RBA Premium Astrophotography
Posted: April 12th, 2017
For the last few years I've been following a rule when it comes to describing my nightscape images: if the image is a composite (definition below) I would always state it, otherwise it is not. In other words, I'd always disclose composite images upfront, but if I don't say anything about a particular image, it means it is not a composite.
From now own however, rather than using that method, I'll be using a similar method as the one people started using in the Milky Way Chasers group, and every new image I post on social media will include a quick tag/label describing the type of image.
#SINGLE: A single image, end of story.
#BLEND: An image composed of several different images sharing the same field of view but captured at either different times or using different exposure settings, always during the same session.
#HDR: A special place of "blend" that aims at producing an image with a larger dynamic range than what may be achievable with a single shot at certain exposure time and settings. The main difference between a BLEND and an HDR is that HDR images blend the very bright areas of long exposures with the darker equivalent of shorter exposures, and vice-versa, through an automated process. Blending, on the other hand, involves manual selections of the different images being combined.
#STACKED: a series of images of the same area and at the same settings, that were later stacked together, regardless of whether they were registered (to increase the Signal-to-Noise ratio) or not (star trails and similar images). Tracking - that is, using a mount that "follows" the stars as Earth rotates - may or may not be involved.
#MOSAIC: An image that was built by stitching together several different photographs, all at the same settings and exposure, and during the same session, usually seconds apart.
#COMPOSITE: An image that was built from elements taken from several different images that does not fit into any of the previous categories. A classic example in nightscape images is an image where the landscape was taken from one photograph (or set of photographs) and the sky was captured separately, on a different night or location, with different optics or pointing at a different area.
I encourage other photographers to use a similar approach when they share their image. You don't have to categorize them exactly as I did, although you're welcome to do it if you like.