There is a feature in your camera Sony have chosen to call it Dynamic Range Optimisation (DRO for short). The DRO feature doesn’t actually increase the camera’s dynamic range, as that determined by the sensor and signal amplification electronics. What DRO actually does is to brighten the shadowed areas of some images while still preserving highlight details, thus making better use of the dynamic range that’s actually available. If this description seems to belittle DRO’s effect, make no mistake: Under the appropriate circumstances, it can have a very significant impact on your pictures.
DRO Modes and their effect
These general settings and effectiveness may vary from camera model to camera model , and are also dependant on your firmware version. In general the newer the camera model and the newer the firmware the more settings and effective DRO settings will be. There are cameras that have DRO settings that other cameras don’t have e.g. DRO bracketing in the A900 and 850. DRO settings will only have an affect JPEG files, and will not adjust RAW files. But if you are shooting in RAW mode, you can apply any of the DRO options in Sony’s SR 3 software.
- Off: The camera operates normally, with no DRO processing performed.
- D-R: This is the “normal” setting for DRO, and the default operating mode for the camera. In this mode, the Alpha’s processor evaluates the contrast and brightness of each image, and adjusts the tone curve used to map the raw sensor data to the final brightness values in the JPEG images. Sony says that this is more than a simple gamma-value adjustment.
- D-R+: DRO “plus” mode performs the same analysis on the image as in normal D-R mode, but adds a further level of intelligence by adjusting the brightness of the image locally. Shadow areas are made brighter, highlights are held back a bit. (The shadow adjustments are much more evident, adjustments to highlight regions were very subtle in our tests.)
When and where to use it.
In my experience you will get the best results, in very high contrast lighting with the DRO set to Level 2. That should provide adequate mid-tone and shadow detail without an over-processed effect or a significant increase in the visibility of digital noise. You will get the best results with low ISO values. High ISO levels, and long exposure will create a lot of digital noise in combination with an increased DRO setting.
Using DRO in difficult lighting situations and be an invaluable tool, but overdoing your settings in the wrong situations will create a lot of digital noise and loss of detail. The best way to learn how use the DRO settings is to get out there and take photos. Set your camera up on a tripod, and take the same shot several times with different settings e.g. ISO and DRO. That was you will soon find out that settings suit your shooting style….