![]() ![]() As sensor exposure (what happens when the shutter is open) decreases, the information content decreases. The S/N is a metric of data information content. Maximizing exposure maximizes the data signal-to-noise ratio. There are many, many others.įrom a technical point of view, the in camera histogram is an exposure estimate. One example would be color temperature parameters. The goal of the histogram of a rendered image is to maximize perception aesthetics. Nothing affects the technical quality of a rendered image more than exposure. ![]() To quote the author of the Raw Digger article linked by Brian Kimble, " Ultimately, the end goal of photography isn’t a histogram, it’s the photograph." The goal of an in-camera histogram is to optimize exposure. Of course the model for the data is not the same as the model used for a JPEG or TIFF file. Consequently, it is also impossible to display a meaningful histogram before developing a raw file, because this would first require demosaicking, then applying a logarithmic gradation curve, and finally applying a white balance setting.Īs Brian Kimble stated above, raw file data can be displayed as a histogram. So, not being able to display the contents of a raw file is a technical limitation, not a marketing decision. This will be compensated by applying a white balance that defines correction factors for the various color values during the file development process. That is, due to the higher number of green color filter pixels in the file, an image would have a strong green cast. The raw file records sensor data independently of any white balance setting. ![]() This means that if you were to display a raw file directly (assuming that you would perform demosaicking), you would get to see an image that both is too dark and only exhibits very flat contrast. The raw file records brightness values in a linear fashion, whereas our eye, and any JPEG image representation display brightness values on a logarithmical scale.The demosaicking process Does more than just combine pixels with corresponding color values, but also performs a number of rather complex mathematical operations that act as noise reduction, sharpening, white balance setting etc. To convert this into a color image, you first need to demosaic it, that is to combine the various pixels with their associated primary colors Into a pixel that has read, green and blue color values. That is, the image contained in the raw file essentially is a monochrome image. it simply records the pixel data of all pixels regardless of the color of the corresponding filter that is located in front of the pixel well. The raw file records image sensor data without demosaicking, i.e.There is a setting in Capture One which lets you get much closer to this flat look, which can be useful if you are trying to maintain the maximum range of lights to darks, but which rarely looks decent-the image generally needs a good bit of work in post to make it passable.Ī raw image file typically has three properties that make it difficult if not impossible to display its contents: ![]() The sensor also interprets the light in a literal flat line and we prefer the curve (which traditional film "adds" by its nature). We prefer images with greater sharpness and contrast than we see from a straight RAW conversion, because a straight RAW conversion has interpolated the color data from the individual sensors (demosaicing them) to produce an image, which introduces a lack of sharpness which must be counteracted for a more pleasing image. You can determine how much latitude you have by testing it (just as Ansel Adams tested his films, back in the old raises a very important point: your jpeg settings have an impact on the interpretation, including on the embedded jpeg in the RAW file. As you adjust the interpretation with the tools in the RAW conversion program, the Histogram will be updated.Īs a result, your cameras Histogram will show clipping of data before data is clipped and unrecoverable from the data in the RAW file. The histogram you can see from a RAW conversion program requires the RAW conversion program to interpret the data in the RAW file into an image and to base the Histogram on that interpretation. The RAW file is sensor data, which has to be interpreted into image data. A RAW file does not, strictly speaking, have a histogram except from the embedded JPEG. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |