Tested: Video Quality vs Dome Bubble

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?

Key Lessons

For most cameras, 1080p and below, there was little difference in practical image quality with dome on versus off, in either narrow or wide fields of view. Only very fine text was less legible with the dome on.

For multi-megapixel cameras, such as the 10MP in this test, image quality was moderately reduced with dome on, with fine details such as small text more difficult to read, though facial details were similar.

Image quality through both the center and side (edge) of dome was similar, with no practical difference in details delivered. 

Image Examples

Testing with five cameras from three manufacturers, both minidome and full size, we found that there was little practical difference in image quality with the dome on versus off. In the 1080p and 720p cameras tested, details delivered were nearly the same. 

The comparison below shows these five cameras side by side, in a ~25' horizontal field of view, with the top row showing the dome on, the bottom row off.

Wider Field of View

Widening the field of view, details with dome on and off are again similar in the 720p/1080p cameras. Only in one instance, third from the left below, were details reduced with the dome on, with facial and test chart details harder to discern.

Effects on Multi-Megapixel Cameras

Unlike low resolution models, in the 10MP camera, details were slightly reduced by the dome, with small (~3/4" tall) text more difficult to discern, though facial details similar due to very high PPF (~145).

The same was true in a wider field of view, ~77 PPF, with facial details similar, but small text more difficult to make out.

Dome Center Versus Edge

There was no practical difference between cameras viewing through the center of the dome and those viewing through the edge.

This was true in the low cost minidome seen below:

As well as a high end full size dome seen here: