Before I start, I want to make it clear that I in no way oppose using iPhones for video. My concern is that there are a lot of articles and videos on the Internet that misrepresent how easy it is to create a movie using iPhones, and I don't want people to get the idea that they can simply buy a phone and automatically have everything they need to create something on par with an award-winning indie film. Maybe someday, but we're not there yet.
We always have a laptop on set and cable the phone to it and copy the files. You can also use bluetooth or wifi to offload the footage.
That IS a pipeline issue. We always have a laptop on set and cable the phone to it and copy the files. You can also use bluetooth or wifi to offload the footage.
Wifi may not exist on location, and many people, such as myself, don't have laptops or iPhone cables, so those would be additional costs to consider. Also, your phone may be competing with the smartphones, tablets and Bluetooth devices of anyone on set, even if you have Wifi. (That's not even considering all the low-budget wireless lavalier systems that run in the same frequency band as Bluetooth and 2.4GHz Wifi.)
Also true, BUT almost every film with decent sound uses a second sound system. As such a Smartphone is not much different in this regard. Given the terrible sound on most fanfilms I doubt these make any functional difference to most fanfilm makers.
Audio is more important than video. People will tolerate imperfections in your video, and may even think they're an artistic choice, but they'll click away immediately if they don't like the audio. We shouldn't be encouraging fan productions to neglect sound quality, especially when it's the biggest problem in fan films. There's a reason the Tangerine crew recorded all the sound using a Sound Devices 664 recorder, Schoeps microphones, Lectrosonic receivers/transmitters and Sanken COS-11D lavalier mics, and NOT the iPhones they shot the video with.
To give you an idea of what's possible, let's look at an expensive iPhone. I found a listing for an Apple iPhone 12 Pro Max 128GB Fully Unlocked for $1,329.99.
For that much money, I can get a Canon EOS 60D with the 18-136mm kit lens, a Tascam DR-60DmkII, a six foot Amazon Basics XLR cable and a Sennheiser MKE 600 and almost have enough money left over to buy a brand new Rode Wireless Go. That's all brand new. You could probably find it for cheaper second-hand.
(Note that the vast majority of people watching video on YouTube, your most likely means of distribution for your fan film, are NOT watching video in 4K, so you can easily get low-cost, second-hand cameras that are more than adequate for 1080p video.)
Almost everyone has one, so if you use something like Filmic Pro (to standardize settings) you can...
* have other members of the crew use theirs as B and C cameras
* Bluetooth a second phone/tablet to it and have your 1st A.C. pull focus and zoom remotely
Those are both cool things you can do with those devices, but using other people's equipment means that you're asking other people to take on the liability of those phones being damaged during the shoot. Another problem is that the owner of the camera might simply take the camera home without giving you footage. Or worse, your camera person may get upset and simply delete the footage. And what happens if you give someone your lock code to get the footage of your phone, and they take more than you thought they would? This is something that doesn't happen with dedicated hardware.
Gimbals and similar devices for them are much cheaper than for an SLR or video camera due to their small size and light weight
True, but you can get a Glidecam knock-off for $50, and you can get four DJI Osmo Pockets for the price of a high-end iPhone.
Sometimes a framerate non-native to the device ends up being slightly wobbly. I ran into this where the frame rate was set to 24 and would wobble around from like 23.98 to 24.01, which caused occasional dropped frames or stuttering when imported to the fixed framerate of a projectm and that required some post-production fiddling to eliminate.
Actually, that's a serious problem if you're trying to sync up multiple video and/or audio sources from several phones. They may very well desynchronize over time, even if the beginnings are properly lined up.