- Look at an object with your concave lens.
- Draw the image you see
- Look at an object with your convex lens.
- Again, draw what you see. How is the image different?
When looking through a lens, there are two types of images that you could see. The concave lens should have given you an upside down image, also known as a real image. As light goes through a concave lens, it refracts and converges after exiting. However, it converges underneath the principle axis and looks upside down.
The image you saw through the convex lens is called a virtual image. A virtual image occurs when rays of light enter a lens and diverge after exiting. As a result, it looks like the light is converging at a point where it really isn’t, hence the name virtual image. You can identify a virtual image because it will be upright, look smaller than it is, and look closer to the lens.