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Home > Astrophotography > Masks > Focusing Masks > Farpoint > Snap-in > Farpoint Bahtinov snap-in focus mask for DSLRs with 77mm filter diameter

Farpoint Bahtinov snap-in focus mask for DSLRs with 77mm filter diameter

Product no.: 52165
Manufacturer: Farpoint

$ 21.90

incl. VAT
plus shipping costs

Express shipment possible for delivery tomorrow, 18.10.2019!

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This product is available in the following variants:
Diameter (mm) Price
52 $ 21.90
58 $ 21.90
62 $ 21.90
67 $ 21.90
72 $ 21.90
77 $ 21.90
82 $ 21.90
Product description
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Product description:

In the case that this article currently is not available from the warehouse, please note the following: we order from this supplier in regular intervals. Please place your order now, so that we may take into account your order and deliver the article to you by the above-mentioned date. If you need the article earlier, we can rush it for you for an additional price. In this case, please contact our customer service department.

Similar to illustration. (bracket not included)

Bahtinov focus mask

The focus mask is used to facilitate accurate focusing when doing astrophotography.

Focusing with your Bahtinov mask is simple. Start by snapping the Bahtinov mask into an inexpensive UV or Skylight filter that fits your camera lens. (FILTER NOT INCLUDED, MUST BE PURCHASED SEPARATELY) Center a fairly bright start in your camera and achieve a rough focus, then loosely screw the filter holding the mask onto your camera lens.

Take a short exposure. The image of the star will show diffraction spikes. The “center” set will most likely be shifted to one side or the other. This is showing the defocus.

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 against the star and the other spikes. When you achieve a symmetrical pattern, you have achieved the best possible focus. Remove the mask, center your target object and take your images!

The Bahtinov focus technique works best with longer focal lengths. It gets less useful with shorter focal lengths. The practical useful limit is around 100mm focal length or longer.

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