35mm cameras were the most commonly used cameras before digital cameras became the norm. GEAR, PHOTOGRAPHY TIPS. Audrey Ann. Find the right DSLR lens for every photographic opportunity. The last frame was with the 300mm and a 2X extender, for an effective focal length of 600mm. Focal Length Comparison. Focal Length Comparison Chart: (click to view the full size) 16mm/wide: By keeping Diana’s face relatively the same size even as I change focal lengths, you can see the shift in perspective, especially if you pay attention to the backgrounds of the images. I finally got around to photographing focal length comparisons again this week - I know these can be really helpful as a reference point so it's about time I got around to it! At 16mm, it’s as if the entire background wraps around you. August 25, 2015. Browse Sigma lenses including over 45 camera lenses available for most major mounts including Sigma, Canon, Nikon, Sony, Pentax and Micro Four Thirds Systems. I also show the equivalent focal length in 35mm terms. The term 35mm equivalent focal length is a comparison of the field of view seen through a digital camera lens compared to the field of view produced by the older 35mm film cameras. The lenses used were 40mm, 90mm, 180mm and 300mm in focal length. A simple and easy to use tool for a visual comparison of the focal length and the angle of view of two camera lenses. In 6X6cm medium format this is an almost ideal spacing of focal lengths, logarithmically placed about 2 "stops" apart.