#ReflectionFocus #PhotographyQuestion
Hey there! 📸 Have you ever wondered why the focus of a reflection is the same as the item being reflected and not the item it’s reflected off of? Let’s dive into this interesting phenomenon together!
## The Science Behind Reflection Focus
When you were capturing the reflection of the exit sign in your photo, you noticed that the focus seemed to be on the sign itself, even though you were actually shooting the screen of a phone that was much closer. This is due to the way light behaves when it is reflected off a surface.
### Light Reflection and Focal Points
Light reflects off surfaces in a predictable manner. When light is reflected off a surface, it bounces back at an angle equal to the angle it hit the surface. This is known as the law of reflection. The focal point of the reflection is essentially the same as the focal point of the object being reflected because the light is bouncing off the object and onto the reflective surface.
### Depth of Field and Focus
In your scenario, setting the focus to about 20ft allowed the reflection of the exit sign to be crystal clear, even though the phone screen and table were out of focus. This is because the reflected light from the sign was hitting the phone screen at a 20ft focal distance, creating a sharp image of the sign in the reflection.
## Actionable Steps for Capturing Reflection Focus
Now that you understand the science behind reflection focus, here are some actionable steps you can take to capture reflections more effectively in your photography:
– Experiment with different focal distances to see how they affect the clarity of reflections.
– Use a tripod to stabilize your camera and maintain focus on the reflection.
– Pay attention to the angle of incidence when capturing reflections to achieve the desired focus.
– Explore different lighting conditions to enhance the reflection and focal point in your photos.
Next time you’re capturing reflections in your photography, remember the relationship between the focus of the reflection and the object being reflected. Keep experimenting and have fun with your photography journey! 🌟
An interesting comparison can be made with rear view mirrors in cars. When glancing at your mirrors, the focus point is roughly the same as that through the windscreen, so your eyes do not have to re-focus. However, a number of modern cars now have camera based mirrors. When looking at those, the eye is required to focus on the actual screen itself, requiring the eye to re-focus, which takes a small amount of time.
Oh, ok. Dang, I was thinking only about the two objects and not the “photo” in “photography”. I’m not taking a picture of the sign but rather the light reflected off of it, so the distance to me from the sign is how far its light travels regardless of whether Im shooting it directly or through the reflection. I think I understand. Please correct me if I’m wrong. Thanks for the explanations, everyone!
Physically, there is no difference between a perfect mirror, reflecting an object behind you, and a transparent pane of glass through which you see an object in front of you. In both cases, the light had to travel the same distance, and arrives at the same angle, so the optical equations are exactly the same.
As a result, even though the *mirror surface* is only a foot away, the *light* from the object you are examining moves and behaves exactly as though it is as far away from the phone as though it were “really” on the other side of the mirror.
This fact, that you can pretend that reflections are actually mirror-side real things, is used in math and physics to simplify the solution to complex differential equations it is called the “method of images.” Quite useful.
The path that light has to travel from the object to your camera was 21 feet long, 20 ft from object to mirror then 1 ft from mirror to camera. You’re trying to focus on the object, not the mirror itself, so it’s just like any other time you’re trying to focus on an object 21 feet away. The fact that there’s a mirror changing the angle of this path partway through doesn’t matter or affect anything.
[This](https://i.sstatic.net/9twPx.png) diagram shows the path of two light beams as they bounce off of a mirror. As you can see, the angle that they reflect makes an image which appears to be a distance behind the mirror (the dotted lines).
Because it’s geometry, the visual of the diagram is going to be far more helpful than a wall of text.
Think about taking a photo through a window. You don’t focus on the window glass; you focus on the things beyond the window. A mirror is essentially the same thing except it bounces the light. You’re essentially looking “through” a mirror to an image that’s “behind” it, and you this have to focus your camera on the distance “behind.”