Varifocal versus fixed cameras.

[Justin Blackburn]

I have a few fixed cameras, but the focus on them never seems as good as varifocal. I know fixed lens options are around 30 bucks cheaper, but if a particular camera is offered in a varifocal, I can’t see myself buying a fixed lens version of it. I know everyone may have different opinions on this. I wanted to see what some of the reasons are that you pick a fixed lens version.

Fixed Lens Pros:
1) Slightly cheaper. (30 bucks doesn’t mean a lot to me when spending 150+ on a camera.)
2) Slightly smaller. (The varifocal models I got seem slightly larger than the fixed lens, but it’s a small difference.)
3) Some models may not offer a varifocal. (Like the newer dual lens or 4K-X)

Varifocal Pros:
1) Ability to zoom in to get the exact portion of coverage needed. (This may or may not coincide with an available fixed lens for sale at cheaper price.)
2) picture always seems sharper to me. (This is due to the wide range of focus and this is the one that a fixed lens can’t overcome.)

What reasons do you all have when buying one over another other than what’s above?

 

[wittaj]

What most people don't realize is that even though the fixed lens is an "infinity" focus, it really isn't, and every manufacturer has a sweet spot distance for the focus. Some are worse than others, but it can certainly be more pronounced with higher MP cams.

The issue is too many people buy the fixed lens and install too high and the sweet spot distance is lost vertically and the optimal focus is somewhere in the middle of the air that an object won't be at.

Unless you know for sure that your object will fall within the sweet spot distance and the camera isn't installed too high, the fixed usually will have slightly better optics (better f-stop in some instances). Some people notice a difference and others don't. YMMV.

My preference is to go with the varifocal option if possible. Much more flexible in placement. If you upgrade the camera, the old varifocal can probably be added someone else, and most of the time after a camera is installed, we wish we had more optical zoom.

 

[StevenFromTexas]

I've got eleven cameras . . . so far. They're all varifocal. I have absolutely zero interest in a fixed lens camera and have no plans to ever purchase one.

 

[Flintstone61]

The only fixed lens that i found surprising, is the 6mm 5442 mounted 11 feet up on a telephone pole in the problem area of my condo parking lot.

 

[bigredfish]

One benefit of fixed lens, in the 5442 or 7000 series models, is better low light performance. Look at the Fstop on a VF at zoom vs a fixed of the same model. Ive shown/seen this many times.

Post #26

Review: Dahua HFW5442T-ASE 4MP Starlight+

Awesome. Thanks! The online spec sheets are often wrong, as I can set my cameras to 10240, but the spec says it maxes out at 8192. 20Mbps is much better, and is more reasonable for a 4MP camera.

ipcamtalk.com

 

[The Automation Guy]

A fixed lens should perform better than a variable lens. All things being equal, the added lenses and components needed for the variable part of the lens will reduce the overall quality of the capture images. All that is theoretical however. Obviously this depends on the manufacturer and even the particular camera itself. Not every camera has the same tolerances and quality control from unit to unit.

Variable lenses are great, but honestly the are unnecessary when you know your final focal length matches up with a fixed focal length lens of that particular camera model. This generally occurs at the wider focal lengths. IE getting a variable focal length camera and setting it at 2.8mm is a waste and it would be better to simply get the 2.8mm version of that camera. Of course this may never occur at your location. It may be that all of your cameras need a non-standard focal length to optimize them.