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Comprehensive Ophthalmology Free Papers metering modes usually available are multi, central and spot in case of most of compact digital cameras. In the multi metering mode the exposure is decided by taking reading of light falling on entire frame to be captured. In case of central metering the exposure is calculated on the brightness or light falling at the centre of the frame to be captured. Spot metering decides the exposure of the brightness of the small central point. In case of high end compact cameras and digital SLR the spot in the frame can be changed by the user. In case of slit lamp photography it is best to use either central or spot meter to get the correct exposure of the picture taken. Exposure Compensation It is important to use a compact digital camera with a facility to adjust the exposure. In this one can increase or decrease the brightness from the exposure reading mode by the camera. In slit lamp photography the Halogen light falling on the eye and viewed through the slit lamp is quite bright at the centre and the surrounding areas are reasonably dark. Hence the camera metering is fooled to believe that there is less light. Hence the exposure in normal mode results in washout of all the details in the centre which is the main area to be captured and documented, this happens even when spot metering is used. Hence most of the time it is essential to reduce the exposure to either -1 or -2 steps below the exposure reading made by the camera. Steady Shot This reduces the vibration of the hand while taking the picture and should be always on Image Size In principle always use the highest resolution available in the camera for capturing the images. Flash Most compact cameras gives multiple options of using the in built flash. They are usually auto flash, flash ON, slow synchronization flash and flash OFF. In documenting the anterior segment through the slit lamp always set the flash to OFF mode. In case of direct photographing the eye and the face the flash can be set at either mode OFF or flash ON. Zoom Always use the optical zoom to a minimum extent to maintain good depth of field. DRO In DRO OFF mode there is no recovery of the shadow details. In case of slit lamp photography always put OFF the DRO, as the area of interest is already brightly lit with slit lamp light. 477
70th AIOC Proceedings, Cochin 2012 Picture Capture Modes Most of the standard compact cameras provide multiple modes to take pictures. Some of standard modes available are scene selection mode, complete 478
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