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Canon XH Series HDV Camcorders
Canon XH G1S / G1 (with SDI), Canon XH A1S / A1 (without SDI).


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Old June 17th, 2007, 02:28 PM   #1
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Depth of Field

I just bought my Canon XH A1 a few weeks ago. I having trouble messing with my depth of field in manual mode? Am i doing it wrong? not enough distance from objects and background? Any help would be nice.
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Old June 17th, 2007, 02:31 PM   #2
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Welcome aboard. Start with http://www.dvinfo.net/articles/optics/dofskinny.php.
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Old June 20th, 2007, 01:28 PM   #3
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I hear ya

I'm trying to control my DOF with the A1 I just got too. I'm trying to get a good look without buying one of those add-ons. Let me know what you find Mike, and I'll let you know what I find. The Article that Chris mentioned is a great place to start, but we got to do the trial and error thing.
good luck--let me know how it goes
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Old June 20th, 2007, 02:17 PM   #4
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In my opinion, to get significantly shallow depth with the A1 simply requires too much working space. By the time you're down the barrel of the A1, you're already losing a stop or more of aperture, which compounds the problem unless you're in a lot of light.

Sure, you can do it, and you can do it well if working space and light are no issue, but it's not going to be a dependable look on a consistent enough basis.

$.02

I'd love to hear from detractors.
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Old June 20th, 2007, 02:39 PM   #5
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There are plenty of articles online about DOF... basically these key things to get shallow DOF...

Assuming you are full manual operation.
1- Aperture/Iris/F-stop (same things) need to be wide open (lower fstop number)
2- Use ND filters and/or higher shutter speeds to lower the light amount if needed and not use the iris ring.
3- Distance... play with it some. Zoom in slightly if needed, but if not a lot of available light, DON'T zoom in all the way to achieve this as your f-stop rises as you zoom in!

Play with it, you can get good DOF with stock lens in most situations.
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Old June 20th, 2007, 02:41 PM   #6
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i think you can start to get noticeable separation starting at the middle of the zoom range with the xha1 stock lens. shooting room aside, another thing to consider is that the more you're on the telephoto end of the zoom, the more the depth in your picture will be compressed, meaning objects in the background will appear closer/bigger than they actually are. if you want to stay wide and exaggerate the depth of objects in the background, AND maintain shallow DOF, you couldn't achieve that with the stock lens alone. a 35mm adapter will give you some more creative options in this way.
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Old June 20th, 2007, 02:53 PM   #7
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Dof

Well, I realize I'm probably stating the absolute obvious to many people here,
but this is indeed the problem that many of us face everyday with our
sub $10K cameras. Some things we always practice are.
1. Longest room you can shoot in, i.e. max distance between subject and BKGD.
2. Shoot with the iris wide open and light to that, not adjust iris to the lighting.
3. If it's an interview, I try to add a very mild SFX filter on the lens.
4. A darker subtley lit background helps mask the long DOF a little better.
5. Try to place the camera at least 8-10 feet from the subject. (this ususally ends up being a trade off in practicallity, since you rarely get to specify exactly where you shoot)

Anyway hope that helps someone, even though it may be obvious to many others. I've included a link to a video that at about 2 min into it has some interviews that were shot with a Z1 (1/3 inch Chip) Sorry to make someone sit thru the whole beginning of the vid to see the interview, but it's what I had handy. http://nglassviewer.com/viewer/index/219
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Old June 20th, 2007, 04:47 PM   #8
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Quote:
Originally Posted by Jerome Cloninger View Post
There are plenty of articles online about DOF... basically these key things to get shallow DOF...

Assuming you are full manual operation.
1- Apeture/Iris/F-stop (same things) need to be wide open (lower fstop number)
2- Use ND filters and/or higher shutter speeds to lower the light amount if needed and not use the iris ring.
3- Distance... play with it some. Zoom in slightly if needed, but if not a lot of available light, DON'T zoom in all the way to achieve this as your f-stop rises as you zoom in!

Play with it, you can get good DOF with stock lens in most situations.
One other trick to get to wide open aperture/iris with too much light to attain a shallow DOF is to turn the gain down. Dropping the gain into -3 or more also has the added advantage of knocking down some of the "Video look" edge sharpness and noise.
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Old June 20th, 2007, 05:01 PM   #9
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Shallowest depth of field is obtained by

1. opening iris as wide as possible. Use ND filters if necessary in bright lighting situations.

2. getting as close to subject as possible and manually focusing on the subject, leaving background out of focus.

3. using telephoto end of zoom range as much as possible,
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Old June 20th, 2007, 06:42 PM   #10
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Just as everyone said. This was my first day with the A1 and this is a snap shot I took while getting use to the controls.

http://i25.photobucket.com/albums/c7.../XHA1Still.jpg
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Old June 21st, 2007, 02:39 PM   #11
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Quote:
Originally Posted by Mike Redding View Post
I just bought my Canon XH A1 a few weeks ago. I having trouble messing with my depth of field in manual mode? Am i doing it wrong? not enough distance from objects and background? Any help would be nice.
Background blur has many factors:

1. Aperture (wider the better).

2. Focal length (longer magnifies a smaller portion of the out-of-focus area).

3. Framing (AKA camera-to-subject distance, the closer the better).

4. Subject-to-background distance (farther the better).

5. Uncontrollables: lens bokeh, capture medium size, sensor characteristics, etc.

I have the XH A1, and for headshots I like to use a zoom of Z54, which permits me a maximum aperture of f/2.0, much wider than the f/3.4 at full zoom, but still enough to magnify the OOF quite a bit without losing too much light (for ambient indoor conditions). One downside is that some subjects don't like you getting up in their face.
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Old June 25th, 2007, 08:47 AM   #12
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I just got done shooting a Michalobe light Commercial this weekend on my A1 and they wanted a lot of rack focusing and very blurred backgrounds. ive found the distance makes the difference. i was 10-15 from my subject at all times. zoomed right in of course but i was able to easily get the effect i wanted. Thnx for all the help.
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Old June 25th, 2007, 03:42 PM   #13
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cobcerning Daniel's post on June 21st

Quote:
Originally Posted by Daniel Browning View Post
Background blur has many factors:

1. Aperture (wider the better).

2. Focal length (longer magnifies a smaller portion of the out-of-focus area).

3. Framing (AKA camera-to-subject distance, the closer the better).

4. Subject-to-background distance (farther the better).

5. Uncontrollables: lens bokeh, capture medium size, sensor characteristics, etc.

I have the XH A1, and for headshots I like to use a zoom of Z54, which permits me a maximum aperture of f/2.0, much wider than the f/3.4 at full zoom, but still enough to magnify the OOF quite a bit without losing too much light (for ambient indoor conditions). One downside is that some subjects don't like you getting up in their face.
Hey Daniel, I hope you don't mind, but I have a few questions about the
> jargon on your post about DOF. When you said use a zoom of z54 does that
> mean zoom in halfway? What does OOF mean, lens bokeh. I have recently
> bought the XHA1, and I am really trying to control DOF without buying an
> adapter of some sort. I appreciate your time any help would be fantastic.
>
> Thank You
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Old June 25th, 2007, 03:55 PM   #14
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Quote:
Originally Posted by Brendan Brooks View Post
When you said use a zoom of z54 does that
mean zoom in halfway?
Yes. The XH A1 has only one zoom indication, a "Z" display that goes from 1 to 100. Z54 is about half-way, or a 35mm focal length of approximately 300mm. I would rather it displayed AOV (angle of view) values instead.

You can achieve excellent background blur at wide angle *or* maximum telephoto, just by controlling framing and subject-to-background distance.
For example, the greatest blur that the camera can achieve is filming small flowers. At a minimum focus distance of just an inch or two, with 5 feet to the background, at f/1.6, the background blur is very easy to achieve.

But most subjects aren't small flowers. At maximum telephoto, even at f/3.4, you can achieve background blur by framing tightly and moving the background out 20 feet or so.

Quote:
Originally Posted by Brendan Brooks View Post
What does OOF mean, lens bokeh.
OOF stands for "out-of-focus". When you frame a subject, then switch to a longer lens, it will magnify the background, and less of it will be visible. A given aperture will only ever have one level of blur, but by magnifying it, it appears more blurred.

Lens bokeh is the aesthetic qualities of the OOF area, particularly specular highlights. Round and smooth are the features that people look for, while aberration, coma, etc. take away from it. I listed bokeh as an "uncontrollable" because the XH A1 lens is not interchangable. Aside from the chromatic aberration, I find the XH A1 bokeh to be very pleasing, especially considering the low price.
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Old June 25th, 2007, 04:53 PM   #15
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Depth of field vs. background blur

I would like to clarify a few things. In every thread about depth of field, including this one, I've seen a lot of misinformation that tells me people are confusing depth of field with background blur. They are not the same, and I would like to help educate readers so they can tell the difference.

DoF is very, very simple. Framing and aperture. That's it. Not focal length. Not working space. Not background. Let me explain.

Many people recommend using a longer focal length for thinner DoF, but neglect to mention framing. A longer lens will *not* give you thinner DoF if you move the camera back to compensate! It will only give you greater background blur. Similarly, subject distance doesn't change DoF, by itself, unless you again change the framing.

"Working space" has nothing to do with DoF, either. Backing up and zooming in will *not* make your DoF thinner! Getting close and using a wider angle will not affect it either. You must change framing to change DoF.

This may come as a surprise to some of you, but the thinnest DoF that the camera can achieve is at wide angle! Put a small subject at the minimum focus distance and see how the DoF can be measured in millimeters. (Obviously, most subjects are not small enough to be framed within 2-3 inches of the lens, but the fact remains.)

Background blur, again, does depend on more than just framing and aperture, as I explained above.

To test the difference between background blur and DoF yourself, try framing a small subject so that it perfectly fills the frame at wide angle and f/3.4. Take specific note of how the background looks. Then increase your focal length by zooming in, without changing the framing at all (this will require you to move the camera backwards). As you do, you will notice that the depth of field is the exact same: the subject is still in the same amount of focus as it was. But the background becomes more magnified (and perspective changes). The OOF area gets larger, increasing the perception of blur. Try it again at f/9.5 and you may see that the clear background just gets larger and easier to see (if the background is within the hyperfocal distance).

Lastly, Jeff's article on DoF explains all of this as well as the effect of the size of the capture medium. However, he neglects to mention background blur at all.

Last edited by Daniel Browning; June 25th, 2007 at 04:57 PM. Reason: Fix grammar.
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