Fixed-Focal vs Vari-Focal

[tuvow]

Comparing IPC-T54IR-AS-S3 (Fixed-Focal) to IPC-T54IR-ZE-S3 (Vari-Focal), there seems to be a few advantages with the Fixed-Focal:

• Cheaper
• 50m max illumination versus 40m max illumination
• F1.6 versus F1.8, so I assume slightly better light sensitivity?

Does the Fixed-Focal have any downsides in terms of picture quality or features that I should be aware of other than the fixed field of view?

 

[wittaj]

If you know that the fixed focal will fit your needs, it will benefit from a slightly better image.

But if you are not sure if you may need more optical zoom, then the varifocal is the way to go.

Keep in mind though that most end up deciding they want more zoom:

i-want-2-8mm-cameras-everywhere-to-see-everything-this-is-why-you-need-specific-fovs-with-purposeful-focal-lengths.70053/

 

[Ri22o]

I wasn't sure which way you meant the "also comes with a mic" detail, but wanted to clarify for the OP, just in case.

Both versions come with an onboard mic for audio, the -ZE just doesn't have the letter in its model name to denote this. It really should be -ASZE for Audio, SD Card, Motorized Lens, and ePOE.


If you know you only need 2.8mm or 3.6mm, then there isn't much reason to go with the varifocal. However, if you are considering a 6mm, I typically suggest going for the varifocal because you will likely end up at the full 12mm.

I will throw some pictures from the above link in here.

T54IR-AS in 2.8mm at 11ft distance and 5ft install height compared to a T54IR-AS in 3.6mm at 11ft and 9.5ft install height.


T54IR-ZE set to 12mm:
40ft


25ft


18ft

 

[Revo2Maxx]

Fixed has a F1.6 max and to me that I guess is also for the 6mm, Then the Zoom camera has a max of f/1.8 and this is at the 2.8mm zoomed out and not sure what it would be at 6mm let alone 12mm.. I know that my 22x has a f/1.5 and zoomed in full is about f/3.4 and i am sure the 12mm might not be much over f/2.0 but if needing low light quality at night wouldn't 6mm with a fixed f/1.6 be a better option?

 

[bigredfish]

The Varifocal MAX (most wide open =Best) Aperture is F 1.8 at no zoom. Like ALL varifocals, including PTZs, it will get Larger or Worse as you zoom out. It gets worse fast.

I wish they would show standard VF cameras F-stop the same way they show PTZs

Look at the F-Stop on the Mini PTZ - F1.6–F3.6

SD4A425DB-HNY - Dahua International

SD4A425DB-HNY

www.dahuasecurity.com

Even the cheapy 3 series 5X zoom PTZ shows F1.6–F3.0

https://www.dahuasecurity.com/products/All-Products/PTZ-Cameras/WizSense-Series/SD3/SD3C405DB-GNY-A-PV

 

[bigredfish]

Fixed has a F1.6 max and to me that I guess is also for the 6mm, Then the Zoom camera has a max of f/1.8 and this is at the 2.8mm zoomed out and not sure what it would be at 6mm let alone 12mm.. I know that my 22x has a f/1.5 and zoomed in full is about f/3.4 and i am sure the 12mm might not be much over f/2.0 but if needing low light quality at night wouldn't 6mm with a fixed f/1.6 be a better option?

Yes