Camera Filtering

In some fluorescence imaging applications, it is necessary to image two (or more) emission wavelengths in relatively rapid succession - meaning faster than moving the filter cubes manually or automatically (motorised filter cube turrets on automated microscopes generally operate in 0.5-1 second).

Examples are:

• Ratiometric imaging using dyes with dual emission wavelengths. For example, the calcium indicator INDO-1 is excited at a single wavelength (355 nm) and has emissions at two wavelengths (405/495 nm)(in contrast to say FURA-2 which is excited at two wavelengths but has a single emission wavelength).

• Any application using two different fluorophores (eg. colocalisation studies, FRET) where a reasonably rapid time course is required.

An efficient solution is possible provided the two fluorophores can share a common dichroic mirror in the microscope. In this case, the dichroic can be left alone and the emission filters installed in front of the camera. The two wavelengths can then be captured using either a filter wheel or an image splitter.

Sutter Lambda 10-2

The Lambda 10-2 and Lambda 10-C filter wheels may be used in a microscope emission path to automatically change emission filters as required.

• Uses standard 25 mm diameter interference filters (a 32 mm version is available)
• Adaptors available for most microscopes
• Switching time between adjacent filters is 55 ms (Lambda 10-2) or 90 ms (Lambda 10-C)
• Control by keypad, RS-232, or parallel port
• Compatible with SimplePCI imaging software
• For more details, please see our Fluorescent Light Sources page.

Hamamatsu W-View

The Hamamatsu W-View is a static image splitter that gives dual images at the camera, separated by wavelength. The W-View contains (exchangeable) interference filters and dichroics so that the final image at the camera contains two halves, one at each of the wavelengths of interest.

• Images are obtained simultaneously, with no moving parts
• Ideal for single-excitation, dual-emission dyes such as INDO-1
• Filter sets are available for INDO, cAMP, fluo-3/furared, cameleon etc.