Easy Focus Star Focus Filter for Stars and Planetary Photography

FAQ

❓ What is the shortest (widest) focal length this filter can be used with?

✅ The filter can be used on wide-angle lenses, but the visibility of the Bahtinov focusing pattern varies with focal length.

For best results, we recommend lenses of 50mm or longer.

• 50mm+ — Best performance
• 24–50mm — Generally works well
• Below 24mm — The diffraction pattern may be weaker and harder to observe depending on the lens and shooting conditions.

The longer the focal length, the easier it is to see and use the focusing pattern.

❓ I have a Nikon 24-70 that has an 82mm thread for filters. Does the 82mm have a thread to fit my lens?

✅ Yes, the filter has the thread to fit into the lens.

❓ Once you have it aligned, do you need to remove the filter?

✅ Yes. The filter should be removed before taking the exposure.

❓ Can I use my current set of step-up rings?

✅ Yes. If your step-up rings go from 82mm to your lens diameter and the 82mm side uses the standard 82 × 0.75mm thread, they will fit properly.

❓ What’s included in the “Star Focus Filter + All Adapters Below” option?

✅This option includes one 82mm Star Focus Filter and a set of 8 adapter rings:
49mm, 52mm, 55mm, 58mm, 62mm, 67mm, 72mm, and 77mm.

Introduction
Star Focus Filter is used to work with cameras to achieve precise focus on the stars, Focusing a camera lens in the dark is always a difficult thing in astrophotography. Through the Bahtinov Mask on the filter, Star Focus Filter can help the camera get an accurate focus on stars.
Specification

Compatible lens	82mm
Filter Material	high-clarity acrylic
Adapter Rings Material	aluminum
Threaed Size	82 ×0.75 mm
Camera Adapter Rings	49mm、52mm、55mm、58mm、62mm、67mm、72mm、77mm
Weight（g）	without adapter ring 20g  with adapter ring 30.3g

How to Choose a Suitable Adapter ?

Does it work with zoom lens?

Yes, it's ok for zoom lens. The longer the focus length the better the performance. Below video is tested with indoor red led, Canon 600D, Canon EF-S 18-135mm f/3.5-5.6 @18mm How to Use Star Focus Filter(video)?

Method 1

1. Mount the Star Focus Filter onto your camera.

1. Turn on the live view mode, adjust the ISO to the biggest (ISO 1600 or above), and set the shutter speed to 10s or more.

1. Adjust the frame and make sure the bright star or light source is in the middle of the frame. It is recommended that you look for a bright star of magnitude 1 to focus on.

1. Magnify the frame and adjust the focusing rings at the same time until three fine spike lines show out in the frame.

1. Rotate the focusing ring to make the three spikes intersect at one point. This the when the precise focus is achieved.

Method 2

If you can't find a brighter star or the lens aperture is too small, you can take several testing pictures to get the focus.

1. Mount the Star Focus Filter onto your camera.

1. Adjust the focus rings to get an infinity focus

1. Set the high ISO and short exposure (several seconds), and take one testing shot

1. Check the three spike lines in the frame, if the central spike is closing to the left, screw the focus ring to the right. If the central spike is closing to the right, screw the focus ring to the left.

1. Take a second testing shot, and repeat step 4 until three spikes intersect at one point. Then a precise focus is achieved.

 Note: Hand holding the filter, then it can work with the lens without the adapter 

 Tips:

1. It will need to position the bright star in the middle of the frame, choosing the bright star of magnitude 1 or close to the magnitude 1

1. For the wide lenses, please turn the aperture to the biggest

1. The filter is not wear-resistant, please store it in a filter case after use. If there is dust or oil, please use an air blower and neutral detergent to remove them

1. Do not place it in high temperature environment

Recommended Apertures with different focal lengths
Focal Length (MM)	10-11	12	14	16	18	20	24	28-600 or longer
Aperture (F)	1.2-2.5	1.2-2.8	1.2-3.5	1.2-4.0	1.2-4.5	1.2-5.0	1.2-5.6	1.2-5.6 or lower