Step 3 : Creating The Protective Sleeve

After you have the cardboard insert properly sized, bend it at regular intervals so that it is pliable enough to form a cylinder. You can bend it at as many places as you like. Just make sure you are bending along the corrugations, not against them. This will ensure that the cardboard cylinder remains rigid length-wise.

After you have made the cardboard insert pliable enough to form a nice cylinder, wrap it in bubble wrap and tape everything properly. Make it a snug fit because if there's too much play, you may not be able to tape it into a proper cylinder later.

Next, tape the two ends of the cardboard insert together to form a cylinder. It should look something like this. Once done, you will have a rigid protective sleeve for the lens. When installed, it will look like the second picture below. As you can see, the sleeve extends beyond the lens.

If there's a direct impact on the front of the sleeve, the bubble wrap reduces the impact while rigid cardboard insert transmits the remaining force to the camera body. This completely protects the lens from any direct impact from the front. The sleeve also protects the lens from side impacts. The double layer of bubble wrap provides protection against the shock from any side impacts.