Angles of Incidence and Reflection

Learn how to position your lights right every time.

If you’ve ever struggled to position a light correctly, or wondered how to avoid glaring reflections in an image, this class will answer all of your questions.

Here, Karl breaks down some simple laws of physics to help you get to grips with how reflections work and how you can optimise them in your photography.

After describing the four different types of reflection, Karl goes on to explain the angle of incidence and the angle of reflection. (In the video, the latter is sometimes referred to as the ‘angle of reflectance’.)

Understanding how these angles relate to one another is crucial to capturing successful photographs. Using graphical examples, mirrors, laser pointers, smoke pellets and even a Harley Davidson motorcycle, Karl demonstrates how to put this key aspect of lighting theory into practice.

To wrap up the class, he shares a handy technique for removing glaring reflections from a shot – without having to move your lights.

By the end of the video, you’ll have a deeper understanding of how light works and how to harness and manipulate it for stronger images.

In this photography class:

  • The four types of reflection
  • The angle of incidence
  • The angle of reflection
  • Using polarising filters in photography
  • How to use a laser pointer to position studio lights
  • Adjusting focal length to alter reflections

If you enjoyed this class, check out Understanding Light or Harley Davidson Night Rod Photoshoot.

You may also like to watch How and Why to Polarise Light in Studio Photography, which Karl mentions in the conclusion to this class.

Questions? Please post them in the comments below.

Comments

  1. Karl, this was the best explanation on angle of incidence and reflection. I used to play a lot of billiards would it be correct to say these same principles apply? Your course is the best so far in explaining photography principles. Thanks for offering these courses!

    1. Hi Lucas, Thanks and yes theoretically its the same but due to spin of the ball or various imperfections in the material it would not yield the exact same response.

  5. Thanks Karl. Many of your educational video’s you have commented about the laws of physics and that is such a necessary part of photography. Previously I was a member with another educational program but best I can recall they never mentioned physics. Your educational courses are much better.
    Have often used lighting on a background to reflect onto a flat surface supporting a product but all other lighting set ups have struggled where to place them….now with your help it will be much easier.

    Have considered using a DSLR for reviewing images as I set up the lighting, but then switch to a Sinar P2 4 x 5 for the final shot using film. Scanning would create a very high resolution image. If you have time would like to get your thoughts about it.

    1. Hi and thank you. Yes the Sinar 5×4 would give incredible results. I used to use a P2 with Ektachrome which was then drum scanned to provide incredibly highly detailed digital images so yes the results can be amazing but you need good scans to get good results so it will also depend on the scanner operator and their machine. The idea of using the DSLR for reviewing your lighting like a polaroid is reasonable but obviously going to be more time consuming.

  7. Thank you so much!! That was really helpful !!!

  8. Thank you very much for the detailed and clear explanation, plus the examples. Especially the top down view (diagram) is super helpful, unwanted reflections have basically plagued me many, many times.
    This education course is pure gold 👍

  9. Felice

    Hi Karl
    Thank you for this very helpful lesson.

    One problem: direct reflections in glasses when shooting portraits:
    I know the laws of light and often use large softboxes and work with distance when shooting persons with glasses. But sometimes I would like to have more direct and harder light.

    To avoid reflections in glasses with harder light, do you have any helpful tips? Maybe change the distance of the camera and the focal length as in your lesson?

    Thank you very much for your portal. I will be happy to renew my subscription.

    Felix

    1. Hi Felix, I find if you worry too much about the glasses then you have to compromise many other things with your lighting, pose etc. So what I do is photograph the person with glasses and then when I’m happy with the shot (even if it has a reflection on the lenses) then I get them to repeat a very similar pose without glasses and I use this one for the eyes where needed. Alternatively if you want to use harder lighting then it should be from up higher anyway so it would only likely clip the top of the glasses in the reflection.

      1. Felice

        Thank you, Karl, you are right.
        I’m a bit of a perfectionist, because I have a lot of elderly and disabled clients who have had a lot of negative experiences with photos of and about them.
        I like your idea. That’s what I’m going to do.

        Thank you for the great offer on your website and the quick help.

  10. Remig

    Thank you for this great lesson Karl! These 3D animations are really amazing and help a lot to understand the concepts you explain 🙂

  12. i hope you can make an example on portrait photography to know how can we sit the back light or rim light .. and be so effective … thanks alot .. much love

  13. Brian R.

    Great stuff as always Karl! I wouldn’t have initially thought to change the focal length when shooting flat glossy subjects. I did a quick search but do you have a session on refraction? ie a smooth clear glass filled partially with clear water, understanding reflections and refractions from an object in front of or behind it. I always have to think a moment on what shows on the opposite side, especially when backlighting hehe.

    1. Hi Brian, glad you enjoyed it and yes we also changed the focal length here on the flat copy stuff and the 3D graphics showed the relationship between the angles of lighting permissible as that focal length changed. With bottles with liquid yes you get lensing and refraction which means things are the opposite way round which always requires thought on where your lighting is on the background. I cover this on the clear gin/vodka classes.

  14. Great class! What I really like of your classes (and that makes your edu-platform a way better than the others) is that you talk not (just) the “how” but about the “why” and this is what we all need. It’s like the old saying “give a man a fish and you feed him for a day; teach a man to fish and you feed him for life”… if this has sense. Thanks, Karl.

  15. Another excellent lesson, so well explained and shown in practice and diagram form. If I can understand this (and I can), then anybody can grasp it! Just one question: Where do you get your laser lights from!? Amazon don’t seem to sell them. I ordered one, which I thought was a laser (it was described that way), but turned out to be just an LED pencil torch.
    Many thank again.

    1. Hi Thank you. We did buy this one from Amazon some years ago so maybe they’ve stopped selling them? But any laser pointer for slide shows will do the trick so you could try an office supply shop.

      1. Thanks Karl. I managed to figure out a UK supplier and have ordered one. I discovered they’re called ‘laser pointers’ and have some restrictions relating to the permitted power – hence Amazon not selling them. But anyway, thanks so much for this great lesson – so fundamental, and answers a number of questions I hadn’t resolved.

        1. No problem, they don’t need to be very powerful as you only need to see where the dot ends up. The one we have is a super high power so we can see the beam of light for effect in filming but I’m sure we got it on Amazon some years ago.

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