Think of varifocal cameras like buying the right fixed focal length camera for each application. Say you need 3 cameras, and you think that you will need a wide angle with a 4mm lens, a moderate angle with an 8mm lens and one a narrow angle with a 12mm lens.
So you order these three cameras and it turns out that once they are mounted the 4mm is a little too wide angle and a 4.5mm or a 5mm would have been a better fit. The 8mm is pretty much perfect but the 12mm is a little too zoomed in and narrow so an 11mm or even a 10.5mm would have been a better choice. If instead of buying 3 fixed focal length cameras you had bought 3 varifocal cameras such as the 5231R-Z then you can adjust the focal length to the perfect fit for each of the 3 cameras. Once the three varifocal cameras are mounted and zoomed to the perfect focal length they are left that way pretty much forever. The pan and tilt aspects of a varifocal camera are utterly manual, you have to physically adjust these aspects each time you want them changed.
Compare and contrast a PTZ or Pan Tilt Zoom camera which are necessarily more expensive as they have motors to pan the camera and motors to tilt the camera in addition to the motors to zoom the camera. A PTZ camera is designed to be in anything between constant motion to infrequent motion.
PTZ cameras do come in a wide variety of prices. As the old adage goes, you get what you pay for. An inexpensive PTZ camera such as a logitech or Arlo might be suitable for your needs but perhaps you would be better served with a slightly more expensive PTZ camera. PTZ cameras can range from less than $100 to $15,000 or more. The sub $100 category looks like a minefield of trouble to me, I did a google search for "cheapest ptz camera" and naturally eBay was the top result. Some of them are brand names I recognize but can only imagine they are knock offs or scams at that low a price, I could of course be wrong but I am not willing to roll those particular dice. The majority of PTZ cameras you will see on this site with high regard are probably in the $150 to $1,400 range depending on bells and whistles. One of the biggest jumps in price occurs when a camera is "outdoor" rated and so able to withstand the elements to a lesser or greater degree. The PTZ camera
@looney2ns mentioned (Dahua SD29204T-GN for $170) looks like an excellent fit for your needs
The enclosure you want to view is not very large so optical zoom is of limited benefit. It appears to be well protected from the elements so you could probably get away with an indoor rated camera. The thing that might make a big difference for you is BLC (Back Light Compensation), WDR (Wide Dynamic Range) and DWDR (Digital Wide Dynamic Range) etc. These technologies address how the camera handles a scene with part of it in deep shadow and part of it in direct sunlight. These technologies work to ultimately darken the bright areas and brighten the dark areas to try to make everything visible to the viewer. The different technologies have their own strengths and weaknesses, and even the best or highest regarded of these technologies still have a cost associated with their use such as washed out colors or graininess etc.
This question you face of which camera to buy is not unlike which car to buy. Do you want ultra basic and therefore the least expensive? do you have to haul a trailer up a hill? do you want to have speeds in excess of 175mph? do you want maximum fuel efficiency? etc. Just as there is no perfect car that fits all these needs so too is there no perfect security camera that fits all needs. Fortunately this site contains a great wealth of knowledge that can be readily searched for and if the answers are still unclear there are a great many users here who will gladly help.
Hope this helps
