Dedicated 3rd Party Lens Discussion (Examples Updated)

pyrate · Mar 17, 2016

franknitty69 said:
i'll answer your hack question in the other thread. but here are some examples:

5.4mm

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I assume this is a Chinese model?

franknitty69 · Mar 17, 2016

3.8mm

3.8mm 2.7k 60

franknitty69 · Mar 17, 2016

pyrate said:
I assume this is a Chinese model?

i purchased the 5.4 from surveillzone

pyrate · Mar 17, 2016

well best laid plans,
looks like I can only do 5 media links in that post
bummer

pete · Mar 17, 2016

Thierry said:
Plug and Play, awesome. So it's a different model, but same optics I assume?
Order in 100 units minimum though.

they sell even just one (ask for test sample), I paid $49 for the lens, just don't know which version they sent me, my order was few weeks ago, still waiting for it.

pyrate · Mar 17, 2016

franknitty69 said:
i purchased the 5.4 from surveillzone

that 3.8 looks as good as any I have seen
Are they going to make it available in smaller lots?
I may snag one for the 3 Black

pyrate · Mar 17, 2016

I need JR to pick up from the first post and link the next 4 examples
I can do 5 more after that since I have the third post, should have reserved some

Thierry · Mar 17, 2016

franknitty69 said:
this is the same lens as before. same lens structure/grouping. the physical characteristics have been modified to support focus in a gopro without altering the gopro.

This is awesome news @franknitty69
Do you know who is selling these by the unit? I don't need 100

J R · Mar 17, 2016

pyrate said:
I need JR to pick up from the first post and link the next 4 examples
I can do 5 more after that since I have the third post, should have reserved some

Pyrate,

What do you want me to do?

Jerry

pyrate · Mar 17, 2016

Just gather up the next 5 videos that have been linked here and post them
trying to get one of each lens at the front of the page, its no bigger if you don't

J R · Mar 17, 2016

pyrate said:
Just gather up the next 5 videos that have been linked here and post them
trying to get one of each lens at the front of the page, its no bigger if you don't

Pyrate,

Call me dumb but I'm not sure which ones you want up there. If you give me post #'s I'll see if I can't get them in my post #2.

Jerry

pete · Mar 18, 2016

franknitty69 said:
New 3.8mm with shorter bfl and flange. plug and play, no cutting.

View attachment 2830

1/2.3" 3.8mm 16Megapixel S Mount Low-Distortion Board Lens for Drone Gopro 4

received my 3.80mm, it's the new type, went straight in, no hassles.
how do you focus this ? I have it connected to my TV and can focus easily on objects in the room, but watching Ramcage youtube video they suggest to focus on an object 150ft away, I really don't want to drag my TV outdoor

and do you secure the new lens in the thread with glue or leave it free ? I like the idea of not using the glue, I could then swap lenses quite easily all the time. apart from the stock lens I also have another after market lens : 2.7mm low-distortion 12MP, in case I really need wide view with minimal distortion.

franknitty69 · Mar 18, 2016

pete said:
received my 3.80mm, it's the new type, went straight in, no hassles.
how do you focus this ? I have it connected to my TV and can focus easily on objects in the room, but watching Ramcage youtube video they suggest to focus on an object 150ft away, I really don't want to drag my TV outdoor

and do you secure the new lens in the thread with glue or leave it free ? I like the idea of not using the glue, I could then swap lenses quite easily all the time. apart from the stock lens I also have another after market lens : 2.7mm low-distortion 12MP, in case I really need wide view with minimal distortion.

its best to use a large flat screen connected via hdmi. i think setting the gopro to 1080 narrow is the easiest. as far as the distance, you can either point at a random object at some distance, a car 25ft away for example, and adjust until the object has the best focus (find the best focus, nudge cw, nudge ccw, use the best one between the 3 positions).

me personally, i like to use the hyperfocal method which calculates the optimal focus distance based on sensor size and focal length. once the optimal distance is calculated you would place a focus chart at that distance and adjust til the chart is in focus. the idea with hyperfocal distance is that at certain distance and beyond, focus will be at infinity.

and to secure the lens, just use a little bit of teflon tape (plumbers tape).

pyrate · Mar 18, 2016

Man, that Frankitty dude will make your brain work

In order to calculate hyperfocal distance, you need to know three things:

Focal length – This will depend on what lens you're using.
Circle of confusion value – Commonly 0.03 and 0.02; depends on sensor type.
F-stop – f/11 and f/13 are often regarded as optimal for landscape photography.

So not sure what the circle of confusion setting is for a gopro camera is, but here is an online calculator
Hyperfocal Distance Table Calculator -- PanoHelp.com

franknitty69 · Mar 18, 2016

i didn't want to go down the rabbit hole but the circle of confusion for the Hero4 is 0.005mm.

pyrate · Mar 18, 2016

Oh heck what are pyrates for, I will go down their
well now using the calculator we can figure it out

Jubalr · Mar 18, 2016

I bought 4 of the 3.8 that Frank mentioned above and thought I would share the savings on shipping. So 3 available at $69 shipped Priority Mail in the US. I had them shipped to me DHL and I should have them the end of next week. (3/25)

Jubalr · Mar 18, 2016

Jubalr said:
I bought 4 of the 3.8 that Frank mentioned above and thought I would share the savings on shipping. So 3 available at $69 shipped Priority Mail in the US. I had them shipped to me DHL and I should have them the end of next week. (3/25)

OK. 1 just spoken for. 2 available now. PM to secure a lens.

pete · Mar 18, 2016

franknitty69 said:
me personally, i like to use the hyperfocal method which calculates the optimal focus distance based on sensor size and focal length. once the optimal distance is calculated you would place a focus chart at that distance and adjust til the chart is in focus. the idea with hyperfocal distance is that at certain distance and beyond, focus will be at infinity.

pyrate said:
In order to calculate hyperfocal distance, you need to know three things:

Focal length – This will depend on what lens you're using.

Circle of confusion value – Commonly 0.03 and 0.02; depends on sensor type.

F-stop – f/11 and f/13 are often regarded as optimal for landscape photography.

thanks for the home work guys

so according to my calculations, I should place my target object 33.5m (110ft) away.

I used 21.66mm as my focal length as I'm assuming this needs to be 35mm equivalent, I used this calculator for the equiv. focal length : 35mm Equivalent Focal Length Calculator

and in the hyperfocal distance calculator I used f/2.8 since this is the fixed aperture on the 3.80mm lens.

-------------------------------------------------------
Lens Multiplication Factor for 1/2.3" sensor is 5.7

3.80 * 5.7 = 21.66

Hyperfocal distance :

h = (21.66 * 21.66) / (2.8 * 0.005) + 21.66 = 33532.77mm = 33.5m = 110ft
(don't even understand why bother to add the additional 21.66mm at the end of the formula, makes only 0.06% of a difference)

pete · Mar 19, 2016

very happy with the 3.80mm on my GoPro H3+
I think I nailed that focusing 100%
if I use burst photo function to take 30 pictures and then merge them, I can't get anywhere near this detail even with my Sony RX100M3 (1" sensor).

and as for the 3.97mm (which I also received this week), that's not even a contest.

I can't even notice any distortion on 3.80mm whereas the 3.97mm is extremely soft overall and very distorted in corners.

I'll upload some photos and videos for comparison later...

(this is actually exported from Picasa only at 85% quality, the original on my Mac is 9Mb)
(edit: reduced the quality even further, now it's down to 1.6Mb, previous version was loading forever)