The Importance of Focal Length over MP in camera selection

[David L]

And a recognition that DORI numbers are ideal, best case scenario with ideal light and no movement.

Most here will cut that number in half during the day, and cut that half number in at least half at night.

Need a tablet next to our cameras that would flash a beautiful woman, when tripped, so the intruders would stare at the camera so we would get a good clear focused pic LOL

Which brings me to Height of CAMs. Best placement would be eye level, too high and all you get is the top of their heads...one reason Doorbell CAMs get good shots, everyone does look directly at the Doorbell when they push the button and you get to see if they have anything in their nose too

 

[JPmedia]

For reference, here are my front door 5442s. Height is about 9.5'. One is above the front door, the other is about 11' away. They are both 3.6mm. It depends on the person and what they're doing as to whether I can get a good face capture or not.
View attachment 214184

View attachment 214183

I also have a 2.8mm next to the door, just above the doorbell. I have considered changing it out for a 3.6mm, but it hasn't been a strong consideration. I do need to work on some settings adjustments though. The seasons really make a difference with lighting and cloud cover.
View attachment 214185

I also just made this to tell people I am both not interested and to draw more attention to looking over that way.
View attachment 214182

Probably a little overcooked, but with the right settings, it can make a difference

 

[David L]

Probably a little overcooked, but with the right settings, it can make a difference

You got em' coming and going...

 

[Ri22o]

You got em' coming and going...
View attachment 216903

Once I finally get back onto this project, and wrap it up, I will have another angle as well.

Thread 'I need more hobbies.. Working on a PVC post discrete camera housing... (a better birdhouse)'

Jan 13, 2025

I want another view for anyone coming up the walk to the house and have wanted to add a camera at about 42-48" high on the approach to my front door. This has been something I have been thinking about for a while now. Originally I bought one of the small, wooden birdhouses and was going to use it, but have had a better thought... After having my neighbor 3D print some camera spacer rings for me I started considering getting my own printer. Walking around the house realizing all of the simple problems that having one could solve, I decided to order a Bambu P1S. The printer hasn't arrived...

• Ri22o
• Replies: 26
• Forum: Camera Installation Questions

• 
• 

 

[awmos]

Here is a great thread putting together in chart form the appropriate sensor size for the MP you are looking at. If the MP/sensor combo is red, then it will perform poorly at night:

View attachment 145765

Night time camera selection w/motion involved

Everyone shops for a camera with a different approach to what might be the best camera for their install. I always check MP against sensor size as a way to remove undesirable cameras from my search. Once I found a camera with a desirable MP and sensor combo, I would then dig deeper on FOV...

ipcamtalk.com

Alright - probably a dumb question (and/or one that's been answered ad nauseam and I'm not searching the right keywords): say I have a 8MP cam with a 1/2.8" sensor (Amcrest 2779EW, if relevant) which is clearly in 'red' territory; assuming that just changing its resolution to 1080p doesn't put it in 'green' territory?

 

[bigredfish]

Nope
The light is still going through all 8 million? tiny holes

 

[wittaj]

Alright - probably a dumb question (and/or one that's been answered ad nauseam and I'm not searching the right keywords): say I have a 8MP cam with a 1/2.8" sensor (Amcrest 2779EW, if relevant) which is clearly in 'red' territory; assuming that just changing its resolution to 1080p doesn't put it in 'green' territory?

Downrezing a camera does not work - It is still using the 8 million pixels - the camera doesn't change the "pixel resolution screen" on the camera when you go from 8MP to 4MP. The sensor still needs 2 times the light going from 8MP to 4MP, so the native 4MP camera will result in a better image at night. The firmware will make some algorithm attempt at downrezing it, but it could be a complete crap image or a somewhat usable image, but if there is a concern that the 8MP isn't performing or wouldn't perform well at night, then it is better to go with the 4MP.

I have a 4MP and 2MP on the same 1/2.8" sensor and the picture quality is quite different between the two and the 2MP kicks it's butt at night.

In most instances, you want to get a camera that will perform at your location for the worse situation, which for most of us is at night when it is dark and there is little to no light. If a camera performs at night, it is easier to tweak settings to make it work during the day than it is the other way around.

My 2MP cameras outperform my neighbors 4K (8MP) cameras....why....because they are both on the same size sensor.

When we had a thief come thru here and get into a lot of cars, the police couldn't use one video or photo from anyone's system but mine. Not even my other neighbors $1,300 8MP system provided useful info - the cams just didn't cut it at night.

My neighbor tried the "I will just downrez the 8MP to 2MP" and the image was a soft dark mess.

His system wasn't even a year old and after that event has started replacing with cameras purchased from Andy based on my recommendation and seeing my results. He is still shocked a 2MP camera performs better than his 4k cameras and he cannot figure out why downrezing from 8MP to 2MP doesn't work properly... It is all about the amount of light needed and getting the right camera for the right location and downrezing doesn't change the physics of the camera.

 

[bigredfish]

Shine a flashlight through a chain link fence

Now shine that same flashlight through mesh pool screen meant to keep out tiny mosquitos.

 

[David L]

Shine a flashlight through a chain link fence

Now shine that same flashlight through mesh pool screen meant to keep out tiny mosquitos.

Good analogy.

Learning from you guys. Sensor size to MP size will make or break a Camera. Too small of a sensor on an 8MP is no good, especially at night.

Every camera is only as good at the light provided to it...no matter how expensive the camera is.

 

[awmos]

Downrezing a camera does not work - It is still using the 8 million pixels - the camera doesn't change the "pixel resolution screen" on the camera when you go from 8MP to 4MP. The sensor still needs 2 times the light going from 8MP to 4MP, so the native 4MP camera will result in a better image at night. The firmware will make some algorithm attempt at downrezing it, but it could be a complete crap image or a somewhat usable image, but if there is a concern that the 8MP isn't performing or wouldn't perform well at night, then it is better to go with the 4MP.

Shine a flashlight through a chain link fence

Now shine that same flashlight through mesh pool screen meant to keep out tiny mosquitos.

Incredible to get both a technical explanation and an immediately graspable analogy within ~15 mins of posting this question.

Thank's y'all, this community is rad.

 

[bigredfish]

You should see us when we’re drunk!

 

[David L]

Incredible to get both a technical explanation and an immediately graspable analogy within ~15 mins of posting this question.

Thank's y'all, this community is rad.

Stick around, I have been here about 3 years and still learning from these guys...

I think the key is knowing the basics. For me, like so many when we first start out, think we only need a few cameras, a dozen cameras later, lol, each camera has a job and there is no one camera that does them all.

Our Cliff Notes is a good read, I learned alot of the basics there. It is a bit long but full of alot of great tips...