Real world biology works different.
Pupil is actually the "hole" on the iris. It lets different ammount of outer light reflections reaching inner side of the eyes. The inside of a human eye is covered with a layer called 'retina', this contains the specific bodypart, which turns outer light reflections into electric signals possible to be processed by the brain.
First dependency: Is the retina same or better/less developed?
Second dependency: Is the brain image processing is same or better/less developed?
Third dependency: What is the light reflections perceptable around?
I believe this latter one is the point you are interested in, as visibly "big-black-eyed" creatures adapt better to low light (even if smallest measuarble ammount. With no emitted light, an eye structure is useless) environments. Should you expose them to overwhelming type and ammount of light (please everyone, don't do that), it will temp/perm damage their eyes or even brain.
Multiple other dependencies still follows, but the question is covered.
2) What do you mean at "looking around"?
The basic mechanics you can discover also with just a hand of yours using as obstacle, positioned in front of you.
In short, if you turn "your lens" behind a covering material (even if partly), it will of course block you from getting a complete image.
Forth dependency: Distribution of light processing types on retina? If ever wondered, why our retina exactly goes wide or pointy, it is because the different location of percepting 'sticks'. In sharp light, the middle ones work better, in dim light, perimeter ones work better. You can try to read a digital clock panel by night with no room lights on. You will be able to get clear numbers only if not focusing on the panel, but just close to it.
So in dim light, if the pupil is wide, and location of dim light processing units located on perimeter area, image is obstructed in the ration of blocked
line cone of sight related to completely unblocked. The brain mght still try to complete the vision with memory stored segments, however it will be not a real-time vision, but this will not necessarily be known to the person. Might require extensive knowledge on the topic.
3) DEPENDS. On social culture.
It absolutely depends on what the people associate individually or collectively with this specifics. They can be superhumans, falsely mistified gifteds, disadvantage holders...it comes mostly from history and folklore.