Better Light 7 manual Appendix B, Manipulating Exposure, Exposure Adjustments, Line Time

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Appendix B

Manipulating Exposure

The Better Light digital camera system provides a very flexible set of controls for adjusting both exposure and processing. Most of these controls are directly analogous to their film photography namesakes, but several have not previously been readily available to the photographer, and none have provided the precision and consistency now available with this system. As with film, there are also some image quality trade-offs among these adjustments, and optimum ranges for each control.

Exposure Adjustments

Exposure changes are typically used for controlling under- or over-exposure conditions, and for equalizing the range of data values produced by each color channel (gray balancing). The primary rule of exposure, signal (density or data) = light x time is unchanged; less light requires more exposure time to produce the same signal level, whether it is a given density in a film image, or a given data value in a digital image. The amount of light is up to the photographer, and is a function of many variables, including the lens aperture setting. Exposure time is now controlled digitally; the shutter in the lens stays open during the entire imaging process. All three color channels of the CCD are controlled simultaneously by exposure time changes.

In addition to exposure time, the photographer now has the ability to independently adjust the effective sensitivity of each color channel of the CCD (its ISO rating) over a continuous range of more than four EV (f-stops), on a shot-by-shot basis. This powerful control allows precise gray bal- ancing of image data with nearly any continuous light source, and provides a wide range of effective ISO settings for increased flexibility in setting an exposure.

Finally, the Tone Curves can be used to “push” or “pull” a given exposure without significantly affecting contrast or color rendition. This function of the Tone Curves, while not strictly speaking an exposure adjustment, will be treated separately from Tone adjustments, which do affect contrast and color.

Line Time

This setting is equivalent to the shutter speed setting on a film camera. It controls the amount of time that each line of the image is exposed; adjustable in 1/3 EV (f-stop) increments. Longer line times provide increased absorption of light but can also increase scan times significantly. Longer line times also produce more dark current, which can increase shadow noise.

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Contents Revision D March Large Format Digital Scanning Camera SystemAcknowledgements Page Page Contents Locking Both Lock Crop RatioAltering Color Balance for Mood or Effect Audio Focusing Aid Multiple Color FocusingSaving a High Bit Depth Image Limit LineAutomatically Opening the Image Exporting NotesLine Time Hardware Setup Software OperationLighting Parts List Connector Identification Getting Started Installing and Configuring the ViewFinder SoftwareSystem Requirements Memory RequirementsMacintosh PC PC version of the software is requiredConnect the camera insert to the control unit Quick Start GuideConnect the control unit to the host computer Mate the female end of the cable with the DBInstall the viewing overlay on the camera’s ground glass Connect the AC power to the control unitTurn on the digital camera Turn on the host computerMm thick Tungsten infrared blocking filter Install the infrared blocking filterCompose and focus the image Select the image capture settingsPut the insert into the camera Start the ViewFinder softwareTake the picture PrescanTransfer the file to the computer View the final imageMaking a Prescan PrescanningFast Prescans Cropped Prescans Super View Prescans Saving and Viewing Prescans Canceling a PrescanColor Managed Prescans Guides RulersResolution Image Capture SettingsPage Line Time ISO Exposure Lock Capture ModeScanning Canceling a ScanScanning to the Camera Disk Automatically Naming Images Naming the ImageAdding Notes to Your Picture Digital Spot Metering Exposure EvaluationRGB Data Values, EV Units Determining Relative Exposure Static Spot Meter Tool Setting the Spot Meter Size Judging Overall and Spot Exposures HistogramStatic Spot Meter Location Readings Magnify Tool Tool BarHand Tool Panorama Tool Measure Tool Mac onlyToneZones Tool Page Grid Tool Crop Mask ToolPage Size Panel Tab PanelsScan Area & Cropping Different unit. Example 15.24 cm x 10.16 cm at 300 pixels per Size of the cropped area may still be adjusted whileClicking up or down buttons of Scan Area Lock Crop Ratio To set a specific shape for crop rectangleLock File Size To specify an exact file size Seconds Scan direction Faster Scans for FreeEstablishing Neutral Color Balance Color PanelSaving Color Balances Deleting Color Balances Changing Existing Color BalancesAltering Color Balance for Mood or Effect Tagging Images with ICC Profiles Reverting to a Previous Color BalanceTone Curve Selections Tone PanelSaving a High Bit Depth Image Brightness/Contrast Tone Curve Adjustments Manual Tone Curve Adjustments Spot Meter Reference Points Limit LineNegative Curves Bit Tone CurvesTone Curve Histogram Setting the EV Scale ReferenceSelecting an Output Tone Scale Deleting Tone Curves Saving Tone CurvesLarge Focus Display Focus PanelSelecting a Focus Site Reading the Focus Displays and Adjusting Focus Multiple Color Focusing Audio Focusing Aid Mac onlyInfrared Focus Image File Management and Retrieval ViewFinder File Manager Adding more Notes to Your Pictures Sorting Image FilesExporting Notes Automatically Opening the Image Automatically Saving Files to a FolderRetrieving Image Files Selecting the Retrieval Tone Curve USB controller only Hard Drive Storage Capacity Deleting Image FilesFile Menu MenusEdit Menu Display Menu Camera Menu Clean/Park Capture ModeDiagnostics Opens the Clean/Park window to expose the CCD for cleaningAutomatically Retrieving Images Saving Files User PreferencesAfter highlighting the desired folder, click Right of the Save scan folder labelAuto Naming Automatically Save PrescansAutomatic Scan Viewing in an Application Auto File Open Mask Auto-rotate Retrieved FilesGuides GridBaseline ISO Setting Using SoundsISO Increment Selection Use this feature, the factory settings are adequate Pano SettingsTime Lapse CropAppendix a Cleaning the CCD Cover GlassAppendix B Exposure AdjustmentsManipulating Exposure Line TimeTone Curves Color Balance SensitivityLens Aperture Lighting Appendix C Line Time SettingsAppendix D Resolution SelectionsModel 4000E-HS Model 6000-HS, 6000E-HSSuper 6K-HS Super 8K-HS Power Status IndicatorsAppendix E StatusAppendix F Hardware SetupPanoramic Adapter Scene PanoramaPage Rollout Panorama Hardware is assembled just as it is for a Rollout panorama Object PanoramaCamera reported error Not Ready Error MessagesCamera reported error No Room Camera reported error Conversion ErrorCamera reported error Math Error Camera reported error Value ErrorScsi Errors Comm returned error Other Errors Unknown ErrorCamera Timed Out
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