If I had £10 for every time I'd been asked the question "how long should my video be?" I would be retired now and living on my yacht. It's a perennial question for filmmakers and in these days of short attention spans and a multiplicity of video it's an absolutely crucial one to get right.
At the BBC when we trained our first video journalists one of the things we noticed was how difficult it sometimes was for them to be objective about how long their stories should be; Ian (name changed to protect his identity) worked for me as a VJ. I sent him to cover a week long voyage around the British Isles on a traditional gaff rigged sail boat where children were being taught to sail the old fashioned way. Of course the shots were beautiful and being on the ship for an entire week (because he couldn't get off), Ian felt obliged to shoot absolutely everything that happened. He came back to the newsroom with a suitcase full of tapes, literally. He then began the painful process of going through each one and slowly editing his story. He'd been asked for a three minute piece but after much agonising and cutting down he was struggling to get the story below seven minutes! He had completely lost any objectivity about what he'd filmed and had fallen in love with almost every shot. This is a recipe for disaster.
Over-shooting a story is a classic mistake and one to be avoided. It's also the mistake that's most likely to lead you down the road of creating a video that is just too long and not sufficiently engaging. For beginners we like to work on a ratio of 15 to 20 minutes of raw footage for one minute of cut material. In the face to face video boot-camps we run we insist that students cut their stories to just one minute because unless you learn the discipline of being able to tell a simple story in a minute you will forever struggle to create compelling stories. Once you have that discipline and you understand the basics of storytelling then in theory you can edit anything from a short video for the web to a two hour feature film and still be able to hold your audience.
Once you have your "rough cut" completed you need to be able to step back and look at it objectively. This is tough to do because by this stage you are incredibly invested in the project and may not be able to see what doesn't work. It's at this stage that you may want to enlist the help of someone you trust to give you a second opinion and you have to be prepared to act on their advice. Someone watching your video for the first time is going to have a much stronger sense of whether it works and crucially whether it's too long.
So now to the $64,000 question (so little thanks to inflation) of how long is too long? (this blog probably) For online video one thing is clear; the "dump out" factor is extremely high. Some reports put it as high as 40% of viewers "dumping out" in the first 10 seconds so for the web shorter is definitely better and anything over two or three minutes is going to be a tough sell. Likewise for sizzle reels and promotional videos the shorter the better. Two minutes of highly produced, compelling content is going to sell your work or your idea much more effectively than ten minutes that gives your prospective client more to dislike and time for the boredom factor to set in.
The very first rule I learned in journalism school was "if in doubt, leave it out" and when it comes to online video less is usually more.