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I'm trying to film my rugby practices with my iPhone and wondering what is the best lens to use to capture the entire field without much that fish eye look?

I noticed that the new iPhone 11 (Pro) has a 120 degree ultra wide angle lens and from the looks of it it doesn't look fish eyed at all. Could I buy a new iPhone Pro and add a lens to it to get from 120 to 170 / 180 degrees of view with only limited fish eyeing?

I really have no idea whether lenses are additive where if you add the same wide angle lens to a 60 degree field of view lens and compare it to adding it to a 120 degree field of view lens, will the 120 just be incrementally wider than the 60 based on the attributes of the lens?

Or should I consider an anamorphic type lens e.g. https://www.shopmoment.com/shop/anamorphic-lens Would this give me the desired look, where I can see almost all the field assuming the camera isn't that far away from the side of the pitch.

Apologies for the ignorance about lenses, really don't know a lot about how they work or whether physics will just make what I'm trying to do impossible, but your help is much appreciated.

  • If you have a lens that covers the whole field, the players are going to show up as a few dancing pixels in many places of the field (along the opposite sideline, and at both ends). You would have a more uniform coverage by putting the lens farther away for the field and using a tele lens. – xenoid Sep 14 at 23:46
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Your question comes down to angle of view.

It sounds like your camera is on the sidelines somewhere near the pitch, rather than in the stands. Let's use some assumptions to calculate some numbers.

  1. You are setting up the camera 10 ft (3 m) from the pitch sideline, at the halfway line.
  2. The pitch is standard 69m wide by 100m, try line to try line.

Then the corresponding angles of view are:

  • 2 * atan(50 / 3) = 173°, from try-line to try-line on the sideline next to the camera.
  • 2 * atan(50 / 37.5) = 106°, from the centers of the try-lines between the uprights, end to end.
  • 2 * atan(50 / 72) = 70°, from try-line to try-line on the far sideline.

So, without adding anything, you'll be able to see all of the far half of the field, basically from the nearest uprights on each try line, to the far side. The triangle from the nearest upright, along the try line to the near side line, to somewhere between the 10m and 22m line on the sideline, will be out of your field of view (on both the left and right sides of the camera).

You can't make a wide angle of view wider without introducing some degree of fisheye-ness.

Your idea of adding an anamorphic lens is good — in theory — assuming an anamorphic lens just "squishes" anything in front of the camera by the anamorphic factor (anywhere from 1.4:1 – 2.6:1). Unfortunately, it doesn't work that way. Any lens has a maximum angle of view, irrespective of what's behind the lens. You will have to find a specific near-180°-wide AoV anamorphic lens, which I'm not sure exists, in order to achieve what you want. And even then, even assuming anamorphic, 180° wide will still produce fisheye effects.

  • appreciate your thoughtful answer! I don't mind a little fish eye, but just hate the massive fish eye look I get from the lenses I've been trying to use. It is unwatchable. You are right, I'm really only looking for 170 degrees given I can place it about 10 ft away from the pitch. So if I added this (which has a 0.6X zoom) in theory on top of the 120 ultra wide lens on the new iphone, would I get up to 200 degress of field of view (given 120 degrees / 0.6 = 200). amazon.com/dp/B07PQQXZ3B/ref=psdc_15124502011_t4_B0767BZZKY – avian Sep 15 at 0:52
  • @avian The math doesn't work like you think it does. You can't just multiply the "0.6x" magnification by the angle of view to widen the angle. I know it sucks, but that's not how optics work. That lens is described as "nearly 2x wider field of view" than the existing wide angle iPhone's wide angle lens. But because of trigonometry, ~2x wider field of view does not equal 2x wider angle of view. If the field of view is something like x feet wide at a perpendicular distance d, then a 2x wider FoV, still at d away, translates to an angle of 2*atan( x / d). Compare that to ... – scottbb Sep 15 at 1:00
  • @avian ... the original AoV (without 2x) of 2*atan(x / 2 d). If you run those through a graphing calculator, you'll see that the AoV for the 2x lens is always less than 180°, and definitely less than 2x the AoV without the added lens. Furthermore, just like I mentioned with the anamorphic lens, any lens or lens modifier has a maximum AoV. I wish I could find a side-on view of the lens you're talking about, but from looking at it, I'm pretty sure you can't see the lens's glass from directly to the side of it. If that's the case, there is no way the lens can see 90° to either side. – scottbb Sep 15 at 1:03
  • @avian My hunch is that using the ultra-wide angle lens on the new iPhone 11 Pro, if you added the lens you linked to, all you would get is the maximum viewing angle of the added lens (I don't know what it is), but shrunk down a bit in the image, looking somewhat like a partially circular fisheye, with lots of black space on the sides. Something like this: i2.wp.com/digital-photography-school.com/wp-content/uploads/…. It probably won't see much more than the phone's lens would see by itself. – scottbb Sep 15 at 1:12
  • ah, this is making more sense now. I need to figure out how to find a lend with the best max AOV (got your point about the side view, and if the glass doesn't show above the edge, there is no possibility of it getting any of the action at 180 degrees -- where I see the fish eye the lenses pop out beyond the edge of the lens). – avian Sep 15 at 5:00

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