Review-OEM Loryta IPC-T5442T-ZE Varifocal 4mp camera (Dahua)

samplenhold said:
Set the Zoom Speed to '1'. Hover your cursor over the slider and a value will pop up. This is the current setting.
Move the slider to the far left to get the minimum number, and to the far right to get the maximum number.

View attachment 153763

Go to the calculator that you linked to and use these numbers.

Realize that for the 5442 cams, the fixed lenes are on a different mount than the varifocal cams. Which means that the calculated value will not be the exact value of the fixed lens version. I did a test of this in the following thread:

Comparison of a Fixed Lens and a Varifocal Lens Camera's FOV

I was testing out a new Dahua T5442T-ZE 2.7-12mm Varifocal camera (from @EMPIRETECANDY ) and was going to compare it's performance to the Dahua HDW5231R-ZE and the HDW5431R-ZE cameras, which are 2.7-13.5mm varifocals, along with the T5442TM-AS fixed lens at 6mm camera. The HDW5431R-ZE has been...
ipcamtalk.com ipcamtalk.com

What I have found is that the fixed lens versions have slightly better specs, but I do not think that this translates to a better image that one can see in real life.
Click to expand...

I was nearly concluding I needed 6mm, I'm glad you posted here. A fixed 6mm is way different then the varifocal at theoretical 6mm, I thought life was going to be easier just testing the varifocal all around and then going shopping for fixed lenses knowing they would fit... God, this is not easy!
 
  • Like
Reactions: David L
from the calculator, it was giving me about 6mm at the zoom I wanted, but that would convert to perhaps 3.5 on a fixed lens with same sensor size? It seems like I'll need to buy a fixed camera to test. I'm wondering how much different a fixed 3.5mm would be from a varifocal at 2.7mm.
 
  • Like
Reactions: David L
bigredfish said:
I think it’s mostly about F Stop

With the current 5442 VF MAX aperture is F1.8
The fixed is F1.6

Again not a photography expert but the MAX aperture assumes 2.7mm focus in this case on the 2.7-12mm VF. As you zoom, that number increases. (Lower is better) so at say 6mm the FStop might be 2.0?

With higher zoom PTZs it becomes more obvious, and the specs typically give the aperture range based on zoom

Example:
On my SD6AL433XA-HNR
Max. ApertureF1.5–F4.8
Click to expand...

I think that is why a fixed lens would have better low light quality, it will have bigger aperture, if you get the varifocal to match that 3.5 or 6mm, then the aperture gets smaller and you get less light in, right? Sorry I'm just learning all these things from reading posts here :)
 
  • Like
Reactions: David L and bigredfish
  • Like
  • Haha
Reactions: CCTVCam, David L and mephisto_uk
  • Like
Reactions: CCTVCam and bigredfish
mephisto_uk said:
I was nearly concluding I needed 6mm, I'm glad you posted here. A fixed 6mm is way different then the varifocal at theoretical 6mm, I thought life was going to be easier just testing the varifocal all around and then going shopping for fixed lenses knowing they would fit... God, this is not easy!
Click to expand...
I thought life was going to be easier just testing the varifocal all around and then going shopping for fixed lenses knowing they would fit

For this simple minded old guy, that is what I did, haha, it worked for me, I think, LOL Well at least I bought the right CAMs, all Fixed 5442s, @samplenhold is right, the Varifocal mount is much bigger, but for me the Varifocal got me enough info for what I needed.

Sites like this helped me too:

Lens Calculator

www.jvsg.com www.jvsg.com

Sorry for my ignorance...just chiming in.

These were the settings I entered for Front yard CAM:
1675989049189.png
My Installation Heights are 8 foot, under my Eves,
I know this is a bit vague, but it helped me see my Dead
Spot under my CAMs...before I tested with the Varifocal...
 
Last edited:
  • Like
Reactions: samplenhold and bigredfish
You must log in or register to reply here.
Top Bottom