Selecting the exposure settings

The camera offers four methods of exposuremetering - evaluative metering, partial meter-ing, spot metering and center-weighted metering.The chosen metering method will be shown onthe LCD-Display. The different methods canbe assessed with Menu 2 | metering mode(see Canon manual page 86).

Evaluative metering:This type of measurement - which is best suited for most imagescenes - is the standard default setting of the camera. In thecase of manual focus, the evaluative metering is based on thecentral AF measuring field.

Partial metering:This type of measurement is useful when the background ismuch brighter than the object to be measured. The selectivearea covers about 9% of the central viewfinder area.

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3 Further information on how to make luminance measurements

Spot metering:This is for metering a specific part of the subject or scene.The gray area in the figure is where the brightness is meteredto obtain the standard exposure. This metering mode is foradvanced users.

Center-weighted average metering:The brightness is metered at the center and then averaged forthe entire scene.

For practical applications, it can be useful to differ between the following situations:

Homogeneous scenes:These include scenes presenting a largely homo-geneous level of brightness. For this kind of lumi-nance measurements, the evaluative meteringis recommendable. Here, attention must be paidto the fact that the Auto-focus of the camera isactivated.

Scenes with small light sources of high lu-minance:In the case of such scenes, the evaluative me-tering performed by the camera often deter-mines too long exposure times. This can resultin the fact that - even in the case of HighDyncaptures - the LMK LabSoft analysis softwarecan not evaluate the interesting image regionspresenting those high luminances due to pixeloverflow. In such a situation, it is recommend-able to utilize the partial metering or also thecenter-weighted average metering functionof the camera. Here, however, attention has tobe paid to the fact that the object to be evalu-ated is aligned to the center of the image. If theobject can not be aligned or if the exposure mea-surement yields wrong values maybe the spotmetering is suitable. By using this meteringmethod it is possible to shift the spot for the me-tering area over the image.

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Does all exposure metering methods do deliver wrong exposure settings (see paragraph3.2), they have to be shifted and corrected via a manual exposure compensations (seeparagraph 3.4).

Dark scenes:If the dark regions of a mixed scene are of in-terest, the evaluative metering could possiblyyield too short exposure times, which would re-sult in insufficient loads of the dark regions. Alsoin this case, it is necessary to apply the partialmetering or also the center-weighted aver-age metering, depending on the size of the ob-ject concerned. If this is not possible or if theexposure measurement yields wrong values nev-ertheless, it must again be adapted by setting themanually exposure compensation function (seeparagraph 3.4 ).

3.2 Checking the exposure settings

With the help of the shooting information display of the camera you are able to checkall necessary exposure settings immediately. For this you have to press the Shootingsettings display button once or twice a time. On the LCD-Display the last capturedimage together with a histogram and the exposure and lens settings is shown (see Canonmanual page 131). With the Cross keys you can switch to other captured images. In theexamples given, on the left-hand side you can see an image, with shooting informationand the histogram of the brightness distribution. The right image shows the histogramfor each R,G and B channel separately.

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3.3 HighDyn measurements with Auto Exposure Bracketing(AEB)

If the exposure time is automatically changed in the manual capture mode ’M’, thecamera is able to shift the exposure by up to ±2 exposure values (EV) in 1/3 stepsfor three successive captures. This is called auto exposure bracketing AEB (see Canonmanual page 89).After having set the picture frequency to Continous shooting the three captures willbe made consecutively (please keep the shutter release depressed long enough), and thebracketing series is finished automatically.The picture frequency being set to single shot,the shutter button will have to be pressed three times.

When the RAW image data of one HighDyn-capture (AEB exposure series) areread into the LMK LabSoft software for analysing information, always successive imageswill be compared with each other. Due to the image information contained in the EXIF-header of each image file, the images of one exposure series can be identified and combinedto create one HighDyn luminance image. Compared with single shots, this type ofimage capture offers the advantage that scenes presenting high interesting luminancedynamics (high contrast range) can be captured with one measuring image and thenevaluated. Furthermore, wrong calculated exposure setting of the automatic exposuremetering, which may result from inhomogeneous light conditions and high dynamics, canbe compensated in a relatively easy way. In addition to the AEB, also the start valuecan be modified by manually exposure compensation. Also in this case, the start value isdetermined by the chosen method of exposure measurement. If the start value, however,is not suitable, it can also be modified by up to ±2 EV in 1/3 steps (see Canon manualpage 87). Thus, for example, in the case of a set AEB of ±1 EV and a manual exposurecompensation of -2 EV, a serial capture with the following levels of exposure will result:-3; -2 and -1 with the start value of the exposure measurement determined.

3.4 Manual exposure compensation

If do not trust or be unsure of the choice of the exposure time, it will always be betterto capture several images at various exposure times. By doing this, you will have morereliability by an amount of several different single captures for the later analysis.To do this, the exposure time proposed by the camera shall be determined first. Then,an image is captured using this setting. Afterwards, one, two or more images shallbe captured by using other exposure times. The exposure time can be changed withthe Main dial and is displayed on the LCD-Display and in the Viewfinder. If theexposure metering is activated (slightly pressing the Shutter button), there result is

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represented with the exposure level indicator on the LCD-Display.The image can be lighted up (overexposure) or darkened (underexposure). The exposurecompensation function allows settings in 1/3 steps by up to ±2 exposure values (EV)(see Canon manual page 83).Furthermore, this compensation allows the alignment of the AEB to be influenced (seeparagraph 3.3 and Canon manual page 87). It is recommended to shift the start exposuresetting of the AEB in this way with ±6 EV and to adjust the spread to the maximumof ±2 EV. The finally manually combined images will have a distance of 2 EV to oneanother.IMPORTANT: For the HighDyn functionality in the LMK LabSoft softwareit is recommended to change only the exposure time and not the aperturevalue while making exposure bracketing series.

3.5 Setting the ISO speed

The sensitivity of the imaging sensor can be adjusted over the gain. The given gainsteps are provided in equivalent film speeds also known as ISO-speeds. With increasingISO sensitivity not only the amplification and the sensitivity also the image noise of thedetector will increases (see Canon manual page 62).

Therefore the ISO-speed automatic mode mustbe deactivated and the ISO-speed value has tobe set to 100. The ISO value shall only be raisedfor apertures set to F4 and exposure times ofmore than 3s became necessary or even if step-ping down the aperture is necessary but not pos-sible due to higher demands placed on the depthof field and thus causing the integration times toexceed 3sec and more.Using the ISO-speed automatic is not per-mitted for measuring luminances.

3.6 Using optional neutral density filters

The aperture number being set to F11, the shortest exposure time Ti = 1/4000s will notbe sufficient any more to avoid overexposure. This will be shown in the LCD-Display(see paragraph 3.2)by Blinking of the overloaded image area in the playback functionfor the captured images. Then it is necessary to adapt the measuring range of the camerato the light conditions by using optional neutral density filters (ND-filters).For extending or shifting of the measuring range, by decreasing the sensitivity, of theLMK mobile advanced up to higher luminances addtional neutral density glas filter withtransmisson down to 0,1% are available.

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3.7 Dirt and Dust

Exact measuring results can only be obtained by using clear and clean lenses. Impuritiessuch as dust, fluff, big dust particles or finger prints may quickly cause measuring errorsof >5%. Therefore, while exchanging the lens, attention will have to be paid to the factthat neither the sensor nor the rear of the lens becomes dirty. If necessary, the sensorcleaning function should be applied (see Canon manual page 150).

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