Settings for Video in Low Light

[Harry Simpson]

Originally Posted by Kris Koster

I don't own anything slower than f2 here

I'm wondering how you ever get anything in focus with all your lenses being that fast. I like to shoot wide open all the time but even with an f/4 I find it difficult to get the proper DOF for good focus at that.

f1.4 50mm even at 12 feet which I'm sure you'd want to be closer with the 50 only provides a DOF of 1.42 ft
That's less than 18" which if your subject is moving or a group of people need to be in focus is little wiggle room and a bear to keep subjects in focus.

How do you fast lens users handle DOF at those f2s and less?

I usually use IS with the 24-105 f/4L too. Seems like handshake would creep in here too with the non-IS lenses.

[Tony Davies-Patrick]

A 'fast' f/1.2-f/2.8 lens provides a much brighter viewfinder and therefore far easier to focus on subjects than a 'slow' f/4 lens (although this advantage is mainly during shooting stills and is lost to some extent when using Live View).

I do not use IS with any of my lenses for shooting video with the 5D Mark II.

[Harry Simpson]

I understand brighter for focusing. It's the DOF that these fast lenses provide is so shallow whether you have perfect light or not the DOF is going to be too shallow wide open....

[Tony Davies-Patrick]

Just because a lens opens up to f/1.2 doesn't mean that it needs to be used only at that aperture...

Plus that fact that DOF between a 50mm f1.2 or f/1.4 or f1.8 is not that different.

[Harry Simpson]

But between a 50 f/1.2 and a 50 f/4 at 12 ft it's about a three foot difference which would mean the difference in a group being in or out of focus. That's why I usually shoot at f/4 or so anyway...

[Kris Koster]

Originally Posted by Harry Simpson

I'm wondering how you ever get anything in focus with all your lenses being that fast. I like to shoot wide open all the time but even with an f/4 I find it difficult to get the proper DOF for good focus at that.

f1.4 50mm even at 12 feet which I'm sure you'd want to be closer with the 50 only provides a DOF of 1.42 ft
That's less than 18" which if your subject is moving or a group of people need to be in focus is little wiggle room and a bear to keep subjects in focus.

How do you fast lens users handle DOF at those f2s and less?

I usually use IS with the 24-105 f/4L too. Seems like handshake would creep in here too with the non-IS lenses.

Hi Harry,

To answer your questions, first of all I don't always open up to 1.2 on the 50mm, in fact I rarely do unless I'm doing something specific. For a start, it's not at its sharpest at 1.2 anyway. That particular lens peaks at around f2. This is typical of lenses where a lens may well be able to achieve 1.2, but it's at its best at f2. So you may well say, 'well why not save a bunch of money and get a 1.4', and the reason is that you have the same problem where you need to stop down a couple of times to reach that lens's peak performance. But you're right - at 1.2 you can turn a penny at an angle and the DOF is so shallow, some of it will be in focus and the rest won't be.

But what I said in my post, it does depend what your work is when selecting lenses. I don't do weddings, event work, etc. I usually only do commercial spots, drama, music promos, or corporate work. I spend an age setting up a shot that is going to be consistent and actors/artists on their marks where I want to completely throw the background (or foreground) out of focus. so either I pull focus or someone else does.

We use the Z-finder by Zacuto to help us achieve critical focus at various points throughout a scene most of the time and also not forgetting that it's not always crucial when making something artistic to have your subject stay entirely in focus anyway. Shallow DOFs are important to me from an artistic / storytelling viewpoint, so that's the reason I use fast glass and fader NDs to dial in our light thoroughput. But for more complex scenes where people are moving about, or whenever it's put on a steadicam or jib, I have the flexibility to go deeper by closing it up or using my wide f4.

[Erik Andersen]

Similar to what Kris says, you need to select the appropriate DOF for a given shot. You can most definitely shoot an event at something like f/1.2, the majority of events at say a wedding are quite static. Look at how photographers compose shots: everything important in one plane. Neat trick.

For moving subjects, use and wider lens and its hyperfocal distance to keep the subject in focus. When you need to be even more flexible, you always have the option of going to f/4.0 and beyond. But f/4.0 lenses like the 24-105 don't give you a similar option when you need more light ;)

[Nigel Barker]

Nearly two years ago when I first got my 5DII with the 24-105mm F4L kit lens I was quite disappointed at the low light performance compared to the amazing early samples that I had seen which had of course been shot with much larger aperture lenses. I was relieved when I bought some wider aperture lenses to find that I hadn't wasted my money:-) In low light situations an F2.8 (2X light gathering capacity of an F4) or an F2 (4X) let alone an F1.4 (8X) makes a hell of a difference.

The 24-105mm F4L is a lovely lens especially because of the IS but the maximum aperture means that you really cannot use it indoors without adding a lot of extra lighting. It';s fantastic outside in daylight though.

[Kris Koster]

Originally Posted by Harry Simpson

But between a 50 f/1.2 and a 50 f/4 at 12 ft it's about a three foot difference which would mean the difference in a group being in or out of focus. That's why I usually shoot at f/4 or so anyway...

But that frame of mind is restricting you artistically. F/4+ is cool when you want to get the whole group in focus, but you can use and abuse shallow DOFs to draw attention to something, or take a more interesting photograph.

Let's say there is one man in that group of yours that is important. Let's say he's going to wink to the woman OS in front of him and you want to draw your viewer to that subtle interchange. You might use a really shallow DOF to throw the people in that group on either side of him out of focus to help your eventual viewer see the interchange you want them to notice. In this case, your aperature of 1.2 is telling a whole different story to f/4.

Or a photographer, who is taking a shot of a flower and wants to have the stigma super sharp and throw the petals out of focus, or an insect super sharp and its background a nice soft bokeh...

These are all reasons we use shallow DOFs which have nothing whatsoever to do with trying to throw more light onto the sensor.

[Harry Simpson]

I've been a professional photographer for many years so I understand DOF for stills. I know artistic merit and light x multipiers of the diff stops.
All I was talking about was DOF for filming with the 5Dmk2. Thinking of one performance in particular I shot in a dark dive in Nashville. Even at f/4 (which worked by the way) the talent was moving back and forth away from the mic and it was very hard to keep focus sharp. And yes one can always say the blur shots are art but as we all know many of them are us trying to scamble to pull focus.
Since that night I'm using a 7" external monitor which helps with focus alot.
Only reason I chimed in was the no lens slower than f2 comment which left me scratching my head about DOF cause it gets razor thin at those Fs.
I think we're all on the same page and no new news here. ;-) Just different ways to say it.
Happy New Year!!

[Kris Koster]

Hey Harry,

Sorry if my post appeared to be stating the obvious. As with all these things, one can never guess the level of expertise of other posters.

As for DOF and pulling focus at razor thin distances, I think focus pullers are a whole different breed of people. I've worked with some that don't even mark the disk, they just seem to 'know' exactly where the focal point is and rack the focus perfectly. I never could quite fathom out how they do it!

[Mike Hammond]

Hi everyone,

Just wanted to follow up on my original post and thank everyone for their input. I've been shooting manual mode now with a much better understanding of the camera and how to use the different settings. I've also developed a clearer idea of which lenses I'm going to be getting as money allows.

Thanks again!