Adjustable Bahtinov Mask for Various DSLR Lenses

Description

Never worry about blurry stars again. Get perfect focus for astrophotography every time with a bahtinov mask.
If you've ever spent hours trying to manually focus your camera on the stars at night, you know the struggle. A bahtinov mask will cut your set up time down to mere minutes with ease.
The simplest, easiest to use Bahtinov Mask for camera lenses.
Clips to the Exterior of the Lens
The mask clips on to the exterior of the lens, allowing for easy mounting and dismounting, even in the dark. Removing the mask won't bump your focus ring.
Three sizes are available to fit lenses with an exterior diameter between 50 and 120 mm. Be sure to measure the
exterior
diameter of the lens or dew shield for the best fit.
Bahtinov focus masks are easy to use. Before attaching the mask, aim your lens or telescope at a bright star and manually adjust the focus of your lens or telescope until it looks close to focus. Then, gently attach the bahtinov mask. The mask will diffract the light into three spikes. Adjust focus until the middle spike is centered, then carefully remove the mask to begin viewing.
This product is NOT a medical device.