Where most of the problems arise with first time filmmakers? A dangerous trait that often infects the amateur film producer is the idealism that "exposure to a skill" is just as good as being schooled and trained in a professional art. In simple terms, some people are either too proud or desire instant satisfaction of success, that they'll live with the guise that "just because they witnessed someone use a film technique, like guerilla-style filming on a project," that they know how to produce an entire film. Guerilla Style Filming [GSF] isn't an approved skill provided in film school, as it doesn't require the use of specific lighting or on set camera rigs or use of "lens scoping" to prepare in capturing a scene, due to the lack of lack of obtaining permits or requiring authorization.
GSF is rarely practiced in Hollywood today, but during the independent film genre production rise of the 1980's and 90's, classic films like Jim Cameron's THE TERMINATOR or John Carpenter's HALLOWEEN, epic films that are filled with GSF, that production staffs were scrambling to gain authorization permits up to the final hours prior to the nationwide release of these now classically successful films. Ultra-low budgeted Indie films today have to try and prosper in making films using GSF throughout their production. Many have to try and fake the viewer by using camera tricks and editing software to hide the lack of production efforts in making their films look pristine. Some film makers are successful at hiding their lack of production prowess, some fail, and some don't even try to hide the fact that they lack the skill and training of working a camera.
Knowing how and when to use lighting is a skill, not an option. Amateur filmmakers who claim to know how use proper cinematography usually fail to practice the proper use of lighting, even when there is plenty of light around to fill the scene requirement.
Even some of the most basic standard lighting practices are learned in the photography world; learning how to adjust a camera, correcting shutter speeds, aperture adjustments and even using soft lighting. Most of these basic camera adjustments [or formats] can be easily spotted in a film when they are not in use. Most first time filmmakers make the mistake of using DSLR [Digital Single Lens Reflex] cameras and fail to calibrate the lenses prior to each use. DSLRs may seem easy to use, especially in films that require a ton of action and movement, but they also show that some cinematographers are "playing it safe" using such rigs to capture an entire film.
Inexperience can definitely ruin a films production even before the first camera begins to roll film, especially if the film team plans on thriving with what they've seen in another film production, but not what they've actually learned over time, with proper training and leadership. Case in point is the photo to your right; shooting a photo with the sun directly behind the model and on regular shutter, speed, the model is darkened out. But with the proper settings on camera and with soft light, a more perfect and pristine photo can be captured without the loss of the sun in the background. This part of photography theology is paramount to the experience of a good cinematographer.
In professional film production, the sun cannot be an element that changes the location of the scene at hand or the direction which one must film. Cinematographers must think their way through each scene, keeping focus on balancing the light from any angle. During a day shoot, a strong camera operator should measure the obstacles that might arise during production [as seen below and to your left].
Is lighting truly that important in making your first film? Both yes and no. If you are a high school student or amateur making your first film, you'll look passed the requirements and become instantly elated that you completed your first film, even though parts of it have horrible balance, some bad lighting arrangements, some scenes are slightly out of focus, and it only cost you a few dollars to make. So if your first film makes you truly happy and your closest friends agree, then no.
Most small film teams are only excited that their first film, even with all of it's obvious imperfections, was complete and released for all to see. The concern of being exposed to the rest of the real filmmaking world is the problem and a large part of where one might learn that an experienced camera operator or film director might have some criticisms about the film that your overly excited about making. The reviews may seem harsh and abrasive, but the advice that one should accept as an element to grow will provide providence for future success.
Where you will see that lighting IS important, is when you deliver a film that is well balanced and the views take positive recognition in your efforts to provide the best beauty in every shot of the film. The proper measured lighting will bring in the best color environments that allows one scene to seamlessly cross into another, not bringing any doubt that the film was captured in the best format with the best hands possible.
Even though THE BLAIR WITCH gained significant fame with fans, professional directors and cinematographers were not impressed with the format of the film and over the course of time, the Directors Guild of America took action to prevent films with ultra-low productions to openly cut corners and allow indie films to enter into prominent industry studio contracts without completing prior format and film requirements prior to acceptance. So the "fake it until you make it" mentality will eventually fail.
Should a first time filmmaker consider going to school for the trade? If you want to be taken seriously as a professional in the field, yes.