ok so my installer said the above two cameras are pretty much the same except for the 4mp vs 8mp. the 4mp needs less light. he also said that when using software to zoom in on something, it will look better on the 8mp camera. my question is, do you think the image quality be too low when zooming in on the 4mp camera vs the 8mp camera?
That is what we have been saying.
It is the same camera just the resolution is different.
Both cameras are on the same sensor and processor, so the processor will have to work harder to deal with the 8MP than the 4MP.
It is almost always best to chose a camera with lower MP on the same size sensor as a higher MP camera.
Digital zoom only works in the movies and TV. See this
thread where someone was upset that the digital zoom didn't work better with a higher MP camera (8MP versus 3MP). It is because movies and TV make it look like magic.
Sure we can get away with some, but not a lot.
During the day it would be beneficial in some situations, but most of us the bad stuff happens when it is dark and that is where the 4MP will do better.
You are better off to have a camera with the optical zoom for the area you want than relying on digital zoom after the fact.
At night, at the fringes, the 4MP will show an identifiable image where the 8MP will show an unidentifiable blob. And when the 4MP is showing an unidentifiable blob, the 8MP won't know anything is there at all.