Photo Notes
for Sunday, 7/19/2015

See also general flying [Photo Notes]

In my rush to launch, I forgot to configure my camera settings. For bright light outdoor flying photos with clouds, I normally configure for a high shutter priority setting and let the aperture choke down as necessary achieve the calculated exposure automatically.  Unfortunately, my camera was set to aperture priority with the lens wide open and an ISO of 200, which is ok for general point and shoot around the house, but with bright daylight the shutter isn't fast enough for the fixed lens opening.  As a result, all my photos from Sunday were badly overexposed.

Fortunately I recorded in both RAW and JPG.  A jpg file is a "rendered" image from the raw sensor data.  The raw file contains much more information.  The jpg uses what it needs based on preferences, either automatic or manual, then discards the extra information that isn't needed to render the image at the defined settings in a small file size.  In a nutshell, the raw file contains a much wider range of luminance data which the jpg discards, so a poorly exposed image can be corrected somewhat by processing the raw data with offsets to adjust the exposure.  It's still better to get the exposure close because there are amplification issues which translate to noise when programmatically increasing the exposure in post processing, and if the exposure is past saturation (badly overexposed), there is nothing to recover.  Flight photos on cloudy days pose a challenge with "Dynamic Range".  The bright stuff tends to be overexposed, and the darker stuff in the shadows tends to be under exposed.  If the exposure is close, we can often correct for the poor dynamic range of the sensor in post processing, but if the exposure was significantly off center one way or the other, then it may not be possible to balance the whole image.

Anyway, my whole photo set from Sunday was badly overexposed, which might not be quite as bad as under exposed because I think more noise is introduce in amplifying the dark areas compared to dirking the light areas, however, stuff that would normally be on the bright side of the dynamic gets oversaturated and "clipped", so there is no information to recover and it just looks white or varying shades of grey with no color contrast detail.

The two photos below are examples of the original JPG version and the process RAW version of the same shot from Sunday.