In the case of spherical observation, there are two issues: 1. surface condition (specular or diffuse reflective material) and 2. depth of focus.
The observed object is a 5 mm sphere with a specular surface.



ハイビジョンマイクロスコープ TG200BA

Model used 
High-definition microscope TG200BA






1.Surface condition


If the object is a sphere, everything will be R-reflected (the angle that causes direct reflection is always included).
If the object is a specular surface, the areas of the specular surface that are directly reflected by the illumination will be white out,
and the rest of the specular surface will be in shadow.



・When photographed normally  
・HDR (High Dynamic Range) function  
The difference between shadows and white spots is less than in normal photography.
・HDR function + polarization filter  
The white areas can be suppressed somewhat, but the rest of the image is slightly easier to see with the HDR function alone.
・Surround the object with reflective panels  

In addition, when a USB camera type is used, the camera’s gamma function can be used as shown below to observe less difference between shadows and white splash, like the HDR function of a high-definition camera.


USB3.0マイクロスコープ TG500CS

Model used
USB3.0 Microscope TG500CS





・When photographed normally  
・When the camera’s gamma correction is applied  
・Gamma correction + reflector around the object
Arranged to be illuminated by indirect light  

With any technique, if the object is close to a specular object, it will be more difficult to capture a clear image.
If it is more or less a diffuse reflective object or something close to it, it will be easier to observe with the use of HDR functions, etc.


■Depth of focus


In addition, spherical surfaces can cause depth of focus problems.
Lubricant is added to the above spherical sample to see how far into focus it will be.
The photo below shows the above 5mm spherical sample with lubricant.
The focus is set at the apex of the sphere.
The aperture is stopped down, the depth of focus is deeper, and the entire image is less blurry.



絞りを絞った場合 絞りを開放した時
When the aperture is stopped down When the aperture is wide open