Farpoint DSLR Bahtinov Masks
Farpoints DSLR Bahtinov Masks extend the range of focusing masks available for astrophotography. In 2008, Pavel Bahtinov, a Russian amateur telescope maker and astronomer, revealed an ingenious new way to easily determine how sharply stars are focused for astrophotography. The method is simple, very intuitive, and the device has universally been named after the inventor: The Bahtinov Mask.
Focusing with your Bahtinov mask is simple. The most effective method is to insert the Bahtinov mask into an inexpensive UV or Skylight filter that fits your camera lens. Center a fairly bright star in your camera and achieve a rough focus, then loosely screw the filter holding the mask onto your camera lens.
A short exposure of the star will show diffraction spikes. The longer “center” set will most likely be shifted to one side or the other and indicates the star is not properly focused.
Slightly adjust the focus of your camera and re-expose the star, once again showing the diffraction spike pattern. Iterate the process until you get the central diffraction spike centered on the star and point at which the other spikes intersect. When you achieve a symmetrical pattern, you have achieved the best possible focus. Remove the mask, center your target object and you are ready to image!
Farpoint manufactures this “lifesaving” astrophotography tool out of virtually indestructible ABS plastic in a range of sizes for DSLR camera lenses.
Currently available in 52mm, 58mm, 62mm, 67mm, 72mm, 77mm, and 82mm. These masks are designed to snap onto a UV filter. The Farpoint snap-in Bahtinov Masks do NOT include a filter. Typically, photographers keep a UV filter on their lens permanently just to protect the lens. Since camera lens filters are stackable, Farpoint recommends that you keep a UV filter permanently on your lens and then LOOSELY thread a second UV filter with the snap-in Bahtinov onto your protective UV filter. That way, your lens will always be protected and you will be able to easily remove the Bahtinov to take your photos.