It's a bird

by Vian Esterhuizen

submit your photo


Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

Tag Info

New answers tagged

6

The 1200mm lens you cite is something of an aberration, since it's built-to-order, not a general-market lens — see Why are some big telephoto lenses so expensive compared to telescopes? and Why are some lenses so expensive?. But the general rule holds true: lenses for DSLRs and most mirrorless cameras are gigantic compared to those in superzoom cameras. ...


2

The Canon lens has focal length of 1200mm and maximum aperture of f/5.6, whereas the Nikon lens has a focal length (at the long end) of 357mm and maximum aperture of f/6.5. So the Canon lens is longer and has a faster aperture, which requires a larger front element, 214mm vs 55mm. This is a substantial difference and makes the Canon larger, heavier and more ...


0

The simple and fast explanation is the lens on Nikon camera is created for sensor with size 1/2.3". Canon lens is created for fullframe camera (24x36 mm sensor). This is very huge difference, crop factor is something like 6. To project the same amount of light on the big sensor you need big lenses inside compared to much small sensor. And with the rise of ...


0

Assuming a "medium" brightness (averaging day & night), ISO 25, f/64, with a 9-stop ND should get you to about 30 days. I haven't seen a reciprocity failure chart that goes that high, but I would assume that would carry you out as far as you want to go. A lot of assumptions, but it sounds possible to me.


0

As @BobT suggests, a sharp lens with neutral-density filter(s) could do the job, or you might use multiple short exposures. In any case, take into account reciprocity failure, which will; require yet longer exposures in very dim lighting, and which causes color shifts on most emulsions. It should be interesting to see the photos here, showing only really ...


0

There are basically two ways to make a pinhole camera sharper. as Olin Lathrop said, the smaller the pinhole the sharper the image, but if it gets too small, diffraction come into play. There is an optimal diameter of the pinhole and this formula calculates it: Diameter = Constant x sqrt(Focal Length x Wavelength of light) There is a bit of mess about what ...


1

No, there is no lens design that allows for sharpening a pinhole image. This is because pinhole cameras by definition don't have lenses. You can replace the pinhole with a lens to get more sharpness with lower f-stops. That's why normal cameras have lenses instead of pinholes. With a pinhole, the sharpness gets better as the pinhole gets smaller, which ...


5

No, this is not diffraction. Let's start by recalling how the image is formed by the lens (focused and defocused): Each point of your large aperture lens contributes to just one point of the defocused image: (by the way, this also shows why aperture size affects (de)focus) And what happens if you place an obstacle (your hands) near the lens? Not all ...


0

As a partial answer, I'd like to point out that it could be short-sighted to only look for the image quality. As a still photographer, I can work with a gripped old DSLR that looks like a brick, is about as heavy and was mistaken for a bag in the past. That's because it hangs of my shoulder and my arms rarely have to carry it. But can you hold that heavy ...


0

There are lots of lens review sites but also lots of factors for regarding lenses as "good". For example for serious video minimal focus breathing, constant aperture (if a zoom) and being parfocal are big plusses, less so for casual shooting. For hand-held video stabilisation is a big plus. For stills there is sharpness but there is also colour fringing ...


0

I guess it depends how accurately you want to measure, but this is how I would do it: Wikipedia has a formula for calculating the horizontal/vertical angles of view of a lens from the lens' focal length and sensor dimensions: https://en.wikipedia.org/wiki/Angle_of_view#Calculating_a_camera.27s_angle_of_view In the case of the Sigma DP1, the focal length ...


1

This can be derived from the basic lens formulas. The lens divides the entire system in two halves: the subject side, with two variables S the real size of the subject, this is what you are looking for s the distance between the subject and the lens, this is the altitude the image side, also with two variables I the size of the subject in the image, ...


0

From what I have read and and seen about aspherical lenses, they are designed to prevent aberration of light hitting the surface of the lens. This means, it prevents image distortion for the person wearing the lenses. This is accomplished by making the edges of the lens curve out, away from the curve of the spherical design of the lens, making it a sphere in ...


0

Barrel distortion is also a consequence of real life trigonometry and perspective. Please, do an image search for the term "Vanishing point", specially as related to drawing. Now let's do a thought experiment. If you stand on a very long straight trench of train tracks, you'd see as if rails converge in an imaginary point very far away (That point is ...


3

Barrel distortion is a form of distortion (not to be confused with other aberrations). It is often found with shorter focal lengths such as the lens in a phone - especially those trying to get the wide rather than narrow angle field of view. This distortion is also often seen with a single element lens, such as those associated with magnifying glass. If ...


0

Assuming both the lenses cast light circles at least large enough to cover the entire sensor, an f/1.4 lens will always be faster than an f/1.7 lens by almost one half stop. The aperture size has nothing to do with the size of the image circle a lens casts. The elements of a lens behind the aperture diaphragm and how much they bend the light allowed through ...



Top 50 recent answers are included