Mobius 5MP Varifocal Zoom 6-22mm ƒ/1.6

[Dashmellow]

I think Rick mean the focus position.

Yeah, I was a little confused about the way @jokiin posed the question which seemed a bit vague, hence the "If you are talking about" remark. The lens has those two knurled lugs for focusing and zooming. As long as you tighten them enough they'll stay put. On one or two occasions going back to the other varifocal lens I started posting about nine months ago I got home and discovered that I had lost focus because I hadn't tightened the lugs enough so now I make sure I do that and have had no issues locking everything into position. It's just part of what I do along with making sure the ball joint mount on the windshield is properly tightened as well.

 

[Lola]

@Lola, you may have missed it but I posted about Treeye switching to installing the IR cut filter inside the lens tube on all their varifocal lens about a month ago back on June 7th, along with their new photo of the lens.

https://dashcamtalk.com/forum/threads/mobius-5mp-varifocal-zoom-6-22mm-ƒ-1-6.34263/post-409717

The CPL I used is a cheap one I bought on eBay years ago. I don't have a link for it but many similar ones are available if you just search for them. Keep in mine that there is no easy way to attach the filter to the varifocal lens. I will talk more about my experiences with that soon but basically I had to glue it on using UV cement. Anybody who wants to install a CPL on this lens will need to come up with a suitable method of attachment. So far, UV cement appears to be a secure but easily reversible way to do it.

Interesting, I thought it was a mechanical instillation, when talk of turning a ring was mentioned. Anyway I'll check them out, thanks.

 

[Dashmellow]

Interesting, I thought it was a mechanical instillation, when talk of turning a ring was mentioned. Anyway I'll check them out, thanks.

The threads of the CPL fit perfectly just inside the bezel of the lens except that there are no threads on the lens to screw it into. Once it is glued on properly the mechanical CPL filter ring turns as it would normally.
At first I tried using three little dabs of UV cement around the lens but when I went to adjust the filter it just came off in my hand. And one time I twisted it right off the lens by accident because I'm in the habit of doing that with the lens cap but forgot that it was now a CPL filter and not a lens cap.

Anyway, I finally had to use a fair amount of UV cement carefully applied along the edge of the filter. The interesting thing is that it holds very well but the UV cement can be removed easily and cleanly with no damage using a disposable plastic knife like the kind you would take on a picnic or get from a take out restaurant. The cured UV cement will basically just pop off in one piece leaving little or no residue behind.

Oh, I should mention that I first tried attaching the filter using black electrical tape and partly because we are in the middle of a week long intense heat wave, the tape immediately turned into a disgusting, sticky mess. So, I cleaned it all up with some alcohol and went with the glue method.

 

[Lola]

The threads of the CPL fit perfectly just inside the bezel of the lens except that there are no threads on the lens to screw it into. Once it is glued on properly the mechanical CPL filter ring turns as it would normally.
At first I tried using three little dabs of UV cement around the lens but when I went to adjust the filter it just came off in my hand. And one time I twisted it right off the lens by accident because I'm in the habit of doing that with the lens cap but forgot that it was now a CPL filter and not a lens cap.

Anyway, I finally had to use a fair amount of UV cement carefully applied along the edge of the filter. The interesting thing is that it holds very well but the UV cement can be removed easily and cleanly with no damage using a disposable plastic knife like the kind you would take on a picnic or get from a take out restaurant. The cured UV cement will basically just pop off in one piece leaving little or no residue behind.

Oh, I should mention that I first tried attaching the filter using black electrical tape and partly because we are in the middle of a week long intense heat wave, the tape immediately turned into a disgusting, sticky mess. So, I cleaned it all up with some alcohol and went with the glue method.

Thanks, now I see what you did. It's the housing you made semi permanent, the lens itself was sill turnable/adjustable.

Question: Why wouldn't a Cut UV-IR filter also work in this fashion on the front lens (M12), in stead of on the back end of the lens?

 

[Dashmellow]

Thanks, now I see what you did. It's the housing you made semi permanent, the lens itself was sill turnable/adjustable.

Question: Why wouldn't a Cut UV-IR filter also work in this fashion on the front lens (M12), in stead of on the back end of the lens?

I assume you are now talking about IR Cut filters not CPLs. Yes, in theory an IR filter would work in front of an M12 lens except that IR Cut filters are thin film dichroic filters which are made using certain chemicals that are applied to the glass in a vacuum chamber and they tend to be very delicate. For this reason they are always used inside cameras, telescopes, microscopes, etc. where they are protected from abrasion and the elements.

Edit: IR cut filters do exist that go on the front of camera lenses such as DSLRs and cinema equipment and screw in just like any other dedicated camera filter but they tend to be very expensive and as far as I know are not made in sizes that would fit the average M12 lens. Some of these filters are made to pass or cut very specific wavelengths and are used for very specific effects or technical purposes. Having them on the front of the camera gives the camera operator a lot of flexibility different from what typical IR cut filters do behind the lenses of digital cameras like dash and action cams.

 

[Lola]

I assume you are now talking about IR Cut filters not CPLs. Yes, in theory an IR filter would work in front of an M12 lens except that IR Cut filters are thin film dichroic filters which are made using certain chemicals that are applied to the glass in a vacuum chamber and they tend to be very delicate. For this reason they are always used inside cameras, telescopes, microscopes, etc. where they are protected from abrasion and the elements.

Edit: IR cut filters do exist that go on the front of camera lenses such as DSLRs and cinema equipment and screw in just like any other dedicated camera filter but they tend to be very expensive and as far as I know are not made in sizes that would fit the average M12 lens. Some of these filters are made to pass or cut very specific wave lengths and are used for very specific effects or technical purposes. Having them on the front of the camera gives the camera operator a lot of flexibility different from what typical IR cut filters do behind the lenses of digital cameras like dash and action cams.

Thanks for the explanation, sorry I jumped the conversation to IR filters.

Now back to CPL filters. I measured the 6-22 lens front housing, however I just have plastic cheap mm measuring tools, but they have shown to have remarkable accuracy capability.
The outside of the housing is 28mm and the inside measures 23mm so I was wondering if you measured yours. It seems a 24mm CPL would not fit this lens (be to tight to go over the outside of the housing)
or am I missing something? Forgot to get a link to the CPL, be right back. Here is the one I was looking at. https://www.aliexpress.com/item/24m...For-Car-Camera-DVR-Mini-0806/32319664391.html

It lists some cameras that this particular CPL is designed for I guess, the first 1 or 2 are Mobius cameras I think 0806, 0903, however I have never had an interest in them.
I now see that they are called "mini series".

 

[Dashmellow]

Thanks for the explanation, sorry I jumped the conversation to IR filters.

Now back to CPL filters. I measured the 6-22 lens front housing, however I just have plastic cheap mm measuring tools, but they have shown to have remarkable accuracy capability.
The outside of the housing is 28mm and the inside measures 23mm so I was wondering if you measured yours. It seems a 24mm CPL would not fit this lens (be to tight to go over the outside of the housing)
or am I missing something? Forgot to get a link to the CPL, be right back. Here is the one I was looking at. https://www.aliexpress.com/item/24m...For-Car-Camera-DVR-Mini-0806/32319664391.html

It lists some cameras that this particular CPL is designed for I guess, the first 1 or 2 are Mobius cameras I think.

OMG! Sorry! You are quite right, it's a 30mm polarizer! It seems I confused it with another CPL I have which is 24mm. Maybe it's the crazy hot weather? The truth of the matter is that I didn't measure anything. I simply held the CPL up against the varifocal lens bezel and the threaded part of the filter fit perfectly just along the outer edge of the lens. I then checked how things looked on screen in web mode to make sure there was no vignetting and saw that it was fine, so I was good to go. My apologies for any confusion I may have caused. Good catch...Thanks!

BTW, I found a current eBay link to the CPL filter I have. There's a little interesting story about my experience with this filter which partially explains one aspect of my forgetting the actual diameter. When I ordered this filter several years ago, the photo on the eBay page showed a black metal filter bezel but when it arrived it was a silver metal filter. So I contacted the (USA) seller and asked if they could provide a black one like on their sales page, offering to return the one they sent. Instead, they immediately issued a full refund and let me keep the silver filter. So, now I had a useless, very unstealthy dash cam CPL I didn't know what to do with. I ended up carefully masking the glass part of the filter and spray painted it black. It came out so perfect that you would never know it didn't come from the factory that way. The result though is that the markings on the side of the filter that say 30mm are now covered in black paint.

 

[Lola]

OMG! Sorry! You are quite right, it's a 30mm polarizer! It seems I confused it with another CPL I have which is 24mm. Maybe it's the crazy hot weather? The truth of the matter is that I didn't measure anything. I simply held the CPL up against the varifocal lens bezel and the threaded part of the filter fit perfectly just along the outer edge of the lens. I then checked how things looked on screen in web mode to make sure there was no vignetting and saw that it was fine, so I was good to go. My apologies for any confusion I may have caused. Good catch...Thanks!

BTW, I found a current eBay link to the CPL filter I have. There's a little interesting story about my experience with this filter which partially explains one aspect of my forgetting the actual diameter. When I ordered this filter several years ago, the photo on the eBay page showed a black metal filter bezel but when it arrived it was a silver metal filter. So I contacted the (USA) seller and asked if they could provide a black one like on their sales page, offering to return the one they sent. Instead, they immediately issued a full refund and let me keep the silver filter. So, now I had a useless, very unstealthy dash cam CPL I didn't know what to do with. I ended up carefully masking the glass part of the filter and spray painted it black. It came out so perfect that you would never know it didn't come from the factory that way. The result though is that the markings on the side of the filter that say 30mm are now covered in black paint.

LOL, I like the story, sounds like something I would do, and have.

Question, When they say a (example) 30mm lens what measurement are they talking about, the diameter of the glass, inside diameter, or what? Vignetting is also a concern so if the lens barrel is say 28mm how much clearance do you need to ensure no vignetting ? I guess I'm asking is there a standard they go by relative to measurements of this kind?

 

[Dashmellow]

LOL, I like the story, sounds like something I would do, and have.

Question, When they say a (example) 30mm lens what measurement are they talking about, the diameter of the glass, inside diameter, or what? Vignetting is also a concern so if the lens barrel is say 28mm how much clearance do you need to ensure no vignetting ? I guess I'm asking is there a standard they go by relative to measurements of this kind?

Generally, for example, a 30mm filter is 30mm in diameter to the edge of the bezel. The glass might be slightly smaller. It's hard to say about vignetting. If the filter has a big thick, deep metal bezel you might get vignetting but the same size filter in a thin bezel might not. When you buy a dedicated filter for a DSLR lens it should work. It's when you get into doing oddball things like gluing a CPL to a CCTV lens that things could get weird. Trial and error seems the best approach. Actually, one thing I've done with dash cam attachments like the DIY lens shade I once made out of a 35mm film canister is to look at the camera's image on a monitor and hold an object along the edge of the lens. Slowly moving the object forward or backwards until you see it encroaching in the image will tell you when you will experience vignetting.

 

[jokiin]

Yeah, I was a little confused about the way @jokiin posed the question which seemed a bit vague, hence the "If you are talking about" remark. The lens has those two knurled lugs for focusing and zooming. As long as you tighten them enough they'll stay put. On one or two occasions going back to the other varifocal lens I started posting about nine months ago I got home and discovered that I had lost focus because I hadn't tightened the lugs enough so now I make sure I do that and have had no issues locking everything into position. It's just part of what I do along with making sure the ball joint mount on the windshield is properly tightened as well.

yeah sorry, reading my question again I can see why it wasn't clear, wasn't asking about the CPL and I was referring to the focus and zoom and how well it held your settings once done which you ended up answering here, thanks

 

[Dashmellow]

yeah sorry, reading my question again I can see why it wasn't clear, wasn't asking about the CPL and I was referring to the focus and zoom and how well it held your settings once done which you ended up answering here, thanks

I guess since the first part of your post referred to the CPL I assumed you were referring to that as well when you asked about it holding position.

Although I have yet to find the need to use them, notice that the focus and zooming lugs on these varifocals include slots for a screw driver so you could really crank them down tight if you wanted to.

 

[Lola]

Generally, for example, a 30mm filter is 30mm in diameter to the edge of the bezel. The glass might be slightly smaller. It's hard to say about vignetting. If the filter has a big thick, deep metal bezel you might get vignetting but the same size filter in a thin bezel might not. When you buy a dedicated filter for a DSLR lens it should work. It's when you get into doing oddball things like gluing a CPL to a CCTV lens that things could get weird. Trial and error seems the best approach. Actually, one thing I've done with dash cam attachments like the DIY lens shade I once made out of a 35mm film canister is to look at the camera's image on a monitor and hold an object along the edge of the lens. Slowly moving the object forward or backwards until you see it encroaching in the image will tell you when you will experience vignetting.

I understand now, it's not an exact science, just use some common sense! That along with what you have explained should lead me in the right direction. Thanks a lot for taking the time to answer and help me.

 

[Lola]

As you can see the lens housing is 28mm so I need some suggestions/ideas on mounting a CPL filter on this housing that would have complete function like a normal lens added to a camera with exchangeable lenses capability.

1 thought would be to find a CPL filter lens with an inside area of 28mm that I could put over this lens housing and glue it there. (Dashmellow once did this sort of thing).

I know very little about what adapters or available on CPL lens hardware so I am putting the concept out to you guys for ideas.

The lens that dashmellow used was a 30mm lens that gave enough room at the outside edges for NO vignetting problems so this would be a function of a thin bezel and a 30mm filter relative to the 28mm housing. This does not mean the lens has to be 30mm, it could be larger but a common size.

Looking for good ideas that are relatively cheap.

 

[Dashmellow]

@Lola, I'm not entirely sure what you mean by "complete function like a normal lens added to a camera with exchangeable lenses capability", but if you mean that you would like to have the ability to easily install and remove a CPL filter on this Varifocal CCTV lens that is not designed for removable filters then you would need to add some threads to screw it into.

That wouldn't be all that hard to achieve. All you would need to do is glue a suitable threaded filter adapter onto the front bezel of the lens. There would be several options for how to go about this. For example you could install a 28mm to larger diameter adapter such as this 28-37mm step-up ring. An adapter that takes a much larger CPL which might be desirable to eliminate any possibility of vignetting. Many adapter sizes and options are available. Of course, the back side of these filter adapters are male threaded and that is the part that you would need to glue to the front of the lens. The 30mm CPL filter I glued to my varifocal lens has rear male threads that are just about 28mm in diameter and all I did was glue the threaded part of the filter to the front of the varifocal using UV cement. It was pretty easy and it fit nicely on the front bezel of the lens. If you want to you could even grind or sand down the male threads on an adapter to create a flat or flatter surface for gluing.

FYI, 28mm CPL filters are widely available. Any size CPL you purchase will have rear threads that are a couple of millimeters smaller than the diameter of the filter bezel itself as you can see in the third photo below.

Typical threaded step-up filter rings look like this with female threads for the filter you wish to install.


They come in a wide range of sizes to adapt different sized filters to different sized lens bezels.


As mentioned, the back of these adapters are male threaded and look like this.

 

[Lola]

@Lola, I'm not entirely sure what you mean by "complete function like a normal lens added to a camera with exchangeable lenses capability", but if you mean that you would like to have the ability to easily install and remove a CPL filter on this Varifocal CCTV lens that is not designed for removable filters then you would need to add some threads to screw it into.

That wouldn't be all that hard to achieve. All you would need to do is glue a suitable threaded filter adapter onto the front bezel of the lens. There would be several options for how to go about this. For example you could install a 28mm to larger diameter adapter such as this 28-37mm step-up ring. An adapter that takes a much larger CPL which might be desirable to eliminate any possibility of vignetting. Many adapter sizes and options are available. Of course, the back side of these filter adapters are male threaded and that is the part that you would need to glue to the front of the lens. The 30mm CPL filter I glued to my varifocal lens has rear male threads that are just about 28mm in diameter and all I did was glue the threaded part of the filter to the front of the varifocal using UV cement. It was pretty easy and it fit nicely on the front bezel of the lens. If you want to you could even grind or sand down the male threads on an adapter to create a flat or flatter surface for gluing.

FYI, 28mm CPL filters are widely available. Any size CPL you purchase will have rear threads that are a couple of millimeters smaller than the diameter of the filter bezel itself as you can see in the third photo below.

Typical threaded step-up filter rings look like this with female threads for the filter you wish to install.
View attachment 39787

They come in a wide range of sizes to adapt different sized filters to different sized lens bezels.
View attachment 39788

As mentioned, the back of these adapters are male threaded and look like this.
View attachment 39789

After writing the above post for ideas I did a search and came up with the same information you just gave. My one concern is I would want the adapter to slip on the front part of the 6-22 housing which is 28mm so if one buys a 28mmm to 37mm adapter what would the back side of the threaded area be? I think I might be confused about which side screws in to the "normal" camera with threads.
OH now I get it, we are talking about the same thing, sorta, it's just I don't know if the side with the 28mm thread is outward from the housing are inward towards the lenses, from what you are showing on the above adapter the threads are outward from the housing and the back side of this threaded area is towards the housing, it's the backside of this area that I want to slip over the 28mm lens barrel, does this make sense to you? Understand?

 

[Dashmellow]

After writing the above post for ideas I did a search and came up with the same information you just gave. My one concern is I would want the adapter to slip on the front part of the 6-22 housing which is 28mm so if one buys a 28mmm to 37mm adapter what would the back side of the threaded area be? I think I might be confused about which side screws in to the "normal" camera with threads.
OH now I get it, we are talking about the same thing, sorta, it's just I don't know if the side with the 28mm thread is outward from the housing are inward towards the lenses, from what you are showing on the above adapter the threads are outward from the housing and the back side of this threaded area is towards the housing, it's the backside of this area that I want to slip over the 28mm lens barrel, does this make sense to you? Understand?

As I said in my previous post, "The 30mm CPL filter I glued to my varifocal lens has rear male threads that are just about 28mm in diameter". It just fits around the front edge of the varifocal lens bezel enough to allow me to carefully apply UV cement around its threads. If you want to install a step-up ring on the 6-22mm varifocal so that you have a removable CPL then you will probably want to go with the 30-37mm step-up ring shown above that "should" have rear 28mm diameter threads. Then you would want to go with a 37mm CPL such as THIS one. The larger CPL size will help avoid vignetting since you are creating a deep filter bezel by adding both a CPL as well as a step-up ring.

 

[Lola]

As I said in my previous post, "The 30mm CPL filter I glued to my varifocal lens has rear male threads that are just about 28mm in diameter". It just fits around the front edge of the varifocal lens bezel enough to allow me to carefully apply UV cement around its threads. If you want to install a step-up ring on the 6-22mm varifocal so that you have a removable CPL then you will probably want to go with the 30-37mm step-up ring shown above that "should" have rear 28mm diameter threads. Then you would want to go with a 37mm CPL such as THIS one. The larger CPL size will help avoid vignetting since you are creating a deep filter bezel by adding both a CPL as well as a step-up ring.

I know what you said and I agree, I just had a confusing way of looking at it, so I drew it all out on a piece of paper till I was satisfied and placed an order on AliEx for a twin pack of Thin adapters, 28mm treads at camera end, 30 and 37mm for CPL filters. I also ordered a FOGFA thin/narrow multi coated CPL filter 37mm ($9.50).
It's been a while since I bought any filters and almost had a heart attack looking at prices in the US, so I placed a bet ($9.50) on FOGFA Chinese filter.
Tomorrow I'll measure the other varifocal lenses and see what the housing size on them are, I have a feeling they are probably the same as the 6-22, if they are the same (28mm) this should make it a sinch to fit them up with adapters, if, it worth doing!

So that's it for now till all the things come in and I get it together, thanks for the help and advise .

 

[meanie2]

Wonder if there are any m12 zoom lens between 4-24mm that has less than 1% optical distortion.

 

[Harsh]

Wonder if there are any m12 zoom lens between 4-24mm that has less than 1% optical distortion.

https://www.aliexpress.com/store/pr...Camera-Free-Shipping/1862644_32463510661.html

 

[Dashmellow]

Wonder if there are any m12 zoom lens between 4-24mm that has less than 1% optical distortion.

You are unlikely to find any variable focal length CCTV lens with that level of barrel distortion correction. For one thing CCTV cameras have no need for that level of correction and for another, as a varifocal, the level of optical distortion will change as you go from the widest setting to the telephoto setting, decreasing at the longer lens extensions. As you can see in all of the (varifocal) telephoto images in this thread there is virtually no barrel distortion to be concerned with anyway and if you think about it, there is no compelling reason to use these varifocal lenses on a dash cam for anything other than their telephoto capabilities. Anyone seeking a distortion free wide angle lens on a dash cam would be better served by installing a well corrected fixed focal length lens.