Bahtinov Masks with camera NOT telescope?

[the lemming]

Hello

Its been a few years since I've been on here and I have a small personal project coming up in a couple of weeks. I'm hoping to tick off the Milky Way on my Bucket List and I've been doing a bit of random reading about focusing on stars.

I'm hoping to capture the Milky Way with my Panasonic GH5 and 7.5mm lens, which is coming in the post, soon. But not soon enough 😀

The lens is completely manual Laowa f2.

I have also read about people using Bahtinov Masks to focus digital cameras that are attached to telescopes.

 

Is it possible, or even worthwhile attaching a Bahtinov Mask to a 7.5mm lens+camera combo to achieve focus. Or is it just as effective to use the camera's screen and use peak focusing on a bright star?

If it is worth getting a Bahtinov mask, where could I get one for a 46mm screw filter thread?

 

Cheers muchly.

[almcl]

Afraid I can't answer your first question about whether it would be worthwhile, but how to get one is a bit easier.

I tried to get one for my 200 mm Canon lens and failed miserably: there seemed to be no commercially produced ones available.

So instead I used one of the on-line websites to generate  a graphic, inputting lens diameter and the other details the site required, then printed it on to OHP transparency film and attached it to a cardboard ring which fits over the lens hood.  It works OK and was cheap enough to make that I don't mind if it gets damaged occasionally.

[the lemming]

3 minutes ago, almcl said:

Afraid I can't answer your first question about whether it would be worthwhile, but how to get one is a bit easier.

I tried to get one for my 200 mm Canon lens and failed miserably: there seemed to be no commercially produced ones available.

So instead I used one of the on-line websites to generate  a graphic, inputting lens diameter and the other details the site required, then printed it on to OHP transparency film and attached it to a cardboard ring which fits over the lens hood.  It works OK and was cheap enough to make that I don't mind if it gets damaged occasionally.

Does this mean that you have used a mask with your camera+lens, and NOT a telescope?

If this is the case, did you notice any difference in your images when using the mask or manually focusing your camera using your 'Mark 1' eyeball?

[almcl]

1 minute ago, the lemming said:

Does this mean that you have used a mask with your camera+lens, and NOT a telescope?

If this is the case, did you notice any difference in your images when using the mask or manually focusing your camera using your 'Mark 1' eyeball?

Definitely used with lens, and yes, the focus was better.  Not sure how much difference it will make on a wide angle lens?

Here's the only image I can find of the mask in action (pre final adjustment):

[the lemming]

That's great.

Cheers

[edarter]

Have done the same, used an on line site to input the data and print off a mask (I just did it on paper) and then used a scalpel to cut out the slits and mounted it to the lens hood. Wish I had thought of the ohp film trick! No cutting required! 

Mine was for my Canon mk1 100-400 and focussing was spot on when I used it. 

 

[TerryMcK]

I bought a 52mm mask from here https://www.secure-eshop.com/epages/www_astrograph_net.sf/en_GB/?ObjectPath=/Shops/www_astrograph_net/Categories/Shop/Focusing_Aids and fixed it to my lens (49mm) with a step up ring. It works supremely well. You could do the same with a step down ring from 49mm to 46mm. You are only interested in a bright star, like Vega, and the slight amount of vignetting caused by the step down ring won't really matter.

I also fixed it into a plastic mount I made so I don't have to use any form of adaptor when attaching to my guidescopes. It can also be used on a camera lens with a hood.

 

Edited September 7, 2020 by TerryMcK

[the lemming]

Thank you everybody for your help