Peculiar Effect Nikon 200-500 5.6

Miserable day, rain or snow nearly all the time. Let the dogs were out during a brief respite. Had the 200-500 on the D 7200 for some returning songbirds and took this shot - 110 or so yards out. Carmine, the dog nearer the house, is quite large, 110 lbs. His friend Chili, further from the house, weighs nearly 50 lbs less, shorter as well, the smallest dog we've ever had. In this photo seems larger than Carmine. Have been very pleased with the lens, though due to weather, haven't used it a great deal. Any ideas? Haven't seen anything like this in nearly six decades of mostly Nikon photography.

It's a trick of perspective that is created by a few intermingled factors. First of all, it's obvious that Chili is behind Carmine (that is, further away from you and the camera). Subconsciously, you expect the dog that is further away to subtend a smaller angle than the closer dog. But in this case, that expectation is foiled by the compressing effect of the telephoto lens. The distance between the two dogs is insignificant compared to the great distance between the camera and both dogs, which means that the angles subtended by them will correspond much more closely to their actual comparative sizes, and not be influenced by their relative distance from the camera. Confusingly, Chili does in fact subtend a larger angle than Carmine (the bigger dog) because Carmine is standing at an angle, not parallel to the focal plane as Chili is. The fact that Chili subtends a larger angle leads your unconscious mind to believe that he's bigger than Carmine, especially because he's behind him.

Either that, or you should send your 200-500mm to Nikon to have them take a look at it for decentering.

Agreed - the lens is only to blame in as much as it's a tight shot at quite a long distance, and the relative difference in distance to the two dogs (how far they are apart in comparison with how near they are to you) is small. That means the nearer dog will appear larger by less than if they were closer to you.

As for why Carmine actually looks smaller - I agree with chulster: a combination of the angle they're standing at (so Chili looks longer), Chili's legs being obscured by grass so you can't see how tall he is(n't), and an expectation that, if they were the same size, Chili would look smaller than he does because you'd normally be closer to them to get a view like this.

Same trick as using a very long lens to isolate a silhouetted person against the moon: the moon doesn't become huge, we're just used to seeing a person at a certain size also being at a certain distance to the naked eye, and that distance isn't far enough to make the person smaller than the moon. The brain can handle quite a variation in perspective, but very wide and very long shots do throw it a bit.

Definitely an optical illusion Sandy.

I just put a crop frame over the front-to-rear haunches of Chilli, then moved it over Carmine. Carmine was still longer in the body, even disallowing the forshortening from not being squarely side-on to the camera.

Remember, rotating, say, a ruler by 45 degrees to the camera will make its length apparently less by nearly 30%. Or nearly 14% less for a 30 degree rotation.

It looks as if Carmine is standing at an angle of somewhere between 30 and 45 degrees to the camera, and is also on a downhill incline. So no mystery in my view.

As a thought experiment, I was trying to work out whether it's possible to make a lens that does render nearer objects smaller than farther ones. At a distance, obviously not - but in trying to read the "cardinal point (optics)" page on Wikipedia it feels as though it should be possible to use a telephoto lens to take a photo of something nearer to the camera than the front principal plane, and that this might cause an object nearer to the principal plane (but farther from the camera) to look larger than an object farther from the principal plane (but nearer to the camera). I've not tried to work out what this means for focus. There's a limit (I think) to how far in front of the lens you can move the principal plane in front of the lens, so truly distant objects will always be smaller than closer ones, but it feels like there's a cross-over point, and it should be possible to engineer it to be somewhere that you can actually photograph. Not that I know why you'd want to, except possibly for some really weird macro photography effects (could you use it to make, say, a small insect look bigger than a model figure?)

Anyone with a sounder knowledge of optics than I feel up to telling me whether I'm talking gibberish? Ray tracing in my head, it feels logical, but real-world optics are complicated.

Update after a bit more time on Wikipedia: conventional lenses that make more distant objects look smaller are "endocentric"; "pericentric" lenses make more distant objects look bigger. That'd be quite cool to try out, but a bit expensive unless I sit down with a selection of broken lens elements and play until something works...

Weird and fascinating stuff.

Actually, just reverse your binoculars or rifle scope - smaller!

Make sure to take the scope off the rifle before trying that.

Miserable day, rain or snow nearly all the time. Let the dogs were out during a brief respite. Had the 200-500 on the D 7200 for some returning songbirds and took this shot - 110 or so yards out. Carmine, the dog nearer the house, is quite large, 110 lbs. His friend Chili, further from the house, weighs nearly 50 lbs less, shorter as well, the smallest dog we've ever had. In this photo seems larger than Carmine. Have been very pleased with the lens, though due to weather, haven't used it a great deal. Any ideas? Haven't seen anything like this in nearly six decades of mostly Nikon photography.

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The fact that Carmine is a relatively short haired dog and is on a contrasting background while Chili is a long haired dog and blends with the colored background may have something to do with it as well as the perspective of the image. Carmine is quartering to the line of sight while Chili is broadside which would make him appear larger.

The phenomenon is called compression distortion, the opposite of expansion distortion for wide-angle lenses.

Here's a link to Wikipedia which discusses in detail: Perspective distortion (photography) - Wikipedia

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In this picture the two dogs are standing on level ground and both are quartering away from the camera. In the original post I am not sure the ground is level. Is it? And as I wrote, one dog is quartering toward the camera while the other is broadside.

BTW, nice dogs.