Also called flat field magnifiers, bar magnifiers allow sight-impaired and low vision users the ability to read any kinds of printed materials. By providing magnifying power up to 3.5 the size of the original text, bar magnifiers assist individuals with reading or seeing various types of printed pages.

Calculate FoVfrom image

Bar magnifiers work by placing them flat on the page that is desired for viewing. Depending on the model used, they will magnify the viewed text anywhere from 1 to 3.5 times of its original size. Because they only magnify one to three lines of text at a time, users simply slide the magnifier down the page to continue reading. One of the main advantages to utilizing a bar magnifier is that it makes it easier for users to track along a line of text without losing their place.

We have a utility called the FoV calculator which is available on this site, access it by following the procedure below:

Calculate FOVfrom focal length

While other kinds of magnifying devices require constant adjustment to ensure proper magnification levels for individual user needs, bar magnifiers come pre-set with a permanent magnification power. Therefore, no focusing is needed, which makes the reading experience much simpler and streamlined. They help immensely with reducing eye strain for both low vision and regular-sighted users, especially for smaller sized print.

Bar magnifiers are one of the simplest magnifying aids to use for reading purposes. In addition to books, magazines and newspapers, bar magnifiers help low vision users to more easily peruse menus, important contracts and documents, stock quotes, architectural plans, maps, telephone directories, charts and any other flat reading materials.

How tocalculate FOVmicroscope

Available in a variety of lengths and magnification powers, bar magnifiers are typically shaped as flat devices that are placed directly over the text on a page. They are often constructed from acrylic plastics for the best durability and viewing clearness. Some may include handles, while others are formulated to be ergonomically correct for the simplest and most comfortable operation. While they are often referred to as ruler magnifiers because of their flat, elongated shape (and included measured increments), alternative designs may be rounded, smaller or otherwise configured to better fulfill other user requirements and personal preferences.

To know if a camera can measure a target at a certain distance some calculations can be done. We have a utility called the FoV calculator which is available on this site, access it by following the procedure below: Go to Download Datasheet and select a camera series Click the FoV Calc. hyperlink for a camera–lens combination. This displays the FoV calculator. To select a different camera–lens combination for a particular camera, select the new combination in the drop-down menu. The FoV calculator displays the following results: HFOV: horizontal field of view in meters and feet. VFOV: vertical field of view in meters and feet. Depth of field—far limit in meters and feet. Depth of field—near limit in meters and feet. IFOV: instantaneous field of view in millimeters and inches. Distance to target in meters and feet. Tips Each camera may have interchangeable lenses. If this is the case, you can choose a lens from the drop down menu. You can switch between metric or imperial units using the drop-down menu. Type in several distances separated by commas to calculate the FoV at all desired distances.   Example for an A655sc 45° Go to camera datasheets and select the product:   Select the 45° lens from the dropdown menu:   Type in the desired distance to calculate the FoV or use the listed default values.

How tocalculate FOVsim racing

While some bar magnifiers may use the ambient light of the room that the user is reading in to enhance the magnified reading experience, most bar magnifiers do not require any added lighted features to operate efficiently.

Rehabmart is pleased to offer an extensive selection of innovative bar magnifiers from our superior quality vendors, LSS and MaxiAids.

Bar magnifiers are specifically designed to glide easily over any flat page or surface. Because of their 1-3 line limited viewing space, they also help users to stay on track with what they are reading, keeping un-magnified text out of the user’s view until they are ready to read it. Some bar magnifiers also include highlighted red or yellow lines to further enhance the user’s ability to stay in place.

A bar magnifier is about the size of a six-inch ruler, flat on the bottom side and dome-shaped on the top side, constructed from optically clear polished acrylic that can provide magnifying power up to 3.5 times the original text for low vision users.