Z7 focus issue, depending on temperature

chris-s

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Strange... when my Z7 is hot, it's working fine.
But when I leave it in the car at about 10°C, focus becomes nearer.

Look at both pictures.
First was taken after driving an hour : focus is OK.
Second was taken after leaving the car for 3 hours at 10°C : focus too short, look at windscreen impact.

The upper right arrow show an impact of my broken windscreen.

Does anyone have an idea on how to disassemble the Z7 ?




 
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VIIVIIIXIII

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I also experience this focus issue, particularly at night when the car has been sitting in a cold garage. Please update if you find a solution to fix. :D
 
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chris-s

chris-s

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I've refocused this dashcam.
Will be tested tomorrow.

I've already compared to my another Z7, my refocusing is better than original focus of my other Z7 :confused:

Conclusion : focus from the factory is bad
 

reverend

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Even after refocusing it wouldn't stop drifting - maybe it's a similar lens holder problem to what the G90 had? I never popped mine open but it looked to be a similar size to that which the GT680W used.

Was it glued in place then?

I saw Dome have the G55 I think it is which is the same OV2715 sensor which BlackVue are using - that could be an interesting little dashcam.
 
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Fandy

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Even after refocusing it shouldn't stop drifting - maybe it's a similar lens holder problem to what the G90 had? I never popped mine open but it looked to be a similar size to that which the GT680W used.

Was it glued in place then?

I saw Dome have the G55 I think it is which is the same OV2715 sensor which BlackVue are using - that could be an interesting little dashcam.
G55W (1).jpg G55W (2).jpg G55W (3).jpg G55W (5).jpg G55W (7).jpg G55W (9).jpg
You mean this model? (See pictures). There are two versions.

G55: Novatek 96650 + AR0330
G55W: Blackview LD6188 + OV2710, Support WIFI, and real time control by Smart Phone APP.
 

GearBest

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View attachment 9775 View attachment 9776 View attachment 9777 View attachment 9778 View attachment 9779 View attachment 9780
You mean this model? (See pictures). There are two versions.

G55: Novatek 96650 + AR0330
G55W: Blackview LD6188 + OV2710, Support WIFI, and real time control by Smart Phone APP.
Thanks a lot for @Fandy reply, I think @chris-s means the model Z7, check it here: http://www.gearbest.com/car-dvr/pp_68776.html . Please offer some solutions.

Also, we contact our supplier SZDome directly, they said you could give it a try by adjusting the function of digital zoom.

-Gearbest
 
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chris-s

chris-s

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Should be a joke.... Digital zoom only helped me to adjust the focus directly on the cam after disassembly ;)

Now I have a perfect focus on my Z7 #1
Comparing to my Z7 #2, focus is now better on #1

So I will have to refocus #2 too.
Factory focus is bad.

@GearBest , please tell this to the factory.
 

GearBest

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Should be a joke.... Digital zoom only helped me to adjust the focus directly on the cam after disassembly ;)

Now I have a perfect focus on my Z7 #1
Comparing to my Z7 #2, focus is now better on #1

So I will have to refocus #2 too.
Factory focus is bad.

@GearBest , please tell this to the factory.
I didn't buy this joke neither.
But well-done Chris, I've informed them(SZDome) , and let's see what's going on next. ;)
 
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chris-s

chris-s

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@reverend yes the lens was glued around

I need now to check if temperature will change my focus tuning
 

Fandy

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I didn't buy this joke neither.
But well-done Chris, I've informed them(SZDome) , and let's see what's going on next. ;)
Gearbest, focus issue doesn't matter with digital zoom. I guess like #4 re.. said. Same problem like G90.
If it OEM order, which can be asked to improve specially.
 

niko

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Hope it uses a heat-resistant plastic of lens holder, not the standard cheap one which may be affected by temperature ?!
 

reverend

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This is my first winter with dashcams - does that mean that not only do the cheap ones have a focus issue when it's warm but also when it's freezing?

I guess this is a drawback of the really cheap dashcams - corners have to be cut somewhere to keep costs down.

As for the G55W it was this review I'd read - http://www.gadgetvictims.com/2014/08/dash-cam-g55w-review.html - looks like the specs there are wrong :)
 

petepete

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I think it wise to focus the lens when its cold...

On my g1wh s I found you could set it 1 and 1/2 mm either way before it went out of focus so I set mine 1 and 1/2 mm screwed in figuring things would expand in high heat and it has the equivalent of a 3mm turn to expand and stay in focus ..
 
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chris-s

chris-s

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You were right, after refocusing, it is still drifting with temperature.

Look at next both pictures.
Focus varies with temperature but not equally from center to border of the picture !!! :mad:

First "hot" :
A : focused
B : not focused
C : not focused (10cm from lens)

Second "cold":
A : not focused
B : focused
C : better focused (10cm from lens)


HOT


COLD

 
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chris-s

chris-s

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So, @jokiin, you confirm that the lens lose its shape with temperature variation ?
 

reverend

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Are you turning the screen off as that generates some heat in these?
 

VIIVIIIXIII

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How does one turn off the screen? I would like to know actually. I've only experienced this focus issue a nighttime, day has always been fine.

Are you turning the screen off as that generates some heat in these?
 

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