3.8mm 12MP 1/2.3" lens for Yi 4k II Action Camera

[ifone2006]

I bought the 3.8mm 16MP 1/2.3" lens from Aliexpress and I replaced it for the Yi 4k II Action Camera. The lens is longer than stock but there is no fisheye as stock. The 3,8mm lens is the best for video, 4k is amazing, very sharp, nice angle for daylight video recordings.

 

[kamkar]

Is it me ? or is that new lens focused a little bit short ?

And don't you feel bad about that it it is, nailing focus on these little lenses can be tricky

 

[ifone2006]

I saw one test clip reports 3.8mm lens for Gopro Hero posted on Vimeo. The picture is so amazing so I decided to replace the lens 3.8mm for Yi 4k Camera. I think the picture of this lens on Yi 4k Camera is better than Gopro as test clip. I don't have the Quadcopter Drone to test this lens. Here is the test clip from Greg Parker with 3.8mm lens Gopro:

 

[mowbs]

I bought the 3.8mm 12MP 1/2.3" lens from Aliexpress and I replaced it for the Yi 4k II Action Camera. The lens is longer than stock but there is no fisheye as stock. The 3,8mm lens is the best for video, 4k is amazing, very sharp, nice angle for daylight video recordings.

I have installed what might be the same lens in my Yi 4k, mine is the 3.87mm git lens. It was a pain to get at as you have to fully dismantle the camera, then rebuild to adjust focus, then dismantle to glue the lens. How did you replace the lens? I have seen the plastic cap removed around the lens but can't see a way to get this off without damaging it. Also where did you settle on hyperfocal distance? I tried 1m but ended up about 4m to get the distant objects in focus, still not sure I'm happy with the focus though.

 

[ifone2006]

I have installed what might be the same lens in my Yi 4k, mine is the 3.87mm git lens. It was a pain to get at as you have to fully dismantle the camera, then rebuild to adjust focus, then dismantle to glue the lens. How did you replace the lens? I have seen the plastic cap removed around the lens but can't see a way to get this off without damaging it. Also where did you settle on hyperfocal distance? I tried 1m but ended up about 4m to get the distant objects in focus, still not sure I'm happy with the focus though.

First, you need tear down the camera , you will get the lens comes with Sony sensor from motherboard.
Second, you use 0.5mm Flat blade Screwdriver to remove the glue around the lens and take off the lens.
Finally, you replace the new lens as you want and install all parts to the camera.
I think the 3.87mm lens from Git2 has color are little bit more washed out compared to the 3.8mm lens. The 3.80mm has the blue filter and 3.87 mm has red filter that attached flat across the bottom.

Here is the star for the focus. You can see in the center there is a small ring. You should focus it from 5-8 feet away. Look at the frame when center point is better focused

I think you would be happy with the result

 

[mavortium]

Thanks for posting all this ifone2006. I have one question for you: I know that the 3.87 Git2 lens protrudes farther than the stock lens but does the 3.8 protrude as much? My concern is that I need to use the underwater housing but don't want the lens mashed up against the glass element of the underwater case.

Thanks!

 

[mowbs]

The 3.87mm git lens only protrudes an extra mm or so more than the standard lens. I have tried it in the housing and does touch the front of the housing but with a small shim on the front of the camera will still fit in the housing just fine due to the foam in the back of the housing. I have gone back to the standard lens for now as I wasn't happy with the focus and colours. Will be doing some further testing of this lens in the Yi 1 before fitting it back in the Yi 2 as it's much easier to install and adjust focus in the Yi 1.

Sent from my LG-D855 using Tapatalk

 

[mavortium]

Thanks mowbs. Hopefully ifone2006 can give the same kind of info on the 3.8 .

 

[mowbs]

Thanks mowbs. Hopefully ifone2006 can give the same kind of info on the 3.8 .

Just to note that this was using an aftermarket housing and not the official Yi housing. It's a bit worrying reading the thread about the original housing seal leaking [emoji30]

 

[mavortium]

I just saw that. I'm worried about that official housing. Which aftermarket housing did you use and do you have a link please?

 

[mowbs]

It's a deyard housing from Amazon, quality looks good but not tried in anger yet.

Sent from my LG-D855 using Tapatalk

 

[ifone2006]

The 3.8mm lens protrudes a little bit than the stock lens as shown the photo. I try to cut 4 small round rubber pieces on the back of the housing, it will gently not push forward the camera. Finally, the 3.8mm lens will fit with the waterproof housing.
I bought the waterproof housing case from Amazon : https://www.amazon.com/gp/B01H85ZOPA

 

[mavortium]

The 3.8mm lens protrudes a little bit than the stock lens as shown the photo. I try to cut 4 small round rubber pieces on the back of the housing, it will gently not push forward the camera. Finally, the 3.8mm lens will fit with the waterproof housing.

Thanks for the info and the photos! I notice on Aliexpress there is a second 3.8mm choice that's marked 16MP. Is there any reason you went with the 12MP instead of the 16MP?

 

[ifone2006]

The 3.8mm lens has 2 dimensions: 17.5mm*21.05mm and 20mm*20.78mm. I just found the first 17.5mm*21.05mm 3.8mm lens has 16MP resolution and the second 20mm*20.78mm 3.8mm lens has 12MP !! The 17.5mm*21.05mm lens is longer than the 20mm*20.78mm lens. The lens that I replaced is the first. It is 16MP not 12MP as the title. Thank you for your information.

 

[mavortium]

So I went ahead and did this. I ended up removing the face plate from the camera (to avoid marking it) and then using a box cutter to pry off the ring around the lens in one motion. This left me with virtually no discernible marks aside from the place where I used the knife and this isn't immediately obvious. I carefully used a vice grip to unglue and remove the lens - no marks!! Screwed in the 3.8mm and focused it for my first purpose which is underwater macro video. It fits in the third party case as you guys mentioned and I have no issues. I have decided to leave the ring off the camera and to not glue the lens in position so that I can refocus it as needed. Since the lens isn't fixed in place, I've subtly marked the lens and the housing with a sharpie so I can tell if it's not focused when I go to use it. This has also been very handy for adjusting the focal point for the macro video I've been making. I'm using the 3.8mm 16MP. For anyone interested, it's a great lens (equal to the original but without the fish eye distortion) but there is distortion and distinct loss of contrast near the edges, but this is to be expected.

Update: I'm definitely seeing a color hue difference from the center to the edges using this lens filming underwater. I will do some out of water filming and update.

 

[quiqq]

Does lenses, who fits in the GoPro Hero 4 also fits in the Yi 4k?

 

[ifone2006]

You are right, the color lens 3.8mm are little bit more washed out from the edge. You can see the filters at the bottom, the 3.80mm has blue filter and stock lens has red filter. I don't know if this would affect anything, for example color. I have ordered the CPL Filter glass for Yi 4k to test the color. It said that using the filter, the colors shall become brighter and clearer and the contrast shall be strengthened.

 

[mavortium]

Does lenses, who fits in the GoPro Hero 4 also fits in the Yi 4k?

Yes, they should since they're both M12 form factor. The lenses don't fit the Sony action cam series though - I've tried with an Sony AS200V and they don't screw in far - I believe it has a different mount.

I have ordered the CPL Filter glass for Yi 4k to test the color. It said that using the filter, the colors shall become brighter and clearer and the contrast shall be strengthened.

Don't get your hopes up on that - this is a lens artifact, and the polarizer is unlikely to fix it, just add more contrast to everything.

 

[mavortium]

So I did some more experimenting with the 3.8mm 16MP. It vignettes pretty significantly, and it distorts and loses contrast starting not far from the center in wide mode (UPDATE: the distortion and contrast loss is mostly due to the macro focal length I was using it at having such a narrow depth of field). This seems to be pushing the red saturation higher in those areas in my underwater video (I haven't verified the red issue above water, but the distortion and vignetting holds true above water). An inverted and feathered color correction mask (global red -4%) in final cut pro X remedies the color shift nearly perfectly. A similar mask for sharpening helps the edges a little.

I'm actually a little disappointed in this lens. I'm tempted by the following lens, having read a lot of positive feedback and seen video from it elsewhere: https://www.peauproductions.com/collections/gopro-hero-4-black-silver-lenses/products/gp39728

UPDATE: I'm really only disappointed by the vignetting now - very good lens.

 

[mavortium]

So the red color is likely not the 3.8mm lens: https://www.peauproductions.com/col...ice-remove-gopro-lens-profile-no-pink-corners
That link is talking about the color profile in a gopro that corrects for the color vignette in a gopro camera with stock fish eye lens. I suspect it's the same issue here with the Yi 4k. In the gopro you can get access to the software on the camera (they call it "rooting" the camera) - that is likely not an option with the Yi... yet!