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

[Dashmellow]

Dashmellow,
Have you checked for aperture vignetting with your CPL?
Hard black circle cutoff is obvious.
Loss of full aperture and light loss in the corners is not as noticeable.

I'm not seeing anything like that, at least that I am aware of. I think the fact that this lens is designed for a 1/2.5" sensor but is installed on a camera with a 1/3" sensor may reduce the chances for something like that anyway as it's using the center most portion of the circle of coverage.

In any event, I'm happy with the results I posted a couple of weeks ago, earlier in this thread but I'm open to any observations you may have. The only obvious thing I notice is increased motion blur due to the ND exposure factor from the CPL.

 

[Lola]

Of course, I don't quite know what you mean when you say, "they are not going to work for me the way I want them to", so I can only speak to my own experience so far. As I've mentioned, I just happened to have this old CPL sitting in my drawer and I got it to fit. The metal bezel of the CPL measures an O.D of 32.28mm with the actual front glass surface of the filter measuring only 25.58mm. On the back threaded side the I.D. of the threads measure just about 28mm and so it just makes it around the outside of the len's front bezel allowing me to glue it in place with UV cement on the outside of the lens housing. This is important because you want to be certain to avoid doing anything with the UV cement that might impede the ability to zoom the lens in and out.

I was surprised to discover that this 30mm CPL only has a glass that measures 25.58mm in diameter and I don't know if other similar CPLs are the same but I have not had any issues with vignetting. I would think that a 37mm CPL with 28mm threads should and could be made to fit this lens just fine but I'm saying that without knowing what it looks like. As for @Harsh's 24mm CPL working without vignetting, I too am skeptical that it will work and I am now wondering what the actual diameter of the 24mm CPL's glass is but we'll have to wait and see what he reports back. One thing about the CPL I installed compared with the style Harsh has in that mine is fully mechanically adjustable even after gluing it to the bezel of the lens which has been a big plus here. One reason I seem to have obtained such good results with this CPL is that I've been able to drive to an optimal location (supermarket parking lot) and hook the camera up to my 7 inch LCD monitor and "tune-in" the CPL to my precise preferences for eliminating windshield reflections from cars in the FOV as opposed to internal windshield reflections from my own vehicle. (although there is some beneficial overlap anyway)

I originally wanted the filter adapter to entirely slip over the cameras lens housing, but that's not going to happen, So I will be installing it like you did, the 28mm lens adapter over the 27mm housing and glue it in place.
How in the world did you get the filter adapter steady enough to glue it down over the tiny 27mm section of lens housing. Mine sits precariously there and the slightest movement makes it fall off. I've thought about taping one side down to stabilize it, and then glue the other side, then take off the tape and glue that side, how did you do it (very tricky)?
Also, I ordered some Visbella UV glue yesterday from Bangood, less then $6.00, AliExpress wanted $16.00 (same amount of glue). I remembered you saying you were ordering some, a while back. Did it work OK for you?
I've been having some problems with AliExpress lately, they seem to think they can treat me like I'm one of their people!

 

[Lola]

@Dashmellow, are you still using your dash mat?

 

[Dashmellow]

I originally wanted the filter adapter to entirely slip over the cameras lens housing, but that's not going to happen, So I will be installing it like you did, the 28mm lens adapter over the 27mm housing and glue it in place.
How in the world did you get the filter adapter steady enough to glue it down over the tiny 27mm section of lens housing. Mine sits precariously there and the slightest movement makes it fall off. I've thought about taping one side down to stabilize it, and then glue the other side, then take off the tape and glue that side, how did you do it (very tricky)?
Also, I ordered some Visbella UV glue yesterday from Bangood, less then $6.00, AliExpress wanted $16.00 (same amount of glue). I remembered you saying you were ordering some, a while back. Did it work OK for you?
I've been having some problems with AliExpress lately, they seem to think they can treat me like I'm one of their people!

Yes, the Visabella UV glue works very well for this purpose. I simply held the lens with my left hand with my thumb and forefinger holding the CPL in the precise place it required for mounting. Then I applied a dab of UV cement carefully where the filter makes contact with the lens housing, and then, still holding everything carefully in place I applied UV light on the cement, using my right hand to hold the light. Once you get one small dab of cured UV cement on there everything will hold together well enough to handle the lens and CPL assembly so that you can continue to apply some cement around the periphery of the CPL threads. I applied about a 3/4 inch strip of cement along two opposite sides of the lens as it is not at all necessary to apply cement all the way around the bezel for adequate adhesion. You don't want to overdo it with the glue. As mentioned previously, the UV cement is fairly easy to remove cleanly with minimal work if you want to return the lens to its previous condition.

 

[Dashmellow]

@Dashmellow, are you still using your dash mat?

Yes, of course. Wouldn't be without it!

 

[TonyM]

@Dashmellow since you're enjoying using this 6-22mm lens so much, are you still using the 2.8-12mm lens too?

 

[meanie2]

In the interest of experimentation, I have tried a Mobius 1 with the 6-22mm lens as a rear-facing camera.

This is close enough to observe other drivers using mobile phones etc. but is it too close?

privacy advocates gonna scream, female drivers gonna go creep! pervert!

 

[TonyM]

privacy advocates gonna scream, female drivers gonna go creep! pervert!

Why? It's not much closer than I can see through my rear view mirror.

 

[Dashmellow]

@Dashmellow since you're enjoying using this 6-22mm lens so much, are you still using the 2.8-12mm lens too?

Yes, but not for dash cam work.

 

[Harsh]

Mounted the 6-22mm. Have it currently set to 6mm.

Night

Comparison with my fixed 5PM 12mm

Haven't attached the CPL yet as my old Android which I use for aiming in the car was acting up. All good now, will attach it tomorrow.

Checked if there's any vignetting throughout the range by pointing it at light coloured wall while holding the CPL as if it was attached, no vignetting whatsoever! Couldn't even see the tips of my fingers while I was holding it in front.

 

[Dashmellow]

Lookin' good @Harsh!

If you don't mind a suggestion based on personal experience, I would recommend spending some time with the new lens without the CPL just to get a feel for how it performs by itself. Then install the CPL later once you know what to expect from this lens. For one thing, this will be especially useful for gauging the CPL's effect on motion blur once you install it.

 

[Harsh]

Lookin' good @Harsh!

If you don't mind a suggestion based on personal experience, I would recommend spending some time with the new lens without the CPL just to get a feel for how it performs by itself. Then install the CPL later once you know what to expect from this lens. For one thing, this will be especially useful for gauging the CPL's effect on motion blur once you install it.

May remove it later but first I want to compare this Varifocal set to the same FOV as the 12mm, with the CPL on and off.

 

[Dashmellow]

Checked if there's any vignetting throughout the range by pointing it at light coloured wall while holding the CPL as if it was attached, no vignetting whatsoever! Couldn't even see the tips of my fingers while I was holding it in front.

As I mentioned a couple of days ago when @Rocketvapor asked about the possibility of aperture vignetting, I think the fact that this lens is designed for a 1/2.5" sensor but is installed on a camera with a 1/3" sensor likely reduces the chances for any kind of vignetting caused by a filter attached to the front lens bezel. I hadn't really considered this previously until Rocketvapor asked but it certainly makes sense. The sensor is only seeing the center-most portion of the lens's circle of coverage so any vignetting would get cropped out of the image.

I guess I'll drag out the illustration I created again to show what I mean. The RED rectangle would be more like what the Mobius is actually seeing. The sensor represented by the WHITE rectangle would come closer to experiencing vignetting but who knows since these rectangles were drawn randomly just for demonstration but you get the idea.

I may have to try out one of my 24mm CPLs now because it would make for a cleaner, more discreet install except that I'm still enjoying the 30mm's ability to be adjusted on the fly by turning the front ring after the filter gets glued to the bezel.

 

[Harsh]

That Newhart background again.

 

[Dashmellow]

That Newhart background again.

Yes, I live in the US state of Newhart! I took the photo on a hiking trip about twenty five miles from my house.

 

[Lola]

As I mentioned a couple of days ago when @Rocketvapor asked about the possibility of aperture vignetting, I think the fact that this lens is designed for a 1/2.5" sensor but is installed on a camera with a 1/3" sensor likely reduces the chances for any kind of vignetting caused by a filter attached to the front lens bezel. I hadn't really considered this previously until Rocketvapor asked but it certainly makes sense. The sensor is only seeing the center-most portion of the lens's circle of coverage so any vignetting would get cropped out of the image.

I guess I'll drag out the illustration I created again to show what I mean. The RED rectangle would be more like what the Mobius is actually seeing. The sensor represented by the WHITE rectangle would come closer to experiencing vignetting but who knows since these rectangles were drawn randomly just for demonstration but you get the idea.

I may have to try out one of my 24mm CPLs now because it would make for a cleaner, more discreet install except that I'm still enjoying the 30mm's ability to be adjusted on the fly by turning the front ring after the filter gets glued to the bezel.

View attachment 40396

Wow, I never even thought about the sensor cropping out, because of it using the lens center portion, my statement about Harsh's filter size might very well be extraneous BS brought on by not thinking this through correctly!

 

[jokiin]

The sensor is only seeing the center-most portion of the lens's circle of coverage so any vignetting would get cropped out of the image.

possibly part of the reason why it works so well for the Mobius also, the center area of the lenses often are a lot better for focus than the edges of the lenses are, maybe not something that would be an issue on a larger size lens like a regular camera uses but the smaller ones do seem prone to this, not a lot of room for error I guess as things get smaller

 

[Harsh]

HID's + white coloured cars in front darkens the image, don't think it's due to the CPL. I remember experiencing similar darkening with the A2.

The wider FOV seems to be the culprit, appears to be more susceptible to such darkening, never experienced such behaviour with 8 and 12mm lenses.

 

[Harsh]

 

[Dashmellow]

HID's + white coloured cars in front darkens the image, don't think it's due to the CPL. I remember experiencing similar darkening with the A2.

The wider FOV seems to be the culprit, appears to be more susceptible to such darkening, never experienced such behaviour with 8 and 12mm lenses.

I've always found white cars to be a bit problematic for the M1 regardless of lens, although each lens provides differing results. Of course, night time performance with the M1 has never been stellar.

Have you made any adjustments to the exposure, contrast and saturation settings? Some trial end error experimentation should improve your results. I think adjustment choices will depend on whether you want to optimize for day or night driving.