Anamorphic Cookbook – hFOV Calculator

February 13, 2016

UPDATE – DECEMBER 2016: I updated the calculator! Click here to check the new one. It is more accurate and complete than the original version.

After being asked thousands of times “how wide can I go using this camera, so and so as taking lens, X anamorphic and, oh, I’m also using this chinese focal reducer!”. A few comments on that: there are way too many cameras out there. I use a 5D3, a camera that’s already four years old – so I’m not too into what’s trending now – and has a full frame sensor. The main reason I chose full frame is because I hate crop factors; I hate doing that math. I haven’t used other cameras since I got the 5D3; I don’t know – and I don’t WANT TO know – all the specifics for all cameras available at all times in the market. Gladly, they can be grouped in categories based around crop factors and sensor size.

With a little bit of research, many hours of coding (and a super helpful plugin) I came up with this calculator. It should answer most questions about vignetting and horizontal field of view (hFOV) while using anamorphic lenses. All settings are picked from the dropdown menus, except the taking lens, where you can input whatever weird glass you like. Of course, you can override any of them with your own custom values. Below are a few notes about each setting. Enjoy.

CAMERA: The standard crop factors are here. If you don’t know your camera’s sensor size or crop factor, Google “NAME_OF_YOUR_CAMERA_HERE crop factor” and you’ll know what to pick from the list. If you’re recording with a different crop, check the “custom” checkbox and input your crop factor manually. Blackmagic instated chaos and every single one of their cameras has a different crop. I’ve included the URSA (because of its anamorphic mode) and the Pocket Cinema Camera (because of its popularity) on the list, but if you’re using something else, input it manually.

FOCAL REDUCER: RJ Focal Reducer and Vizelex’s Light Cannon are filed under “Others”. Metabones’s SpeedBooster is 0.71x. The numbers of focal reducers are also growing, so if you can’t find yours in the list, select “custom” and input the number.

TAKING LENS: Write here whatever’s listed as your focal length. If you don’t know your lens, sorry, I can’t help you! If you wanna know which taking lens will give you a specific hFOV, tick the “I want a taking lens” box and input a focal length in the Resulting hFOV field that shows up.

ANAMORPHIC: I wanted to add the names of the lenses here but the dropdown would be endless and there would be a lot more detail to this calculator. Maybe in the future. For the time being, just pick your stretch factor from the list. If you’re unsure about your stretch factor, google it. I added two variations for the 2x and 1.33x scopes, since they change the math of vignetting a little bit and were worth the modifications. Thanks to all the people who came up to me and pointed this out.

SENSOR ASPECT RATIO: More and more people are shooting with a window other than the default 16:9 This affects vignetting and hFOV directly. If you’re shooting 16:9 and cropping the sides in post, put that ratio here too, since it works the same way. If you have a specific odd final aspect ratio in mind and want to know how your sensor aspect ratio (AR) or settings should be, check the “Tell me my Crop” option and let the calculator know your desired Resulting Aspect Ratio in the field that shows up.

NOTES: All the math revolves around the 1920×1080 proportion. The GH4 anamorphic mode acts a little different as well as Canon with Magic Lantern shooting raw because both cases allow you to change the recorded height (pick these options at the Sensor Aspect Ratio menu). If you’re shooting at different resolutions, adjust your numbers accordingly to match the 1920×1080 proportion before input here or accept the slight differences you might get from not doing so.

Also, if you’re interested in more anamorphic content, check the overall ideas for the Cookbook and the already available for free “Anamorphic on a Budget” Guide!

DISCLAIMER! This is not a scientific tool, it’s designed to get you in the ballpark of which anamorphic goes with each taking lens. There are a few exceptions to the rules shown here and you should do some extra research on your specific anamorphic. Baby Anamorphics (Möller 8/19/1.5x, Baby Hypergonar, Iscomorphot 8/1.5x) are a notable exception to the presented by the calculator and vignette more easily on larger sensors, but they play along fine with smaller taking lenses and sensors. Also, about the GH4, there are some weird situations in which its behavior doesn’t match the math, so be careful and do some more research on your own.

DISCLAIMER 2! I’m officially not replying anymore to questions about “how wide can I go with this anamorphic”. If you wanna know, check the calculator and do your individual research. Post in public places, facebook and EOSHD are great places to start. I might even show up to reply, but there are plenty of people with much more experience than me willing to help beginners and people with questions.

DISCLAIMER 3! I know the calculator could have a lot more intricate fields, more cameras, more lenses, but this is as far as I’m going with it right now. If you wanna work on an advanced version, be my guest. If you want me to repost it, I’d be honored.

UPDATE – DECEMBER 2016: I updated the calculator! Click here to check the new one. It is more accurate and complete than the original version.

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  • rapidotechnology November 2, 2016 at 11:01 pm

    Very cool, thanks