Tested: Video Quality vs Dome Bubble

Author: Ethan Ace, Published on Dec 11, 2014

Often, industry professionals will warn about three problems with using domes:

  • The dome bubble degrades image quality
  • The degradation is worse with megapixel cameras
  • The degradation is worse through the side of the dome bubble rather than the center

But is this true?

We tested six cameras from four different manufacturers in multiple scenes, through both the center and side of the dome to find out.

We answered these key questions:

  • How much practical impact do minidome bubbles actually have on image quality?
  • Do different regions of the dome vary in the resolution they can deliver?
  • Do they impact multi-megapixel cameras more than typical HD 720p/1080p cameras?

*****, ******** ************* **** **** ***** ***** ******** **** ***** domes:

  • *** **** ****** ******** ***** *******
  • *** *********** ** ***** **** ********* *******
  • *** *********** ** ***** ******* *** **** ** *** **** bubble ****** **** *** ******

*** ** **** ****?

** ****** *** ******* **** **** ********* ************* ** ******** scenes, ******* **** *** ****** *** **** ** *** **** to **** ***.

** ******** ***** *** *********:

  • *** **** ********* ****** ** ******** ******* ******** **** ** image *******?
  • ** ********* ******* ** *** **** **** ** *** ********** they *** *******?
  • ** **** ****** *****-********* ******* **** **** ******* ** ****/***** cameras?

[***************]

Key *******

*** **** *******, ***** *** *****, ***** *** ****** ********** in ********* ***** ******* **** **** ** ****** ***, ** either ****** ** **** ****** ** ****. **** **** **** text *** **** ******* **** *** **** **.

*** *****-********* *******, **** ** *** **** ** **** ****, image ******* *** ********** ******* **** **** **, **** **** details **** ** ***** **** **** ********* ** ****, ****** facial ******* **** *******.

***** ******* ******* **** *** ****** *** **** (****) ** dome *** *******, **** ** ********* ********** ** ******* *********.

Image ********

******* **** **** ******* **** ***** *************, **** ******** *** full ****, ** ***** **** ***** *** ****** ********* ********** in ***** ******* **** *** **** ** ****** ***. ** the ***** *** **** ******* ******, ******* ********* **** ****** the ****.

*** ********** ***** ***** ***** **** ******* **** ** ****, in * ~**' ********** ***** ** ****, **** *** *** row ******* *** **** **, *** ****** *** ***.

***** ***** ** ****

******** *** ***** ** ****, ******* **** **** ** *** off *** ***** ******* ** *** ****/***** *******. **** ** one ********, ***** **** *** **** *****, **** ******* ******* with *** **** **, **** ****** *** **** ***** ******* harder ** *******.

Effects ** *****-********* *******

****** *** ********** ******, ** *** **** ******, ******* **** slightly ******* ** *** ****, **** ***** (~*/*" ****) **** more ********* ** *******, ****** ****** ******* ******* *** ** very **** *** (~***).

*** **** *** **** ** * ***** ***** ** ****, ~77 ***, **** ****** ******* *******, *** ***** **** **** difficult ** **** ***.

Dome ****** ****** ****

***** *** ** ********* ********** ******* ******* ******* ******* *** center ** *** **** *** ***** ******* ******* *** ****.

**** *** **** ** *** *** **** ******** **** *****:

** **** ** * **** *** **** **** **** **** here:

Comments (20)

John,

That doesn't jibe with what I've found. There is a noticeable difference in fine focus with the bubble on versus with the bubble off in many applications. The difference is exacerbated with "long" lenses and often gets worse towards the edge of the dome. The focus can be restored by focusing through the bubble but that is a pain to handle.

Some manufacturers (including IndigoVision and Arecont) include a "focus tool", which is basically a cross section of a bubble. Using that to accomplish fine focus does help but it doesn't always guarantee perfect focus with the bubble on. I believe that may be due to slight differences in lens-to-bubble distance and radius of the dome versus radius of the focus tool.

Perhaps we're more "picky" than most but we try to optimize every aspect of our camera installations, including zoom and focus. It makes a difference when attempting to read card values and suits, gaming chips, currency and other things we absolutely have to see. I would guess that identifying faces is a bit less critical.

"There is a noticeable difference in fine focus with the bubble on versus with the bubble off in many applications."

Can you be more specific? You mention 'long lenses' and edge of dome? How long of a lens? What specific models have you found problems? Are you using factory bubbles or third party ones, etc.

On analog cameras, we use 1.8-3.6mm, 2.8-12mm and 5-50mm lenses. While there is little, if any, focus difference bubble on/off with the 1.8-3.6mm lenses, 2.8-12mm lenses exhibit progressively more variability as we zoom in and 5-50mm lenses are even worse. Also as we take the aim closer to horizontal (towards the rim of the dome), the focus issue tends to get more pronounced. In fact, as we near maximum zoom, the difference between bubble on and bubble off becomes very pronounced.

On MP cameras, we typically use Theia 1.8-3.0mm, Arecont 3.3-12mm and various 3.1-8mm and 9-20mm lenses. We have observed the same issues with the MP lenses. We haven't tried 5-50mm or other very long focal length lenses on MP cameras yet.

Obviously, this is not a problem with power zoom/focus lenses since they can be focused with the bubble on. All tests are with factory bubbles.

I certainly can see the issue with the non factory lenses, especially longer ones. Our tests were with manufacturer included lenses.

Btw, we have a discussion on that exact Arecont issue that I am sure you know about but for others - Solution To Focus Problem For Arecont Dome.

I think we agree then it is not typically the bubble itself that inherently degrades quality but the focusing of longer lens inside a bubble, yes?

JH,

I don't get your point about "factory lenses". We get the same thing with the integral 2.8-12mm S-mount lenses on Vitek cameras and have seen it on other domes with integral long focal length lenses. We even get it with the IndigoVision cameras with factory-provided 9-20mm lenses.

I really don't think this can be passed off as a lens issue. It is a bubble issue. I've had manufacturers acknowledge that, especially with longer focal length lenses, the bubble tends to act like an element of the lens.

On a related note: I've never seen this in a camera housing where the front glass is parallel to the front of the lens so my educated guess is that the curvature of the bubble acts like a lens element.

It is a combination issue - long lens + bubble.

Ethan, please check on our cameras what happens with the longest integrated factory lenses we have.

Also, are you claiming that it is inherently worse - long lens + bubble or that it requires a focal adjustment? The latter is what the manufacturers are claiming, e.g., Solution To Focus Problem For Arecont Dome

At minimum a focus adjustment but I've found that at certain angles with narrow FOVs, the bubble distortion can't be totally overcome. If we get one part of the FOV in focus another part is out of focus.

That may be that the lens is not perfectly perpendicular to the sensor. I have had lenses or lens holders where the tightening of the lock screws caused an internal shift which caused that effect.

Bob,

That wouldn't explain why focus is fine across the FOV with the bubble off. I have seen what you describe, though. In at least one case, the lens was cross-threaded into its holder.

Ethan- were the cameras refocused for the on and off shots?

To my eye the dome offs are slightly sharper in all cases than dome on. Same with center vs edge.

The dome bubbles will cause a slight focal shift which is why you see the focus aids.

Ethan- were the cameras refocused for the on and off shots?

Bump. Without knowing this, how can we draw any meaningful conclusions?

Yes they were.

Thanks!

Using test bubble, trial and error, or remote focus?

Great article! Coming from a company that helped design OEM housings for many large manufacturers it takes quite a lot of research to properly design the most optically "clear" bubble possible.

Many will find that the thinner acrylic bubble to be far superior to industry standard polycarbonate bubble. The polycarbonate bubble allows for a more ruggedized window and can acheive an IK10 impact rating. The thinner acrylic while optically superior lacks the impact capabilities of the polycarbonate. New dome materials that can help both these aspects and includes added bonuses such as their ability to be more scratch resistant as well as corrosion resistant exist; however, the price for the material is still 2x-3x that of the polycarbonate and acrylic.

Without getting too technical the keys to optimal optics is high quality uniform extrusions of polycarbonate/acrylic with the most uniform shape to the actual camera lens. The more uniform the overal bubble shape to that of the camera lens the better the overal image of the camera. Meaning the distance from the camera lens to the bubble should be identical across the entire lens. The downfall of this type of solution is you will have a noticeable edge at the very bottom of the dome curve resulting in poor image quality. This is mainly due to the extrusion process resulting in limited horizon degrees for optimal clarity. Acheiving beyond 10-15 degrees above horizon becomes extremely difficult with the degraded extrusion line.

Adding in a tint to the bubble further degrades image quality resulting in a full F-stop typically. Unless a new manufacturing process is implemented or material costs come down we will continue to see this issue regarding dome optics.

Pierce, thanks for the detailed feedback.

Can you comment about how bubble design / manufacturering has changed in the past decade? I am curious what improvements have occured.

Btw, as for tint, we have a test on that: Testing Smoked vs Clear Domes

Dear Pierce McCord,

If possible I would like to have your contact info.

Great test. Appreciated.

Many will find that the thinner acrylic bubble to be far superior to industry standard polycarbonate bubble.

Which type are the domes that were used in the test?

Problems ive had with dome is at night either IR bouncing back off of rain or just dirt on dome which can accumulate in just a few day. Will not use domes outdoors anymore....unless its only hikvision dome with this issue

Login to read this IPVM report.
Why do I need to log in?
IPVM conducts unique testing and research funded by member's payments enabling us to offer the most independent, accurate and in-depth information.

Related Reports on Installation

Access Control Cabling Tutorial on Jan 15, 2019
Access Control is only as reliable as its cables. While this aspect lacks the sexiness of other components, it remains a vital part of every...
Winter 2019 IP Networking Course on Jan 10, 2019
Today is the last day to register for the Winter 2019 IP Networking course. This is the only networking course designed specifically for video...
Project Documentation Forms & Work Order Tutorial on Jan 07, 2019
This form may be one of the most important tools integrators ever have doing install and service work. Inside we provide a sample template form,...
Startup Sunflower Labs' Autonomous Drone Security System on Dec 11, 2018
Startup Sunflower Labs is claiming a unique design on a home security system, combining autonomous drones and 'Sunflower' sensors. Imagine an...
Ubiquiti $79 Flex IP Camera Tested on Dec 07, 2018
U.S. Manufacturer Ubiquiti has released a 1080p, integrated IR IP camera, selling it directly for $79, making this one of the least expensive IP...
ADT Promotes DIFY - "Do It For You" on Nov 30, 2018
"Do It Yourself" (DIY) is a popular expression and has become such a common word that it has even made the Cambridge English dictionary. But why...
Ideal SecuriTest IP Vs Unbranded IP Camera Install Tool Tested on Nov 21, 2018
In our recent IP camera installation tool shootout, multiple members questioned the Ideal SecuriTest IP's features compared to low-cost unbranded...
IP Camera Installation Tool Shootout - Avigilon, Axis, Ideal, Hanwha, Triplett, Veracity on Oct 23, 2018
Setting up IP cameras has historically been challenging, with techs often precariously using a laptop on a ladder or lift. Some options for install...
IP Camera Installability Shootout - Avigilon, Axis, Bosch, Dahua, Hanwha, Hikvision, Uniview, Vivotek on Oct 08, 2018
What are the best and worst cameras from an installation standpoint? Which manufacturers make it harder or easier to install their cameras? We...
Network Cable Testing Guide on Oct 02, 2018
Proper cable installation is key to trouble-free surveillance systems. However, testing is often an afterthought, with problems only discovered...

Most Recent Industry Reports

Cable Trenching for Surveillance on Jan 21, 2019
Trenching cable for surveillance is surprisingly complex. While using shovels, picks, and hoes is not advanced technology, the proper planning,...
Milestone Favorability Results 2019 on Jan 21, 2019
Milestone's favorability moderately strengthed, in new IPVM integrator statistics over their results from 2016. While the industry has been...
Intersec 2019 Live Day 1 - Massive China Presence on Jan 21, 2019
There’s a massive presence from Chinese or China-focused video surveillance firms, chiefly Hikvision, Dahua, Huawei, and Infinova, at...
The IP Camera Lock-In Trend: Meraki and Verkada on Jan 18, 2019
Open systems and interoperability have not only been big buzzwords over the past decade, but they have also become core features of video...
NYPD Refutes False SCMP Hikvision Story on Jan 18, 2019
The NYPD has refuted the SCMP Hikvision story, the Voice of America has reported. On January 11, 2018, the SCMP alleged that the NYPD was using...
Mobile Surveillance Trailers Guide on Jan 17, 2019
Putting cameras in a place for temporary surveillance where power and communications are not readily available can be complicated and expensive....
Exacq Favorability Results 2019 on Jan 17, 2019
Exacq favorability amongst integrators has declined sharply, in new IPVM statistics, compared to 2017 IPVM statistics for Exacq. Now, over 5 since...
Testing Bandwidth Vs. Low Light on Jan 16, 2019
Nighttime bandwidth spikes are a major concern in video surveillance. Many calculate bandwidth as a single 24/7 number, but bit rates vary...
Access Control Records Maintenance Guide on Jan 16, 2019
Weeding out old entries, turning off unused credentials, and updating who carries which credentials is as important as to maintaining security as...
UK Fines Security Firms For Illegal Direct Marketing on Jan 16, 2019
Two UK security firms have paid over $200,000 in fines for illegally making hundreds of thousands of calls to people registered on a government...

The world's leading video surveillance information source, IPVM provides the best reporting, testing and training for 10,000+ members globally. Dedicated to independent and objective information, we uniquely refuse any and all advertisements, sponsorship and consulting from manufacturers.

About | FAQ | Contact