newbie questions, Shutter speed, etc at DVinfo.net

Tylar Mccoy · November 11th, 2002, 11:50 PM

Ok, I finaly got a working gl-1.
I was dealing through onecall.com, I DO NOT RECOMEND THEM.
That said, I have some questions about video. This is my first camcorder.

I want to get some footage of my dog shaking off water, and slow it way down. Can I do this by using a really fast shutter speed, and then use adobe to slow it, without losing detail? I want it to look crisp and smooth in slow-mo. Would the frame mode be more useful for this, or normal interlaced video?

The other question I have is kinda stupid but the manual talks about it. Ill quote the gl-1 manual:

"superb picture quality results from using a larger light capturing area for each pixel (and fewer pixels) to give higher sensitivity, higher SN ratio and greater dynamic range"

Does this mean that the gl-1 would be more sensitive to low light than the gl-2 that uses 410k pixels rather than the gl-1's 270k pixels?

Another dumb question, the manual says you sould remove the tape and battery pack after use, EVERY time. This is a huge pain in the ass for me because i find myself turning the cam off and on a lot. And its kinda like having an unloaded gun. A camera without a tape is useless and if someing happens really fast you dont have time to load ur gun (or camera) and you miss out on the shot. Can the tape be dammaged if i leave in in there for days at a time without it being used?

Ive been lurking around these boards for a while soaking up info and stuff, this seems like a good place to teach myself and help others when I can.

Thanks.

Tyler MccoyJohnson, video newbie.

Josh Bass · November 12th, 2002, 02:03 AM

I think with the tape thing you're okay for short periods of time, to leave the tape in camera. A couple of hours maybe. After that, might want to take it out.

On the other hand, there are people on here who claim to have left their tapes in camera for weeks on end without any problems. I THINK the main reason to take your cassettes out is that when they're in camera for a long time, the tape itself can develop a kink where the tape was wound around the "capstan" (is that the right word?). These tapes are fairly delicate and subject to video and audio dropouts, and you want to take all measures to keep them safe. Also, rewind tapes after each use (I've heard) if it's been more than a couple of hours. This helps keep out kinks as well.

Rob Lohman · November 12th, 2002, 12:09 PM

For some more information on slow motion try this thread:

http://new.dvinfo.net/conf/showthrea...&threadid=4875

Chris Korrow · November 13th, 2002, 02:45 AM

A friend of mine who edits for a living in Nashville said that because mini DV tape is so small it can have a tendency to stretch, hence drop outs.

Chris

Tylar Mccoy · November 13th, 2002, 07:52 PM

Thanks.
I read the thread on slowmo, thanks for directing me to that.
I now take my tape out of the camcorder, Before I was leaving them in overnight.

After reviewing my first "test" tape, I have learned a few things.

I need to learn how to hold the camcorder steady.
I need a tripod.

I have another question tho. There is a little bar in the left hand corner that puts its marker at the middle when it thinks the exposure is perfect (is this right?) but when the marker is in the middle, everything looks a little too bright on my tv. Is it better to leave a few zebras, or get rid of them completely? I know I cannot get rid of them completely if I am filming a person sitting next to a lamp or something, because the light itself wil always have them, But in general outdoor shooting, Should I leave a few or expose everything so there are no zebra bars at all?

Jeff Donald · November 13th, 2002, 10:10 PM

There are no hard and fast rules. Through trial and error you'll have to discover your own personal acceptable standards. During your discovery phase try taping scenes in several different ways. It may help to take notes on the settings for the various scenes. Fairly quickly you'll find what is most pleasing to your eye and the subjects you shoot. I wish I could say do it this way or that but exposure is very subjective and each scene has too many variables.

Jeff

Josh Bass · November 13th, 2002, 10:21 PM

What happens if your stuff is for broad cast, and you have highlights or areas you thought looked good that are over 100 IRE? Will it look about the same viewed on your computer or TV as it will when tranmitted via a television station?

Jeff Donald · November 13th, 2002, 10:30 PM

Broadcasters run the signal through a device that makes the signal "legal" before it is transmitted over the airwaves. It puts a hard clip on the highlights and brings them to 100 IRE. It may look different, depending on how the stations sets their limiter.

So, yes there are hard and fast rules for broadcast. My assumption was that a newbie wasn't doing work for broadcast yet. Thanks for bringing that up, Josh.

Jeff

Josh Bass · November 14th, 2002, 04:52 AM

It's one of those things I wonder about. I know DV clips at 110 IRE, but sometimes those blown out highlights look really cool. It's hard to tell how blown out you can have them before they look like ass.

Andre De Clercq · November 14th, 2002, 01:45 PM

IRE is a perfect level indicator, but w.r.t. transmitter modulation it's the modulation voltage that counts. Of course if IRE and voltage are tracked (what should be), IRE is a good measure for the limitations but not the "final one" as far as the HF modulation concerns. The "blown out" story (clipping, soft clipping, level dependent compression, soft knee techniques...) is a much discussed (and patented) issue, as well in the camera signal processing circuits as in display signal processing techniques. Some camera's can make 160% level picture still looking good, an most LCD projectors start to softclip at 80%.

Josh Bass · November 14th, 2002, 02:22 PM

But just to be safe you should stay just at or under 100 IRE?

Andre De Clercq · November 14th, 2002, 05:30 PM

Yes, if you mean "safe" for transmission. 100 IRE is the max luma level in the FCC transmittter standard, and this corresponds to 12.5% carrier which has to be kept as a minimun value for good intercarrier sound reception. Accidental (non periodic) superimposed color subcarrier amplitudes (on bright,saturated colors= illegal colors) are allowed to surpass the 100 IRE. Broadcasted colorbars have 100 IRE white and fully saturated 75% colors thus avoiding to surpass the 100IRE. It's good practice to never exceed 100 IRE. This is not allways visible on a waveform monitor when the signal is still on YUV level (component editing suite). We (Barco) used to commercialise pro broadcast monitor with "illegal color detection"(zebra) for this problem

November 11th, 2002, 11:50 PM	#1
Tylar Mccoy New Boot Join Date: Sep 2002 Posts: 18	newbie questions, Shutter speed, etc Ok, I finaly got a working gl-1. I was dealing through onecall.com, I DO NOT RECOMEND THEM. That said, I have some questions about video. This is my first camcorder. I want to get some footage of my dog shaking off water, and slow it way down. Can I do this by using a really fast shutter speed, and then use adobe to slow it, without losing detail? I want it to look crisp and smooth in slow-mo. Would the frame mode be more useful for this, or normal interlaced video? The other question I have is kinda stupid but the manual talks about it. Ill quote the gl-1 manual: "superb picture quality results from using a larger light capturing area for each pixel (and fewer pixels) to give higher sensitivity, higher SN ratio and greater dynamic range" Does this mean that the gl-1 would be more sensitive to low light than the gl-2 that uses 410k pixels rather than the gl-1's 270k pixels? Another dumb question, the manual says you sould remove the tape and battery pack after use, EVERY time. This is a huge pain in the ass for me because i find myself turning the cam off and on a lot. And its kinda like having an unloaded gun. A camera without a tape is useless and if someing happens really fast you dont have time to load ur gun (or camera) and you miss out on the shot. Can the tape be dammaged if i leave in in there for days at a time without it being used? Ive been lurking around these boards for a while soaking up info and stuff, this seems like a good place to teach myself and help others when I can. Thanks. Tyler MccoyJohnson, video newbie.

November 12th, 2002, 02:03 AM	#2
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	I think with the tape thing you're okay for short periods of time, to leave the tape in camera. A couple of hours maybe. After that, might want to take it out. On the other hand, there are people on here who claim to have left their tapes in camera for weeks on end without any problems. I THINK the main reason to take your cassettes out is that when they're in camera for a long time, the tape itself can develop a kink where the tape was wound around the "capstan" (is that the right word?). These tapes are fairly delicate and subject to video and audio dropouts, and you want to take all measures to keep them safe. Also, rewind tapes after each use (I've heard) if it's been more than a couple of hours. This helps keep out kinks as well. __________________ The Bass' camerawork The Bass on IMDB

November 12th, 2002, 12:09 PM	#3
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	For some more information on slow motion try this thread: http://new.dvinfo.net/conf/showthrea...&threadid=4875 __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

November 13th, 2002, 10:21 PM	#7
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	What happens if your stuff is for broad cast, and you have highlights or areas you thought looked good that are over 100 IRE? Will it look about the same viewed on your computer or TV as it will when tranmitted via a television station? __________________ The Bass' camerawork The Bass on IMDB

November 14th, 2002, 04:52 AM	#9
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	It's one of those things I wonder about. I know DV clips at 110 IRE, but sometimes those blown out highlights look really cool. It's hard to tell how blown out you can have them before they look like ass. __________________ The Bass' camerawork The Bass on IMDB

November 13th, 2002, 02:45 AM	#4
Chris Korrow Major Player Join Date: Aug 2002 Location: Whidbey Is, WA Posts: 326	A friend of mine who edits for a living in Nashville said that because mini DV tape is so small it can have a tendency to stretch, hence drop outs. Chris

November 13th, 2002, 07:52 PM	#5
Tylar Mccoy New Boot Join Date: Sep 2002 Posts: 18	Thanks. I read the thread on slowmo, thanks for directing me to that. I now take my tape out of the camcorder, Before I was leaving them in overnight. After reviewing my first "test" tape, I have learned a few things. I need to learn how to hold the camcorder steady. I need a tripod. I have another question tho. There is a little bar in the left hand corner that puts its marker at the middle when it thinks the exposure is perfect (is this right?) but when the marker is in the middle, everything looks a little too bright on my tv. Is it better to leave a few zebras, or get rid of them completely? I know I cannot get rid of them completely if I am filming a person sitting next to a lamp or something, because the light itself wil always have them, But in general outdoor shooting, Should I leave a few or expose everything so there are no zebra bars at all?

November 13th, 2002, 10:10 PM	#6
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	There are no hard and fast rules. Through trial and error you'll have to discover your own personal acceptable standards. During your discovery phase try taping scenes in several different ways. It may help to take notes on the settings for the various scenes. Fairly quickly you'll find what is most pleasing to your eye and the subjects you shoot. I wish I could say do it this way or that but exposure is very subjective and each scene has too many variables. Jeff

November 13th, 2002, 10:30 PM	#8
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Broadcasters run the signal through a device that makes the signal "legal" before it is transmitted over the airwaves. It puts a hard clip on the highlights and brings them to 100 IRE. It may look different, depending on how the stations sets their limiter. So, yes there are hard and fast rules for broadcast. My assumption was that a newbie wasn't doing work for broadcast yet. Thanks for bringing that up, Josh. Jeff

November 14th, 2002, 01:45 PM	#10
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	IRE is a perfect level indicator, but w.r.t. transmitter modulation it's the modulation voltage that counts. Of course if IRE and voltage are tracked (what should be), IRE is a good measure for the limitations but not the "final one" as far as the HF modulation concerns. The "blown out" story (clipping, soft clipping, level dependent compression, soft knee techniques...) is a much discussed (and patented) issue, as well in the camera signal processing circuits as in display signal processing techniques. Some camera's can make 160% level picture still looking good, an most LCD projectors start to softclip at 80%.

November 14th, 2002, 02:22 PM	#11
Josh Bass Slash Rules! Join Date: Apr 2002 Location: Houston, Texas Posts: 5,472	But just to be safe you should stay just at or under 100 IRE? __________________ The Bass' camerawork The Bass on IMDB

November 14th, 2002, 05:30 PM	#12
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Yes, if you mean "safe" for transmission. 100 IRE is the max luma level in the FCC transmittter standard, and this corresponds to 12.5% carrier which has to be kept as a minimun value for good intercarrier sound reception. Accidental (non periodic) superimposed color subcarrier amplitudes (on bright,saturated colors= illegal colors) are allowed to surpass the 100 IRE. Broadcasted colorbars have 100 IRE white and fully saturated 75% colors thus avoiding to surpass the 100IRE. It's good practice to never exceed 100 IRE. This is not allways visible on a waveform monitor when the signal is still on YUV level (component editing suite). We (Barco) used to commercialise pro broadcast monitor with "illegal color detection"(zebra) for this problem