what shutter speed do you use when shooting 30P?

[Kevin Lewis]

I have had my xha1 for a while now and have typically shot 60i. I know there are lots of threads that discuss this, but I was wondering what other xha1 users are using.

[Justin Jenkins]

Wouldn't you just use 1/60 to get a 180 degree shutter? That should leave the sensor exposed for half the duration of the frame, correct?

[Kevin Lewis]

The last few shoots I have shot with a shutter speed of 30. It was low light situations and the final result seemed fine. However, it appears that lots of people recommend using a shutter of 60 when shooting 30p. I was wondering if XHA1 users have obtained better results with a shutter of 30 or 60 when shooting 30P.

[Justin Jenkins]

I gotcha. That makes sense. I pretty much would not deviate from the 1/60 shutter speed just for the motion blur. But in low light situations I guess actually exposing the sensor may take precedence over correct motion blur. Because what good is the motion blur if you can't see it? :)

[Jay West]

Since a lot of us still use the old names, I'm assuming that your reference to 60i means 30i and not a slow-motion format. A couple of years ago, the poobahs who set nomenclature standards decreed that the "60i is to be referred to as 30i because we shall refer to frame rates, not to field rates For example, "1080/30i" means shooting 1080 lines at 30 interlaced frames per second which is the same as 60 interlaced fields. 1080/30p is still "30p" for obvious reasons. Same with 1080/60p. Under the new scheme, 60i would be 60 interlaced frames or 120 fields per second. That would be something you would use for slow-mo but not everyday shooting.

So, assuming that we are talking about what you might do different under 30p than 30i, I haven't found much need to do things differently.

Basically, I use 30i for anything with high-motion content. For low light situations at weddings, I go down to 1/30th with 30p. I've also gone with 1/24th when shooting 24p. Some folks would be concerned with motion blur, but dimly lit weddings typically do not have a lot of very rapid motion. I've tried a 1/15th shutter setting, but there was too much motion blur for my tastes. I've never tried 1/8th or 1/4 with any video camera.

If I'm shooting something where I need a high-speed shutter, it is because it is a high-motion activity and I prefer 30i for those kinds of things. (I like 60p but the XHA1 does not offer it.)

In theory (so far as I understand it), there is something to be said for using shutter speeds which are multiples of your frame rate. If you want to try shooting high motion with a 30p frame rate, setting XHA1 to M mode will let you select even multiples of 30 for your shutter speed, say 1/600th. (See p. 57 of the manual). Conversely, if you wanted a film-like motion blur, you could try a lower shutter speed. Beyond this, I recall reading about shutter angles for film cameras, but have not had any jobs where I have needed to understand and apply those concepts. Maybe somebody with more knowledge and a film background (Justin??) could contribute on how to use shutter angles with the XH?

When you set the XH to Tv mode, you get a more limited selection of shutter speeds, most of which are not multiples of 30.

For the most part, I haven't had trouble with using aperture priority and letting the camera set the shutter speed. I'm mostly shooting for DVD for local event customers rather than large scale projection which could make a difference in whether I would see problems or artifacts.

The one thing I've found requires caution with shutter speeds is shooting under older flourescent and mercury vapor light fixtures. The manual warns that can cause flicker We have some near antique fixtures in our local venues in this area and boy do they ever flicker. The XH manual says to use 1/100th as shutter speed (Manual p. 55). That took care of the problem for me and I have not been tempted to experiment since then.

[Kevin Lewis]

Jay thanks for your input, but your post just confused the heck out of me.I'm simply trying to find out what the best shutter speed under normal circumstances when shooting with the xha1 while recording 30p. By normal I mean controlled lighting situations and not shooting a fast motion sporting event.

[Justin Jenkins]

Film cameras have a disc in them that rotates in front of the film. This disc has an opening in it which allows light to expose the film. For film cameras there has to an amount of time where the film is not exposed to light during the duration of the frame so that the next piece of film can be pulled down. This opening in the disc that allows light to expose the film is measured in degrees. This opening is usually 180 degrees. Meaning for half the frame the film is exposed to light, and the other half of the frame the film is in darkness. During this period of darkness the next piece of film is pulled down. Over time people have grown accustomed to the motion blur produced by the 180 degree shutter angle of film and generally find it to be very pleasing.

It's simply not possible for a film camera to have a 360 degree shutter because the next piece of film could not be pulled down. Only in video cameras and digital film cameras is it possible to expose the image during the entire duration of the frame. This produces a much smearier motion blur which quite a lot of people find to be quite ugly.

My knowledge of video pales in comparison to the guys on this forum. So I'm guessing they do all kinds of tricks to make stuff work in particular situations. But the longer you expose the image the more smearier your motion blur. If that doesn't bug you then I guess it's all good, but it's going to look less like film. If you want a beautiful film style motion blur and you are shooting at 30 fps then you need a 1/60 shutter and if you shoot at 24 fps then you need a 1/48 shutter.

-Justin

[Jay West]

Kevin:
Sorry I confused you but my experience is there is no such thing as a single "best" setting. The question , as always, is "best for whom to shoot what and where?"

So, your response helps narrow things down. When you say "controlled lighting" and "not shooting a fast moving event," that sounds to me like it might be studio conditions or, maybe, say, a panel discussion or a meeting room or a church service where you do not need to worry about things like depth of field in your focus.

For that, I would start with 1/60th as the setting most likely to give the best results with 30p under those conditions, and then vary the iris as needed.

Which leads me to the reason I mentioned that there are differences between setting the XH to the Tv (shutter priority) setting on the control dial as opposed to the M (fully manual) setting. With the Tv setting, you are only setting shutter speed and letting the camera handle all of the other settings needed to control exposure. The issue for Tv mode is that you get far fewer choices than you do with M mode, and not all of those choices seem appropriate for shooting 30p indoors. Under Tv mode, the shutter speed choices (the one appropriate for indoors under controlled lighting) are limited to 1/60th, 1/100th, and 1/250th. But, if you go to fully manual mode, you get some additional choices, such as 1/90th and 1/120th, that may be more appropriate for your specific lighting and setting.

[Jay West]

Originally Posted by Justin Jenkins

My knowledge of video pales in comparison to the guys on this forum. So I'm guessing they do all kinds of tricks to make stuff work in particular situations. But the longer you expose the image the more smearier your motion blur. If that doesn't bug you then I guess it's all good, but it's going to look less like film. If you want a beautiful film style motion blur and you are shooting at 30 fps then you need a 1/60 shutter and if you shoot at 24 fps then you need a 1/48 shutter.

-Justin

Boy howdy, doesn't this forum teach a lot!

I know about as much as you described about shutter angle for film cameras. I just can't quite figure out how to translate that to what I do in video. From film classes (a ling time ago) I remember a lot more about aperture settings affecting depth of field, and that, at least, I still understand.

I'm not so sure you get lot of motion blur at 30p with a 1/60th shutter if you've got a relatively static scene (say, people talking from a table). If you have somebody walking back and forth, I think it will be different. 1/90th or 1/120th might be a better choice for 30p indoors in those conditions. A lot of the time /160th will be as fine for 30p as for 30i.

[Kevin Lewis]

Jay: You are correct, it is a studio setting that I will be filming in. I am doing a green screen shoot under very controlled condidtions. When the camera is set to the "A" mode, it appears that it uses a default shutter of 30 when shooting 30p, which seems to be contrary to what i've been reading. As far as the green screen shoot is concerned, the subject will remain in one postion the whole time and wont move from the mark.

[Jay West]

I suggest you set the XH to "M" mode, set your shutter speed to 1/60th, set your zebra stripes to 100%, and dial the iris to adjust the exposure. Switch to manual focus to avoid any possibility of variation or any change in lighting causing the autofocus to hunt.

[Bill Busby]

Originally Posted by Jay West

If I'm shooting something where I need a high-speed shutter, it is because it is a high-motion activity and I prefer 30i for those kinds of things. (I like 60p but the XHA1 does not offer it.)

Jay, the A1 doesn't offer 30i either! :D So how are you accomplishing that?

[Justin Jenkins]

Originally Posted by Jay West

I just can't quite figure out how to translate that to what I do in video.

There's not terribly much to do honestly. for video to look more like film then shoot 24 fps with a 1/48 shutter speed. People debate the heck out of this idea, but I'm pretty much on board with 24 fps and a 1/48 shutter speed. I guess the game changes when you're not concerned about the film look. It seems like people shooting weddings and stuff like that are more worried about other concerns. But if you're shooting in controlled conditions with directed lighting I can't imagine why anyone would want to shoot at any other settings. Unless of course you have to cut that footage in with other footage shot in non-controlled conditions in a remote location. Then maybe you'd want to match settings between the two.

[Pavel Sedlak]

Originally Posted by Justin Jenkins

...If you want a beautiful film style motion blur and you are shooting at 30 fps then you need a 1/60 shutter and if you shoot at 24 fps then you need a 1/48 shutter. Justin

I don't agree, because no CCD camcorder can make a beautiful film style motion blur. It is impossible at HD resolution (1920x1080) with a CCD/CMOS technology.

Shutter speed is CCD/CMOS parameter, it is time for exposure the light-sensitive sensor elements. If you want max. amount of light, you can set 1/50 shutter speed at 1080/50i (right 25i) or 1/25 shutter speed at 1080/25p (*europe version).

CCD of the XH-A1 is native interlaced processed, 1/50 sh.speed is right for 1080/50i (I do not know the internal structure of CCD, it is possible, that CCD scan at 50p but one half of the information is immediately destroyed...).

The rest about "a beautiful film style motion blur" is illusion and fantasy .-) .

---

On the other hand is right, that with fast moving you can use a shorter time for a sharper picture (at 1080/25i or 1080/25p) , but it can cause a strobe effect (it depends on speed in scene and shutter time).

[Jay West]

Originally Posted by Bill Busby

Jay, the A1 doesn't offer 30i either! :D So how are you accomplishing that?

Sure it offers 30i. As explained at the outset, the international standard terminology has been revised. What we used to call 60i is now officially described by international standards as 30i -- that is 30 frames (okay, 29.97 frames) per second interlaced to produce alternating fields which is to say, 60 fields. A lot of folks still say "60i" because it is in the camera manual and because it makes intuitive sense -- 60i sounds like describing 60 interlaced fields. The standards bodies thought that frames were more important as a standard. Hence, 30i and old 60i are the same thing. 30p and 60p were not and are not the same.