Logitech StreamCam Webcam, 1920 x 1080 Full HD, 2.1 MP, 60 fps, 78°

Ultra-short distance projector:
Special short-distance projectors equipped with a wide-angle lens have been developed for conference room and classroom use. These projectors are also usually used for operation with interactive whiteboards. These projectors have the ability to project a large image from a very short distance. Ultra-short distance projectors are extremely popular in presenter circles because, for one thing, the image is not obscured when the presenter is standing in front of the screen. Secondly, the presenter is not or only slightly dazzled by the projector. An increase in this effect is offered by ultra-short distance projectors, which project the correspondingly large image from a distance of only a few centimetres.

Resolution:
The resolution of a projector is the maximum number of image points (pixels) that a projector can display based on its naturally existing technology, i.e. without conversion or cropping of the image. The native resolution is the number of pixels that a projector physically has to display the image. A projector usually interpolates a resolution when it receives an image signal with a higher resolution than the native one. If this is the case, there may be a lack of image detail or general blurring in the displayed image. If a projector receives an image signal with a lower resolution than the native, it also interpolates, it scales the image up to the native resolution, calculates corresponding additional pixels, if possible without changing the image information. The disadvantage here is that although the image is displayed larger than fed, the original individual pixels may become much more visible as they are multiplied by the conversion.

4K:
4K refers to the resolution of 3840 x 2160 or Ultra High Definition Television (UHDTV). This resolution corresponds to 4 times the resolution of Full HD. To record films with this resolution, special cameras are needed that can record at around 8 megapixels (4K).

Full HD:
The term Full HD is used to describe devices that can physically display or output HDTV signals in full (1920 x 1080 pixels).

1080p:
1080p is the specification of the vertical picture lines. Among other things, it refers to the resolution 1920 x 1080. The "p" in this case means full frames, so all picture lines are displayed simultaneously.

1080i:
1080i is the specification of the vertical picture lines. The "i" in this case means fields. This signal is usually displayed interpolated (e.g. by devices with a 1280 x 720 HDready resolution). The interpolation digitally adds pixels, but also offers a slight blurring. In contrast, 1080p playback uses full frames.

Focus:
Many projectors are equipped with a focus, which ensures that the image on the screen is in focus. There are three different types of focus. There is the manual focus, which is set by hand using a rotary wheel. On the other hand, there is a motorised focus, which can be adjusted precisely at the touch of a button. The motorised focus has the advantage for ceiling installations that the adjustment can be made very comfortably via the remote control. Last but not least, there is the autofocus, which automatically takes over the focusing by means of a camera.