openEyA -- Lenses on the Webcam

Our problem

With the webcam 4m away from the blackboard, we got poor image quality.

We tried to improve lighting conditions, change the blackboard, etc. Not much improvement.

We concluded that the main problem was focus. Webcams are made to film objects at close range (faces on skype). They are not good dealing with far away objects.

Our solution

We tried to correct the focus by putting optical lenses in front of the webcam.

We concluded that, in our set up, a lense with -1.5 diopters would improve the image.

We bought the lens at regular optician shop. White, spherical lenses with no special treatments.

We asked the optician to cut the lenses in a circular shape with diameter adapted to the camera (30mm for Logitech C910). Altogether the price was 14 Eur.

The lens was attached to the webcam with Blutak/Bostik. Could also glue it.


In our case the focus improved:


The same camera, in the same room, in the same position. Blackboard on the left is dirtier. Nevertheless, focus improvement is significant.

This solution is more appropriate for permanent instalations of openEyA. We are using it at University of Porto and IST-Lisbon.

Do try it if you have focus problems.


Contact:   Joao Oliveira Baptista   (joao.o.baptista address in gmail)