Mobius Telephoto Dashcam

Dashmellow

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I agree. The 6mm seems optimal for a secondary dash cam telephoto lens. As I mentioned in another recent post I think it's important to capture the oncoming lane of traffic as well as the lane you are traveling in and the 6mm seems to provide a magnified view of both without being so a long a telephoto that it invites vibrations with every little bump in the road,
 
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TonyM

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I agree. The 6mm seems optimal for a secondary dash cam telephoto lens. As I mentioned in another recent post I think it's important to capture the oncoming lane of traffic as well as the lane you are traveling in and the 6mm seems to provide a magnified view of both without being so a long a telephoto that it invites vibrations with every little bump in the road,
What are your thoughts on the narrow depth of field on the F1.2 lens and keeping it in focus, vs a slower lens?
 

Dashmellow

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What are your thoughts on the narrow depth of field on the F1.2 lens and keeping it in focus, vs a slower lens?
That's a good question and one I've been thinking about recently. As interesting and cool as these ƒ/1.2 lenses are, I'm a bit frustrated with them. The short depth of field is an issue, to be sure. And all in all, no matter what I do for focusing I find them not to be anywhere near as sharp as other lenses I own. Sometimes it just feels like the 6mm is hard to focus, and it is, but even when I get it about as good as seems possible it can disappoint a bit. For example, my Varifocal IR 2.8-12mm ƒ/1.4 lens provides dramatically better sharpness and acuity than this 6mm ƒ/1.2 in my results or any I've seen posted by others here. Take a look at just about any of the examples I posted in the Varifocal IR thread, such as HERE and see if you don't agree. That lens has proved quite remarkable. Soon, I hope to finally get around to installing an IR cut filter on that lens and if the results are still as good as I achieved with the manually color corrected IR version I will probably go back to it full time. The telephoto magnification can be set to exactly match the 6mm ƒ/1.2 and the improved depth of field is a real plus. And all in all the ƒ/1.4 varifocal lens is quite fast, even if not quite so fast when racked out to 12mm or as fast as these "Starlight" lenses.
 
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TonyM

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That's a good question and one I've been thinking about recently. As interesting and cool as these ƒ/1.2 lenses are, I'm a bit frustrated with them. The short depth of field is an issue, to be sure. And all in all, no matter what I do for focusing I find them not to be anywhere near as sharp as other lenses I own. Sometimes it just feels like the 6mm is hard to focus, and it is, but even when I get it about as good as seems possible it can disappoint a bit. For example, my Varifocal IR 2.8-12mm ƒ/1.4 lens provides dramatically better sharpness and acuity than this 6mm ƒ/1.2 in my results or any I've seen posted by others here. Take a look at just about any of the examples I posted in the Varifocal IR thread, such as HERE and see if you don't agree. That lens has proved quite remarkable. Soon, I hope to finally get around to installing an IR cut filter on that lens and if the results are still as good as I achieved with the manually color corrected IR version I will probably go back to it full time. The telephoto magnification can be set to exactly match the 6mm ƒ/1.2 and the improved depth of field is a real plus. And all in all the ƒ/1.4 varifocal lens is quite fast, even if not quite so fast when racked out to 12mm or as fast as these "Starlight" lenses.
As with most things in life, you tend to get what you pay for. These fast 'starlight' lenses are cheap, and we should not expect too much from them. @kamkar1 spent $40 on his 12mm lens and i think his results were a lot sharper than anything I have seen from my cheap telephoto lenses.
 

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As with most things in life, you tend to get what you pay for. These fast 'starlight' lenses are cheap, and we should not expect too much from them.
yes it's quite possible that they're not just difficult to focus due to the specification and it may just be a lower quality product, to be fair if you're buying cheap there's only so much that can be delivered at that price point
 

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The 8 mm lens i used before was just a lens meant for regular analogue CCTV use, and it cost less than 40 USD for sure, i think it was around 10 USD.
And while it was not a stellar performing lens i felt good enough about to use it for a long while, and i might still put it to use one day on a rear camera, cuz in the back i feel just as strong about a "zoom" lens as i do in the front.
Actually the only place where i can say for sure i will never put a zoom lens are in the side of the car, since day #1 with the 90 degree Innovv C3 covering my Right side it have bothered me a little its a narrow FOV lens.
Okay i wont put fisheye lenses in the side either, i think for side use the current 150 or so degree lenses are just fine.

I went with the lens from peau productions as i figured they have done most of the legwork for me, so what i got couldn't be that bad,,, and i dont think it are.
 
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Dashmellow

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As with most things in life, you tend to get what you pay for. These fast 'starlight' lenses are cheap, and we should not expect too much from them. @kamkar1 spent $40 on his 12mm lens and i think his results were a lot sharper than anything I have seen from my cheap telephoto lenses.
That varifocal lens is widely available for around $7.00. The optical performance across the board has been outstanding.

These "Starlight" lenses seem to be well made but they were not designed for dash cams or action cams, they are IR lenses intended for static CCTV cameras. It's possible that they would perform better in the types of cameras they were specifically designed for and that feature sensors that match their specs in size.
 
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TonyM

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That varifocal lens is widely available for around $7.00. The optical performance across the board has been outstanding.

These "Starlight" lenses seem to be well made but they were not designed for dash cams or action cams, they are IR lenses intended for static CCTV cameras. It's possible that they would perform better in the types of cameras they were specifically designed for and that feature sensors that match their specs in size.
Yes, that varifocal lens has been very good for you, and at a budget price. I've read about other people having not so good results from it, so maybe you got a good one?
 

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There are some user interfacing with a thing like changing a lens, and maybe some just cant be bothered with going all the way in search of the best possible result.
And so they will settle with kinda okay focus, maybe for a while and then get angry about and ditch the lens totally forgetting that they abandoned the project mid flight, and it is actually a adjustable thing you are working with.
 

Dashmellow

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There are some user interfacing with a thing like changing a lens, and maybe some just cant be bothered with going all the way in search of the best possible result.
And so they will settle with kinda okay focus, maybe for a while and then get angry about and ditch the lens totally forgetting that they abandoned the project mid flight, and it is actually a adjustable thing you are working with.
Yes, I very much agree with you and that is why I am so against the notion of trial and error focusing, where your chances of achieving critical focus are slim at best and where can't make any sort of accurate determination about where to set your hyper-focal distance.

The results I obtained from the varifocal lens are due to its inherent optical performance but also to the care I take to make sure the lens is accurately focused. Sometimes, it's taken several attempts to get it just the way I want it especially when "good enough" just won't cut it. With dash cams and aftermarket lenses the point where you set the optimal focus is of critical importance.

Yes, that varifocal lens has been very good for you, and at a budget price. I've read about other people having not so good results from it, so maybe you got a good one?
I have not read any such commentary about "other people" experiencing poor results from this particular varifocal lens. Can you provide a link to the remarks you are referring to?

BTW, compared to other similar varifocal lenses I've examined, this $7.50 lens is a tiny precison crafted masterpiece made entirely of cast and machined metal parts and with a smooth as silk focusing and zooming mechanism. The lens is amazingly well corrected for optical flaws and is tack sharp. Some other CCTV varifocal lenses I've seen are made of plastic (usually FRP), don't have the optical quality and generally don't feel like they are of the quality of this one. I have no reason to believe I just got lucky and "got a good one".
 

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i had 3 adjustment sessions so far with my 12 mm lens, going back and forth.
I wish it was like photo lenses you just snap on, and auto focus. But that's not it messing with lenses on a dashcam take you right back to the photo class days in the 9 grade in school, and wayyyyy before auto focus.
 

Dashmellow

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i had 3 adjustment sessions so far with my 12 mm lens, going back and forth.
I wish it was like photo lenses you just snap on, and auto focus. But that's not it messing with lenses on a dashcam take you right back to the photo class days in the 9 grade in school, and wayyyyy before auto focus.
Focusing is half the fun!!! :happy:
 
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TonyM

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I have not read any such commentary about "other people" experiencing poor results from this particular varifocal lens. Can you provide a link to the remarks you are referring to?

BTW, compared to other similar varifocal lenses I've examined, this $7.50 lens is a tiny precison crafted masterpiece made entirely of cast and machined metal parts and with a smooth as silk focusing and zooming mechanism. The lens is amazingly well corrected for optical flaws and is tack sharp. Some other CCTV varifocal lenses I've seen are made of plastic (usually FRP), don't have the optical quality and generally don't feel like they are of the quality of this one. I have no reason to believe I just got lucky and "got a good one".
I was thinking of the M1 discussion thread over at RCG where someone had tested a variety of M12 lenses, which I read before I bought any of my recent third party lenses. I remember he immediately discounted a varifocal which kept losing focus. I recall it looked like yours, but tbh it could have been a different one.

Edit: I found the RCG post here https://www.rcgroups.com/forums/showpost.php?p=29765197&postcount=11914
I note that he did not actually test the lens. I should have re-read the RCG post before making my comment earlier.
 
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TonyM

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Check out this Mobius 1 with zoom telephoto lens
(not my photo)
Admittedly, it's not practical for dashcam use!
a7656391-234-13x.jpg
 

Dashmellow

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I was thinking of the M1 discussion thread over at RCG where someone had tested a variety of M12 lenses, which I read before I bought any of my recent third party lenses. I remember he immediately discounted a varifocal which kept losing focus. I recall it looked like yours, but tbh it could have been a different one.

Edit: I found the RCG post here https://www.rcgroups.com/forums/showpost.php?p=29765197&postcount=11914
I note that he did not actually test the lens. I should have re-read the RCG post before making my comment earlier.
I remember that post from Janke on RCGroups from long ago. It got a lot of attention at the time. It's interesting to re-read it again all this time later with a more critical eye though, especially now that I've had a lot more hands-on experience with aftermarket M12 lenses mounted on a Mobius. At this point my opinion is that Janke doesn't really know what he's doing or quite what he's even talking about. In all fairness, I think he did a good job comparing FOV, distortion and different focal lengths which I think was the basic goal but the rest of his approach does raise more questions than he answers.

So.....
  • He admits to editing all the images to make them match up better for exposure and contrast. You CAN'T DO THAT and still have a valid objective lens comparison! And besides that he completely ignores that they have different aperture sizes.
  • He admits that the lenses are not quite in proper focus. You CAN'T DO THAT and still have what he calls "a good indication of the general quality"! There would be no way to judge the resolving power or acuity of the lenses.
  • He says he didn't "shim" the lenses suggesting that somehow they are not properly in focus on one side or the other because of this but that makes no sense! If the lenses are of good quality and the lens holder of the module (barrel) is in proper alignment, then there should be no need to shim individual lenses. His logic is mystifying.
  • He changes all the images to B&W which makes various aspects of comparison impossible, even if some have normal color and some are IR. He should have left the lenses to do what they do normally. (He also doesn't mention whether the change to B&W is done in camera or as part of his editing.)
  • I won't even go into all the wacky stuff he recommends regarding the IR filter mounting such as, "Since the 9.5 mm filter will fit into the lens mount, there is no need to open up the sensor, "just screw in the lens into its thread."! (OMG :eek:) Maybe he figures the IR-cut filter will just get jammed up against the sensor?:jawdrop:
And I've saved what he had to say about the Varifocal lens for last. "I didn't bother with the.....varifocal .......(because) ......"it doesn't stay in focus when zoomed". UNBELIEVABLE!! :arghh::banghead::banghead::banghead:
If you don't tighten the set screw properly OF COURSE the lens won't stay in focus! JEEZ! And zooming won't stay where you want it either unless you tighten the damned set screw enough! What is he thinking?


Well, so much for "other people having not so good results from it" When you made that comment @TonyM I had a strong hunch it wasn't going to hold up. But not to worry, I know what it's like to "mis-remember" somebody's post I'm referring to from some foggy recollection.

Anyway, I had every intention of seeing about installing an IR-cut filter on the varifocal lens but another day got away from me. I awoke to a veritable ice palace this morning and needed to wear crampons just to get from my house out to my truck at which point I then spent a good part of the morning shoveling sand so I could just get out of my driveway. Four wheel drive feels like magic sometimes but it does have its limits. Hopefully soon I can post some varifocal IR-cut filter results. I'm expecting that this lens will continue to perform as well with an IR filter installed as is did before but we'll have to see yet I still say that one way or another the optical and mechanical quality of this lens for $7.50 is a veritable bargain.
 
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TonyM

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My Mobius testing was nearly put on hold today, after my 6 year old son helped himself to 4 of my cameras, including a beta test unit :eek:. He is developing a habit of taking anything he likes :(

I've got them back now. It seems they're safer mounted in the car than on the desk at home.
 

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My Mobius testing was nearly put on hold today, after my 6 year old son helped himself to 4 of my cameras, including a beta test unit :eek:. He is developing a habit of taking anything he likes :(

I've got them back now. It seems they're safer mounted in the car than on the desk at home.
Hey, obviously he has an affinity for cameras and he's taking after his dad! Did he swap any of the lenses before you got the cameras back? :)
 
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TonyM

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Hey, obviously he has an affinity for cameras and he's taking after his dad! Did he swap any of the lenses before you got the cameras back? :)
No, he didn't find my box of spare lenses!

I did some case modifications and lens swaps this afternoon.

6mm F1.2 vs 6mm F2.8 coming soon....
 

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