How precise do you want to get?
Precision method...
Calculate the diagonal of the camera's film image. Compare the lens focal length to that to get your answer.
Example for 35mm camera with 50mm lens:
film image is 24x36; diagonal is square root of (24*24 + 36*36) = 43.267
(remember Pythagorean theorem)? Ratio is 50/43.267 = 1.156. Thus, 50mm lens magnifies image 1.156 times. This is negligible, hence most people consider the 50mm lens to be "normal" for 35mm cameras.
Simple method, same camera & lens:
100 mm lens produces 2x magnification (100/50)
I hope you're not asking because you wish to relate this to telescopes or binoculars. That is a subject I'm not familiar with, and I suspect the field of view for those devices has to be considered. Hope my answer gives you what you needed.
Most consumer cameras are 1/4 x 20 threads. Be careful of the length, too long and it can damage some cameras.
The focal length of a camera's lens refers to the the magnification or telephoto power of the lens and is expressed in the millimeters of the lens, like 100mm, 300mm, etc. www.goldprints.com
To get the exposure level on the sensor correct - it's important in photography on film also. Many cameras attempt to do it automatically.
This describes the focal length range of the lens. It means that the lens can be set between 18mm (a wide angle which takes in a larger field of view) and 200mm (a telephoto, which creates a narrower field of view). ******* Note: the above is certainly true for 35mm format, but focal length is relative to the format. For 4x5 cameras, the equivalent "normal" focal length is around 200mm.
Most cameras don't have a dedicated shutter speed longer than thirty seconds. If you wish to take exposures longer than that, use the bulb function ('B' on most cameras). Bulb allows the shutter to stay open as long as the shutter button is held down. Get a locking cable release, switch camera to bulb, and you can take any length exposure you want.
In optical systems, the relationship between focal length and magnification is inversely proportional. This means that as the focal length increases, the magnification decreases, and vice versa.
The relationship between magnification and focal length in optical systems is that as the focal length of a lens increases, the magnification of the image produced by the lens decreases. Conversely, as the focal length decreases, the magnification increases. This relationship is important in determining the size and clarity of images produced by optical systems.
The focal length of the main optical system and the focal length of the lens forming the image.
The magnification of a convex lens depends on its focal length and the object distance from the lens. Increasing the focal length or decreasing the object distance will usually increase the magnification. The magnification is also affected by the size of the object being viewed and the optical properties of the lens itself.
A negative focal length in optical systems can lead to diverging light rays instead of converging them, resulting in a virtual image that appears on the same side as the object. This can affect the magnification and clarity of the image produced by the optical system.
The radius of curvature in optics is important because it determines the amount of bending that light undergoes when it passes through a lens or mirror. It helps in calculating the focal length and magnification of optical systems, which are crucial for designing and understanding how lenses and mirrors work in various optical devices like cameras, microscopes, and telescopes.
The back focal length in optical systems is important because it determines the distance between the rear focal point of a lens or mirror and the focal plane where an image is formed. This distance affects the magnification, field of view, and overall performance of the optical system.
An optical system with an infinite focal length is significant because it produces parallel rays of light, which can be useful in applications such as telescopes and cameras for capturing distant objects with clarity and precision.
Power in optics is inversely proportional to the focal length of a lens. A lens with a shorter focal length will have greater optical power, while a lens with a longer focal length will have less optical power. This relationship is important in determining the strength and magnification of corrective lenses used in eyeglasses and contact lenses.
Concave lenses are used in eyeglasses to correct nearsightedness by diverging light rays before they enter the eye. They are also used in cameras, telescopes, and binoculars to increase the focal length and to correct optical aberrations. Additionally, concave lenses are used in microscopes to increase the magnification of an image.
Focal length in a lens is the distance between the lens' optical center and the image sensor when the lens is focused at infinity. It determines the angle of view and magnification of the lens, with longer focal lengths resulting in a narrower angle of view and higher magnification, and vice versa. Focal length is commonly measured in millimeters.
I'm not sure I understand your question. If I do, the conversion from focal length of a digital camera to an equivalent 35mm focal length varies based on the cameras sensor size. These sizes vary by camera model. For most Digital SLRs you multiply the camera's focal length by about 1.6, but the multiplier ranges from 1.5 to 2. The multiplier for simple/consumer non-DSLR cameras is somewhere around 4 times.