lens optics

This simple blackboard model explains how a Fresnel lens works

Apr 30, 2021 by John Aldred Add Comment

Fresnel lenses are found in all kinds of things from the lenses and light modifiers we use in photography and filmmaking to lighthouses that guide ships at sea. The lens was developed by French physicist Augustin-Jean Fresnel, after whom it was named, specifically for use in lighthouses. It allows for the construction of huge aperture and short focal length lenses but using less material than more traditional lens optics.

How exactly do they work, though? In the video above, David Willey explains how a Fresnel lens functions and why it is the shape that it is using a simple blackboard model and some magnetic strips. But essentially, Fresnel lenses are just regular lenses with big chunks taken out of them.

Your Aperture Is Sort Of Lying To You: When Is An Aperture Of F1.2 Not Actually A F1.2?

Sep 30, 2014 by Tiffany Mueller 16 Comments

One of the first things we learn as photographers are F stops and how we can use them to properly expose a photograph, but there is also such a thing as T stops and we don’t always give them the attention they deserve. Of course, a T-stop may not be essential knowledge on every photo you take, but understanding what a T stop is will give you a better understanding of light, which is never a bad thing for a photographer to have. (It’s also helpful information to have in your bag if you’re going to be lens shopping soon!). And Matt Granger does an amazing job of explaining the difference.

Dave Williams is an accomplished travel photographer, writer, and best-selling author from the UK. He is also a photography educator and published Aurora expert. Dave has traveled extensively in recent years, capturing stunning images from around the world in a modified van. His work has been featured in various publications and he has worked with notable brands such as Skoda, EE, Boeing, Huawei, Microsoft, BMW, Conde Nast, Electronic Arts, Discovery, BBC, The Guardian, ESPN, NBC, and many others.

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