Recommended Focal Length

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Greetings. I generally use a 35mm focal length when creating short animations with human characters.

What focal length(s) do you prefer?

What effect does focal length have on photo-realism?

Thanks,
Cal

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I think there is not one answer to this. It depends on the effect you are after, for me 35 is a little wide (as if you are right up close to the character.)
I tend to do portraits 50 + (with photography)

If you want the sense of distance from the character 100+ with the camera further away.

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Not much, other than RL photo/cinematography has a general guide when choosing focal length, but it depends on the photo/cinematographer, most of them have a favourite focal length even when it’s not generally used for that type of shot

Personal Favourite:

Still image (FF 35mm):

  • 28mm: street/wide scene
  • 40mm: general normal (most favourite)
  • 100mm: product shot/portrait
  • 135mm: portrait / landscape

Moving image (super35mm):

  • 25mm: general (most favourite)
  • 65mm: tight shot
  • 100mm: close-up

*edit:
effect on photo-realism: not much as stated above,
effect on visual, quite a lot, ie. perspective compression, as the attached image below by @joseph

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IMG_3749

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IMG_37481800×575 250 KB

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IMG_37461200×400 122 KB

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But in “real” photography, focal length is much more than simply “what is in frame.” A zoom lens foreshortens the background and depth of field: things seem closer together along the Z-axis than they actually are.

If you have a real DSLR camera with an appropriate lens, try it for yourself. First, shoot the shot “normal.” (Usually 55mm for such a camera.) Be sure that there are things clearly in the background at various distances from the camera. (Put some of them “quite a ways back …”) Now, back up a considerable distance and “zoom in” (say: 135mm) until you get the same framing. Now, sit down and compare both photos carefully.

Also, experiment with different “f-stops,” which dictate how wide or closed the lens is. You will observe differences in “depth of field” – of how much of what you see is in focus at the same time.

So, there is no “right answer” to this question. It entirely depends on what effect you want to achieve.

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Yes, what you describe here is the scenario that caused me to ask the question.

In Blender, with a human character, I started out with a 35mm and a long shot. Then, in an animation, I dollied forward to a close up.

Then, in a second animation, I moved the camera back to where it was, and zoomed in to a close up (around150mm).

In the dolly version, I found the nose to be unattractive. Not so with zoom.

Thanks for your insight,
Cal

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A really brilliant example of a dolly reversing while zooming in gives you a great ‘perspective’ on this shot…

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If you are still in the phase of finding your favourite/preferred focal length, there’s a simpler way to help you with it, and this is what i teach to my students as well.

What i describe as perspective compression/expansion is actually a combination of shooting distance, the relative distance between your scene elements, and focal length, if we break it down to the individual element, it is a lot simpler, because the focal length in reality only controls the framing, it is the same as cropping your image but without a loss of resolution, that’s why in orthographic camera, they are called an orthographic scale.

The perspective part comes from your shooting distance, ie. the relative distance between the camera, subject and foreground/background, and this is when you decide the relationship between them, and the amount of foreshortening you want.

So, in order to find your favourite focal length, the step is:

  1. place all of the elements of your scene in (roughly) the place you want it to be,
  2. decide where you like your scene to be viewed from, including the distance from your subject (the amount of perspective/foreshortening you want)
  3. you can also tweak the placement of your scene elements if needed at this stage
  4. adjust your focal length to frame your composition (how wide/tight your framing is after you have the perspective you like).
  5. and there you have your preferred focal length.

As a side note, my favourite focal length first comes from analyzing the trend of my photo library I’ve taken for about 10 years, even 10 years later when my lens collection grows, i still tend to use that certain focal length when i do my photography works). And both my most favourite focal length in the list above (40mm and 25mm), is actually have the same field of view (or framing), because of the difference in sensor size.

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