Image stabilization, vibration control, optical stabilization or whatever you wish to call it is an -in lens- operation that reduces pan and tilt vibrations and shake that would blur the captured image. It works by using electromagnets to align a floating lens element, which corrects the shake and vibration over the two axis; left and right, up and down. Image stabilization is included in a range of lenses from manufacturers, but you will notice the heftier price tag in comparison to a non-IS version due to the extra element in the lens. I will try to clarify the importance of using IS when you're out filming, and why I use IS lenses for my work.
When choosing your camera body, tripod, mic and all of the other accessories that seem to be required for DSLR videography, one of the hardest will be choosing the right lenses for what work you would like to do, to cover a wide range of focal lengths and apertures, and how much money you want to spend. All three of those points will affect each other in your final purchase choice, but I hope to help narrow down your choices.
What will you be filming?
One key point to consider, as if you are filming live action sports you will require a different set of tools compared to model and fashion videos. Both however will benefit from at least one IS lens in your kit bag. I work in many different areas and styles of videography, so the kit I carry is an all round solution to whether I'll be at the back of a conference hall, or only centimeters away from my subject so being prepared before you know what you are shooting on the day is key - also where IS lenses come in handy!
It isn't recommended to use Image Stabilization when you are filming on a tripod as this can cause frame-by-frame jitter, where the lens attempts to correct smooth movement. But for all the times the camera is not on a steady support like a tripod, having IS will correct any major shake and blurring that occurs in the lens.
So, imagine holding the camera on a monopod with a lens and then tilting or panning. Inherently some shaking will occur from you moving the camera. Depending on your focal length or how far you have zoomed in, this will also multiply the visible blur, also remember DSLR's rolling shutter which will also be added too if you're not careful! Is that too much to think about when shooting video? Yeah it sure is. But having an IS lens will correct a good portion of the errors.
Another great example is sports, and running and gunning with the camera (wedding videography for example) where you are moving around a lot.
What focal lengths are you working with?
IS lenses come in a range of focal lengths; the standards are the 24-70 range and 70-200 range. If you are working with subjects closer to you, in the wide and portrait range, then having a 24-70mm with IS can be operated pretty well hand-held or on a monopod (I'd always recommend using at least one support method to achieve steady shots, either a tripod, monopod, rig etc). However if you are going to be further away from your subject then the longer focal length of 70-200 will work better for your needs.
The focal ranges in between the wide and telephoto can be achieved either by zooming, or by using prime lenses which traditionally do not have IS so will have more shake regardless of your mounting or grip method.
You will have to pay more for an IS lens, it is an additional function that works to correct the image before it is recorded, but it is worth the cost. You may only end up purchasing one lens with IS, but I recommend choosing the lens you will use the most to future-proof your purchase.
Models of Lenses and Manufacturers
Presumably, if you are filming on a DSLR you'll have a Canon body with an EF-mount for the lenses. Canon manufacture very high quality L series lenses with IS, but if you are starting out in this game they will blow your budget immediately. 3rd party manufacturers like Sigma, Tamron, Tokina and Samyang produce incredible quality lenses too, and just because they aren't Canon doesn't mean you can't use them with the camera you have; many 3rd parties allow you to choose the correct lens mount for the camera.
In many cases you will be using an APS-C size sensor camera like the 60D, 600D, 70D which also have their own range of lenses that are considerably cheaper than their full-frame brothers, some that I have worked with in the past that I can recommend are -
For a longer focal length, above 100mm you'll have to dig a little deeper in your pocket to get a good quality lens with IS. I did purchase this lens when I started, but because I purchased the NON-OS version it has pretty much been gathering dust in my bag, as at 200mm the image was too shaky and had quite a bit of chromatic aberration. Sigma 18-200 F3.5 to 6.3.. a semi pointless purchase for me, so follow this lesson!
How does using a steadicam affect the stabilization?
Good question. A steadicam is a device that counter balances the weight of the camera and lens to achieve a smooth flowing motion to movement, and takes lots of practice. Using a stabilizer won't imitate image stabilization, or make the image less shaky - so to speak. This depends on the lenses you are using, how fast you are moving and the experience of the steadicam operator. Using an IS lens on a steadicam will certainly correct shake over the two axis, but a steadicam works on 3 axis so shake and blur is inherent unless you shoot at a higher frame rate or apply stabilization correction in post production.
I tend to shoot most of my steadicam footage at 50fps, capturing double the frames which when played back in slow motion smooths out any jitter or quick movement. Shooting in slow motion is a really cool and creative tool, so it is worth playing around with, but remember you will be recording at a lower resolution of 720p, not 1080p (darn you Canon hurry up and give me this!!).
I shot the example material today, so will top and tail the clips and get them up tomorrow, so watch this space!
Get a lens with IS, or VC or OS as your standard, go-to lens. If you're going to use a steadicam too, having stabilization on a wide angle lens will be doubly effective and means less stabilization in post!