My main problem using a DSLR at a wedding is the photographers reaction when you produce a camera almost identical in spec to his then trying to explain it’s for filming !
I spent over 15 years filming top end wedding videos for clients and finally pulled out five years ago but the biggest bugbear at any wedding was the photographer. During my last 3 years filming weddings I would take a digital photograph of the happy couple and ask the photographers permission or if I knew he was a pain in the ass I would wait for him to leave then get my picture. The picture was used for the DVD cover shot.
Convincing the photographer is just one of many problems you will face using an HD DSLR…
Filming time is limited to 4GB (Canon 5D2) then the camera will stop filming automatically, remember you can film 4 x 4 chunks of 4GB on a 16Gig CF card but what are you going to miss when the camera stops 4 times. This is far from satisfactory in my books can you imaging loosing part of the vows !
Sound is a nightmare we have a camera that produces crap sound so bad that you are forced to use an external device such as a Tascam DR-100 now that is fraught with danger. You have many things to do at a wedding and remembering to switch on the sound unit just before the bride comes down the isle is playing with fire. The battery may run out, you may forget to put it into REC mode then you have a major problem because you wont be able to rely on the camera sound !
Extra time is something you don’t want in an editing situation, weddings take long enough to edit, the best part of two days the last thing you need is adding to this and I can assure you by the time you have finished editing a wedding with your HD DSLR you could add an extra half day converting 30p to 25p and as a colleague of mine found out recently MPEG Streamclip a program used by many Canon users does not transfer frame for frame leaving you with horrendous sync problems leaving you with Compressor which as you know takes an age to render lots of clips.
Weddings are a one off where you get one chance to get it right so don’t burden yourself further with technology that is in my opinion is not fit for purpose… and is nothing short of a phase, I hate to say it but when Japan wakes up to the film look we will get a proper film look camcorder and this nonsense of using a DSLR will be at an end. RED are producing such a camcorder called Scarlet but at about £8K plus may be out with most of your budgets.
I have seen far too many badly produced wedding videos in my time to set loose a further band of cowboys who think the Canon 5D2 is perfect for filming weddings.
On a more positive spin I came across a wedding edit by “stillmotion” in the USA using one Canon 5D2, two Canon 7Ds and is quite remarkable, steadycam, tracking shots you name it…have a look.