The lenses. Myths and reality
Previously, the material described below was part of an article about types of lenses, but the article grew and broke into two separate parts. When choosing a photo lens, many…

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What is the excerpt
Exposure - this is the time during which the camera captures the image. When photographing, the light is read using a camera matrix or using a film. When we do…

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Makrokoltsa - article from Radozhiva
What are macro rings are ordinary hollow tubes that change the working length of your lens. That is, it's just a tube that is placed between the lens and the…

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Dependence of the viewing angle of the lens on the focusing distance

When focusing on some lenses you can notice a very interesting effect. Many lenses change (usually reduce) the field of view when focusing from infinity to MDF (minimum focusing distance). In Western literature, this effect is called ‘Focus Breathing’.

This can be easily checked, it is enough to turn off the auto focus on the lens and focus on anything from infinity to MDF, and you can see that the frame borders are expanding and tapering, and there is nothing to blur the boundaries.

Lenses that give the same viewing angle when focusing on infinity can give different viewing angles when focusing on MDF. Here is an example from three 85 / 1.8 class lenses. All shot from a tripod with the same focusing distance.

85 85 85
This effect is very noticeable when working with macro lenses that change the maximum aperture value depending on the focusing distance. For example, you can read about it in the Nikon 105mm f / 2.8D AF Micro-Nikkor and Tamron SP AF 90mm 1: 2.8 Di MACRO 1: 1 272E for Nikon macro lenses. For a simple understanding, we can say that when focusing the lens makes an easy zoom. This also applies to the fix lens and zoom lenses. Visually, it is easy to understand the effect using the example of the Tamron SP AF 90mm 1: 2.8 Di MACRO 1: 1 lens fix, in which the trunk is extended when focusing in macro mode, as if the lens performs a zoom, and the field of view also changes.

Personal experience

Changes in the field of view when focusing sometimes unnerve at times, since this leads to the fact that parts of the desired composition fall outside the frame, and you have to approach or move away from the subject. When I shoot a macro, this effect is especially noticeable. Visually, it seems that the focal length of the lens changes, while they say that the lens changes its focal length – this is not quite so. The focal length is measured when focusing at infinity, when the rays go parallel to the optical axis, but when focusing in the direction of MDF, it is no longer possible to talk about focal distance.

findings

The effect described above is not always noticeable in practice and you should not worry much about it. What is ‘Focus Breathing’ well known to videographers, who are more annoyed by this effect than photographers 🙂

What is distortion
Distortion is mainly of two types - barrel-shaped (convex, Barrel distortion) and pillow-shaped (concave, Pincushion distortion). Distortion is usually called simple ‘barrel‘ and ‘pillow‘. But there is also a complex…

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Once I wondered: ‘Why do my Nikon D700 RAW files weigh so little?’. In search of an answer, I found very interesting information. So, when shooting, I sometimes use the…

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Receptions photography at long exposures. Light painting.
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