How Focal Length and Subject Distance Affect Weight… As Seen with a Cat


We’ve written a couple of times in the past on how you can achieve drastically different portrait looks by choosing different lens focal lengths and subject distances. Basically, your choice of glass can make a huge impact on what your subject’s face looks like… and how much they appear to weigh.

Reddit user Popocuffs wanted to demonstrate this, but instead of using a human subject, he used his cat.

These photographs are all of the same cat, and were shot using four different focal lengths and distances. The combos range from 29mm from 1 foot away to 105mm from 12 feet away.

As you can see, the lens/distance combos cause the cat to look like everything from the Cheshire Cat to the Catbus.





As we’ve also shared before, if you use different focal lengths and distances while keeping the subject the same size in the frame, and then string the resulting images together in an animation, you get a Hitchcock zoom.

Image credits: Photographs by Popocuffs and used with permission

  • Daniel Lowe

    Question I’m dying to ask: How did you train the cat to hold still?

    p.s. a few labels on focal lengths would go a long way here. Yeah, I know, the first one is the wide-angle view, last one is telephoto… but this might not be “obvious” to everybody else.

  • Rebecca Morrissey

    This is great…is it possible to share the shooting data for each image?

  • Dave Van den Eynde

    Hey camera, what are you doing? Camera…..STAHP!

  • Mansgame

    I always show these types of samples to some people (mostly those who only shoot prime) when they say “Zooming with your foot is better” because they don’t realize as soon as you move, the perspective is changed and it’s not the same picture.

    Same with Fro Knows Photo guy who never crops. If your lens is only 200mm, if you walk closer, you don’t have the same picture anymore, but if you crop, you would.

  • Stan

    You’re doing it wrong.

  • Bob

    This is a basic photography technique for all of you who cannot be bothered to actually learn the subject!

  • Chairman Meow

    Cat, the ever reliable, always a available, photographic subject :)

  • Ken Elliott

    This is a myth. It is not the focal length – it is the location you shoot from. Here’s how to prove it. Shoot the cat with a 105mm. Without moving, shoot with your wide angle lens. In an editing program, crop the wide angle shot to match the long shot. They have the same prospective. This is a common misunderstanding because the lens selected forces you to move, so you think its the lens. The proper method is to decide where to shoot from for the desired prospective, then select the lens for the best crop.

  • Alec Salisbury

    It’s probably just a lazy cat. Mine lays around on the floor all day and lets me take tons of pictures of him!

  • Nikki Comma

    Agreed on the labels.
    We have two cats who would stay still like that, meanwhile the other one will scramble like a maniac in order to avoid having a good picture taken. Lousy creatures who I love.

  • Renato Murakami

    Nice one! But adding the EXIF for each pic would be more informative…

  • Leliela

    What I really wonder is how he managed to get his cat to stay still.

  • Chuck Testa

    Nope! Chuck Testa

  • krierc

    AMEN!!!! I am so tired of seeing these posts…how focal length affect perspective distortion. Perspective distortion is only affected by the position of camera relative to subject. The only thing focal length does is crop the photo.

  • Ivan

    Agreed. Same goes for the depth of field myth: longer lens, shallower depth of field. Wrong! With the same subject to camera distance, same aperture, same crop from different focal length frames, DOF remains the same. (Longer lenses just *magnify* OOF areas, so apparent DOF decreases but in reality nothing changes compared to shorter lenses.)

    For these reasons “zooming with your feet” is absolutely not possible, since it would change perspective and DOF, while zooming keeps both perspective and DOF unchanged, since zooming is in fact nothing but optical cropping.

  • kendon

    you should start reading the articles before commenting.

  • Guest


  • Phillip Dobson

    Let’s call it “angle of view” instead of “focal length” and we can all be happy.

  • Duke Shin

    I use this technique extensively for senior portraits at school. If you’re cool, you’ll look fine, but the swagfags and yoloers will look pudgy. Not to mention I use a blue filter to make every zit and pore show up clearly.

  • Ken Elliott

    I did. Perhaps you could explain where you disagree with my post, rather than assume I didn’t read the article.

  • Ken Elliott

    Yes, that is a more accurate description.

  • lidocaineus

    How mature. Are you in junior high?

  • Masoud

    What if 4 different cameras are used at the same time?!

  • Danni

    The focal length *and* distance (as the short article says) from the subject is different for each photo. So (as the article says) it’s a combination of both that’s creating the different appearances.

  • OpticsGuy

    I think there’s something wrong with the distances and focal lengths quoted here. The focal length ratio is given as 105mm/29mm = 3.6. The ratio of subject distances is stated to be 12’/1′ = 12. For constant image magnification these two ratios should be approximately the same I believe.

  • Erik Lauri Kulo


  • texasphotochick

    The focal length dictates the change in distance to subject in order to frame approximately the same shot. So yes, it is the focal length. And yes, it is distance to subject. They’re both correct, it just depends on your point of view.

  • texasphotochick

    Why? Focal length is the distance from the front element to the node and is a constant. Field of view is just how much of the image the sensor captures and is not a constant.

  • 3ric15

    Have you tried EXIF data?

  • 3ric15

    Never mind, there’s no shooting data in the EXIF…

  • Ken Elliott

    Sorry, but it is just the distance. Altering the focal length does not alter the perspective if you don’t move the camera. Large format shooters know exactly what I’m talking about. Try the exercise I mentioned and you’ll see.

  • Albi Kl

    I’m not sure I understand what you’re asking but I’ll hazard an answer. Focal length merely alters the apparent “zoom” of the subject whereas field of view alters the perspective; assuming a ‘fixed’ distance between subject and shooter.

    Focal length also stretches or compresses the background, but we were speaking specifically of the effects on the subject here.

  • Dover

    I just watched this for 14 hours. I don’t think it is animated.

  • Ken Elliott

    No worries. You are doing a good thing by experimenting and sharing your experiences. There is a huge amount of misinformation about photography, and most of don’t know all the facts. After 30 years of photography, I started shooting large format and it opened my eyes to things I never realized shooting small cameras. It’s a long journey – and you’ll have fun discovering at each step.

  • stanrogers

    There are two things going on there. First, the photographer has chimed in to mention that the 105mm shot is cropped, so it’ll be equivalent to some longer focal length in field-of-view terms. But that’s not the whole story either; what’s being kept the same size is the width of the cat’s head. Notice that the cat’s nose is much bigger in the wide-angle shot. The distance to work with when figuring out the proportions, then, is the distance to the outline of the cat’s head rather than the simple camera-to-cat distance — that extra two and a half to three inches makes a much bigger difference at a “nose distance” of one foot than it does at a twelve foot distance.

  • Joven

    Is this a joke?

  • bstunt

    See this is how you prove this article is wrong… first take a picture of the cat at 70mm… then.. hold on… my cat won’t stay still… ok, back to what I was talking about… so you shoot at…. dammit, my cat just ran off… w/e…

  • Michal Rosa

    Well done, that’s a pretty good demonstration of what different focal lengths do to perspective.

  • Michael Andrew Broughton

    changing the focal length but not the distance to your subject will have no effect on the subject’s apparent weight. changing the distance to your subject but not the focal length will have an effect. distance to subject ALONE affects perspective distortion. changing the focal length only changes the framing.

  • Elijah Lucian

    yes, but when you shoot with a certain focal length you will naturally move a certain distance from the subject, focal length is the catalyst here. you dont take an 18mm shot at 12 feet and crop… seriously. stop being a know-it-all. we all understand that distance is the reason it looks different, but focal length is the key driver in this, which is why these posts are based on focal length.

  • Elijah Lucian

    focal length dictates framing, which in turn dictates distance. therefore focal length is the main driver here, which is why these articles focus on focal length. you don’t take an 18mm shot at 12 feet and crop down, you use a 105mm lens and stand at the 12 feet and get a nice picture. they are hand in hand but this article is a good reference for people who want to learn what kind of focal length they should start with to get a desired result. this will naturally get them standing at the right distances.

    these articles are not for pros. so go shoot some photos, stop hating, and make some money while we dick around with our cameras.

  • Ken Elliott

    This is where we differ: You describe your method as selecting the focal length first, which drives your distance. I (and others) pick the perspective (thus the distance) we want, and then choose a lens that gives us the field of view we want.