This video tutorial by portrait photographer Nathaniel Dodson (from the website tutvid) takes a look at at perspective in a composite image in Photoshop.
So let’s say that you want to create a composite of two images (in this case Dodson brings in two car images into a forest), just throwing them into the background will (in most cases) not work since the size isn’t right, the perspective isn’t right and usually the lighting isn’t right either, so these are all things that you need to fix in order to make the composite look realistic.
The first step will be to determine where the horizon line is in your image. In this case Dodson works with lines that comes out of the wheels and cross each other somewhere on the horizon line – bringing your car to the right spot in relation to that (and Dodson shows how to do that for both cars in this video) is the most important part of this type of compositing (although again – there are lighting and shadows and size aspects that were not really covered in this video).
Bonus video: How to Composite a Car onto a New Background
We have covered different aspects of perspective on Both Photoshop and Lightroom here on LensVid including the great video by Jesús Ramirez: “Using Perspective and Vanishing Point To Create Composites In Photoshop“, Editing & Manipulating Images in Perspective Using Vanishing Point in Photoshop by Bryan O’Neil Hughes, Travel Photography: Correcting Perspective in Lightroom as well as How to Duplicate Anything in Perspective using Photoshop and “How to Use the Vanishing Point Filter in Photoshop” by Aaron Nace.