Old Mobius 1 A2 lens out of focus even at most extreme rotation

[TonyM]

As @Dashmellow said, the C2 has a wider FOV than your A2 lens. It's worth noting that the C2 is mounted in a long barrel lens holder with the grub screw, so you can adjust and fix focus if needed.

 

[dchang0]

As @Dashmellow said, the C2 has a wider FOV than your A2 lens. It's worth noting that the C2 is mounted in a long barrel lens holder with the grub screw, so you can adjust and fix focus if needed.

Thanks. I do prefer the A2's FoV, but if I buy another lens module, it would be because I found out I have a broken sensor. And in that case, I could transplant my original A2 lens (probably good if the sensor was the part that went bad) to the new lens module, if I find that I prefer the A2 lens over the C2.

So it'd be okay to buy a C2 lens module--I'd end up with one working sensor, two working long lens housings, and three lenses (A2, C2, varifocal). Not too wasteful an end state.

Thanks for pointing out that the C2 has a long lens holder and not a short one.

 

[Dashmellow]

I don't want to repeat what I went through with my A2 where it arrived okay but a couple of years later went out of focus.

BTW, I don't know what happened to your A2 lens that it would go out of focus like it did but I suspect that two of the lens elements "may" have become separated inside the lens barrel. This is very rare but it happens if the lens cement between two glass elements fails. Mobius has a reputation for sourcing very high quality lenses so the chances of this happening again with a new A2 lens are extremely remote. There certainly could be some other explanation like a warped sensor plate. That was a known problem with the older C lens modules but the effect was more subtle than you describe and was only on one side or the other of the image. Anyway, buying the C2 module seems like a good plan. You could even use the new module to test the A2 lens to find out if it indeed has a problem, assuming it will screw in far enough to achieve focus.

 

[dchang0]

Good news: the sensor seems fine. I used a 2.8-12mm varifocal lens and was able to dial it in so that the image is crisp.

So, all I really need to do is replace the A2 lens itself for $8. That's the best possible outcome.

Thanks to everyone for their help!

I probably won't keep the 2.8-12mm varifocal. It's really nice, but it makes the whole camera very front-heavy. I don't know if my windshield mount is going to be able to support this weight. Also, the focus adjustment is very hard to dial in--even the tiniest movement results in a drastic change in the focus.

I'll probably get one of the starlight lenses mentioned elsewhere in this forum.

 

[Dashmellow]

Good news: the sensor seems fine. I used a 2.8-12mm varifocal lens and was able to dial it in so that the image is crisp.

So, all I really need to do is replace the A2 lens itself for $8. That's the best possible outcome.

Thanks to everyone for their help!

I probably won't keep the 2.8-12mm varifocal. It's really nice, but it makes the whole camera very front-heavy. I don't know if my windshield mount is going to be able to support this weight. Also, the focus adjustment is very hard to dial in--even the tiniest movement results in a drastic change in the focus.

I'll probably get one of the starlight lenses mentioned elsewhere in this forum.

Glad to hear the sensor is good! That makes thing simple, easy and inexpensive.

Don't give up on that varifocal just yet! They can be fussy to focus but it is doable. We can help. It can be securely mounted as well without much effort or expense.

Since you are new here, if you are not already familiar with the following two threads you should definitely check them out. Some of us would not be without a telephoto (varifocal) Mobius in addition to our regular dash cams.

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

Mobius Varifocal Zoom IR​

 

[dchang0]

Glad to hear the sensor is good! That makes thing simple, easy and inexpensive.

Don't give up on that varifocal just yet! They can be fussy to focus but it is doable. We can help. It can be securely mounted as well without much effort or expense.

Since you are new here, if you are not already familiar with the following two threads you should definitely check them out. Some of us would not be without a telephoto (varifocal) Mobius in addition to our regular dash cams.

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

Mobius Varifocal Zoom IR​

Thanks--I'll definitely check them out. The varifocal is definitely powerful--it may be worth building a sturdy windshield mount to keep it.

 

[Dashmellow]

Thanks--I'll definitely check them out. The varifocal is definitely powerful--it may be worth building a sturdy windshield mount to keep it.

I have a lot of experience building custom mounts and you could go that route but you really don't need to go to that much trouble. For a few dollars you can buy the generic factory mount on the far left in the photo below and it is all you need. In fact, it is the one I am currently using for my varifocal equipped Mobius as it is very sturdy and reliable, plus in most situations it can be mounted to provide plenty of room for the longer varifocal lens. I used this mount as the basis for the DIY mounts you see here but these mounts are better for other purposes. At the time I built them I purchased several on eBay for less than two bucks each. Some places charge gouging prices for these mounts these days but they are widely available for a lot less. If you want one I think I can help you find one at a decent price.

Another excellent option for a Mobius with a varifocal lens is the iSaddle mini dash cam mount for $7.00 on Amazon. It is very sturdy and solid and offers a lot of adjustment flexibility. (see photo below)

'

Here is the 2.8-12mm varifocal mounted with one of my custom made mounts. The original factory is actually better for the Mobius/varifocal set-up.



iSaddle mini dash cam mount

 

[dchang0]

I have a lot of experience building custom mounts and you could go that route but you really don't need to go to that much trouble. For a few dollars you can buy the generic factory mount on the far left in the photo below and it is all you need. In fact, it is the one I am currently using for my varifocal equipped Mobius as it is very sturdy and reliable, plus in most situations it can be mounted to provide plenty of room for the longer varifocal lens. I used this mount as the basis for the DIY mounts you see here but these mounts are better for other purposes. At the time I built them I purchased several on eBay for less than two bucks each. Some places charge gouging prices for these mounts these days but they are widely available for a lot less. If you want one I think I can help you find one at a decent price.

Another excellent option for a Mobius with a varifocal lens is the iSaddle mini dash cam mount for $7.00 on Amazon. It is very sturdy and solid and offers a lot of adjustment flexibility. (see photo below)

Sweet! The iSaddle looks good to me and is very reasonably-priced! Thanks very much for your help!

 

[dchang0]

Today's rains serendipitously revealed that the failing A2 lens basically went into macro focus. Check out how sharp the raindrops on the windshield are while the car only about 20ft-30ft away is very blurry. This is with the A2 lens screwed all the way into the lens holder. This is a screenshot at 720p 60fps.

The good news is that this absolutely proves the sensor is okay. It also sets a high bar for me to try to achieve with the very sensitive focus ring on the varifocal lens.

 

[kamkar]

to having a "2 zoom camera, i would not be without mine, even if i extremely rare have gone to it for footage.
Actually i will still prefer the zoom camera over the side cameras if i absolutely had to choose between the 2, sida cameras i also only go to extremely rare, but they are side camera, and pretty much all action i have ever captured have been on the front camera.

 

[TonyM]

Getting correct focus with the varifocal lenses can be challenging, but the same can be said for any fast prime lens too. One benefit of the varifocal lenses is that you can refocus them with the camera case closed.

Take your time and you should get a good result.

 

[dchang0]

Getting correct focus with the varifocal lenses can be challenging, but the same can be said for any fast prime lens too. One benefit of the varifocal lenses is that you can refocus them with the camera case closed.

Take your time and you should get a good result.

Thanks. Are you varifocal users finding that the focus comes loose over time? In one of the other threads I read here about the varifocal, someone mentioned having to re-focus them after a few months of driving...
It seems that using a screwdriver to tighten down the thumbscrews is a must; they didn't mention whether some glue would be needed.

 

[TonyM]

No, I don't have a problem with focus over time. I only tighten the screws by hand. It is worth checking though after a period of time, and you can tighten with a screwdriver if necessary.

 

[dchang0]

No, I don't have a problem with focus over time. I only tighten the screws by hand. It is worth checking though after a period of time, and you can tighten with a screwdriver if necessary.

Nice! Thanks--I'll start with just tightening by hand then.

 

[Dashmellow]

Thanks. Are you varifocal users finding that the focus comes loose over time? In one of the other threads I read here about the varifocal, someone mentioned having to re-focus them after a few months of driving...
It seems that using a screwdriver to tighten down the thumbscrews is a must; they didn't mention whether some glue would be needed.

I've had my varifocal go out of focus maybe three times (over four years). As a result I find it best to use a screwdriver to tighten the thumb screws and that eliminates any chance of focus problems. For me the problem may be exacerbated by living on a bumpy dirt mountain road.

The best way I've found to focus the lens is to use a long cable attached to my computer and open the image in web cam mode on the screen. Then I focus very carefully on a tree about 90 feet out from my office window as I look over at my computer screen. Everything from near to far ends up in sharp focus. I find that tightening the thumbscrew just enough to create some resistance when I focus allows me to zero on the precise focus point without overshooting the mark.

 

[dchang0]

I've had my varifocal go our of focus maybe three times (over four years). As a result I find it best to use a screwdriver to tighten the thumb screws and that eliminates any chance of focus problems. For me the problem may be exacerbated by living on a bumpy dirt mountain road.

The best way I've found to focus the lens is to use a long cable attached to my computer and open the image in web cam mode on the screen. Then I focus very carefully on a tree about 90 feet out from my office window as I look over a my computer screen. Everything from near to far ends up in sharp focus. I find that tightening the thumbscrew just enough to create some resistance when I focus allows me to zero on the precise focus point without overshooting the mark.

Thanks for the excellent advice on focusing it to 90 feet and putting slight tension on the thumbscrew to help focus. I'd been focusing at a mere 30 feet but haven't been happy with the results so far. That is likely me overshooting the mark repeatedly...

The roads around here are kinda bumpy, from unfixed potholes, but nothing like a dirt mountain road. Hopefully mine will last longer between re-focuses.