Frequently asked questions

and our answers

Frequently asked questions

and our answers

What have we been asked many times?

What is the difference between the DJ-8 NSV 1×48 and DJ-8 NSV 1×58?

The devices are almost identical in construction. The main difference is the lens. As a result, the 58 lens, by its very nature, provides considerably more residual light to the picture tube. The result is not only more brightness, but also better image quality and a smoother image. This smoother image also allows higher magnifications of a primary optic.

Depending on the image intensifier tube, the DJ-8 NSV 1×48 is suitable up to approximately 10x and the DJ-8 NSV 1×58 up to 30x. However, this does not mean that both devices deliver the same image quality at, for example, eightfold magnification. The higher reserves of the DJ-8 NSV 1×58 always ensure better image quality when used with primary optics.

DJ-8 NSV 1×48

DJ-8 NSV 1×58

How high is the field of view of the devices?

This cannot be answered across the board. Here, the installed image tube, the quality of the primary optics, existing residual light, but also your eye and the resulting personal perception play an essential role. Ask yourself: Have you, for example, in the past, when buying a new pair of binoculars or a riflescope, asked about the possible range? Or was your question not rather aimed at the image quality.

What are the grades?

During the production of an image intensifier tube, dust can always be trapped, or shading or the like can occur. The grading indicates if and how many inclusions can be present:

  • First grade = picture tube without or only with very slight inclusions / defects,
  • Second grade = picture tube with medium to heavy inclusions / defects.

What do the performance categories (PC) mean?

The power categories refer to the performance of the image intensifier tube. Higher categories have more light amplification and a better signal-to-noise ratio, so they produce a better image.

Why are there different power categories?

As the largest civilian customer of the European manufacturer Photonis, we receive very large quantities of image intensifier tubes – so-called batches. These are then tested and categorized by our internal quality assurance department. This is done on the one hand by technical parameters such as signal-to-noise ratio, line pairs, light amplification, etc., but also the visual impression is relevant for the classification.


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