FPV lenses

[Max-U52]

Hey Guys, I need a little help figgerin' this stuff out. I ordered a camera that I can change lenses on, so I'm trying to figger out what the difference between lenses is. Take a look at these

https://www.banggood.com/3_6mm-2_8mm-2_ ... mds=search

So what's the difference between 3.8, 2.8, etc? Does anyone understand this stuff well enough to explain it to an old Gomer like me?

[Dubar]

I had to do a search cause I don't know either:

https://oscarliang.com/best-fpv-camera-quadcopter/

[silversurfer1947]

My experience is with DSLR cameras, but I reckon the basic principles still apply. The 3.6mm will effectively be a telephoto lens with a fairly narrow field of view. At the other end, the 2.1mm will be a wide angle lens and as the name suggests, will have a much wider field of view. However, you are liable to experience considerable barrel distortion, particularly in the peripheral areas. There is a YouTube video which shows the difference between 2.8,2.5 and 2.1mm lenses.

phpBB [video]

[Max-U52]

Richard, that was perfect. Thank you very much. That video showed me everything I need to know. It's interesting that the video was made by force RC because they used to be Diamond Hobby and that's where Erik at Imex sent me when I needed help with my radio. It looks like the smaller the number The Wider the field of view so I'll be going for the longer length. Thanks again.

[43rdRecceReg]

Put crudely..It's all to do do with aperture size. Wide angle lenses have a short focal length, but include more of the landscape in the picture (although the wider the lens, the more distorted the images are apt to be at the extremities). Telephoto lenses
often have shallower depth of Field (clarity over area surveyed) on specific subjects, but are frequently used for long-distance close ups, with a tastefully blurred background. I imagine for a tank, you'd need a wide angle lens to take the surroundings in; a telephoto would pick up a reduced field of activity.
Here's an interesting article of depth-of-field and Aperture sizes.
http://www.techradar.com/how-to/photogr ... ss-1320959

[Max-U52]

Thanks, Highlander, that was informative. Remember that I'm not really thinking of this for driving, but for sighting the gun. Kinda like a scope on a rifle. What I really want to lose is the fish-eye effect from a wide angle lens. From your article I know I want extensive depth of field, but narrow focus. The lenses are very cheap, like under 3 bucks each, so I'll get a couple and experiment. I ordered a better camera (and you can't believe how tickled I am that a "better" camera was still only 15 bucks) and that will be here Saturday. This will be the new eyeball for Herbert. I still can't figger out how to make it look like it belongs on the front of a tank, though.



The hardest part is gonna be lining up the laser pointer so it matches where the paintball lands, but I got some ideas. More to come ...

[Dubar]

Max,

What camera are you getting and what are you using to see the picture?

[silversurfer1947]

For the price I guess it will be a single lens of moulded plastic. There will always be distortion of the periphery. An inevitable consequence, but with optics, you tend to get what you pay for. It should prove adequate for your purposes though.

[Max-U52]

I'm using the little pilot screen and the camera pictured above and seen here



The crazepony which comes with the 3.6mm lens so we'll see how it performs. I'll probably change the j plug for a jst, since the TX has jst already soldered in. It's supposed to be here Saturday, so if the new gun shows up tomorrow we're in business.