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-   -   Shallow depth of field :( (https://www.dvinfo.net/forum/canon-eos-crop-sensor-hd/470221-shallow-depth-field.html)

Bart Wierzbicki December 30th, 2009 02:14 PM

Shallow depth of field :(
 
Hey,
I'm using my 7D especially for Wedding vids and I use my old Nikon lenses on it.
they are mostly f1.4
So with those fast lenses I can lower my ISO, but when I have it wide open it is really difficult to maintain the focus. I'm all the times re-focussing my lenses and it's really annoying in the video.
What do you suggest ? Just keep them for example at f5.6 and just put a higher ISO and more grain ?
I'm curious how you all deal with it.

Bruce S. Yarock December 30th, 2009 02:51 PM

Welcome to the world of trying to focus at an event with the 7d.
If your lenses are wide open and you're fairly close, you'll have very shallow dof, and difficulty focusing in a changing enviornment. You'd need to move farther back and/or stop down and raise the iso ( or find a way to get some additional light).

I've done a lot of weddings, and have recent started using the 7d for selective shots.
The z-finder helps quite a bit. Also, I've had good luck with the Canon 17-55 is and the Tokina 11-16.

There's NO WAY that I would attempt to shoot an entire wedding with only the 7d. I rely on my real video cameras for the fast action, ceremony, etc., and will use the 7d when I can. Beauty shots, some interviews, etc.
Good luck
Bruce Yarock

Bart Wierzbicki December 30th, 2009 03:40 PM

Yeah, so I'm not the only one with those problems. hehe ;o)
During the Ceremony I use the HV30 for a fixed point of view continuesly
Then I use an XHA1 on a steadicam and a 7D on a monopod.

During bridal prep a 7d is nice because they are sitting mostly when doing their hair or putting on some make-up.
But as soon as they start moving. It's really difficult for the focusing.

Raymond Tsang December 30th, 2009 03:54 PM

If necessary, you can always bump the ISO up to 640 (and even 1250) if you need to stop down more. I prefer to stay under 1250.

Ron Chau December 30th, 2009 04:32 PM

Here's a wedding video made with 2 Canon 7d's, no camcorder and one very talented cinematographer.



Bruce S. Yarock December 30th, 2009 04:52 PM

"But as soon as they start moving. It's really difficult for the focusing. "

That's the truth.
Bruce Yarock

Chuck Spaulding December 30th, 2009 05:57 PM

Quote:

Originally Posted by Ron Chau (Post 1466255)
Here's a wedding video made with 2 Canon 7d's, no camcorder and one very talented cinematographer.


jc plus esther // all 7d highlights on Vimeo

Wow I'm always amazed at how good some videographers are.

That was really good. I'm not good enough to something like this with just a 7D but obviously it can be done.

Bart Wierzbicki December 30th, 2009 06:05 PM

Yeah that video is great !
I had seen it before.
Do you also use the Highlight Tone Priority.

I haven't used it yet, while it limits your ISO.
You can't select 100 - 200 ISO settings.

But if I have to use ISO 400 for example.
Do you advise using it ?

Raymond Tsang December 30th, 2009 06:27 PM

I believe they shoot with highlight tone priority ON. I'd have to double check the thread though.

We've been shooting with it on to maintain more details in exchange for some noise (although the noise hasn't been enough to bother us yet).

Michael Liebergot December 30th, 2009 07:47 PM

Interesting how practically all of the shots are where the subject is not moving. No follow or pull focus type shots, where HDSLRs currently don't perform well. So the editor decided to not show the bride walking down the aisle but rather a wide distance walking shot and then she's up front.

It's edited nicely with great audio documentation so the lack of pull focus shots doesn't bother me in the least. Just wanted to mention my observation about how the shooters knew the weaknesses of their tools and found a great way to work around them.

Charles Papert December 30th, 2009 10:29 PM

Quote:

Originally Posted by Michael Liebergot (Post 1466333)
Interesting how practically all of the shots are where the subject is not moving. No follow or pull focus type shots, where HDSLRs currently don't perform well.

That's an interesting way to put it! There's no performance issue with the gear, it's the inherent difficulty of pulling focus in a shallow depth of field environment that makes this more of a human issue than a mechanical one.

1.4 is a stop that even the most experienced focus pullers will wrestle with in the cine world (roughly equivalent to the 7D sensor size). Shooting the same with a 5D is a near assurance that the footage will be soft unless everything is static.

Where the system is the most problematic at the moment is the short barrel throw and limited markings on still lenses which makes focus pulling that much more difficult, at least in the traditional sense. Pulling focus by eye, i.e. by watching a monitor, will always be a hit-and-miss proposition as one is reacting to the image rather than anticipating it. But perhaps you are referring to the idea that eventually some form of autofocus will come into play. It will be interesting to see how the camera manufacturers respond to the challenge of a useable form of autofocus for a large sensor camera--it's a tall order.

Michael Liebergot December 31st, 2009 08:03 AM

Quote:

But perhaps you are referring to the idea that eventually some form of autofocus will come into play. It will be interesting to see how the camera manufacturers respond to the challenge of a useable form of autofocus for a large sensor camera--it's a tall order.
Yep autofocus is the biggest reason why I haven't moved to HDSLR yet.
While I love the depth of field and low light ability of HDSLRs, the ability to get an accurate pull focus in a run and gun, only one time to get the shot (like a wedding), if just to difficult to use only HDSLRs. Unless you have 3-5 of them in use at the same time, with two being focused on a processional aisle (Splitting the aisle of sorts). Another issue with HDSLRs is the ability to shoot for more than 12 minutes without having to push the record button again. So for ceremonies it's a no go, but for receptions more doable. Unless of course you have a pair of HDSLRs on you and you can bounce back and forth.

But back on subject.
Until Canon releases a camera that has good autofocus and can at the least simply breakup the clips at 12 minute intervals, I will be using HDSLR cameras with actual video cameras, as many are doing today. So use the video camera for documenting the shots and HDSLR cameras for beauty wow, stationary shots.

Keith Moreau December 31st, 2009 10:36 PM

I think manual focus on HD camcorders is difficult anyway. There are so many times when I think I'm in focus and I'm slightly off, and that's almost as bad as being really out. That's why I really appreciate the focus 'peaking' function of and the real-time focus-expansion of my EX1 (and to a lesser degree my JVC HM100). The 7D would be so much more functional if it had some focus aids like this.

The Zacuto Z-Finder is great and does help, but the LCD isn't quite sharp enough to know for sure, so you have to zoom past and then back to see what position is the 'least blurry.' With subjects moving relative to the focal plane of the camera, with larger apertures (even smaller than 2.8) focus is challenging. I think part of all this is to study the focus characteristics of the various apertures. I have some handy DOF apps for my iPhone, and I plan to do some studying with a tape measure and verify what I can get away with at a particular aperture and distance.

I also think I need to do some fine tuning on the AF of my lenses. I don't quite trust when I push the AF button that what I'm getting is as sharp as possible. There AF tuning procedures I've read about here in this forum that I plan to implement. I do push the AF button pretty often, ruining the shot for a second or so but sometimes I'd just like to trust the camera to do it for me. Still photographers can use a much faster AF mode than videographers on this camera, and from what I've read and heard, they use AF all the time.

So I feel your 'focus pain.' But it's a skill we'll all get better at, the 7D forces us to face what pro cinematographers have experienced since the beginning.

Brian Luce December 31st, 2009 10:41 PM

Quote:

Originally Posted by Keith Moreau (Post 1466719)
That's why I really appreciate the focus 'peaking' function of and the real-time focus-expansion of my EX1 (and to a lesser degree my JVC HM100). The 7D would be so much more functional if it had some focus aids like this.

You don't find that focus magnification button usable on the 7d?

Also, a loop with some form of magnification makes a huge difference.

Keith Moreau January 1st, 2010 02:55 AM

Hi Brian

Yes, the 3x magnification I get from my Zacuto Z-Finder is indispensable. I still find that the LCD doesn't quite have enough sharpness for me to know if I'm actually in focus as much as I'd like. Some of that is practice, some of it is just that it's not as high a resolution display as would be ideal under critical focus situations. We're all using this 7D in a way that it probably wasn't designed to be used.

The focus magnification button on the 7D is very useful, it would be even more useful if I could activate it while shooting, I'd probably have it on all the time. As you know it cannot be activated while actually recording. It seems realistic to hope that Tram and his Magic Lantern would eventually offer that feature, if it's at all possible.

-Keith


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