There is still a lot of incorrect information out there about - -Depth of field -Crop sensor vs full frame cameras -Speedboosters -Light refraction And it seems many people who profess to know all about their camera gear, don't actually fully know some of the basics regarding- -Aperture -Focal length -The focus plane -Crop factor -The Circle of confusion -ISO -Image noise So I decided to talk about all of the above, and I drew some simple illustrations for you, and also took a few photos to help show what is actually happening to the light as it travels through our cameras lens. I really hope this video is useful.