Is The Working Distance Of The Lens More Or Less Than That Of The Scanning Lens?

The working distance of a scanning lens is a critical characteristic of microscopic objective lenses. This parameter plays a vital role in determining the distance between the lens and the specimen being observed. For scanning lenses, the working distance typically falls in the range of 17-20 mm. This means that the lens can maintain a clear focus on the sample when it is positioned within this distance range. In contrast, high-power lenses, which are designed for magnification, have a much shorter working distance, usually between 0.5-0.7 mm. This substantial difference in working distance reflects the varying design goals of these lenses. Additionally, the resolving power of these lenses varies with the wavelength of light used, with scanning lenses achieving an approximate resolving power of 2.3 μm when illuminated with 450 nm (blue light) and high-power lenses achieving an impressive resolving power of 0.35 μm under similar conditions. Understanding these properties is crucial for selecting the right lens for specific microscopy applications.

The working distance of a high magnification lens is typically shorter compared to that of a scanning lens in most compound microscopes. This phenomenon occurs because, as you increase the magnification, the working distance tends to decrease significantly. Working distance refers to the space between the objective lens and the specimen being observed, and it plays a crucial role in microscopy. As magnification increases, the lens needs to get closer to the specimen to capture finer details, leading to a reduced working distance. This decrease in working distance can impact the ease of focusing and manipulating the specimen, making it an important consideration when selecting the appropriate lens for a specific microscopy task.