Objectives – Objectives A Perspective Correction
Goals in Perspective Correction (PC), also known as Tilt-Shift lenses allow you to make perspective corrections on the image that we want to take, and in particular avoid the annoying lines converge when we carry out a photograph from the bottom up. In the perspective correction targets they are able to move the center of the optical unit relative to the axis orthogonal to the sensor while maintaining unchanged the normal optical axis at the focal plane. This correction is carried out via a pivoting element placed in the front part of the same, which element also allows control of the depth of field.
This pivoting element of a perspective correction lenses can be tilted up or down, right or left http://akusaraprosound.com. In this way it is possible to maintain the horizontal chamber with respect to the ground (and therefore the focusing axis is perpendicular to fire, for example, the building that we face) and tilt the movable element to have the entire building in the frame . Just the fact that the sensor plane remains parallel to the subject, allows to avoid the convergence of architectural lines.
Hotels in perspective correction targets fall into the category with wide-angle focal lengths that range usually between 24 and 35mm. The reason is related to their use mostly were created for architectural shots with longer lengths you could not bring in the same image throughout the building construction object of our photos.
In the picture below an example of the location of the room difference with and without a pivoting objective in the first case (with tilt to zero) you need to tilt the camera to photograph the subject. In the second case, instead, the chamber is kept stationary while to move up the goal is the same.
By using a Nikon 500N it was possible (here the original post) carried a photograph much effect, impossible to achieve with a traditional objective
What are the most famous catadioptric Apart from the Nikkor Nikkor 500N and 1000N of which we saw the shots, they are commercially available in several and at a much more affordable price Samyang, Opteka, Maksutov, Pro-Optic, Falcon, Bower, Vivitar, Phoenix are the brands easily found on the net (especially on ebay). I personally use a Samyang 500mm f 6.3 and I can not complain. All manufacturers usually offer three objectives 800mm f 8 – 500mm f 8 -500mm f 6.3.