hmjgriffon
Known around here
I'm kind of against letting my animals run around outside willy nilly, too many douchebags who like to hurt animals, not to mention the danger of other animals.
Camera Lens Reference Diagram
- Thread starter Kenjusticejr
- Start date
Thank you, digger.
That is neat! Didn't know they existed. I will have to have a closer look at that!
Actually, this one or similar which includes a timer so you can lock them in: http://www.amazon.com/Cat-Mate-Elite-Microchip-Control/dp/B009GODTTK/
Gotta love friendly online folks who share a solution to a brainstorm idea!
As an Amazon Associate IPCamTalk earns from qualifying purchases.
I understand the risk and totally respect that we probably should keep them inside at all times for their safety.
We have less wildlife than digger and actually don't let our cats out all that much, any more. Certainly less than prior years, where they had some free roaming time every day. We lost one cat a few years back, which must have had pure bred hunting dna. Could not keep her inside, used to hunt all the time and came in to sleep (was kept inside with the rest to stay warm in the winter). We think a fisher may have snatched her. We still feel bad about that. Since that time, combined with free roaming dogs & "bully cat" it is pretty much a supervised affair now. We always keep them in at night, when the weather will turn or when we're away from home, unless maybe just running to the grocery store.
It depends on the space too. We have a lot more space now than at our previous in-town property which had just a small fenced in patio. We're away from the road and other properties. The cats like to roam around the house in circles, lounge on the deck, follow their humans in the garden, check for mice, moles & voles. Maybe chase after a squirrel. After 6 months of winter, the cats deserve a little break too. They seem much happier when they've been able to go on patrol a little ... and far less intent on gunning for the door to get out, tripping humans or getting stepped on in the process.
My apologies for taking this thread off topic!!
But happy to learn about RFID cat flaps
We have less wildlife than digger and actually don't let our cats out all that much, any more. Certainly less than prior years, where they had some free roaming time every day. We lost one cat a few years back, which must have had pure bred hunting dna. Could not keep her inside, used to hunt all the time and came in to sleep (was kept inside with the rest to stay warm in the winter). We think a fisher may have snatched her. We still feel bad about that. Since that time, combined with free roaming dogs & "bully cat" it is pretty much a supervised affair now. We always keep them in at night, when the weather will turn or when we're away from home, unless maybe just running to the grocery store.
It depends on the space too. We have a lot more space now than at our previous in-town property which had just a small fenced in patio. We're away from the road and other properties. The cats like to roam around the house in circles, lounge on the deck, follow their humans in the garden, check for mice, moles & voles. Maybe chase after a squirrel. After 6 months of winter, the cats deserve a little break too. They seem much happier when they've been able to go on patrol a little ... and far less intent on gunning for the door to get out, tripping humans or getting stepped on in the process.
My apologies for taking this thread off topic!!
But happy to learn about RFID cat flaps
I just joined this forum and this particular post really helps me to understand the lens size vs. view angle. I do have a few questions about this. 1. I currently have D1 cameras (704x480) that have a 5mm lens and say they have a 60 degree viewing angle. I'm going to upgrade my system to 3mp 1080p PoE and would like to keep my viewing angle about the same. From what I can tell I should be good with 6mm lens, correct? 2. With a 6mm lens I should be able to read a license plate from roughly 15 feet based on this chart. I guess I thought that with a 3mp 1080p camera you should be able to zoom in from even a farther distance. My house is about 20 feet from the curb of the street. Does this mean that I should really be going with a 8-12mm lens if I wanted the ability to read license plates from cars on the street? 3. Does viewing distance change a lot if you go from 2mp - 3mp and 3mp - 5mp?
Thanks in advance!
~Lee
Thanks in advance!
~Lee
Hi Lee, here are 3 articles I wish someone had pointed out to me a few months ago:
An article on pixel density: http://www.axis.com/academy/pixel_count/index.htm
And specific to Hikvision cameras, a couple of technical bulletins on their camera fields of view and pixel density:
ftp://hikfirmware:Hikvision123@ftp....cal Bulletin/2014/IP Camera FOV List v2.0.pdf
ftp://hikfirmware:Hikvision123@ftp....P Camera Lens Pixel Density v2.0_20140124.pdf
An article on pixel density: http://www.axis.com/academy/pixel_count/index.htm
And specific to Hikvision cameras, a couple of technical bulletins on their camera fields of view and pixel density:
ftp://hikfirmware:Hikvision123@ftp....cal Bulletin/2014/IP Camera FOV List v2.0.pdf
ftp://hikfirmware:Hikvision123@ftp....P Camera Lens Pixel Density v2.0_20140124.pdf
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Thank you very much for this information!! The two spec sheets are great!! I skimmed through the part about px/cm and I'm going to have to sit down and really read that to understand it properly. At least I have the information needed to make an informed decision now.
There are some websites too that offer an online Field Of View calculator you can play around with to better determine the needs. Some are okay. The following site & tool may be the best out there, though maybe the software isn't exactly the easiest to use, due to its specialist nature.
Online tool I used:
http://www.jvsg.com/online/#
Offline tool I used:
http://www.jvsg.com/software/ip-video-system-design-tool/
I played around with that as well as a bit of property layout.
But, without enough time to draw up a site plan or one to import; I went old school. Traced a property outline, blew it up to draft plan size and cut some FOV wedges to match the cameras I was interested in at their resolution (3mp set to 1920x1080 for a bit of extra width). Which worked a treat. I felt I needed a) higher resolution cameras than just analog tvl or standard big box kit; and b) a mix of cameras (not just all the same standard 2.8 or 4mm) due to a bit of topography, some medium and longer distances (compared to a city property), landscaping, curved driveway, ... and I particularly want to capture vehicles & registration. Anyway, we all have similar needs. And it really didn't 't take much time to cut some wedges out and move them around to verify my easily accessible mounting points and see what angles and resolutions I'd be looking at.
Then after playing around with it on paper I actually went out on the ladder to get my head up to the lower floor soffit areas to see first hand. (close one eye, hold wedge close to the other eye - helps I wear glasses! - check FOV) Sure enough some results were confirmed. And one was eliminated, because while I can trim the adjacent tree shorter, I can't shoot through nor trim a decorative Japanese maple. From the driveway it looks doable, but once you look from the other way, I'd be recording more tree than driveway. Then factoring in tree growth, wind, ... (other harder location, less concealed, loads more install work required)
Anyway. Just a couple tools & thoughts.
And, PS. I did settle on couple 3 axis domes with varifocal based networkcameracritic's general recommendations and me wanting to dial things in a bit more or less if need be, adjusting the focus & WAF. Was going to just go with smaller & cheaper fixed bullets of varying mm; but then out of the blue the spouse wanted domes! Who knew? Which made it easier to spend the extra dollars for a couple adjustable domes. Will probably get a couple more if these work great. I'm trying to phase it a little as to not put all eggs in one basket and jump in too quick. Test some software, test with a couple cameras, see what works for recording and review. Etc. I may for the one camera need more telephoto, like a 16mm, but I want to build a case for that first before spending the extra $$$ and finding out it is too much and I can't use it at all. A wider or adjustable camera can always move to another spot. Etc.
Online tool I used:
http://www.jvsg.com/online/#
Offline tool I used:
http://www.jvsg.com/software/ip-video-system-design-tool/
I played around with that as well as a bit of property layout.
But, without enough time to draw up a site plan or one to import; I went old school. Traced a property outline, blew it up to draft plan size and cut some FOV wedges to match the cameras I was interested in at their resolution (3mp set to 1920x1080 for a bit of extra width). Which worked a treat. I felt I needed a) higher resolution cameras than just analog tvl or standard big box kit; and b) a mix of cameras (not just all the same standard 2.8 or 4mm) due to a bit of topography, some medium and longer distances (compared to a city property), landscaping, curved driveway, ... and I particularly want to capture vehicles & registration. Anyway, we all have similar needs. And it really didn't 't take much time to cut some wedges out and move them around to verify my easily accessible mounting points and see what angles and resolutions I'd be looking at.
Then after playing around with it on paper I actually went out on the ladder to get my head up to the lower floor soffit areas to see first hand. (close one eye, hold wedge close to the other eye - helps I wear glasses! - check FOV) Sure enough some results were confirmed. And one was eliminated, because while I can trim the adjacent tree shorter, I can't shoot through nor trim a decorative Japanese maple. From the driveway it looks doable, but once you look from the other way, I'd be recording more tree than driveway. Then factoring in tree growth, wind, ... (other harder location, less concealed, loads more install work required)
Anyway. Just a couple tools & thoughts.
And, PS. I did settle on couple 3 axis domes with varifocal based networkcameracritic's general recommendations and me wanting to dial things in a bit more or less if need be, adjusting the focus & WAF. Was going to just go with smaller & cheaper fixed bullets of varying mm; but then out of the blue the spouse wanted domes! Who knew? Which made it easier to spend the extra dollars for a couple adjustable domes. Will probably get a couple more if these work great. I'm trying to phase it a little as to not put all eggs in one basket and jump in too quick. Test some software, test with a couple cameras, see what works for recording and review. Etc. I may for the one camera need more telephoto, like a 16mm, but I want to build a case for that first before spending the extra $$$ and finding out it is too much and I can't use it at all. A wider or adjustable camera can always move to another spot. Etc.
Last edited by a moderator:
lojix
Getting the hang of it
Thanks for your detailed post and for recommendation of JVSG video surveillance design software.
I wonder can you please share the camera layouting you made?
Bradmph
Pulling my weight
How to choose a suitable lens surveillance camera
Table for 1/3in lens
Monitoring the angle of a shot, a proportion of the distance
The relative aperture
F- F F=f/D f= the number of aperture, focal length, aperture D= lens
The focal length of the lens 2.8mm 3.5mm 4mm 4.8mm 6mm 8mm
1/3 "CCD from the angle of 86.3 ° 67.4 ° to 62 ° and 52.2 ° 42.3 ° 32.6 °
The distance of the object 4.3m 5.4m 6m 7.3m 9m 12m
The focal length of the lens 12mm 16mm 25mm 60mm 73.8mm
1/3 "CCD from the angle of 22.1 ° 17.1 ° 10.6 ° 3.5 ° 2.9 °
The distance of the object 18mm 25mm 38mm 120mm 150mm
In order to monitor display 5m objects shall prevail
Lens mounting part diameter of 25.4mm
Lens mounting datum to the focal distance of 17.526mm
C type lens mounted to the camera CS interface to add 5mm connecting ring thickness
The main difference is the size of the lens:
Lens more look closer, but the visual range is wide; the lens more see farther, but the visual range is narrow.
Our baby classification inside, dome camera can choose 3.6MM or 6MM lens;
30 meters waterproof infrared camera can choose 3.6MM, 6MM or 8MM lens;
More than 30 meters waterproof infrared camera can choose 4MM, 6MM, 8MM, 12MM, 16MM, 25MM lens (lens. These are big CS lens all metal)
Calculation method for monitoring the camera angle
The 1/3 camera as an example:
The best visual range (m) corresponding to the size of *2- = shot dead
Note: the best visual range is dead outside the distance
Such as: 12MM lens visual angle of 22 degrees, the visual distance the best is 24 meters (including dead distance), according to the formula: visual range of the best angle of 22 degrees, the visual range camera 4 meters to 24 meters
The choice of lens: lens mm smaller numbers, more open field of vision, but look closer; lens mm higher numbers, vision and more narrow, but see the farther the distance, the two can not have it both ways)
The calculation formula of camera lens
Calculation formula:
Department of field of view and the focal length of the calculated field refers to the uptake of object size, field size is the distance to the lens to be ingested objects, camera head and image size required to determine the.
The focal length of the lens, field lens to be calculated as follows: the size and distance of uptake of objects:
f=wL/W
f=hL/h
F: the focal length of the lens W: image width(object imaging width in the CCD target surface)
W: object width
L: object to camera distance
H: image height (an image of an object in the CCD target surface height) field (uptake of scenes) height
H: object height
Because the camera screen width and height with the TV screen width and height, the ratio is 4:3, when the L invariant, H or W increases, f becomes smaller, when H or W unchanged, L increases, f increases.
Calculation of angle of view
If the horizontal or vertical angle can be calculated according to the formula of the width and height. Horizontal view angle β (horizontal viewing angle) β =2tg-1= vertical field of view angle Q (vertical viewing angle) q=2tg-1= type W, H, f. Horizontal view angle and the vertical angle of view as follows: q= or =q listed in Table 2 value B the horizontal view of different sizes and different focal length camera layer of f angle, if the horizontal or vertical angle can be calculated from the field angle can be calculated out of the field H and field width W. height H=2Ltg, W=2Ltg for example; camera tube is 17mm (2/3in), the focal length of the lens f to 12mm, from table 2 check horizontal viewing angle of 40 degrees. Lens and ingested objects at a distance of 2m, find the field width W. W=2Ltg=2 * 2tg=1.46m H=W= * 1.46=1.059m f more and long focal length, field of view angle is small, the goal of surveillance is small.
The graphic method
As previously shown, the camera field of view by the wide (W). High (H) and the distances from the camera (L) decision, once the decision to the camera to monitor the scene, the correct choice of the focal length of the lens on the origin of 3 factors;
* to monitor the dimension of the object
* the camera and the object distance
* camera imager ruler: 1/3 ", 1/2" 2/3 ", or 1"
Graphic lens selection steps: there is a simple relationship between field of view and the focal length of the lens required. Using this relation can choose appropriate lens. Maximum width estimated or measured field; estimation or measurement camera and photographed the scene and the distance between the lens; use 1/3 "used in Figure 2, the use of 1/2 lens used in Figure 3, the use of 2/3" lens use figure 4, using a 1 lens use figure 5. Method: on the icon to W and L axes 2-5, find out the focal length of the lens should be used. To ensure that the object is completely contained in the field, should choose the coordinate intersection, numerical surface that line indicator. For example: wide field of view 50m, distance of 40m, using the 1/3 "format of the lens, at the intersection graphs of 4mm lens than partial line a bit. This shows that if you use the 4mm lens can not cover the 50m field of view. And with a 2.8mm lens can completely cover the field.
f=vD/V
f=hD/H
Wherein, f represents the focal length, V represents the vertical CCD target surface height, V represents the observed object height, H represents the level of CCD target surface width, H represents the observed object width.
Give an example:If 1/2 "CCD camera observation, the object to be measured 440 mm wide, 330 mm high, lens focal distance of 2500 mm objects.
Can be calculated by formula:Focal length f=6.4X2500/440 = 36 mm or 36 mm focal length is f=4.8X2500/330
When the focal length is numerical calculated, if there is no corresponding to the focal length of the lens is very normal, then according to the catalogue choice of similar models, the general selection value smaller than the calculation, this view will be greater.
In order to obtain the same point of view from the 1/3 "and 1/2" 1/3 "CCD CCD camera, camera lens focal length must be reduced; if the same focal length in 1/3" CCD and 1/2 "CCD camera lens, the situation and how? 1/3" CCD camera than 1/2 "CCD camera is decreased obviously, at the same time image 1/3 ″ CCD camera, image on the monitor than 1/2 ″ CCD amplification, produced using the telephoto lens effect. In addition we select the lens should pay attention to such a principle: small size target surface CCD can use large size target surface CCD cameras, not vice versa. The reason is: if 1/2 "CCD by 1/3" camera lens, the light becomes smaller, the color will become worse, even image will defect; on the contrary, the amount of light will become large, the color will change, image effects will certainly be better. Of course, integrated a variety of factors, the camera or to choose the best matching lens.
Table for 1/3in lens
Monitoring the angle of a shot, a proportion of the distance
The relative aperture
F- F F=f/D f= the number of aperture, focal length, aperture D= lens
The focal length of the lens 2.8mm 3.5mm 4mm 4.8mm 6mm 8mm
1/3 "CCD from the angle of 86.3 ° 67.4 ° to 62 ° and 52.2 ° 42.3 ° 32.6 °
The distance of the object 4.3m 5.4m 6m 7.3m 9m 12m
The focal length of the lens 12mm 16mm 25mm 60mm 73.8mm
1/3 "CCD from the angle of 22.1 ° 17.1 ° 10.6 ° 3.5 ° 2.9 °
The distance of the object 18mm 25mm 38mm 120mm 150mm
In order to monitor display 5m objects shall prevail
Lens mounting part diameter of 25.4mm
Lens mounting datum to the focal distance of 17.526mm
C type lens mounted to the camera CS interface to add 5mm connecting ring thickness
The main difference is the size of the lens:
Lens more look closer, but the visual range is wide; the lens more see farther, but the visual range is narrow.
Our baby classification inside, dome camera can choose 3.6MM or 6MM lens;
30 meters waterproof infrared camera can choose 3.6MM, 6MM or 8MM lens;
More than 30 meters waterproof infrared camera can choose 4MM, 6MM, 8MM, 12MM, 16MM, 25MM lens (lens. These are big CS lens all metal)
Calculation method for monitoring the camera angle
The 1/3 camera as an example:
The best visual range (m) corresponding to the size of *2- = shot dead
Note: the best visual range is dead outside the distance
Such as: 12MM lens visual angle of 22 degrees, the visual distance the best is 24 meters (including dead distance), according to the formula: visual range of the best angle of 22 degrees, the visual range camera 4 meters to 24 meters
The choice of lens: lens mm smaller numbers, more open field of vision, but look closer; lens mm higher numbers, vision and more narrow, but see the farther the distance, the two can not have it both ways)
The calculation formula of camera lens
Calculation formula:
Department of field of view and the focal length of the calculated field refers to the uptake of object size, field size is the distance to the lens to be ingested objects, camera head and image size required to determine the.
The focal length of the lens, field lens to be calculated as follows: the size and distance of uptake of objects:
f=wL/W
f=hL/h
F: the focal length of the lens W: image width(object imaging width in the CCD target surface)
W: object width
L: object to camera distance
H: image height (an image of an object in the CCD target surface height) field (uptake of scenes) height
H: object height
Because the camera screen width and height with the TV screen width and height, the ratio is 4:3, when the L invariant, H or W increases, f becomes smaller, when H or W unchanged, L increases, f increases.
Calculation of angle of view
If the horizontal or vertical angle can be calculated according to the formula of the width and height. Horizontal view angle β (horizontal viewing angle) β =2tg-1= vertical field of view angle Q (vertical viewing angle) q=2tg-1= type W, H, f. Horizontal view angle and the vertical angle of view as follows: q= or =q listed in Table 2 value B the horizontal view of different sizes and different focal length camera layer of f angle, if the horizontal or vertical angle can be calculated from the field angle can be calculated out of the field H and field width W. height H=2Ltg, W=2Ltg for example; camera tube is 17mm (2/3in), the focal length of the lens f to 12mm, from table 2 check horizontal viewing angle of 40 degrees. Lens and ingested objects at a distance of 2m, find the field width W. W=2Ltg=2 * 2tg=1.46m H=W= * 1.46=1.059m f more and long focal length, field of view angle is small, the goal of surveillance is small.
The graphic method
As previously shown, the camera field of view by the wide (W). High (H) and the distances from the camera (L) decision, once the decision to the camera to monitor the scene, the correct choice of the focal length of the lens on the origin of 3 factors;
* to monitor the dimension of the object
* the camera and the object distance
* camera imager ruler: 1/3 ", 1/2" 2/3 ", or 1"
Graphic lens selection steps: there is a simple relationship between field of view and the focal length of the lens required. Using this relation can choose appropriate lens. Maximum width estimated or measured field; estimation or measurement camera and photographed the scene and the distance between the lens; use 1/3 "used in Figure 2, the use of 1/2 lens used in Figure 3, the use of 2/3" lens use figure 4, using a 1 lens use figure 5. Method: on the icon to W and L axes 2-5, find out the focal length of the lens should be used. To ensure that the object is completely contained in the field, should choose the coordinate intersection, numerical surface that line indicator. For example: wide field of view 50m, distance of 40m, using the 1/3 "format of the lens, at the intersection graphs of 4mm lens than partial line a bit. This shows that if you use the 4mm lens can not cover the 50m field of view. And with a 2.8mm lens can completely cover the field.
f=vD/V
f=hD/H
Wherein, f represents the focal length, V represents the vertical CCD target surface height, V represents the observed object height, H represents the level of CCD target surface width, H represents the observed object width.
Give an example:If 1/2 "CCD camera observation, the object to be measured 440 mm wide, 330 mm high, lens focal distance of 2500 mm objects.
Can be calculated by formula:Focal length f=6.4X2500/440 = 36 mm or 36 mm focal length is f=4.8X2500/330
When the focal length is numerical calculated, if there is no corresponding to the focal length of the lens is very normal, then according to the catalogue choice of similar models, the general selection value smaller than the calculation, this view will be greater.
In order to obtain the same point of view from the 1/3 "and 1/2" 1/3 "CCD CCD camera, camera lens focal length must be reduced; if the same focal length in 1/3" CCD and 1/2 "CCD camera lens, the situation and how? 1/3" CCD camera than 1/2 "CCD camera is decreased obviously, at the same time image 1/3 ″ CCD camera, image on the monitor than 1/2 ″ CCD amplification, produced using the telephoto lens effect. In addition we select the lens should pay attention to such a principle: small size target surface CCD can use large size target surface CCD cameras, not vice versa. The reason is: if 1/2 "CCD by 1/3" camera lens, the light becomes smaller, the color will become worse, even image will defect; on the contrary, the amount of light will become large, the color will change, image effects will certainly be better. Of course, integrated a variety of factors, the camera or to choose the best matching lens.
Attachments
A very helpful topic. Do I presume that it is the megapixel value of the camera which determines how grainy the picture is?
tangent
IPCT Contributor
- May 12, 2016
- 4,636
- 3,988
It's more complicated than that. More pixels without more light just means more noise (sensor size matters). There's some good info in this thread: https://www.ipcamtalk.com/showthread.php/7097-Resource-Guide-on-IP-Technology-for-all-Noobs
sirius99
Young grasshopper
- Dec 11, 2016
- 55
- 2
I just installed a 4mm hik camera thinking it would do my entire front drive but finding it only covers about 50% of its width due to it being about 6m long and maybe 15m wide ... don't want to install a 2nd but would a 2mm lens capture more of that width , if so any idea how much?
nayr
IPCT Contributor
2.8mm lenses are the worst choice for driveways.. move your camera, the key points are car doors.. the rest can be discarded.
sirius99
Young grasshopper
- Dec 11, 2016
- 55
- 2
Easy to say ... much harder to do without leaving a gaping hole in the wall cladding and honestly there is nowhere else to put it as frontage below cladding is almost entirely glass AND I still have the width issue ...
nayr
IPCT Contributor
You need more cameras then, 2.8mm can't identify faces further away than 10ft or so
Sent from my HTC One_M8 using Tapatalk
Sent from my HTC One_M8 using Tapatalk
looney2ns
IPCT Contributor
i have the exact same issue, installed a Hikvision 2.8mm dome camera in the center of the front house wall, thinking it will be enough to capture my 2 cars, side-by-side driveway, but nope, it does not capture enough area. have been thinking if a turrent camera will improve coverage
what do you recommend using for driveway then?