The Importance of Focal Length over MP in camera selection

badandy996

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While your statement is certainly true though as it relates to LPR - you are wrong as it relates to THIS thread LOL.

The entire purpose of this thread is to show how FOCAL length AKA OPTICAL zoom is more important than MP and DIGITAL zoom. And in some cases 2MP is the better option based on DISTANCE as the higher MP/sensor ratios are not available in the higher focal lengths.

The issue we see too many times is someone comes here with their fancy 4K 2.8 or 3.6mm camera and complains they cannot make out a face or plate at 60 feet away at night.

That is the problem. At 60 feet away, a larger focal length is needed and there isn't a 4K varifocal available (except in PTZ) on the proper MP/sensor ratio large enough for 60 feet, so a 5442-Z4E or 5241-Z12E will be the better choice for that distance.

But to clear up confusion some have, generally yes a higher MP camera on the ideal MP/sensor ratio for the same focal length will generally beat the lower MP camera at that same focal length for an object the same distance away. But we have also seen several people that are dissatisfied with the 4K cameras on the ideal MP/sensor ratio and feel like the 4MP 5442 camera is a better camera overall. I suspect some of the dissatisfaction relates to you still cannot digital zoom it at night.

So yes, a 4MP 5442 of the same fixed focal length will beat a 2MP 2231 or 5241of the same focal length. It is when you have maxed out the focal length of the 5442 or try to apply too much digital zoom that the higher focal length 2MP optically zoomed to the area of interest becomes the better choice. And don't mistake a brighter static image at night as a better image if one is comparing a fixed lens 5442 over an optical zoomed larger 2MP camera. The whole point is to get a clean capture of the perp, not nice bright static images and once digital zoom is applied to the brighter static image, it will become pixelated real quick, especially at night, and that is where the 2MP that is optically zoomed to the distance will be the better choice, even if the static image is darker.

The issue is the when the focal lengths are different.

As I showed in Post 16, here is a great example of two images taken at the same time (early AM while still dark out) of the same person 60 feet away from just slightly different angles - one from the 5442-ZE 4MP set to 3.6mm that I digitally zoomed to make the person about the same size as the person in the 2MP varifocal optically zoomed.

The digitally zoomed image of this 3.6mm focal length of a 4MP on the ideal MP/sensor ratio could not be used by police to IDENTIFY. This camera is added by white light AND infrared, so it is getting more total light than the 2MP.



trash 4MP digital zoom.jpg




Meanwhile this 2MP camera OPTICALLY zoomed with the higher focal length to capture IDENTIFY at this distance is better than the 4MP on the ideal MP/sensor ratio that was DIGITAL zoomed.


trash 2MP optical zoomed.png




In case someone cannot figure it out, the 4MP that is digitally zoomed in is the B&W picture and the 2MP varifocal optically zoomed in is the color picture LOL.

I think most would agree that the optically zoomed 2MP picture beats the digitally zoomed 4MP picture - you can make out details and read some of the signage and make out bolts, etc. that are just a blur on the 4MP, which is being benefited by the same light the 2MP camera is getting plus the IR.

This is the point of this thread.
What camera are you using to get such a clean colored picture at night?
 

wittaj

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What camera are you using to get such a clean colored picture at night?

That is the 5241-Z12E, known now as B52IR-Z12E


 
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badandy996

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Will I be able to get color videos with the bullet 4mp verifocal?


That is the 5241-Z12E, known now as B52IR-Z12E


 
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Mike A.

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Not unless you have quite a bit of white light. Think a well lit parking lot level of light. You can get a static image in color with a lot less but you won't get good motion capture without more.
 

wittaj

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Will I be able to get color videos with the bullet 4mp verifocal?

As mentioned above, any camera can provide a static image in color at night - slow down the shutter and crank up the gain - that is what the consumer brands do. But then motion is crap.

If you want color at night, you need visible light. Even the "full color" cameras need white light and are not magic.

For the same focal length, the 4MP on the 1/1.8" sensor will perform better than the 2MP on the 1/2.8" sensor.

But the point of this whole thread is to get the proper camera for the distance you want to IDENTIFY. If your IDENTIFY distance is 60 feet, that 4MP varifocal with 12mm focal length will not outperform the 2MP varifocal with the focal length set to 50mm.
 
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MacFun

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Regarding camera selections, the distance to be covered from the camera to the object location is the most important factor and more important than MP.

You need to identify the areas you want to cover and pick a camera designed to cover that distance. In some instances, it may be a 2MP or 4MP that is the right camera and not an 8MP. DO NOT CHASE MP!!!

It is why we recommend to purchase one good varifocal and test it at all the proposed locations day and night to figure out the correct focal lengths and cams.

A few other tips....It is simple LOL do not chase MP - do not buy a 4MP camera that is anything smaller than a 1/1.8" sensor. Do not buy a 2MP camera that is anything smaller than a 1/2.8" sensor. Do not buy a 4K (8MP) camera on anything smaller than a 1/1.2" sensor. Unfortunately, most 4k (8MP) cams are on the same sensor as a 2MP and thus the 2MP will kick its butt all night long as the 4k will need 4 times the light than the 2MP... 4k will do very poor at night unless you have stadium quality lighting (well a lot of lighting LOL).


Here are my general distance and camera recommendations, but switch out the Dahua 5442 series camera to the equivalent 2MP on the 1/2.8" sensor or equivalent Hikvision works as well. These particular cameras are generally accepted by many here as the best balance of performance day and night, price, and features. With all the cameras I have used and tested over the years, these are the ones I also currently use.
  • 5442 fixed lens 2.8mm - anything within 10-15 feet of camera OR as an overview camera. This camera is still considered the "gold standard" and many will say 4MP on the 1/1.8" sensor is the sweet spot for surveillance cameras.
  • 4K/X bullet or 4K/X turret - anything within 20 feet of the camera OR as an overview camera. The turret versions have a mic and the 4K/X bullet has two-way audio. These cameras need light and cannot see infrared. Keep in mind the larger sensor does mean the camera has a more shallow focus and has a definite sweet spot for focus and anything closer or further away will be a little soft. It is why most use it as an overview camera to capture color.
  • Color4K-T180 - is a great overview camera and can see 180 degrees left-right, so one on the front of the house can see down the entire front (unless you have obstructions LOL). This camera needs light and cannot see infrared. Most would not use this as an IDENTIFY camera. This camera has two-way audio.
  • T5449H-ASE-D2 2.8mm fixed lens - anything within 10 feet of camera where the object would be in a backlit condition at night (meaning the object is in between the camera and the light source which is common for a house with no lights but a streetlight - the person will be in the shadow of the streetlight from the camera's perspective). This camera has two-way audio.
  • 5441F-AS-E2 (AKA Boobie cam) or E3241F-AS-M- great choice for a front door camera. The boobie cam can have one lens pointed down for packages. This camera has a mic.
  • T5241H-AS-PV - Great little active deterrence camera with two way talk. Good for anything within 10 feet of camera or as an overview camera.
  • 5442 ZE or 5842-ZE- varifocal up to 13mm- distances up to 40-50 feet (personally I wouldn't go past the 30 foot range but I like things closer). This camera has a mic.
  • 5442 Z4E - varifocal up to 32mm - anything up to 80-100 feet (personally I wouldn't go past 60 feet but I like things closer).
  • 5241-Z12E - varifocal up to 64mm - anything from 80 feet to almost 200 feet (personally I wouldn't go past 150 feet because I like things closer).
  • 5241-Z12E - for a license plate cam that you would angle up the street to get plates up to about 175 feet away, or up to 220 with additional IR.
  • PTZs - the 49425 is great sub $450 auto-track PTZ or the SD4A425DB-HNY mini-PTZ (sub $400) and in conjunction with an NVR or Blue Iris and the cameras above that you can use as spotter cams to point the PTZ to the correct location to compliment the fixed cams. If you have the budget though, the PTZ5A4M-25X is the best option unless you have an even bigger budget and could go with the PTZ4K45X-AI
  • Indoors, the IP2M-841 is a cheap common camera choice. Works with Dahua NVR and Blue Iris. Has wifi and ability to use POE with this adapter. Has two-way talk and basic autotracking.

You need to get the correct camera for the area trying to be covered. A wide angle 2.8mm to IDENTIFY someone 40 feet away is the wrong camera regardless of how good the camera is. A 2.8mm camera to IDENTIFY someone within 10 feet is a good choice OR it is an overview camera to see something happened but not be able to identify who.

One camera cannot be the be all, see all. Each one is selected for covering a specific area. Most of us here have different brands and types, from fixed cams, to varifocals, to PTZs, each one selected for it's primary purpose and to utilize the strength of that particular camera.

So you will need to identify the distance the camera would be from the activities you want to IDENTIFY on and purchase the correct camera for that distance as an optical zoom.

If you want to see things far away, you need optical zoom, digital zoom only works in the movies and TV...And the optical zoom is done real time - for a varifocal it is a set it and forget it. You cannot go to recorded video and optically zoom in later, at that point it is digital zoom, and the sensors on these cameras are so small which is why digital zoom doesn't work very well after the fact.


Also, do not be sold by the terms FULL COLOR, COLORVU and the like. All cameras need light - either visible light or infrared. While the full color cameras are great, if you do not have ambient light or refuse to use the built-in white LED, then you are better off with a camera that can see infrared. Full Color cameras cannot see infrared, so you cannot add it later.

Many people have come here after buying a full color camera and expressing their disappointment in the picture quality of the camera because they were expecting magic. If you do not have ambient light outside or do not like the white LED lights on, you are better off with cameras that can see infrared as these type of cameras cannot see infrared, so you can't add infrared later.

Here is link to a thread of many that shows the disappointment of many thinking a ColorVu camera was magic and could defy physics. Full Color type cameras are great if you have light, but will be horrible if you do not have enough light.



This image shows the importance of understanding focal length and its role in DORI (Detect, Observe, Recognize, Identify) and how one camera cannot do it all. If you want to IDENTIFY in the DOR part, then you need a camera with optical zoom to that location.

Now keep in mind DORI is based on manufacturer testing and is usually under perfect and ideal situations. Most of us here have seen you have to cut the DORI number in half during the day and cut that half in half at night for realistic distance approximations for a subject moving.

View attachment 130488


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



We also have a couple of great threads put together by @samplenhold about the importance of redundant cameras and considerations for plate reading LPR:



Do you have an updated version of this document where you list some favorite cameras for 2024...?

Thanks,

R
 
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wittaj

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Do you have an updated version of this document where you list some favorite cameras for 2024...?

Thanks,

R
Post 2 of this thread are still the latest. I update thst list when something new that folks recommend comes about. There just isn't much new other than updated models with the S3 designation or addition of TIOC to existing models, so there isn't a lot "new" for 2024 that is recommended.
 

MacFun

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Post 2 of this thread are still the latest. I update thst list when something new that folks recommend comes about. There just isn't much new other than updated models with the S3 designation or addition of TIOC to existing models, so there isn't a lot "new" for 2024 that is recommended.
So the original post from March of 2022 is the latest.... Or rather you are able to edit the 2022 list to keep it up to date..... Got it!

Does S3 refer to the WizMind S Series? What benefits of the S3? Did the model number change?
 
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wittaj

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So the original post from March of 2022 is the latest.... Or rather you are able to edit the 2022 list to keep it up to date..... Got it!

Does S3 refer to the WizMind S Series? What benefits of the S3? Did the model number change?
If you look at the bottom of Post#2 - it shows it was Last edited: May 29, 2024

The S3 simply means that it has a different chipset than the previous version of the 5442 model. But the 5442 model (54IR with Andy's version) is still the current king of cameras and most recommended model.

But we have seen the improvement so good they probably could have called it a new model.

You can see the comparison in this thread:

 
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