Higher Resolution vs Higher MM Lens - At what point would you recommend one over the other?

[Kn10]

This is a little bit about the theory, but to view a distant object clearer, you can either go higher resolution (to a point), or better optical zoom. At what point does one become better than the other?

I have a target at around 18 metres away. I have a 4MP varifocal that can do 12mm optical zoom. I also have a 4K camera.

At 18 metres, they produce pretty similar results in regards of clarity (at least during the day).

At what point would you recommend one over the other to another person? To go higher resolution or tighter lens? (general public person, your best friend, your mother etc.)

 

[user8963]

just compare your 8mp vs 4mp at night when there are moving objects and you will have your answer. (doesnt count if you compare it with new color 2.0 8mp model or similiar)

if both cams are cheap crap than they will be the same even at night LOL

even a toaster give me a good picture on day.. but its hard to believe that 12mm vs 3.6mm digital zoomed have the same sharpness

 

[IAmATeaf]

Tighter lens zoomed in all day long, the magnification results you see in films surprisingly doesn’t work in the real world.

 

[biggen]

Tighter optical zoom always gets my vote. The jump from 4MP to 8MP isn't a big deal to me. The resolution is already so good at 4MP so unless you are outputting to a massive screen and viewing at close range I'd always go for tighter zoom over a higher megapixel camera.

 

[bigredfish]

Agree. I would most always choose tighter optical zoom

 

[wittaj]

I would go with optical zoom as well. Digital zoom so far only works in the movies and on TV shows.

My 2MP varifocal at a given distance outperforms a higher resolution camera using digital zoom to make the person the same size as I have optically with the 2MP varifocal.

 

[wittaj]

Here is a great example of two images taken at the same time (6am so it is dark out) of the same person from just slightly different angles - one from a 4MP 3.6mm camera that I digitally zoomed to make the person about the same size as the person is in the 2MP varifocal optically zoomed.





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.

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

 

[Kn10]

Tighter lens zoomed in all day long, the magnification results you see in films surprisingly doesn’t work in the real world.

I would go with optical zoom as well. Digital zoom so far only works in the movies and on TV shows.

Yep, of course. I know "Enhance! Enhance!" doesn't work, you cant add any more data than has already been captured. However, you can capture twice as much data from 4MP to 8MP (during the day, and obviously there are other variables too).
I guess the argument I am going for is 4MP optically zoomed in to 12mm, verses just capturing twice as much data at the original distance of 18 metres.

I have a 2MP Dahua bullet (5241E-Z12E) for LPR that zooms to 64mm and absolutely kills anything I have. Easily captures license plates at 50 metres in both day and night. So I understand the relationship of lens verses res/sensor.
So not trying to ask the newbie questions that are often asked, but at a "not too far distance" of 18m, capturing double the amount of pixels, versus optical zoom. I know about PPI and the relationship to FOV. Less FOV, more dense, but you can double the number of pixels over the wider FOV too.

Angle and attitude doesn't translate well into text, but I want to tickle some brains and find the tipping point of higher res verses better zoom. Just a bit of discussion.

As @user8963 said, a big difference is going to be at night, just due to the number of pixels hitting the sensor with the 4MP getting in more light per pixel verses a 8MP.
And a 4MP @ 12mm will use smaller storage size too of course.

 

[bigredfish]

The trade off is FOV yes? Along with a better image in most cases using optical zoom…

 

[wittaj]

Yep, of course. I know "Enhance! Enhance!" doesn't work, you cant add any more data than has already been captured. However, you can capture twice as much data from 4MP to 8MP (during the day, and obviously there are other variables too).
I guess the argument I am going for is 4MP optically zoomed in to 12mm, verses just capturing twice as much data at the original distance of 18 metres.

I have a 2MP Dahua bullet for LPR that zooms to 64mm and absolutely kills anything I have. Easily captures license plates at 50 metres in both day and night. So I understand the relationship of lens verses res/sensor.

Angle and attitude doesn't translate well into text, but I want to tickle some brains and find the tipping point of higher res verses better zoom. Just a bit of discussion.

As @user8963 said, a big difference is going to be at night, just due to the number of pixels hitting the sensor with the 4MP getting in more light per pixel verses a 8MP.
And a 4MP @ 12mm will use smaller storage size too of course.

And a digital zoom you capture twice as much noise and other artifacts. Economically, the sensor size simply isn't available to us (nor would we want the size of the camera to accommodate it) isn't there to provide us with meaningful digital zoom beyond just a little bit.

It is why we say one camera cannot be the do all, see all.

Most of us have a wide angle fixed camera as an overview to OBSERVE a wider view and can serve to IDENTIFY when a subject is within the DORI distance for that particular camera, supplemented with optical zoomed cameras zoomed in to pinch points or other points of interest further out.

 

[wittaj]

And since you asked for it LOL, here are comparable daytime pics taken at the same time (noon) of the same vehicle from just slightly different angles - one from a 4MP 3.6mm camera that I digitally zoomed to make the vehicle about the same size as the vehicle is in the 2MP varifocal optically zoomed. You can make out the phone number in the 2MP optically zoomed picture, but not in the 4MP digitally zoomed picture.





This would be at your ""not too far distance" of 18m, capturing double the amount of pixels, versus optical zoom" and I think the answer is obvious....

Any questions?

 

[Kn10]

This would be at your ""not too far distance" of 18m, capturing double the amount of pixels, versus optical zoom" and I think the answer is obvious....

I may be wrong, but I feel like bitrate/compression is playing a greater part in the differences in that picture. Or the optical zoom in MM is vastly more than the benefits that higher megapixels (2 to 4) give. For example, the zoom in MM is more than double.

I am not disagreeing with you that more optical can be better than more pixels. My 2MP at 64mm will kill my 4K with no zoom, but 64mm optical verses 4 times the pixels isn't a fair fight.

For an Apples to Apples comparison, The 4MP is at 3.6mm, What mm is the 2MP at?


The reason why I think compression/bitrate is playing a greater part in the example above is it didn't just capture it in lower resolution (where you would expect it to be blockier or blurrier), it changed things entirely.
Look at the 1800 phone number, its not blurry, a large compression block just nuked the middle of it.
Look under the "e" of the main Fed Ex sign, below the black stripe. It added two lines from a frame or two before. I think its from the door lines 2ft to the front of the truck.

I researched some more, I think this article explains the question I am asking better than I can. It's from the Senior technical trainer at Axis: Security Cameras: Digital Zoom vs More Megapixels vs Optical Zoom

Points from that are More optical adds more cost, whereas more Megapixels is cheaper (to a point of course).
But more optical gives less work for the imager. And as user8963 said, low res, better nighttime.

 

[wittaj]

I may be wrong, but I feel like bitrate/compression is playing a greater part in the differences in that picture. Or the optical zoom in MM is vastly more than the benefits that higher megapixels (2 to 4) give. For example, the zoom in MM is more than double.

For some parts, it didn't just capture it in lower resolution (where you would expect it to be blockier or blurrier), it changed things entirely.
Look at the 1800 phone number, its not blurry, a large compression block just nuked the middle of it.
Look under the "e" of the main Fed Ex sign, below the black stripe. It added information from a frame or two before. I think its from the door lines 2ft to the front of the truck.

For an Apples to Apples comparison, The 4MP is at 3.6mm, What mm is the 2MP at?

I researched some more, I think this article explains the question I am asking better than I can. It's from the Senior technical trainer at Axis: Security Cameras: Digital Zoom vs More Megapixels vs Optical Zoom

Points from that are More optical adds more cost, whereas more Megapixels is cheaper (to a point of course).
But more optical gives less work for the imager. And as user8963 said, low res, better nighttime.

The 2MP camera is 4092 CBR bitrate and the 4MP is 8192 CBR bitrate, which are appropriate for their relative resolutions. Both at H264. H265 is even worse digital zoomed due to how it blocks for compression. This is what I said earlier that when you digital zoom something 18M away, every artifact is exaggerated and artifacts are introduced, even if I ran a higher bitrate.

Digital zoom is using an algorithm to achieve that zoom and that also introduces artifacts. It isn't like taking a magnifying glass to a hard copy of something. Digital zoom introduces artifacts not present.

Believe me a tested all of this when I got the camera by digital zooming to something across the street and changing bitrates until I saw a difference - I wanted to try to squeeze as much digital zoom as I could out of it, and the simple fact is you just can't do a lot.

Not digital zoomed and the 4MP image looks great and something within the DORI number for IDENTIFY looks great. But when you digital zoom, this is what you get, unless you are in a movie or on TV and then you are seeing nose hairs when digital zooming LOL.

You can't do a mm Apples to Apples comparison between a digital zoom 3.6mm 4MP and an optically zoomed varifocal 2MP - that is the whole point of optical zoom is to get a clearer picture at a distance. This is the Z12E about halfway or a little more, so the 2MP would be around 40mm or so.

And as we said, it is a trade off. Do you want a wide field of view but lose details at distance, or a narrow field of view but able to get details at distance.

Again, it is why we say one camera cannot do all, be all, see all. A 2.8mm or 3.6mm fixed cam is a great overview camera to get a big wide picture, but it isn't going to be used to IDENTIFY a stranger at 18m. You need another camera optically zoomed to that area.

 

[SouthernYankee]

The lens MM and the sensor size are the two most import things to get quality distant shots, NOT the MP.
for the same sensor size
An 8MP has 1/2 the light per pixel than a 4 MP.
A 4MP has 1/2 the light per pixel as a 2MP.

The current go to cameras are 4MP with a 1/1.8 sensor in the consumer price range.

IPC-HDW5442t-ZE .... Dahua IPC-HDW5442T-ZE 4MP Varifocal Turret - Night Perfomance testing -- variable focus 2.7 mm-12mm 4 MP Starlight

 

[TVille]

...

I researched some more, I think this article explains the question I am asking better than I can. It's from the Senior technical trainer at Axis: Security Cameras: Digital Zoom vs More Megapixels vs Optical Zoom

Points from that are More optical adds more cost, whereas more Megapixels is cheaper (to a point of course).
But more optical gives less work for the imager. And as user8963 said, low res, better nighttime.

My takeaway from the article is different from yours:

"When presented with an imaging challenge where more detail is needed in the final image, choose to add more lens before adding more megapixels. "​

He implies that digital zooming will create issues, but does not clearly state it.

"In other words, the image may be doubled but the quality might be halved. Think about what happens when a photocopy is made of a photocopy which was made of a photocopy. Every newer iteration of the image is more degraded than the last."​

While it is counter intuitive, to me, that a 4 MP camera can't cover twice the area of a 2 MP camera and give the same level of detail, that is how it comes out.

 

[bob.m]

And since you asked for it LOL, here are comparable daytime pics taken at the same time (noon) of the same vehicle from just slightly different angles - one from a 4MP 3.6mm camera that I optically zoomed to make the vehicle about the same size as the vehicle is in the 2MP varifocal optically zoomed. You can make out the phone number in the 2MP optically zoomed picture, but not in the 4MP digitally zoomed picture.

Just so I'm on the right page here, did you mean to say that you digitally zoomed in to make the image the same size? Sorry if I'm reading this wrong.

 

[wittaj]

Just so I'm on the right page here, did you mean to say that you digitally zoomed in to make the image the same size? Sorry if I'm reading this wrong.

Good catch! I corrected the original post. Yes, it should be digitally zoomed to make the vehicle the same size as it is a picture taken optically zoomed.

 

[Holbs]

All of my outdoor security related cameras will be 4MP varifocal, for that clarity to give the police that will get a thumbs up for a judge or jury.
I do have a couple 8MP cameras in my wood working shop at 2.8mm. I needed the wide FOV since lots of real estate to cover. 8MP vs 2 or 4MP incase I do have to digitally zoom in a tad here or there.