Filming documentaries can be an expensive business but if one is clever, it is possible to create a low budget skeleton kit of only the essentials while maintaining high production values. The last documentary I made can be seen above. I produced this film alone without assistants, using the exact skeleton kit described in this post, but it is worth noting that having a second person is very useful! Documentary films should only be shot alone once you've had a whole bunch of experience.
The Camera
The camera body ideally needs to have a full frame censor.
The Canon EOS 5D Mark II is an old body (so should be cheaper) but still one of the best. Nikon is the only other brand I recommend, but in the end any full frame censor camera body will do. The full frame censor gives you better picture quality than the smaller, cheaper sensors.
The Memory Card
You will need a compact flash memory card for recording with a full frame sensor. Though some cameras take the smaller sized cards. I use a SanDisk Extreme 64G for my Canon EOS 5D Mark II but other brands will work fine too. You can use memory cards with smaller capacity but depending on how much you shoot, you may need to offload the card during the day to make space.
The Lens
The lens is just as important as the body because this is what gives you the film look, using the manual focus.
You will need a lens with a low F number. For example, Canon make an f1.4 24mm which is the lens I use for anything filmic.
The low f number means you can open your aperture further than standard lenses, creating a shallow depth of field. What this means is that the focal point of the image is very small, giving you a soft focus for everything which is foreground & background. The 24mm is perfect for me but some people prefer 50mm.
While these fixed lenses are great to capture beautiful cinematic moments, they do not lend themselves to documentary situations in which you are trying to get a wide variety of shots… close-ups, mid-shots & wide-shots.
To achieve this variety of shots you will need a second lens which has zoom capabilities. Personally I use the Canon 24-105, seen here.
This lens is great for capturing a variety of shots but not so great for the shallow depth of field, unless it is zoomed right in. This is because zoom lenses cannot have the lower f numbers. So, this one is an f4, but still good enough to get the shots you need and mix them with the more cinematic shots from the F1.4
As far as I am concerned you only need these two lenses but most other cameramen will tell you to get a whole bunch more! Potentially a wide angle lens, something like a 14mm. And if you can get it, a macro lens can offer beautiful close-up opportunities. Something like a 58mm 0.43x.
The Tripod
I know you said you have a tripod but my experience tells me it is likely not the right type. A basic tripod will work fine if the shot is 100% static, so in an interview situation for example. However, if you are looking to pan the shot, you will need one with a fluid head which permits slow and smooth movements. You can do without the fluid head if you are intending to shoot all of this handheld, but I should warn you that it takes a fair bit of practice to get really good at creating professional looking handheld shots. So, a fluid head tripod will help you create much smoother camera movements. But the disadvantage is that you are stuck in one place, attached to a tripod.
The oldest piece of kit I own is my fluid head tripod. Must be 15 years old now and still works great.
Having a bag is important too, as these things are quite heavy. Please note this item is not essential. Just useful in certain situations.
The Sound
To capture quality sound, the internal camera mic is not good enough. While most people will recommend the more bulky zoom recorders, the basic model is cheap, small and (in my opinion) good enough to get the job done.
Don't forget to buy a mini memory card for this! Audio has small files so even a 2G memory card will be fine.
It is important however to have a decent cable mic plugged into this. The wireless kits are expensive and time consuming to set up, so better to go for a cable lapel mic, ideally made by Sennheiser.
I did not have a Sennheiser for the documentary I posted at the top here and if you listen, you can hear at times how the sound quality lets it down a little. In addition to this, many shots looked great but I could not use them in the edit due to bad sound being created by a cheep mic. So, quality sound needs a quality mic.
The Lights
If you are in an interview situation (with electricity) I recommend having two lights on stands. I use two Dedolights for this purpose because they are small and lightweight. And long lasting! Like the tripod, I think mine have been going for around 15 years. The only thing I ever need to replace are the bulbs.
If you are in a situation with no electricity, a battery powered hand held light is important. Doesn't really matter what make it is.
Sometimes you may want to use it on the camera but other times you may want to attach the light to a tripod, or have your assistant hold it off to one side. The orange filter is used to match the colours with artificial lighting or a fire. While the white/blue filter is for sunlight situations. Cameras are notoriously bad at capturing quality video in low light, so having extra light is essential for dark situations.
I know you are thinking of filming in low light, so this will be important for you. If you are able to get an f1.4 lens this will help a lot with the low light situations. The low f number means a wide open aperture and therefore more light getting to the camera censor.
The Drone
Getting shots from the air brings a whole new level of professionally to your production but the downside is that plenty of practice is needed to become a proficient operator and they are not so cheap. But getting cheaper all the time!
The DJI Mavic mini looks perfect for documentary producers. You can almost put it in your pocket!
The Editing
Probably the most important and time-consuming part of any film project is the editing so it is useful to have a decent program like Final Cut Pro X or Adobe Premiere. It is possible to edit on phones these days but for the best final product a computer is preferred.
I hope I haven't freaked you out with this list @joseacabrerav & @auelitairene
It sounds to me like you have a great subject to capture and whatever you decide to do, I feel sure it will be awesome.
I realise it may not be possible to get your hands on all this kit, but you do at least now have a list of the essential bits and something to aim for.
We don't say "good luck" in the film industry. For some strange reason this is considered to be bad luck! So, instead what we tend to say is "break a leg" though if I'm gonna be honest this doesn't seem much better!
What I prefer to say to you is that anything can be achieved when the desire & vibrational foundations are strong enough.
Where there is a will, there is a way.
And it seems to me you have a strong will.
Keep in touch my friends, I am here to help.