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Focus lock and fisheye
185 5 2019-12-6
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TriProt
lvl.3
Flight distance : 1866093 ft
United States
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Prior to purchasing the OA I asked the seller if there was a way to lock the focus and they said yes. I purchased and just got it in the mail today and don't see that ability. Hopefully I am missing something and wasn't lied to to get the sale. I mentioned I want to use the camera to capture video footage of my 3D Printer in action. The camera will be about 15" above the build plate. I want to be able to lock the focus so when the gantry goes by the camera wont try to adjust focus as the gantry goes by, which happens every few seconds.One image shows the setup using a RunCam2 (meant for FPV drones) and the other shows the view of the build plate, but the RunCam2 creates too much fisheye. Did I make the wrong purchase buying the OA?

Setup

Setup

Build Plate

Build Plate
2019-12-6
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CemAygun
First Officer
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I would say no, it is not a wrong purchase. Osmo Action has a "fixed focus", which means it never needs to focus at a certain distance or on an object. Everything further than it's minimum focus distance (I believe about 15cm / 6") would always be in focus. So you never have to worry about things passing in front of the lens affecting focus as the Action cannot adjust it's focus anyways.

Not that it matters, but you you have been sort of lied to when you were told that you can lock focus, as there is nothing to lock

Hope this helps.
2019-12-6
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peiter
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you can use dewarp on videos in post production, most higher end software have this feature.
All action cameras,,,,, and dash cameras too have a fixed focus lens, some times you can be unlucky and have one that's not focused right, or in the case of dashcams the focus can shift due to the camera sitting in your car on a sunny day in very high temperatures.
Heat related focus shift can some times shift back when the camera cool down, or it can remain out of focus, in which case you have to refocus the lens by turning it ( these are often locked in place with a bit of glue )

If your footage get a little blurred when the gantry move, that is probably motion blur and should only be there on the thing that move, the only way to combat that is to have more light so the camera use a faster exposure.

You can replace the lens on your runcam too, these are M12 fine thread lenses, and there are a lot of sellers that sell these, from nasty 180 degree fish eye lenses to 35 mm or so.
Just make sure your lens will have a IR cut filter, most you find will not have this as they are ment for CCTV use and so must be able to see IR light at night.
Also be sure you get a quality megapixel one, and not a one ment for old analog low resolution cameras.



Plenty of videos on youtube on how to refocus a lens on a action or dash camera, and the same go for lens replacement.

2019-12-6
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TriProt
lvl.3
Flight distance : 1866093 ft
United States
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Thanks for the input CemAygun and peiter, much appreciated. The printer is down for maintenance right now so I wont be able to test until next week. I am excited to see the results and try out the slow motion and timelapse features of the OA. Originally I was looking at the Osmo Pocket, but saw the spec for minimum focus length is at 1.5m which I dont have that much distance available. Thanks for the tip about heat. This powder based system does not have a heated build chamber, but does go thru a drying time (1.5 hours at up to 90 degrees F) after the print is completed. I will make sure to pull the camera out before the drying process starts.
edit: do you think this will work on the RunCam2? https://www.banggood.com/Foxeer-MTV-M12-35mm-Megapixel-CCTV-Camera-Lens-for-LEGEND-2-p-1208563.html?rmmds=buy&cur_warehouse=CN

2019-12-7
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peiter
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It will screw into the foxxer camera just fine, but unsure if it can do that without modification, and it is not something you can use close up.

I have this old video that demo a regular dashcam, with a 140 deg or so horizontal FOV VS another dashcam fitted with a 12 mm lens.
As you can see the 12 mm camera let me see things clearly further away but at a massive trade off in FOV.
The 2 clips are just the middle 50 % of each video, nothing have been trimmed off on the side.



So that 35 mm lens on a dashcam you can get a plate capture wayyyyy out ahead ,it is a Angle of view (AOV): 8 degree lens ( and those 8 degree are maybe diagonal which some like to use so even less horizontal )
So unless you put your camera up under the sealing 16 feet or so over the printer i don't think you can use it for that.
With the camera that close to the action i assume you need something around 90 degrees FOV / AOV, maybe a little less than that.
Something like this https://www.peauproductions.com/ ... es/products/gp39728
Though you can probably find a similar lens cheaper, there are a few stores that sell lenses like that on aliexpress.
https://treeyelens.ar.aliexpress ... cShopHead_2762671.0
https://fulekan.ar.aliexpress.co ... 05.1.5ea7570fbEvk9w

Both as i recall will fit a IR cut filter for you if you fancy one without, that save you the trouble of doing it yourself and buy the filter and UV curing glue to put it in place.

Just don't ask why my links now come up in,,,,, i have no idea some form of raghead language.
2019-12-7
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CemAygun
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TriProt Posted at 12-7 07:45
Thanks for the input CemAygun and peiter, much appreciated. The printer is down for maintenance right now so I wont be able to test until next week. I am excited to see the results and try out the slow motion and timelapse features of the OA. Originally I was looking at the Osmo Pocket, but saw the spec for minimum focus length is at 1.5m which I dont have that much distance available. Thanks for the tip about heat. This powder based system does not have a heated build chamber, but does go thru a drying time (1.5 hours at up to 90 degrees F) after the print is completed. I will make sure to pull the camera out before the drying process starts.
edit: do you think this will work on the RunCam2? https://www.banggood.com/Foxeer-MTV-M12-35mm-Megapixel-CCTV-Camera-Lens-for-LEGEND-2-p-1208563.html?rmmds=buy&cur_warehouse=CN

You're welcome! Well, both Action and Pocket have their respective advantages over each other. I believe Action is a good choice in your case as it is robust and thanks to it's shape/size you can squeeze it in interesting places for some creative 3d printing shots. It also has much better control over time lapse. But I have to say, slow motion is a "novelty" mode at best due to extreme aliasing.

PS: The minimum focus distance for the pocket is about 20cm, but you would have had to be careful about locking focus with that, as it has variable focus.
2019-12-7
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