Mobius A2 lens experiences & observations

Dashmellow

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It's been taking longer than I anticipated thanks in part to the harsh winter weather and some other priorities but I've been testing out the new Mobius A2 lens for the last two months using a camera that ships with the A2 module installed which was graciously provided to me by the developer.

Firstly, the new A2 lens is a superb optic that is extremely well corrected. While it is the narrowest FOV lens offered by Mobius it is still a "wide angle" and as such it provides an image that has only the most minimal level of barrel distortion. What little distortion exists is negligible and can essentially be ignored, assuming you even notice it in the first place. There is virtually no lens flare to speak of, even in the most challenging lighting. There is no noticeable color fringing. There is little evidence of field curvature as the lens is quite sharp edge to edge. The lens has good contrast, resolution and resolving power.

All in all the lens is highly capable and the camera generally performs beautifully even in some challenging environments. It's a late generation Mobius 1 v.3, after all.

A2_snowy_highway.jpg

That said, there have been some highly unexpected and unusual problems regarding white balance corrections and color shifts.

During the early "Phase 1" Mobius firmware development there was a widely known issue with AWB stabilization where the camera would suddenly experience significant color shifts when the camera became overwhelmed by a specific RGB color entering the FOV when the amount of that color would reach a threshold level where it would trigger a shift to its opposite RGB color value on a typical RGB color wheel.

So, a large RED vehicle would trigger a CYAN/BLUE color cast or a large BLUE vehicle like a truck would trigger a YELLOW cast and a YELLOW vehicle might trigger a BLUE shift.

This color balance stabilization issue was "cured" during several early Phase one firmware iterations and was fully resolved by the time firmware v.59 was released.

For some odd reason this problem has reappeared in the A2 camera unit that was provided to me and at this point in time it is not clear what the cause is. The developer is evaluating sample clips I have provided and as yet there is no definitive explanation. Stay tuned.

In the meantime, my personal theory is that this may be more related to the sensor in the new A2 module than the lens itself but it is possible that the firmware needs to be tweaked to accommodate the specific characteristics of the new optic. It is unclear if there have been any specific changes to the sensor in the module on the new A2. Maybe there is even a one-off defect?

I do recall when I put a "B" lens into an original "C" module nearly two years ago, the color balance was off (blueish bias). The fix-it was to re-set the camera for the "B" lens using mSetup rather than the "C" setting the module had been set to previously when it had the "C" optic installed. The various specific lens setting options on the Mobius are all tuned to the color characteristics of each lens and Mobius may in turn have to provide an "A2" setting specific to that lens in the mSetup GUI.

Still, this does not explain the abrupt color shifts. A general color cast is one thing but shifting with changes in the scene colors is another matter altogether.

Finally, the other issue I have noticed is that it is not uncommon for certain challenging lighting conditions to cause the camera to produce unusually dark images. This often happens if the camera confronts a situation with a bright sky against an otherwise flatly lit scene. On a few occasions, a dark overcast day seems to make for darker underexposed images. This may be due to the smaller apparent aperture on the A2 lens but I am as yet not privy to what the aperture number is on the A2. (I'm working on that. :))

*************************************************************************

So, I mounted both an original Mobius camera (v.1 pcb with original first generation A lens module) and the new v.3 Mobius A2 lens camera side by side touching each other on a small wooden board. This way both cameras have an exactly synchronized FOV for comparison.

Both cameras are set to the identical default settings at the highest bit rate with WDR-ON.

Here are some recent screen shots to peruse. (shot in my "backyard" :) - looking 100 miles North/Northeast from Southern Vermont USA towards the lower White Mountains in New Hampshire and up the Connecticut River Valley towards Mount Ascutney in Vermont.)

The first thing to notice is that the new A2 lens is slightly longer in focal length and therefore has a slightly narrower FOV with greater magnification.

The second thing you will observe is that the new A2 lens has a distinctly blueish color cast (at least on snow).

The third thing to notice is that the A2 lens has excellent contrast characteristics compared to the original A lens. (which is not bad itself.)

Original Mobius A lens
M1_original-1080.jpg

New Mobius A2 lens
A2-lens_1080.jpg

Here I've demarcated the differences between the FOV coverage of the two lenses.
M1_original-1080_final_small.jpg

A2-lens_1080#2.jpg

*************************************************************
Color Shifting


There is an issue with RED/CYAN,BLUE color shifts which can happen quite often during a days driving around with the A2 lens camera. There was no evidence of any BLUE/YELLOW shifting.

Here are two short YouTube clips shot on different days in the same location. I wish I could have provided longer clips but with my abysmal bandwidth out here in the middle of nowhere it's the best I can do as each one minute or so clip takes 30-40 minutes to upload. :(



For anyone interested, here are the raw clips of the above videos uploaded to MEGA.NZ

https://mega.nz/#!YwdiRLgI!LQnrYU3_GPrDkkhxyM3LIGwhntsQZMrC90Azw2Q8IGM

https://mega.nz/#!U89SVL5L!NrikOWBAW5CpUypjc-64d10R-Rj9Mq9RcksCVkSbDD4

Finally, here are several examples of the A2 camera going dark in settings where it really shouldn't. Usually, there is an exaggerated response to a bright sky, even if it is only a small percentage of the FOV but this is not always the case. In all of these shots the ambient lighting was much brighter than the images captured.

A2_dark_2.jpg

A2_dark.jpg

A2_dark_3.jpg




 
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jokiin

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swap one of the lenses from your other cameras onto this one and set the lens type correctly, if the colour balance/white balance issues go away then it will be something they need to address in the firmware, the physical lens properties may be different enough to cause the problem, if the problem remains you may have a hardware issue and they're chasing a non existent problem, testing this lens on one of your other cameras could verify this or not, if you do this suggest swapping lenses only, not lens and sensor assembly so that the hardware is consistent for the tests
 
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Dashmellow

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swap one of the lenses from your other cameras onto this one and set the lens type correctly, if the colour balance/white balance issues go away then it will be something they need to address in the firmware, the physical lens properties may be different enough to cause the problem, if the problem remains you may have a hardware issue and they're chasing a non existent problem, testing this lens on one of your other cameras could verify this or not, if you do this suggest swapping lenses only, not lens and sensor assembly so that the hardware is consistent for the tests

Yes, I've been intending to do that, however for the time being I do not want to alter the original camera in any way until I do some further testing and until I hear back from the guys at Mobius who are evaluating the footage I sent them just the other day.

I do happen to have an original A lens optic handy that I will put into this camera when I am ready to do so. Switching entire "A" modules here would be out of the question anyway since my "A" modules won't fit in the new case design.
 

jokiin

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swapping the lenses is easily reversed so at least you can test back and forth easily, having a second sample would be beneficial also and could simplify/speed the testing
 
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Dashmellow

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swapping the lenses is easily reversed so at least you can test back and forth easily, having a second sample would be beneficial also and could simplify/speed the testing

I understand but I've decided to not mess with the new camera at all for the time being. I will, please be patient. :) As you might imagine, Mobius is exploring this on their own and there may be other reports about this coming in.

Edit: At the moment I also want to continue testing the original A lens against the new A2 lens.
 
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Dashmellow

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I was looking through some recent Mobius A2 footage and came across this unique example.

Driving along a country road at 3PM during a snow storm the footage has a distinct CYAN cast but then suddenly shifts towards RED.

Typically, a significant percentage of a particular RGB color needs to fill the frame before a camera will shift towards the opposite RGB color to the one that entered the frame.

Here, under exceptionally neutral color and lighting conditions the sudden appearance of the black windshield wiper blade entering the frame causes the color shift.


For much of my journey up that road the footage looked very neutral. There is no obvious explanation as to why the color cast shifted to CYAN/BLUE in the first place before then shifting to RED about a minute after this screen shot.

A2lens_mobius.jpg
 
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Dashmellow

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You live in a very beautiful area. Thanks for keeping us informed on the M2 progress.

Thanks! It is a beautiful place to live.

Just to clarify, this thread is all about the original Mobius (1) camera, sporting the newly introduced A2 lens module. That's mainly why the color shifting is so puzzling.

I do hope to report about the Mobius 2 camera sometime soon though. :)
 

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Wow! That kind of snowfall brings back really old memories. Haven't had the opportunity to witness snow falling for more than a decade.

The backyard looks awesome too. You've good it good bro.. crisp air, right in the middle of nature.. what more could one ask for.

Loved Bob Newhart's TV series Newhart; gave glimpses of Vermont when it aired here back in the 90's.
 
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Dashmellow

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Wow! That kind of snowfall brings back really old memories. Haven't had the opportunity to witness snow falling for more than a decade.

The backyard looks awesome too. You've good it good bro.. crisp air, right in the middle of nature.. what more could one ask for.

Loved Bob Newhart's TV series Newhart; that gave glimpses of Vermont when it aired here back in the 90's.

Well, for anyone who has ever actually lived here the Newhart show was never a very accurate depiction of life in Vermont but the program was often hilarious. There was the sense that most of the writers had never even been to the state and were essentially just indulging all the stereotypes and cliches about rural town folk, but Larry, Darryl and Darryl were always one of the funniest things about the show.

So, yeah, it is indeed a beautiful place but it ain't all paradise. :p In about a month that snow covered road will turn to pure mud when the frost makes it way out of the ground and some years the road becomes completely impassable to all but the most rugged four wheel drive vehicles that have good ground clearance. It's known as mud season and can last many weeks. After that, the black flies and other bugs come out! :D

mud_road.jpg
 
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Harsh

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Well, for anyone who has ever actually lived here the Newhart show was never a very accurate depiction of life in Vermont but the program was often hilarious. There was the sense that most of the writers had never even been to the state and were essentially just indulging all the stereotypes and cliches about rural town folk

Interesting.

Well, for anyone who has ever actually lived here the Newhart show was never a very accurate depiction of life in Vermont but the program was often hilarious. There was the sense that most of the writers had never even been to the state and were essentially just indulging all the stereotypes and cliches about rural town folk, but Larry, Darryl and Darryl were always one of the funniest things about the show.

I'm doubtful that some of the sequences set outside the Stratford were actually shot in Vermont, a days worth of shooting anyway would be enough to cover an entire season as most of the episodes were set inside the inn (which was obviously a set elsewhere).

Didn't matter, it was a setting one was supposed to believe, and back then I definitely did. Was hooked!

Dick's dry humour; Larry, Darryl and Darryl; adorable George; 'Miss. I'm too good for everything' Stephanie; the pitiful boyfriend Michael; 'crazy' Rick, Joanna; officer Shifflett; the Mayor. Epic Larry, Darryl and Darryl's entrances and segments. It just worked!

Revisited it a year or so back on DVD, still laughed just as much going through the seasons.

So, yeah, it is indeed a beautiful place but it ain't all paradise. :p In a about a month that snow covered road will turn to pure mud when the frost makes it way out of the ground and some years the road becomes completely impassable to all but the most rugged four wheel drive vehicles that have good ground clearance. It's known as mud season and can last many weeks. After that, the black flies and other bugs come out! :D

View attachment 29423





Stop complaining! :)
 
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Deleted member 46308

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Interesting.



I'm doubtful that some of the sequences set outside the Stratford were actually shot in Vermont, a days worth of shooting anyway would be enough to cover an entire season as most of the episodes were set inside the inn (which was obviously a set elsewhere).

Didn't matter, it was a setting one was supposed to believe, and back then I definitely did. Was hooked!

Dick's dry humour, Larry, Darryl and Darryl, adorable George, "Miss. I'm too good for everything" Stephanie, the pitiful boyfriend Michael, "crazy" Rick, Joanna, officer Shifflett, the Mayor. Epic Larry, Darryl and Darryl's entrances and segments. It just worked!

Revisited it a year or so back on DVD, still laughed just as much going through the seasons.







Stop complaining! :D
:D
 
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Dashmellow

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I'm doubtful that some of the sequences set outside the Stratford were actually shot in Vermont, a days worth of shooting anyway would be enough to cover an entire season as most of the episodes were set inside the inn (which was obviously a set elsewhere).

I know that many of the settings were in fact filmed in Vermont and the Inn was based on an actual Vermont establishment called the Waybury Inn. The show's lack of authenticity was really more because it was a Hollywood version of life in Vermont that doesn't really exist and for a network TV show like that it really didn't matter for the program's success.

Edit: From Wikipedia - "The Waybury Inn was used as a location for exterior shots on the Bob Newhart television series, Newhart, from 1982 to 1990. Featured as the Stratford Inn, the Waybury Inn was painted white for the show. After the show went off the air in 1990, the inn was repainted green to match the nearby Green Mountains."
 
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Dashmellow

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I've continued to experience very consistent color shifting with the Mobius A2 lens camera along with a tendency for the image to very often (but not always) produce an overall CYAN color bias. The camera also produces underexposed images that are far darker than one would want.

I speculated in another thread a few days ago that what may ultimately be required for the A2 lens to function properly will be the addition of a dedicated setting specific to the A2 lens in the mSetup GUI.

Some recent Mobius discussions made me aware that there seem to be some misconceptions regarding exactly what the specific A - B - C lens type settings do in the mSetup firmware configuration application.

Each lens optic that goes into every dash cam or action camera on the market has its own inherent optical characteristics and each manufacturer needs to tweak the firmware for optimal results with each chosen lens that is used in each product when it comes to such things as white balance, contrast, exposure and default sharpness.

Unlike any other camera on the market, the Mobius offers a choice of lenses that can be fitted to the camera and the unique performance characteristics of each lens needs to be accommodated in the firmware. This is the reason for the different A, B and C type setting options in the Mobius firmware. These settings have nothing to do with the focal lengths of each lens or it's FOV and I think this is where people sometimes get confused. The settings are only for the purpose of white balance optimization and exposure, etc., not the focal length.

Most of you will recall that two weeks ago I posted my results of swapping an original A lens into the A2 lens camera with dramatically different results. This indicated to me that the overall CYAN color bias often seen on the A2 was likely a firmware issue specific to the A2 glass.

Thinking about those lens swapping results prompted me try some further experimentation and the upshot of the testing was rather enlightening. I simply programmed the A2 lens camera using all three lens type settings - A lens - B lens - & C lens to see what might happen and here are the results. Camera is set to highest data rate, 1920 x 1080 30 fps -WDR-ON with all advanced exposure and color settings at their defaults.

Here is the A2 lens Mobius camera set for "Lens A" in mSetup
Notice the general greenish-blue (CYAN) color balance and overly dark, underexposed appearance of the image.

A-lens.jpg

Here is the A2 lens Mobius camera set for "Lens B" in mSetup
Notice here the more natural color balance such as more purely white snow and the somewhat improved, less dark exposure.

B_lens.jpg

Here is the A2 lens Mobius camera set for "Lens C" in mSetup.
The results here are similar to the "B lens" setting but yields further improvement in the exposure of the image rendering it a little brighter. Also notice that the snow in this image
is very subtly less red than in the B setting capture.
C_lens.jpg

The results of this testing suggest using the "C lens" setting with the A2 lens, however further testing under differing lighting conditions (like a sunny day) will be required.

The big question will be to see if changing the lens type designation in mSetup will have any effect on the color shifting problem or whether the changed setting will only effect the general color cast and exposure issues we are seeing when the "A lens" setting is selected for the A2 lens. Stay tuned.
 
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Dashmellow

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So, I was able to do some further testing today with the A2 lens Mobius camera mounted in my vehicle. As an added bonus the sun finally came out! :)

I can report unequivocally that with the camera set to the "C lens" setting in mSetup with the A2 lens, the color balance is now nearly perfect and the color shift issue where the camera would previously shift to an overall CYAN bias when encountering a large RED object such as a building has been eliminated!

A2 camera set to "A lens" setting in mSetup
A2-setting.jpg

A2 camera set to "C lens" setting in mSetup
C_setting_.jpg
 
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Deleted member 46308

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So, I was able to do some further testing today with the A2 lens Mobius camera mounted in my vehicle. As an added bonus the sun finally came out! :)

I can report unequivocally that with the camera set to the "C lens" setting in mSetup with the A2 lens, the color balance is now nearly perfect and the color shift issue where the camera would previously shift to an overall CYAN bias when encountering a large RED object such as a building has been eliminated!

A2 camera set to "A lens" setting in mSetup
View attachment 30120

A2 camera set to "C lens" setting in mSetup
View attachment 30119
Nice job with the comparison. Helpful to see them with such clarity.
 

jokiin

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Thanks! Yes, the difference is quite remarkable really.

do you have two the same so you can do side by side, the difference is quite noticeable but the lighting is also quite different which may be further influencing the results
 
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Dashmellow

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do you have two the same so you can do side by side, the difference is quite noticeable but the lighting is also quite different which may be further influencing the results

I think I can state that the sunny lighting is basically irrelevant. The sun came in and out of the clouds all day as I drove around all afternoon conducting my business making various stops and the color balance was generally quite fine compared with the camera set to the "A lens" setting previously.

The lens type setting in mSetup appears to be the culprit here. All in all it could stand to be tweaked in subtle ways specifically for the A2 lens and I do hope Peter attends to this but the RGB and other lens specific settings in the firmware are what need addressing here.
 
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