How to refocus Len "A"

[PRoz]

.....are that many of them out of focus in the first place, I wouldn't think so

I have had 3 M1's and they all needed re focusing as it had been set so further away was out of focus. Doing this did not change the focus on close up in any way.

 

[PRoz]

First, the lens holder is rather short, so there's not much space to fit a screw.

Second, the lens does not engage very far into the holder, so again not much space to fit a screw and hold the lens securely.

Third, the lens barrel is plastic, unlike Lens B and other Mobius lenses which are metal, so a set screw is more likely to damage the lens - although I suppose the set screw would get a good bite into the plastic to hold it in place!

Could you just indicate where is the glue so I can be sure to turn the right bits.

Where I have put the Red arrow is that bit removable and if so for what reason?

Thanks

 

[TonyM]

View attachment 45060
Could you just indicate where is the glue so I can be sure to turn the right bits.

Where I have put the Red arrow is that bit removable and if so for what reason?

Thanks

The glue is on the lens threads, where it meets the lens holder



That front part you have indicated is probably a retaining ring that holds the lens elements together. Best not to fiddle with that!

 

[Dashmellow]

In addition to the response from @Dashmellow , I can see three practical reasons for not having a set screw on the A lens:
View attachment 45056

First, the lens holder is rather short, so there's not much space to fit a screw.

Second, the lens does not engage very far into the holder, so again not much space to fit a screw and hold the lens securely.

Third, the lens barrel is plastic, unlike Lens B and other Mobius lenses which are metal, so a set screw is more likely to damage the lens - although I suppose the set screw would get a good bite into the plastic to hold it in place!

There do appear to be numerous M12 mounts available that are quite similar to and even a bit lower profile than the one that is used in the Maxi, (and the M2) that have a grub screw hole.




I don't happen to own a Maxi A lens module so I've never examined one first hand but I'm also surprised to hear that Mobius would use a lens that barely engages very far into the holder. How far are we talking about?

 

[jmdlcar]

Is all the M12 mounts the same size? I found these is why I am asking. https://www.ebay.com/itm/122566718231

 

[TonyM]

There do appear to be numerous M12 mounts available that are quite similar to and even a bit lower profile than the one that is used in the Maxi, (and the M2).

View attachment 45070


I don't happen to own a Maxi A lens module so I've never examined one first hand but I'm also surprised to hear that Mobius would use a lens that barely engages very far into the holder. How far are we talking about?

Thanks for sharing that photo. I did not think it was practical to put a screw so close to the edge of the holder, but I see that I was wrong.

I've not measured how far the lens goes into the holder when correctly focused. In hindsight I should have checked before making that statement.

Perhaps it would be better if someone from Mobius could comment on the lack of a set screw?

 

[jokiin]

Perhaps it would be better if someone from Mobius could comment on the lack of a set screw?

have never seen them comment on anything publicly

 

[Dashmellow]

Thanks for sharing that photo. I did not think it was practical to put a screw so close to the edge of the holder, but I see that I was wrong.

I've not measured how far the lens goes into the holder when correctly focused. In hindsight I should have checked before making that statement.

Perhaps it would be better if someone from Mobius could comment on the lack of a set screw?

Yeah, I guess without actually unscrewing the lens from the module there's no way to know how much thread depth exists on the lens barrel.

 

[TonyM]

Yeah, I guess without actually unscrewing the lens from the module there's no way to know how much thread depth exists on the lens barrel.

Well, it's sitting in my bag doing nothing. Might as well unscrew it and find out!

 

[TonyM]

have never seen them comment on anything publicly

Until then, I'll try to answer the best that I can, even if I get it wrong sometimes

 

[Dashmellow]

Well, it's sitting in my bag doing nothing. Might as well unscrew it and find out!

It will be interesting to hear what you find out.

 

[Dashmellow]

Until then, I'll try to answer the best that I can, even if I get it wrong sometimes

We all get it wrong sometimes.

 

[TonyM]

It will be interesting to hear what you find out.

I found another one already removed from the holder so you can compare them. It looks to be about 5-6 turns, so probably just enough.

 

[Dashmellow]

I found another one already removed from the holder so you can compare them. It looks to be about 5-6 turns, so probably just enough.
View attachment 45072

So, that looks about right considering the depth of the lens holder and it seems as if it would certainly be secure enough. And this answers another question I had in regard to your comment that "the lens does not engage very far into the holder". I was wondering what the BFL would be like if the lens was not engaging far into the holder. It looks like that would be about right as well.

So, it still looks like a grub screw option would work here.

Thanks for doing this!