Noise problem

[John Cambell]

heres some clips that I have gotten on my Xh A1 so far...if you guys have any advice on how to get better pictures let me know please. I know the filming is bad but I have it wired now so that wont be a factor anymore.

http://vimeo.com/1120774

[Mark Fry]

Originally Posted by Phil Taylor

As far as your shutter speed is concerned I would shoot at 1/300 or so. You will get blurring at slower shutter speeds in shots involving movement such as surfing.

Only reduce your shutter speed if you want jittery motion. The faster the shutter, the more jittery the motion effect will be. For smooth motion, shoot 60i at 1/60 or 50i at 1/50. This is moving-, not still-photography.

Originally Posted by Phil Taylor

I shoot mostly outdoor video and I try to keep exposure f stops at 5.6 or higher. In the outdoors f 11 is great as most of the time you are looking for great depth of field.

Although this is normal practice with 35mm still cameras, it's not good advice when using such small detectors/short focal lengths as in a 1/3"-chip video camera. You will find that you start to get colour fringes appearing on high-contrast edges at appertures smaller than about f5.6. Now, it is possible to make lenses this short that don't do this, but they are very expensive and very heavy, and zooms are even harder than fixed-length lenses. The Canon lens is better than most, but not perfect. This is why Tom Roper was talking about the lens' "sweet spot". Except at the long end of the zoom or when focusing on very near objects, lack of depth-of-field is not a problem with such short lenses/small detectors. (Indeed - some videographers go to great lengths to try to reduce the depth-of-field of these cameras! Just look at all the discussions of Red Rock and Letus lens adaptors, for example)

There will always be occassions when these rules-of-thumb don't apply, but most of the time:
- match the shutter speed to the frame rate,
- use higher frame rates for smoother motion,
- keep the apperture between about f3.2 and f5.6,
- turn off auto-gain,
- use the ND filters (and perhaps set gain to -3db?) to help keep things where you want them.

As the light decreases, this is what I do:
- remove ND filters;
- open the apperture;
- use a slower frame rate and/or shutter speed (I sometimes use 1/25 with 50i, which works well enough for slow-moving subjects);
- change knee and/or black settings (for more dynamic range, more detail in shadows, etc) ;
- add gain: with a little help from the NR2 and/or coring settings, +6dB is not too bad;
- in extremis, switch on AGC, on the basis that any shot is better than none!

HTH

[Bill Grant]

John,
What was wrong with that clip? I didn't see any problem at all. This why I'm happy about not being an "expert" I can overlook the little things and just enjoy life. BTW that was some SICK surfing footage. WOw. I'm from a place where that type of thing is just on TV much less happening right in front of me, much less getting to film it. Great stuff. And apparrently you have skaters there that can land tricks. None of the kids here can land tricks... oh well.
Bill

[Phil Taylor]

I stand by my suggestions! Experience your camera and don't get caught up in all the technical lingo that confuses the real world for you.

[Phil Taylor]

As a follow up this is an article by Marshal Rosenthal for Videomaker several years ago. It explains in more detail the relationship of shutter speed, f stop and frame rate.

Speed Tips
Marshal Rosenthal
October 2004
Most of us don't think twice about the shutter speed that our video camera is using. True: it can be set to manual, but since the camera can automatically take care of it, why should we bother? The answer is that you gain control. And you get control over more than just exposure. This means that you can shoot video that isn't blurred (or is), that the scenes don't look too dark, that, in a nutshell, what you've shot appears the way you want it to look.

The Way Video Cameras Work
Now let's take all this and apply it to a video camera which, while it has a shutter, is dealing not with a single image, but with dozens upon dozens of single images strung together. And the speed at which these frames are moving must be both constant and fast enough to create correct looking, full-motion video when played back.
So the video camera shutter is firing very fast as the recording media (video tape, DVD, memory chip) is being bombarded by the light which has been converted into data by a light sensing chip. Still, as the light is first going through a lens, physical properties such as the amount of light in the scene and how fast the shutter is going off apply here just as they do to a still camera. So the faster the video camera shutter fires, the more light is needed to keep the scene from becoming too dark. Being aware of this means knowing when you feel it makes sense to manually change the shutter speed of the camera, speeding it up or slowing it down, depending upon what you're shooting.

Focus, Depth of Field and The Shutter
We know that when we watch a movie or TV we're actually seeing a successive number of frames flipping by one after another and that it's our eye working with the brain that stitches them together to create motion. While a still image that is blurred will be obvious, in a movie, individually blurred frames are less noticeable. In fact, a slight blurring might be a very desirable effect. Video that is too crisp and sharp can have a very artificial feel to it.

Understanding the Terms
To better understand how this all interacts, let's look at what the terms mean. Focus, at its most basic, is when an object is sharp and clear. Whether focus is for a single object, say a cow in a meadow, or for an entire scene (the cow, the meadow and the mountains in the distance) is the result of the depth of field. This is the range where focus is sharp in front and behind an object. A narrow (shallow) depth of field limits what is in sharp focus, while a wide (deep) depth of field keeps everything in focus, from one foot to infinity. For example, say you focus on an orange sitting on a table. Depending upon the depth of field, the orange could be in focus, while the front of the place mat is not and the chair at the end of the table behind the orange is also out of focus. Sufficient depth of field insures that more than just the object in your sights is in focus. A narrower depth of field is great for artistic purposes or to emphasize a subject.
The camera lens F-stop primarily determines the depth of field. The F-stop is a ratio measure of the size of the aperture (iris). This is all about the amount of light that a lens can gather. When shooting a scene, an F-stop of 1.4 or 2.0, for example, will be able to work in lower light situations, such as when it's dusk or inside a room with little illumination. Depth of field decreases as the F-stop number shrinks. Conversely, if there's more light to work with, you can go to a higher F-stop such as 5.6, 16 or 22. The higher the F-stop, the more depth of field there is and so the greater the range of focus. Since the F-stop and the shutter work together to control the exposure, you can choose a lower F-stop and higher shutter or a lower shutter and higher F-stop to maintain your exposure.

Preset Shutter Speed Settings
Rather than being forced to either leave the camera totally on automatic or make all the choices for yourself, many video cameras have preset scene settings, such as for sports or action shooting, landscapes, night scenes and portraiture. Each of these settings alters the shutter speed to what is more optimal for the given situation. For example, say you're shooting a football game, which means fast moving people. Freezing the action (on a frame-by-frame basis) requires a very fast shutter speed, say 1/1,000th of a second or greater, assuming that we otherwise have plenty of light. By the same token, using a setting designed for shooting a still life subject means a lower shutter speed, since movement is assumed to be more minimal. In all cases, the frame rate (30 fps) remains constant, since that is defined by the video format.

It's Your Choice
It's fine to let the camera's automation do the work for you, but that shouldn't make you lazy. Understanding how the shutter speed works is the first step towards deciding when it's the right time to control the camera by yourself, so that you can get the results you want.

Marshal M. Rosenthal is a technology/entertainment writer whose experience in the industry spans 20+ years.

SIDEBAR:
Slow Shutter and Effects
When you drop the shutter speed to 1/30 or below, you are losing every other line of resolution in your camcorder (unless you are shooting progressive on a special camera). At 1/15, you'll find that the video is noticeably stuttering. At 1/4 (four frames a second), the video will look rather poor and will show a lot of blurred action. You will, however, be able to shoot in very dark situations and, in our opinion, if that is the difference between getting the shot and not, 4 fps is better than zero.

SIDEBAR:
1/60 Default
Technically, the minimum shutter speed you should consider for video is 1/60 second. In fact, you should consider this the default shutter speed, since this is a rate that matches television in the US. Any higher shutter speeds (as discussed in this article) are for effect only.

[John Cambell]

Thanks for all your guys help. I really appreciate it and will definitely use it in my filming. We are supposed to get a swell in the next couple days and I will try and film with my new settings that I got with your help, and I will try to post it on vimeo. Thanks again

[Jonathan Shaw]

Just looked at the Vimeo link John, its hard to see real issues due to compression etc.

I liked the footage... was that shot in 30F.

As per previous posts, I would play around with the camera, with surfing you can go nuts to get different effects / feels. No rules...

The only this I wouldn't do is shoot different frame rates on the same tape. I'm sure people do but it makes capture a little more interesting.

[Richard Hunter]

Originally Posted by Phil Taylor

I stand by my suggestions! Experience your camera and don't get caught up in all the technical lingo that confuses the real world for you.

Phil, the XH-A1 does not give good results at f11. Diffraction may be technical lingo but that doesn't mean it's not real.

Richard

[Matthew Ebenezer]

Hey John,

I checked out your footage on Vimeo. Man, those are some good riders - that'd be heaps fun to shoot.

Looking at this footage, most of the noise I'm seeing seems to be from the compression rather than the camera. You'll generally get some compression artifacts with fast moving subjects like the ones you're filming - especially waves, leaves etc ... The skateboarding stuff didn't seem to have the same issues as the surfing stuff.

With my old XL2 I used to shoot on 0+- gain all the time but I've found the A1 to be a bit noisier at 0 so I use -3db almost all the time.

Most of the time I shoot in TV mode and let the camera take care the exposure - unless the light is changing quite dramatically. I love the Exposure Lock button as well - it's good for 'tricking' the camera - i.e. point the camera at an area with the correct exposure you're after, hit the exposure lock and away you go. It's often a combination of a lot of things - i.e. correct exposure, ND filters, sometimes Manual mode is best etc ...

The biggest thing I've learned is that there's no magic recipe as every shooting environment is going to have different light. Experimenting with your camera and shooting lots of footage in different lighting conditions is the best way to figure out how your camera handles different situations and what you need to do to get the best out of it.

That's the cool thing I've found with cameras like the A1 - they are so customisable that there's heaps of different ways to use them. The way I use the camera may be totally different to how another shooter would do things. You just have to spend the time getting to know your camera to find what works for you in producing good looking footage.

Here's some of my stuff on Vimeo that I've shot so far with my A1 - if you want to check it out: http://vimeo.com/ebenezer/videos

Keep at it - the A1 is a sweet camera for sure - especially once you push through the learning curve.

Cheers,

Matthew.

[Bill Busby]

Originally Posted by Richard Hunter

Phil, the XH-A1 does not give good results at f11. Diffraction may be technical lingo but that doesn't mean it's not real.

Richard

I agree wholeheartedly. When I first read Phil's recommendation regarding f11 a couple of days ago, I thought it was a typo :) I'd like to see what that footage at f11 looks like. I'm sure Phil means well but that just isn't sound advice in my opinion. I can't imagine anything with detail holding detail due to diffraction.

I target f5.6 & a tad more open for my sweet spot.

[Phil Taylor]

No typo here. I do shoot quite a bit of video at f11. It looks good and always will if you have enough light to use the smaller lens openings. Otherwise, Canon would not supply such a lens. Nope, I do stand by my statements and suggest John Campbell try a faster shutter speed at f11 (if there is enough light and outdoors in the sun there will be plenty of light). If you want a large depth of field, a desire for most outdoor videographers, you'll have to use larger numbers for iris openings. As Marshall stated, "Depth of field decreases as the F-stop number shrinks. Conversely, if there's more light to work with, you can go to a higher F-stop such as 5.6, 16 or 22. The higher the F-stop, the more depth of field there is and so the greater the range of focus."

[Daniel Browning]

Originally Posted by Phil Taylor

Conversely, if there's more light to work with, you can go to a higher F-stop such as 5.6, 16 or 22.

The narrowest F-stop that the XH-A1 is capable of is F/9.5. Diffraction isn't the only reason to avoid f/5.6 through f/9.5: on my camera it exhibits the dust on the sensors or prism block. (Dust on the lens shows too, but that can be cleaned.)

[Seun Osewa]

You're cheating this forum by not posting full resolution screen grabs.
What should have been a highly educative thread is doomed to be purely speculative.

[Eddie Coates]

All of these Digital enhanced video cameras , produce grain when you use even the slightest Gain db...

[John Cambell]

Hey guys, we had a little south swell yesterday so me and my friends went and surfed and tried out the new settings on the xh a1. It looks a lot better then my other footage I got. Heres a little movie I put together of our 2 sessions. If you have any more advice I would love to hear it. Thanks

http://vimeo.com/1139050