Auto Shutter Speed on PD170 Menu

[Ken McGrath]

Just bought a 170, and I notice a menu switch for "auto shutter speed" (on or off). However, when I am operating the camera with the slider (at the back of the camera) set to auto lock or in manual mode, the shutter speed seems to vary automatically regardless of how the menu switch is set (on or off), unless of course I am manually setting the shutter speed to a specific value. What don't I understand? Thanks.

[Mike Rehmus]

IIRC, you have to have everything in manual in the menus or the camera will still run in auto mode. Like an aperature or shutter preferred priority. At least I think the 170 didn't change from the 150 in that regard.

[Sheila Ward]

Hi Ken. Don't forget about the auto gain function of the PD170. That sucker stumped me for a bit. As Mike says, everything must be in manual mode, including gain. Read through this thread and it may help you out:

http://www.dvinfo.net/conf/showthrea...ght=pd170+gain

[Ken McGrath]

Originally Posted by Sheila Ward

Hi Ken. Don't forget about the auto gain function of the PD170. That sucker stumped me for a bit. As Mike says, everything must be in manual mode, including gain. Read through this thread and it may help you out:

http://www.dvinfo.net/conf/showthrea...ght=pd170+gain

Hi Sheila. The only reason I am confused (I think) is because there is only a switch in the menu for auto shutter (on or off), not for iris, gain, etc. Why only shutter? It seems to me that the shutter speed is adjusted automatically like everything else unless unless you specify a manual setting. So why the menu setting for auto shutter speed???

[Mike Rehmus]

That is like asking Sony why their name is Sony. It just is.

[Sheila Ward]

Originally Posted by Ken McGrath

Hi Sheila. The only reason I am confused (I think) is because there is only a switch in the menu for auto shutter (on or off), not for iris, gain, etc. Why only shutter? It seems to me that the shutter speed is adjusted automatically like everything else unless unless you specify a manual setting. So why the menu setting for auto shutter speed???

I don't have an answer for you on that. Just to drive us crazy I think.

[Dale Paterson]

The 'Auto Shutter' setting in the menu applies only when the camera is set to 'Auto' mode i.e. full auto. When shooting in this mode with the 'Auto Shutter' set to 'Off' only the aperture will be varied automatically by the camera. If 'Auto Shutter' is set to 'On' both the shutter speed and aperture will be varied automatically by the camera.

Like I said before - this only applies when the camera is in full auto. When using manual exposure settings the setting of 'Auto Shutter' has not effect.

You can test (prove) the above by viewing the Date / Cam information during playback.

Regards,

Dale.

[Tom Hardwick]

The best advice I can give is to set auto shutter to off in the menu and simply forget about it. Then remember that if you don't have the icon displayed in your v'finder, then it'll be in auto. So no w'bal symbol visible? Then it's in auto.

The PD170 works at its best in the shutter priority mode. If you vary from the default 1/50th (1/60th NTSC) you'll suffer side-effects - lost resolution if you go slower, staccato footage and more CCD smear if you go higher.

Use other speeds for sure, but know the losses you're taking on board. Use the NDs liberally to avoid small apertures.

tom.

[Ken McGrath]

Originally Posted by Dale Paterson

The 'Auto Shutter' setting in the menu applies only when the camera is set to 'Auto' mode i.e. full auto. When shooting in this mode with the 'Auto Shutter' set to 'Off' only the aperture will be varied automatically by the camera. If 'Auto Shutter' is set to 'On' both the shutter speed and aperture will be varied automatically by the camera.

Like I said before - this only applies when the camera is in full auto. When using manual exposure settings the setting of 'Auto Shutter' has not effect.

You can test (prove) the above by viewing the Date / Cam information during playback.

Regards,

Dale.

Thanks Dale. I'm pretty sure I understand now, but let me make sure with one followup question. When you said above that the auto shutter menu setting only has an effect when the camera is in "full auto" mode, that means with the slider at the back of the camera pushed all the way up, correct? You also said that with the auto shutter set to "off" in the menu, only the aperture would be set automatically in the full auto mode. Wouldn't the WB, and gain would also be varied automatically in this mode as well, even with the auto shutter menu setting at off? Thanks!!

[Ken McGrath]

Originally Posted by Tom Hardwick

The best advice I can give is to set auto shutter to off in the menu and simply forget about it. Then remember that if you don't have the icon displayed in your v'finder, then it'll be in auto. So no w'bal symbol visible? Then it's in auto.

The PD170 works at its best in the shutter priority mode. If you vary from the default 1/50th (1/60th NTSC) you'll suffer side-effects - lost resolution if you go slower, staccato footage and more CCD smear if you go higher.

Use other speeds for sure, but know the losses you're taking on board. Use the NDs liberally to avoid small apertures.

tom.

So, in general, would you recommend that I shoot in manual mode with the shutter set at 1/60, and vary the other manual settings as necessary?

[Tom Hardwick]

Yes Ken. There are very few occasions when shooting in the auto mode is acceptable.
But let’s take a look at some of the automatic helping hands that are included and see if we should be taking control, manually setting the camera and not allowing it to set and select according to its own free will.

If you’re honest you’ll realise that a man’s brain (multi-tasking women are excused this bit) can only concentrate on one thing at a time, so something’s got to give. You can’t be expected to artistically frame each shot, hold the camera rock steady, have the correct exposure, focus, depth of field, white balance and audio level set. It’s an impossibility, which is why there’s automation on board to help you out.

Some camcorder controls really should be set manually I find, whereas others are less visible to the end user and so can be left to the automation. I list here the order of importance as I see it and as I’m sure clients see it when they view the finished and final DVD on their TV.

Exposure. This really cannot be left to the automation simply because we’re filming forward in time. Even on a grey, overcast day, exposure will fluctuate wildy as people in different coloured clothing move in and out of frame. Pans across the little pond will influence the exposure of the grass, and the dark fence will ensure you over-expose the little pink faces of people in long shot. With the exposure intolerance of video, manual exposure is the rule, an almost unbending rule.

Apertures, shutter speeds and neutral density filters all come into play here. You can isolate close-ups of faces by having an out of focus background if you force the camera to use wide apertures by upping the shutter speed or adding ND filters. People look a lot better in telephoto than they do at wide-angle, and back-lit people look even better. For starters they’re not squinting into the sunlight, and having rim-lit over-exposed hair has never bought forth complaints about my work.

Focus. Modern camcorders have amazing fast and accurate auto focus systems, but the chips don’t know what it is you’d really like to be sharp – the face in close-up or the brick wall five metres behind said face. If you stick to the wide-angle end of your zoom the huge depth of field will ensure that even if your auto focus is getting it wrong you’ll not be aware of it and neither will your client.

So manual focus is my next in line for manual control. I’m very happy for the automation to determine the correct focus, but having found it I’d be the first to recommend you lock it down. People are unpredictable things and filming them successfully means luck has a lot to do with it. But you can add to your luck factor by stopping the camera changing its mind, and liking the look of the brick wall better than the face.

White balance

There are basically three options open to us as we film.

1) leave it to the automation
2) set the 'sun' or 'bulb' (daylight or artificial light) setting
3) manually set the white balance

Number 1 is more successful in some situations than others. My Panasonic three-chipper uses a combination of through the lens measurement in combination with a little sensor window to sense the ambient light, and can be easily fooled. The Sony I have is better, but leaving it to the automation will mean that the camera will try and ‘correct’ for the reds of sunsets and they will be diluted.

It can also be confused by shots that contain predominantly one colour, such as a field of purple flowers. But for general subjects, auto white balance works well, and if you're not sure, do as I do, and leave it to the automation. Problems arise due to the hysteresis loop built into the system, where stepping smartly from artificially lit indoors to sun-lit outdoors will have the camera instantly adjust the exposure, but very gently adjust the white balance, such that the colours will be very wrong for 10 seconds or more. On screen this can be quite unacceptable and it’s difficult to correct in post, whereas a quick flick from the ‘bulb’ to the ‘sun’ symbols as you cross the threshold would instantly ensure your colour rendition was correct.

If you have left such things to the automation, a good NLE system will allow you to vary the colour correction over time using key frames, but this is not always a good solution. Many editing cards also have a 'white balance' colour corrector. This is marvellous for aligning two different cameras colour wise. One click on the white table cloth in frames from both films and its done.

There will also be other problems in using the camera’s WB presets, as people under the shade of a tree for instance will look a lot bluer than they should and gentle shifts occur simply when the sun goes behind a cloud. Problems also occur when daylight filters into a room that’s lit by a mix and mess of strip and incandescent light. In these instances you really have to decide what’s important, always remembering that in post it’s a lot easier and more successful to warm up an image than it is to cool it down. If in doubt, set the camera to the artificial light setting.

And lastly to audio. Huge strides have been made since the AGC of yesteryear meant birdsong and cannon thunder were all recorded at the same level onto film stripe. In those days you were lucky or imaginative if you thought you could record anything above 8 kHz with a signal to noise ratio of better than 40 dB.

Camcorders run very quietly indeed, and modern isolation and signal rejection techniques have meant that in-built microphones are far less influenced by tape deck noises and zoom motor whirrings. Recording to DV at 48kHz means frequencies up to 24 kHz are certainly possible, and this better than CD quality means that signal to noise ratios are excellent and wow and flutter have simply ceased to exist. At the same time microphone development has continued apace and prices (in real terms again) have continued to fall.

So admitting that I simply can’t manually control everything, this is the discipline I often leave to the automation. Digital audio means that no over-recording is permitted at all, as the overload effect sounds horrible. Not so in the analogue days, where even the humble ferric emulsion of audio cassette could be considerably over recorded before sounding objectionable. Modern audio limiters are fast acting and to my ears is the most invisible of the automations available to you as a filmmaker.

Sorry to have gone on so long - camcorder automation is a hobby-horse of mine.

tom.

[Dale Paterson]

Now that was an answer!!!

I wish I could find someone to answer my queries in such depth!!!

I only checked the board again now but I am sure that Tom has answered everything and more - a great piece!

In short (just to reply to you) - yes - when in 'Full Auto' i.e. slider all the way up - everything like WB, aperture, gain, etc. etc. is 'Auto' except for 'Auto Shutter Speed' - if you have set it to 'Off' - then it - the shutter speed - will remain fixed at 1/50th sec per frame - but like Tom says - there are a lot of other things to think about).

Regards,

Dale.

[Tom Hardwick]

Thanks for your enthusiasm Dale.
Just a small point in my quest for fastidious detail, you say:''.... remain fixed at 50fps (PAL) or 60fps (NTSC)'', whereas I'm sure you meant to say 1/50th and 1/60th sec per frame.

PAL cameras shoot at 25 fps and NTSC shoot at 29.97 fps.

tom.

[Richard Zlamany]

I've shot stage productions with varying shutter speeds from 30 to 280 with great success. Varying the shutter speed can tweak the image's dynamic range with more subtle control than just the iris control alone.

My point is experiment with the camera with all the controls in different combinations and review so you can tell what controls in what combinations make the picture look the best. Don't just set the shutter to 60 and never touch it again. It has unique use.

[Ken McGrath]

Thanks to all above for very, very helpful and comprehensive answers.

I know that the following question will not have one and only one "correct" answer, but I am curious about choosing a combination of manual and auto settings to maximize my success in taping a school musical play (Bye Bye Birdie) that my daughter will be in this weekend. I am thinking of using the following settings: manual focus, default tungsten white balance, auto iris, manual shutter speed (1/60), and auto gain. Does this make sense?

Edit: The main reason I want to automate iris and gain is that I expect the exposure to vary during the course of the theatrical production in unpredictable ways, and that setting auto iris and gain, while not optimal for the reasons stated above, would be my "safest" course of action. Again, any suggests most welcome for this specific circumstance.