focallength中文

Camera lenses are usually described by two main factors: one is the aperture or f-number (the maximum size of the hole where light gets through to the sensor, where the lower the number, the bigger the hole). The other is focal length, which is in millimetres. You will usually see lenses described by focal length first and then aperture, for example 85mm f/1.8.

TOYOTEC, operator of the Optical Design Technology Navigator, is an all-around optical manufacturer with proficiency in optical, mechanical, and electronical technology. We can design and develop products from scratch based on our customers’ needs, and provides integrated support from design to productization. In addition to manufacturing aspheric lenses, we offer one-stop manufacturing services from ultra-precision machining of lens cores to the design and assembly of lens units, including systems and peripheral components.

Doesfocal lengthaffectaperture

Try: NIKKOR Z 20mm f/1.8 S, NIKKOR Z 14-30mm f/4 S, NIKKOR Z 17-28mm f/2.8, NIKKOR Z DX 12-28mm f/3.5-5.6 PZ VR, NIKKOR Z 24mm f/1.8 S

If you are thinking about something like, “If only there was a product like this…”, or, “Is it possible to do these kind of things with lenses?”, Optical Design Technology Navigator, a website operated by a group of optical design professionals, is the place to go. If you have any questions about optical design, please feel free to contact us at Optical Design Technology Navigator.

There are two types of lenses: primes, which have a fixed focal length, and zooms, where the focal length is variable. Zooms are super-handy as you often only have to carry one lens around that will be capable of shooting lots of different subjects, from landscapes to portraits, so it’s great for travel. Prime lenses, however, are usually lighter and are often available with larger apertures than zooms.

A spherical glass lens is processed by grinding one surface at a time, but grinding and polishing an aspherical lens one surface at a time would be very expensive. For this reason, aspheric shapes are generally processed into molds, which are then transferred and molded onto glass or plastic.

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With fewer lenses, it is possible to reduce lens materials, processing costs, and assembly man-hours, leading to overall cost reductions.

Usually between 70mm and 200mm, a telephoto lens is a popular choice for portraiture and weddings (especially an 85mm focal length) and at the longer end is great for wildlife where you can’t get too close to the subject. At the longer end, a telephoto lens gives you the freedom to shoot as an observer where the subject is unaware of the camera, and so is also great for fly-on-the-wall, reportage-style shooting. This is also the focal length range for many macro lenses.

Aspherical surfaces are classified into two categories: axi-symmetric aspherical surfaces, which have axial symmetry (rotational symmetry) with respect to the lens optical axis, and aspherical surfaces, which do not have axial symmetry. Each type of aspheric surface has its own characteristics.

If you had a simple lens made of a tube with one piece of optical glass at the front that focused the incoming light rays on a point at the back of the tube, the length of the tube would be the focal length of the lens. Modern lenses, however, use lots of different pieces of glass inside the casing to move light around before it hits the sensor and therefore focal length has nothing to do with the physical length of your lens. You can find two 85mm lenses that are completely different in size while, for example, the new NIKKOR Z 600mm f/6.3 VR S is less than 300mm in length.

Spherical surfaces are characterized by the fact that the radius of curvature is the same at all positions on the sphere, and this leads to the fact that they are easy to polish and high precision can be obtained. On the other hand, aspheric lenses require the radius of curvature to be made different depending on the position, which requires precision mold processing and technology to precisely transfer and mold the aspheric shape.

Camera lenses are usually described by two main factors: one is the aperture or f-number (the maximum size of the hole where light gets through to the sensor, where the lower the number, the bigger the hole). The other is focal length, which is in millimetres. You will usually see lenses described by focal length first and then aperture, for example 85mm f/1.8.

At Optical Design Technology Navigator, we use state-of -the-art ultra-precision processing machines to process aspheric surfaces on a sub-micron order, transfer these aspheric surfaces using molding technology that incorporates a high level of know-how, and then transfer these aspheric surfaces into an ultra-precision 3D mold.

We are a comprehensive manufacturer of Opto-mechatronic systems that conceptualize customer needs from design to development.

In this section, we will explain the features, advantages / disadvantages, and manufacturing methods of aspheric lenses.

Focal length

Aspheres that are not axi-symmetrical (rotationally symmetrical) can be used to change the magnification of vertical and horizontal images in imaging optics. Also, in illumination and focusing optics, light emitted from a point light source can be projected in the form of a line. In this way, aspheres that are not axisymmetric (rotationally symmetric) can achieve new functions that cannot be achieved with spherical lenses alone.

In this way, aspherical lenses make it possible to reduce the size and weight of products, and even to cut costs. However, the production of aspherical lenses requires a very high level of manufacturing technology.

In imaging optics, multiple spherical lenses are used in combination to reduce aberrations such as image blur and distortion. By using aspherical lenses, it is possible to reduce the number of lenses while maintaining the same performance. For example, you can achieve the same performance of an 5-spherical-lens optical system with a total of 4 lenses using 2 spherical lenses and 2 aspherical lenses.

An aspherical lens is a lens whose lens surface is not spherical. By using lenses with aspherical surfaces, which offer a high degree of freedom in design, it becomes possible to reduce aberrations that could not be fully corrected with spherical lenses alone.

Aperture and focal lengthin photography

You should also bear in mind that focal length translates differently on a DX camera (such as the Nikon Z 30, Z 50 or Z fc) compared to an FX ‘full-frame’ camera because the sensor on a DX camera is 1.5 times smaller than the FX sensor. For example, if you put a 50mm lens on a DX camera, you will actually get the angle of view and magnification similar to an 75mm lens on an FX camera (because 50 x 1.5 =75).

Axi-symmetric aspheres include rotational parabolas, rotational hyperbolic surfaces, rotational elliptic surfaces, and rotational quadric surfaces. In imaging optics, the use of such axisymmetric aspheres increases the degree of freedom in shape and makes it possible to suppress aberrations that would be difficult with spherical lenses alone.

Try: NIKKOR Z DX 24mm f/1.7, NIKKOR Z 26mm f/2.8, NIKKOR Z 28mm f/2.8, NIKKOR Z DX 16-50mm f/3.5-6.3 VR, NIKKOR Z 35mm f/1.8 S

From 35mm and 70mm, we have the ‘standard’ focal length, which is pretty close to what the human eye sees. Photographers talk about the ‘nifty fifty’ – a large aperture 50mm prime lens such as the NIKKOR Z 50mm f/1.8 S – because a 50mm lens is an ideal day-long companion, suitable for so many different types of shooting, especially in low light situations or indoors. This type of lens also creates a shallow depth of field and great bokeh blur.

Lenses ② to ④ are lenses with continuous, smooth, non-spherical lens surfaces and are called aspherical lenses in a broad sense. ② is a lens with an aspheric surface that is axi-symmetric (rotationally symmetric) with respect to the optical axis of the lens, and is often used in imaging optical systems. Lenses ③ to ④ are aspheric lenses that do not have axisymmetry (rotational symmetry) with respect to the optical axis of the lens, and are mainly used in lighting and focusing optical systems.

If you had a simple lens made of a tube with one piece of optical glass at the front that focused the incoming light rays on a point at the back of the tube, the length of the tube would be the focal length of the lens. Modern lenses, however, use lots of different pieces of glass inside the casing to move light around before it hits the sensor and therefore focal length has nothing to do with the physical length of your lens. You can find two 85mm lenses that are completely different in size while, for example, the new NIKKOR Z 600mm f/6.3 VR S is less than 300mm in length.

The method of manufacturing aspherical lenses by transferring and molding the aspherical shape of the mold onto the lens requires three technologies: ultra-precision mold processing technology, ultra-precision transfer and molding technology, and precision measurement and evaluation technology for these surface shapes.

Try: NIKKOR Z 70-180mm f/2.8, NIKKOR Z 85mm f/1.8 S, NIKKOR Z 135mm f/1.8 S Plena, NIKKOR Z 70-200mm f/2.8 S, NIKKOR Z DX 50-250mm f/4.5-6.3 VR

Check out these images of the same scene shot from the same position but with focal lengths from wide angle 24mm to telephoto 180mm and you can see how the angle of view gets narrower as the magnification gets larger.

Focal lengthcamera

In this section, we will introduce the advantages and disadvantages of axi-symmetric (rotationally symmetric) aspheres in imaging optics. There are three major advantages.

In addition, when axi-symmetric aspheres are used in illumination and focusing optics, it is possible to achieve uniform illumination distribution and increase the degree of freedom in ray control.

Angle of view is how much of the scene your lens will capture from side to side (holding the camera horizontally). A wide angle of view takes in a lot, a narrow angle of view less. Magnification is how ‘close’ you get to the subject of an image with the lens, like a telescope.

Aperture focal lengthformula

The most important thing about focal length, however, is not what it is, but what it does. Focal length defines two main things about any lens: its magnification and its angle of view.

Focal length and aperturerelationship

Try: NIKKOR Z 180-600mm f/5.6-6.3 VR, NIKKOR Z 100-400mm f/4.5-5.6 VR S, NIKKOR Z 400mm f/4.5 VR S, NIKKOR Z 600mm f/6.3 VR S

At 300mm and upwards, we have the super-telephoto range. This is most commonly used by sports and wildlife photographers, where it would be impossible to get close to the subject. At this range, and with such a narrow angle of view, it’s usually advisable to use a monopod or tripod to reduce camera movement (although Nikon’s in-camera vibration reduction (VR) and VR lenses can help with that), and also because lenses this size can be heavy to hold for long periods. Telephoto lenses can also be used with a teleconverter, which can double the focal length of the lens, giving you even more ‘reach’.

On the other hand, in the case of ⑥, the refractive index inside the lens is not homogeneous but distributed, and in the case of ⑦, light is focused and diverged by using the diffraction effect on the surface instead of refraction.

But there’s more. Depth of field determines what part of the image is in focus going from front to back. Lenses with longer focal length tend to have a shallower depth of field, meaning you can focus on and separate (or isolate) a particular object far away, whereas shorter lenses have a deeper depth of field, which means you can get more objects in focus throughout the image.

From 24mm to 35mm, lenses are wide angle. These are beloved by landscape, interiors and architecture photographers, as well as being useful for street scenes and dramatic pictures of the night sky. Get close to your subject and you will accentuate the perspective in the scene. A wide angle is a great travel companion, allowing you to shoot landscapes, cityscapes, people and much more.

There are many different types of lenses. They can be broadly classified as the following according to the principle of light focusing and divergence and the type of surface.

Lens choice can often be difficult, especially with so many options in the Nikon Z mount range (and access to another 300 or so Nikon F mount lenses with the FTZ II converter). So, here’s a quick guide to the different focal lengths and what they often get used for to help you.

Any lens with a focal length of between 8mm and 24mm is usually described as an ultra-wide. You’ll be taking in a huge angle of view of what’s in front of the camera. These are lenses for getting in really close with your subject to create drama and are also used extensively for astrophotography. However, at really low focal lengths there will be significant distortion at the sides of the image where straight lines start to look curved. Ultra-wides are one the hardest lenses to master but, with effort, they can deliver incredible results.

The focal length of a lens also affects the perspective of an image. With a long lens, perspective tends to be compressed, with objects in the background appearing closer to the subject in the foreground, whereas with a wide-angle lens the relative distance between two appears greater.

As angle of view goes down, magnification goes up. For example, a 24mm lens has a wide angle of view (around 84 degrees) and low magnification – perfect for sprawling landscapes. A 600mm lens has a very narrow angle of view and large magnification – great for taking close up shots of faraway wildlife (especially useful when you don’t want to get too close to a lion!).

Lenses ① to ⑤ are lenses that have a focusing and diverging effect solely due to refraction on the lens surface. Of these, lenses ① to ④ have a continuous smooth surface, while lens ⑤ has a lens surface that is divided into discontinuous zones.

Although the time required for transfer and molding is shorter than for the spherical polishing process, manufacturing of precision aspheric molds (which incurs cost) in advance are necessary. For this reason, consideration of whether or not to use aspheric lens prior to production, based on the estimated total cost of the production volume is necessary.