There is a fine line between conceptual and surreal photography, as sometimes it is hard to tell if the meaning behind the image was intended or not; the general rule is if the idea for the image was planned and has a clear and understandable meaning, then it is conceptual, but if there is no apparent meaning and the image portrays elements in an unrecognizable way, then it is surreal.
Abstract photography focuses on patterns, and is often taken in a very minimalist way. The image is free of concept and idea, which allows you to focus more on the texture, form and colour of the image. Abstract images are generally straight shots, but often use in camera techniques such as long exposures, shallow depth of field or macro to capture a part of the world we do not generally see.
Conceptual PhotographyConceptual photography is an image that is formulated off an idea or story, and the original concept is much more important than the image that portrays it. A prime example is advertising photography; where the image is trying to sell the 'idea' of the product. As conceptual photography is predominantly used in advertising, it is often taken in a clean, crisp and vibrant style, which may or may not be photoshopped. On general principle conceptual images blend and combine recognizable objects to create humorous or interesting compositions that have very distinct messages. Conceptual photography tends to get mixed up with surreal photography when the concept isn't believable or clear.
Surreal PhotographySurreal photography is defined as 'dreamlike' and portrays things that we wouldn't be able to see outside the realms of our subconscious mind. The meaning behind surreal artworks is left in the eyes of the viewer, as there isn't a specific concept that is depicted. Many surreal artists never have set ideas for their work, they just let the work transform as they create it. Photomanipulation is almost a necessity of surreal photography, as in order to be surreal, it has to not be something that could be seen in real life; textures and filters are often used to give a grungy, desaturated look, to give hint that the image is of something that is 'out of this world'.