My lower megapixel cameras are sharper

[ekbrewer]

I have a 3mp, a 4mp, and two 2 8mp cameras that I view with blue iris. The 8mp are far less sharp. I held a printout of an image resolution/sharpness test at arms length from each camera then double clicked on the feed in blue iris, waited a second for it to get clear, clicked pause, and took a screen snip of one and put all 4 in the attached word doc. Could anyone take a look and explain why the 8mp are so much less sharp? I've done a lot of research and think I understand the drawbacks of larger MP cameras, especially at night. However, from everything I've seen online, as a rule the 8mp should be more detailed and sharp.
Thanks, Eric

 

[tigerwillow1]

If there was only a single 8 MP camera in play I'd think first it could be a focus issue. With two of them seemingly identical, my first question is what bitrate are the cameras running at? Second, is the amount of light on the target the same for all of the screen shots? Why do some of the images look black-and-white, with others bluish? Also, could it be a close-focus issue? The smaller sensor cameras can possibly have better depth-of-field to focus better at close distances.

 

[wittaj]

+1 above. It needs a bitrate a lot higher than 4MP. Try 16,000 and CBR

 

[ekbrewer]

Thank you for your feedback. The 3mp bitrate is 3072 Kbps, 4mp is 4096, 8mps are 8192. All other video settings are identical (except resolution). The light between them all is very different as they point different directions and are on different sides of the house. However, I consistently get the same results as lighting changes throughout the day: the 8mps are less detailed. I just retried the test at 10 ft and have attached the results. Can really see a difference with this test.
Eric

If there was only a single 8 MP camera in play I'd think first it could be a focus issue. With two of them seemingly identical, my first question is what bitrate are the cameras running at? Second, is the amount of light on the target the same for all of the screen shots? Why do some of the images look black-and-white, with others bluish? Also, could it be a close-focus issue? The smaller sensor cameras can possibly have better depth-of-field to focus better at close distances.

 

[ekbrewer]

Just upped the 8192 to 16000 and didn't see any difference.
Thanks, Eric

+1 above. It needs a bitrate a lot higher than 4MP. Try 16,000 and CBR

 

[wittaj]

I think your settings could be part of the issue.

Most of us run H264 and 8192 bit rate and CBR for 4MP.

But many of us have also seen 4MP really is the sweetspot for these types of cameras.

You also didn't say which model - 8MP on a 1/2.8" sensor designed for 2MP will perform much different than 8MP on the ideal 1/1.2" sensor.

 

[ekbrewer]

Any particular settings you have in mind? I use h264 CBR on all. Just upped the 8mp from 8192 to 16000 with no difference.

The model numbers are in the word doc next to each image. My 8mp cams have 1/1.8" sensor and my 3 and 4mp cams have 1/3".

Thanks, Eric

I think your settings could be part of the issue.

Most of us run H264 and 8192 bit rate and CBR for 4MP.

But many of us have also seen 4MP really is the sweetspot for these types of cameras.

You also didn't say which model - 8MP on a 1/2.8" sensor designed for 2MP will perform much different than 8MP on the ideal 1/1.2" sensor.

 

[tigerwillow1]

I can't tell anything from the little thumbnails a few posts up but from the text I'm assuming the 4 MP image is still clearer. I don't see a close focus distance on the 8 MP spec sheet. I intuitively think 10 feet should be more than a safe distance but don;t know that for sure. There still could be something wonky in the settings like a super fast shutter speed that limits the amount of light the camera has to work with. One test I use is to enable ROI for a small part of the image. If that doesn't sharpen it up, there's an image capture problem. If it does sharpen it up, it's a compression issue.

About 6 years ago I started out with some 4 MP $160 Hikvision cameras. On a random hunch I got a chinese market 4 MP Dahua camera to try, and it's image was way, way sharper. That's when I switched to Dahua. I don't mean this as a general statement as these cameras are all a few generations old now and it's not valid to claim any of it is applicable. My point is that it was a real occurrence in the past, so it's in the realm of possibility that a certain make/model is simply not so good. The Hikvision cameras I'm putting down did sharpen up quite a bit with ROI, leading me to conclude they were using lousy compression.