Epi-fluorescence interference and absorption filter combinations are housed in a filter cube (or optical block) and include an excitation filter, dichromatic beamsplitter (often referred to as a mirror), and a barrier (or emission) filter, as illustrated in Figure 1(a). Use this guide in selecting the appropriate filter set to match the spectral excitation and emission characteristics of chromophores used in widefield fluorescence microscopy investigations. The spectral profiles of a typical high-performance bandpass emission blue excitation filter combination are presented as an example in Figure 1(b). Nikon fluorescence filter combinations are provided in narrow, medium, and wide passband excitation versions with corresponding emission filters available with either bandpass or longpass spectral characteristics.
This filter screws very smoothly on to my Nikkor 80-200 2.8D ED lens. It unscrews as it should; it has never binded, nor come loose or slipped off. My Tiffen filters have never mounted as smoothly to either Nikon or Canon lenses. In this respect, perhaps Nikon filters really are made for Nikon lenses. The front Nikon lens cap included with the above mentioned lens fits easily onto the front of this filter. I've had no problems whatsoever getting it on or having it fall off.
The filter nomenclature employed by Nikon derives from a mixture of terms dating back to the early 1990s. At that time, all of the Nikon complementary filter combinations were produced using the hard coat sputter technique, but many of the currently available filters take advantage of newer softer coating methods. Although soft coats are more susceptible to humidity and heat degradation, and must be handled more carefully than hard coat filters, they exhibit higher blocking value optical densities and provide greater ease of fine-tuning specific wavelength bands. Understanding the Nikon filter combination code nomenclature provides a mechanism to quickly determine whether a particular set will perform adequately for a specific fluorophore.
- The V-2A combination is designed as a standard violet fluorescence filter block having the greatest degree of versatility. With a medium excitation bandpass and longpass emission filter, the images produced are the brightest of the Nikon violet filter group.