Equipment

Helping Determine the Correct Focal Length for Photography & Videography

Published August 20, 2019

Here at Lensrentals.com, we get asked a common question on the daily, which is something to the regards of “I’m shooting X, what do you think the best focal length(s) would be?” By definition, this is an impossible question to answer completely and would need a multitude of variables before we could actually give a recommendation. But at the very least, we thought to ourselves, “Certainly, we could give people a visual representation, right?”

And so, that is where we’re at now. Before we get too far into this demonstration, it’s worth addressing the variables mentioned above. The first one is going to come down to your sensor size. For this test, all of our examples were done with a full-frame 35mm sensor size. If you’re using a crop sensor, your effective focal length might change, so I’ve included a small table showing you what you would be multiplying your focal length by to get a visual result.

Sensor SizeFocal Length Multiplier (Crop Factor)
1/2.5"6.0
1"2.7
4/3" / Four Thirds1.84–2
APS-C1.5-1.6
35mm full frame1.0
Crop Sensor Medium format0.79
Medium format0.64

The second primary variable would be distance and how it relates to the depth of field and image compression. That talking point is worthy of another article itself (and has been covered several times already), so instead, we’re going to touch on the depth of field. If you’re shooting with particular settings, I recommend this handy calculator to help determine your depth of field. While there is a mathematical equation that can be memorized, it’s sometimes easier to use the calculator in your pocket.

For our test, we decided to head over to Mud Island Amphitheater in beautiful Memphis, TN. With us, was an eclectic lineup of various focal lengths, and our lovely model for the day, who I’ve decided to call Beatrice. We then set up six different shooting lengths, 10 feet, 20 feet, 50 feet, 100 feet, 150 feet, and 200 feet, and shot a series of images with Beatrice in the frame.

10 Feet Distance

At 10 feet, we shot a series of focal lengths that would be common within this shooting distance. In general, 10 feet would be considered a pretty typical distance from your subject when shooting a portrait session with one to two subjects. Our results of 16mm-200mm are posted below.

20 Feet Distance

From there, we doubled our distance from our subject and extended our testing to 16mm – 800mm (We were unable to do so on the 10-foot test, because of minimum focusing distance limitations).

50 Feet Distance

You know the routine by now. The following photos were shot at 50 feet from the subject.

100 Feet Distance

150 Feet Distance

200 Feet Distance


Hopefully, this quick piece has given you a better representation of what each focal length looks at different distances. For ease of use, we’ve also put together this handy PDF available for download, which highlights all of the information in this article. And if you’re looking to do your own experiments with focal lengths, be sure to check out our broad range of telephoto lenses.

Author: Lensrentals

Articles written by the entire editorial and technical staff at LensRentals.com. These articles are for when there is more than one author for the entire post, and are written as a community effort.

Posted in Equipment
  • Michael Clark

    Maybe she’s concentrating very hard to keep from falling off that funny looking skateboard she’s standing on in high heels?

  • Calaverasgrande

    no mention of AOV?
    It’s kind of a hard to grasp subject.
    What I did once years ago, was take the same shot from different distances, and used the zoom on the lens I had at the time to frame the picture identically. On a face it is hard to see, due to how our brain detects faces. So it’s easier to see if you pick a static object like a house or a car.
    A wider focal length will have to be much closer to the subject. Taking a house for example. You won’t even see the top of the eaves if you are 10 feet away.
    With a longer focal length you may have to be across the street to frame the picture the same. so now you are seeing the top of the eaves and maybe some other things you cant see up close. But then some details aren’t going to be the same due to the distance.
    There is also that effect that wider lenses make faces look fatter, or more goofy. Exaggerating the nose and ears.
    This is why 85mm and up are often favored for portrait. 50mm and up on APSC.

  • I recommend you treat yourself to that 1987 classic, Mannequin, if you haven’t before.

  • SmithW6079

    Given what passes for a model these days I was struck by how natural she looks. Less plastic than some of those Kardashians, in my opinion.

  • Greg

    Thanks for posting this.

    For me, in choosing a focal length, there are two questions I may be asking. One is the one answered here, which is “I’m going to be standing so far from my subject, what focal length should I use?”

    However, more often, I’m wondering “I want to take an upper body shot of my subject, what will the overall picture (including the background) look like with different focal lengths?” If y’all are feeling masochistic, that would be a very helpful comparison. I realize that one’s more difficult, since it requires shooting from different distances for each focal length, rather than just changing the lenses on the camera at each distance.

    At a minimum, it seems like a 5ft version of this would be helpful, to be able to see a tighter 35mm example.

  • GuyWith

    What an awesome story. I’ve never seen anything on the web quite so useful in relation to focal length.
    Bravo!

  • She seems stoned.

  • Ashley Pomeroy

    I have to say that if I saw that mannequin standing in an empty amphitheatre, I would start by positioning myself 200 feet away from it and then extending the distance until we were separated by several miles.

    I would be worried that it would follow me home.

    I would avoid eye contact.

  • GulliNL

    While this is all very helpful, I keep on being distracted by the model. She doesn’t seem to be… there. You know what I mean? It’s like she is just standing there and not really enjoying herself. It might be ofcourse that doing so many shots with so many lenses tends to get a bit boring.
    So I think there is a lesson to be learned here; no matter how awesome you are in framing your subject and having the lighting in shape and everything, you have to build rapport with your model. Otherwise all your work will be for nothing.

  • Stanislaw Zolczynski

    In film making there`s another situation where you choose focal lenght in relation to framed scene. Spacial relation between two people, a normal conversation distance which miight be face up to across the table, filmed from some 45 degrees. Use too longfocal and the heads seem to be pasted on, use too wide and it introduces a domination of foreground person.

  • DrJon

    If you go to the tawbaware site they have a lot of calculators, including one giving the physical size of the image at a particular distance. You can quickly iterate this to an answer.
    50mm lens, 1.5 crop sensor, 9 feet wide image -> 18.75 feet

  • grubernd

    nice presentation.

    but starting for a portrait at 304,8cm distance is a nogo in my book. you should use a distance related to the intimacy you want to create – the distance you would have to the person in a real interaction – and then pick the lens for the framing you want to achieve.

    portraits happen between 75 and 220cm distance.
    beyond that it’s always more like a fashion picture.

  • J.L. Williams

    This is a useful visual reference, but it doesn’t answer the question I usually have, which is: “I’ve got Lens X; how far away do I need to be to shoot A?” or conversely, “I want to shoot A from a distance of B; what lens do I need?”

    Fortunately, I’ve learned to work this out by taking advantage of the fact that lens-to-sensor and distance-to-subject are “similar triangles” — their proportions are always the same. So as long as you know your actual sensor size (no phony “crop factor” needed) you can usually work out the dimensions in your head with a little judicious rounding.

    Example: “My sensor is 24mm wide and I’ve got a 50mm lens; how far away do I need to be to cover a 9-foot-wide seamless paper?” Well, your lens’ focal length is about 2x your sensor width, so your subject distance will be proportional — about 18 feet away from your 9-foot-wide background.

    Or going the other way: “My sensor is 19mm high and my seat is about 100 feet away from the theater stage; what lens do I need to cover an 10-foot-high space so I can see the performers plus a little scenery?” Well, your distance is 10 times your desired field height, so to fill your 19mm sensor you need about 190mm… a 180 or 200 should work fine. All simple arithmetic.

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