No harm done for purposes of this illustration. Some apps won't deal with a greyscale file, so I have had to convert it to an RGB file to better subsequent versions of it here. Here is the raw, raw, raw file for which no demosaicing, no autoscaling and no gamma-curving have been applied. apply a gamma curve to raise the midtones.There are 3 basic steps to conversion of a raw file. So you're seeing the corrugation pattern. I had set the standards on a piece of cardboard. Those are not Jpg artifacts in the background. My in-camera WB setting was a preset made to be close to the raw composite colours (shown later). (Probably not needed given that a WB dropper can be dragged around an area to average out the WB?)Īll fotos were converted to JPG (q80) and resized in Photo Mechanic. As is always recommended, the photo is slightly soft to prevent grain (or whatever) from influencing colour or WB. And, as always, the blue channel shows noise in the darkest EV areas. It is perhaps slightly underexposed in the red - as you will soon see in the histogram. This photo was taken for the purpose of making a white balance preset in a converter. Gear: Nikon D600-mod + UV-Nikkor 105/2.5 + BaaderU UV-Pass Filter + Sunlight After I get it all posted, please, other members add your comments and suggestions. Here is a extraction series from Raw Digger. This does give me different images to straight jpeg files, so something different is definitely happening, but to be honest I have no idea if this is the right approach, or if I should be doing anything different.īefore I do too much on this, if anyone can comment on whether what I am doing is correct, or if there is a better way, it would be much appreciated. I then save the file as Tiff file, and finally crop it in Photoshop, to isolate the middle of the illuminated area from the port of the integrating sphere, and finally do image analysis in Image J to get the histogram which gives me the grey scale value from 0 (black) - 255 (white) of the light coming from the integrating sphere. To create a 'linear' image from the RAW file my approach was this - open in Darktable and create a 'base curve' which is linear. My understanding is that the camera output to brightness is linear to intensity but processing of images changes this linearity to make the final images more appealing to the eye. I'd then use the brightness of image, in combination with the intensity of the light at different wavelengths as measured with a spectrometer, to work out how sensitive the camera is to that light of that wavelength. The aim is to take photos of the exit port of an integrating sphere, at different wavelengths of light. I am looking to capture images for my work on calibrating the spectral sensitivity of camera/lens combinations to wavelengths between 280nm and 480nm. I am very much a RAW 'newbie' and need some advice please.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |