Trying to decide between 2.8mm and 4mm 2332

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105437

BIT Beta Team
Jun 8, 2015
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I'm trying to determine which ones to buy. The only difference is field of view horizontally, right? I have one location that needs as much vertical FOV as possible, would the 4mm be a better choice there? Does changing the resolution from 3MP to 2MP change the FOV for the camera? Are there any other settings that can help me adjust the FOV given the fact that these are fixed focal length lens?

Thanks and sorry for so many questions!
 
105437 said:
I'm trying to determine which ones to buy. The only difference is field of view horizontally, right? I have one location that needs as much vertical FOV as possible, would the 4mm be a better choice there? Does changing the resolution from 3MP to 2MP change the FOV for the camera? Are there any other settings that can help me adjust the FOV given the fact that these are fixed focal length lens?

Thanks and sorry for so many questions!
Click to expand...

2.8mm is about 90 degrees view (horizontal), 4mm is about 70 (horizontal).

However, you can rotate the camera 90 degrees so that it has a wider vertical FOV than horizontal FOV, now the image is 1536x2048.

Setting to 2MP will make the FOV slightly lower. You would be better getting a different camera than doing that. I've seen <2.8mm lens for sale for 2MP 1080p, I can try to find that again if you need?

Cheers,

Del Boy
 
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In normal orientation, 2 MP is wider horizontlly (and shorter vertically) than 3 MP. So if you want the widest possible image then you use 2MP. If width is of no great concern, then you use 3 MP.

So if you truly require as much vertical FOV as possible, then the best you can do is to get the 2.8mm lens, set the cam to 2MP, and physically rotate the camera 90 degrees. You can set the rotation in the camera firmware also and this will allow it to stream the correct portrait mode view.
 
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Thanks for the replies! I'd like to keep the orientation to horizontal so I'll probably go with 2.8mm @ 2MP for one location and 4mm 3MP at the other. I'm thinking the 4mm to cover the carport and part of the driveway would be better since the objects would be a little larger in the view than 2.8mm. Am I right?
 
Best thing to do is get one of each...and test them in each location...then order more...you can always find a use for it or sell it a bit of a loss...
 
I have a 4mm 2132 covering my carport. It's mounted just above the garage door, about 7 feet off the ground. It does the job just fine.
 
Hi.
I switched one of my cameras from 4mm to 2.8mm to eliminate 2 blind spots.
First pic is 4mm. 2nd pic is 2.8mm
Hope this helps! :D
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It will cause you physical agony to set a 3 MP cam at 2MP because you'll be up at night knowing you lost resolution. What is said above is absolutely true about the FOV, but these are 3 MP cams. You gotta go with the 3 MP :)

My porch I've got on a 2.8 and it gets my front door and a 90 degree to the side so I can see the walk way. My driveway has a 4mm and although it cuts off a good bit, the cars are also always in full frame and the increased pixels to each one is substantial.

If money is no object or time or appearance buy two 6 mm and then you'll be cooking with gas. Have them back to back with their frames parallel to one another :) Somebody else did that here and it looked kind of awesome.
 
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@phoenixone... that comparison makes a big difference for me. It really shows how you get that extra coverage FOV-wise at the expense of size. What I mean by size is the difference of the car in the driveway between both examples.
@LittleBrother... I'm with you! Knowing it's a 3MP camera only running in 2MP mode would drive crazy.

I'm pretty sure I'll get one of each and be good to go!
 
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Great advice guys, this place is awesome!

Another idea for someone else who needs a wide viewing angle, you can put 2x 4mm cameras next to each other to get a 180 degree view with 6MP. Obviously doesn't help you 105437!
 
LittleBrother said:
It will cause you physical agony to set a 3 MP cam at 2MP because you'll be up at night knowing you lost resolution. What is said above is absolutely true about the FOV, but these are 3 MP cams. You gotta go with the 3 MP :)

My porch I've got on a 2.8 and it gets my front door and a 90 degree to the side so I can see the walk way. My driveway has a 4mm and although it cuts off a good bit, the cars are also always in full frame and the increased pixels to each one is substantial.

If money is no object or time or appearance buy two 6 mm and then you'll be cooking with gas. Have them back to back with their frames parallel to one another :) Somebody else did that here and it looked kind of awesome.
Click to expand...
Its important to note the the increase pixel density between 2mp and 3mp is very small..most of the extra resolution is simply used to cover more area...
Also, with hikvision running in 2mp give a wider horizontal FOV, which may be beneficial if you dont need the vertical..
 
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