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ThirdEye handling xs


The depth-of-field

The depth-of-field of a lens varies with the focal length, the aperture (the size of the opening of an iris or diaphragm) of the iris and the working distance (distance between front lens and object). The depth-of-focus further depends on the illumination of the object to be shot. The higher the brightness (measured in lux) by the dental lamp, the smaller the aperture of the iris (and electronic iris !) can be and the wider the dephth-of-focus will be.

The lenses of the ThirdEye-HDmini and ThirdEye-Photo  dental cameras have a fixed iris (besides the electronic iris built in the ccd chip) with a diameter (aperture) of 2,2 mm. This aperture ensures sufficient light falling onto the ccd/cmos chip with all dental lights on the market even those with less lighting intensitiy.



Focussing the lens (ThirdEye-HDmini and ThirdEye-Photo)



We all prefer a certain working-distance  - distance of the front of the dental light to the mouth of the patient - of our dental light. With a good illumination (brightness of dental light) the camera has to be focused to the tooth we are treating only once. Slight changes of the position of the dental light do not need focussing anew, but are compensated by the wide depth-of-field of the system and the image remains sharp.

However, if the alteration of the distance is big - more than 10 to 20 cm - you have to focus again. You focus by turning the outer tubus of the lens.

Why there is no autofocus in ThirdEye-HDmini or ThirdEye-Photo ?

Sometimes it is an advantage, if the lens does not focus automatically. For example, if you move your hand in front the patient´s mouth. An auto focus lens now will focus on your hands and it will take a second till the focus is back on the tooth you are working on, when you retrieve your hand.

Most video cameras with auto focus take the focus in the center of the shot. So, you always have to adjust the object you are working on to the center of the camera optic !

A second disadvantage of an auto focus lenses is, that they lack in depth-of-focus, because they have additional lens groups built-in. More lenses mean less light passing the lenses. Less light means a wider aperture needed and a wider aperture means less depth-of-field ! Our ThirdEye-HDmini has a depth of field of 10-15 centimeter ! A quality, which you might not find in any auto focus lens with a similar focal length.

If you need auto focus, why not buying our ThirdEye-HD. This camera has both auto focus and 10x zoom. The depth-of-focus is about 6 cm (working distance 50cm, depicting full mouth)



The lens hood (ThirdEye-HDmini and ThirdEye-Photo)

The outer tube of the lens is the only part of the camera to be touched by your hands. To prevent a contamination of the lens, we deliver a special lens protection. This lens hood is made out of polypropylene. This material can be disinfected in the disinfection bath or even be autoclaved at 135o Celsius.  The lens hood simultaneously serves as sun shade and ray shade. It prevents other light sources - for example your ceiling light or daylight falling through a window - falling onto the front lens, thus reducing contrast of the system. You can focus the lens with the lens hood in place.

If the lens hood looses grip, just push it together once and it will fit again.


Adjusting the manual white balance (very important !)


All ThirdEye dental cameras can be operated both in automatic or manual white balance modus.The preferred modus should be the manual white balance, because in this modus only you will have optimal color reproduction under any light conditions.
To adjust the manual white balance, switch on dental light, direct the light beam onto a white sheet of paper in front  of your patients mouth or in front of the head rest of the dental unit. Now push the WB button on the camera housing (ThirdEye-HD) or use the "push lock mode " with the joystick (ThirdEye-HDmini) or click "white balance" in the settings menue of ThirdEye-Photo.

Check the colors of the gingiva of your patient or the colors of your skin on the monitor. 

ThirdEye-HD white balance 320


Rotation of the camera

You can rotate all our cameras on the miniature camera stand for about 45 degrees to each side. And the camera will stay in that position ! Thus you always can adjust the lip line or the teeth arch to the horizontal in whatever position the patient´s head or the dental light might be.

Taking shots with the dental mirror 

If you want to shoot subjects or tooth surfaces only visible with your dental mirror the light of your dental light should come out of the direction of your head. The central beam of the dental light then will be parallel to your visual axis. What you see in your dental mirror will be what you get on the monitor screen*.

* provided your dental assistant controls the focus

All user manuals can be downloaded form here.