![]() The Mitutoyo FS-60 is a rather large industrial microscope designed to use incident inclined illumination (from an external light source) and incident coaxial illumination (via a proprietary port for an optical light guide). The gliding stage is adapted from a Zeiss microscope. Thus, enter: The final solution, version 2 Figure 2. This eliminates all problems connected with matching, assembling and tentatively aligning parts from different brands and models, which I was forced to do for version 1. In my particular case, I was able to secure a second-hand Mitutoyo FS-60 microscope on the 'Bay (I mean eBay, not the other 'Bay, which is no good for getting hardware). Other brands of infinity objectives require original tube lenses to correct for some aberrations, while modern Mitutoyo and Nikon ones (and perhaps at least some Olympus objectives) correct all aberrations within the objective and are more tolerant of tube lenses from other manufacturers, and even of telephoto and repro lenses used in place of a tube lens. They are also relatively frequent on the second-hand market, and their prices, although high, are not outside the reach of determined amateur photographers. ![]() Modern infinity-corrected Mitutoyo and Nikon objectives are currently regarded as particularly suitable for this use. A number of original and "alternative" tube lenses have been tested by photographers, with varying degrees of success and practicality. Infinity objectives require additional optics (called "tube lens", but often consisting of multiple elements) between objective and focal plane. Shortly after I finished building this system, it became clear (especially through discussions on the bulletin boards) that infinity microscope objectives designed for incident illumination and long working distances produce better results than finite optical systems. Focusing through the eyepieces is much easier and more precise that carrying out the same operation through a DSLR viewfinder, and in my opinion is even superior to the live view now available in most digital cameras (with the possible exception of the extreme zooming sometimes possible in live view). The above system uses photomacrographic lenses in RMS threads, as well as finite microscope objectives, and works very well for my purposes. 2011: Construction and programming of an autonomous focus stacker. 2011: Digital photography for science: Close-up photography, macrophotography and photomacrography. This system, and the programming of its microcontroller, are discussed in detail in the following references: My first device for autonomous stacking.Ī couple of years ago, I built the automated stacking system shown in Figure 1. In this way, if everything works as intended, the final image can display a high resolution (with good lenses, close to the maximum possible for a given camera) and at the same time an essentially unlimited DOF. At the same time, a moderate amount of overlap of the DOF between adjacent slices helps the stacking software to do its job. The lens aperture is selected as the highest f/value that does not visibly lower resolution. Each image in a stack can be shot with an aperture settings that does not visibly decrease resolution by introducing diffraction. ![]() In general terms, focus stacking works by (1) taking a series ("stack") of photographs of an immobile subject at slightly different focus settings, and (2) combining together the in-focus portions of the stack images, thus obtaining a final image that displays a higher depth of field that possible in a single image. Mitutoyo FS-60 Preface: The final solution (for focus stacking)įocus stacking is a combination of photographic and post-processing techniques that bypasses the intrinsic limitations of depth of field, diffraction and resolution in photography. ![]()
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