|
pc
newsgroups
|
|||||||||||||||||||||||
|
|||||||||||||||||||||||
SONY DCR TRV27E Shutter speed and Gain?
levels with 1/100 sec shutter speed plus 6db gain. I thought the standard shutter speed for a PAL Digital video camera is 1/50 sec (1/60 for NTSC) . The 6db gain introduces noticeable noise. If the shutter speed vwas a normal 1/50 only 3db of gain would be required which should cut down the noise. How many F-stops of exposure is 6db equal to? Regards, Peter Mason <cine***@hotmail.com> wrote:
>Does anybody know why this camera is programmed to shoot in low-light Video cameras don't have shutters, really. Some of them do have the>levels with 1/100 sec shutter speed plus 6db gain. I thought the >standard shutter speed for a PAL Digital video camera is 1/50 sec (1/60 >for NTSC) . The 6db gain introduces noticeable noise. >If the shutter speed vwas a normal 1/50 only 3db of gain would be >required which should cut down the noise. ability to adjust the amount of time the CCD is collecting light, but since you (if you are running 25i) HAVE to shoot 50 fields a second, there is no way it can be collecting for more than 1/50 sec maximum, and due to overhead it can often be much less than that. But the shutter speeds they give you in the book are really just approximations to help you use the meter. >How many F-stops of exposure is 6db equal to? One.--scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." On 11/28/2006, Scott Dorsey posted this:
Show quoteHide quote > <cine***@hotmail.com> wrote: Two stops. 6dB is a factor of 4.>> Does anybody know why this camera is programmed to shoot in low-light >> levels with 1/100 sec shutter speed plus 6db gain. I thought the >> standard shutter speed for a PAL Digital video camera is 1/50 sec (1/60 >> for NTSC) . The 6db gain introduces noticeable noise. >> If the shutter speed vwas a normal 1/50 only 3db of gain would be >> required which should cut down the noise. > > Video cameras don't have shutters, really. Some of them do have the > ability to adjust the amount of time the CCD is collecting light, but > since you (if you are running 25i) HAVE to shoot 50 fields a second, > there is no way it can be collecting for more than 1/50 sec maximum, > and due to overhead it can often be much less than that. > > But the shutter speeds they give you in the book are really just > approximations to help you use the meter. > >> How many F-stops of exposure is 6db equal to? > > One. > --scott -- Gene E. Bloch (Gino) letters617blochg3251 (replace the numbers by "at" and "dotcom") Scott Dorsey wrote:
> <cine***@hotmail.com> wrote: Scott,> >Does anybody know why this camera is programmed to shoot in low-light > >levels with 1/100 sec shutter speed plus 6db gain. I thought the > >standard shutter speed for a PAL Digital video camera is 1/50 sec (1/60 > >for NTSC) . The 6db gain introduces noticeable noise. > >If the shutter speed vwas a normal 1/50 only 3db of gain would be > >required which should cut down the noise. > > Video cameras don't have shutters, really. Some of them do have the > ability to adjust the amount of time the CCD is collecting light, but > since you (if you are running 25i) HAVE to shoot 50 fields a second, > there is no way it can be collecting for more than 1/50 sec maximum, > and due to overhead it can often be much less than that. That's my point ,1/100 sec is exactly half 1/50 sec.This particular camera has a "DATA" button on the Remote Control that (in playback mode) gives on-screen display information regarding , Manual/Auto exp., F stop, Shutter speed, White Balance, Steady Shot (on-off) etc. It will display the aperture and shutter speed being used for any given scene(or even frame) in the video. Since the camera was being used in a low-light situation it would seem to make more sense to have the shutter set to 1/50 since this will allow twice the amount of light to pass as 1/100 sec and then, either 3db of gain or 0db of gain(does anybody know for sure what 6db of gain is equal to in F-stops) could be used rather than 6db, this will improve image quality by cutting down the grain. Regards, Peter mason Show quoteHide quote > > But the shutter speeds they give you in the book are really just > approximations to help you use the meter. > > >How many F-stops of exposure is 6db equal to? > > One. > --scott > -- > "C'est un Nagra. C'est suisse, et tres, tres precis." Unrelated question, but I just have to ask: how does one determine
the proper exposure for video? Do modern professional video cameras have an ASA equivalent? Does one need to drag around a waveform monitor everywhere? Is there some other approach? I've only shot with consumer-grade video cameras where, if they have any exposure adjustments at all, one pretty much has to go with how the image looks in the viewfinder or an external monitor, which seems kind of risky to me. -- Scott Norwood: snorw***@nyx.net, snorw***@redballoon.net Cool Home Page: http://www.redballoon.net/ Lame Quote: Penguins? In Snack Canyon? Scott Norwood wrote:
> Unrelated question, but I just have to ask: how does one determine Some cameras (generally those that are more expensive and > the proper exposure for video? "professional", I think) have an overexposure warning feature called "zebra stripes". If switched on, this function will display a diagonally striped pattern over the overexposed parts of the image. (The pattern is only visible on the viewfinder and on the LCD screen - it will not be recorded on the tape.) Since camcorder manufacturers like to artificially differentiate their product line but tend to use the same (or similar) firmware across a range of their camcorder models, configured a bit differently for each model, some low-end camcorders actually have this as a hidden feature. (It is possible to enable the "zebra stripes" feature at least on early 1st and 2nd generation Sony Digital8 models, such as DCR-TRV210.) > Do modern professional video cameras have an ASA equivalent? I imagine pro cameras _could_ incorporate even more sophisticated > Does one need to drag around a waveform monitor everywhere? > Is there some other approach? built-in monitoring tools these days, such as a live histogram, but I'm not sure if they do. -- znark Jukka Aho wrote:
> Some cameras [...] have an overexposure warning feature called Found a web page which illustrates that feature:> "zebra stripes". <http://thedvshow.com/faq-pro/?action=article&cat_id=002&id=2> -- znark In article <gUJbh.63478$Lz2.41***@reader1.news.jippii.net>,
Jukka Aho <jukka.***@iki.fi> wrote: >Jukka Aho wrote: Interesting. Thanks!> >> Some cameras [...] have an overexposure warning feature called >> "zebra stripes". > >Found a web page which illustrates that feature: ><http://thedvshow.com/faq-pro/?action=article&cat_id=002&id=2> So, basically, you set the exposure so that the highlights aren't clipped and let the shadows take care of themselves? -- Scott Norwood: snorw***@nyx.net, snorw***@redballoon.net Cool Home Page: http://www.redballoon.net/ Lame Quote: Penguins? In Snack Canyon? Scott Norwood <snorw***@redballoon.net> wrote:
Show quoteHide quote >In article <gUJbh.63478$Lz2.41***@reader1.news.jippii.net>, Well, in a perfect world, you'd have a waveform monitor on set, so that you>Jukka Aho <jukka.***@iki.fi> wrote: >>Jukka Aho wrote: >> >>> Some cameras [...] have an overexposure warning feature called >>> "zebra stripes". >> >>Found a web page which illustrates that feature: >><http://thedvshow.com/faq-pro/?action=article&cat_id=002&id=2> > >Interesting. Thanks! > >So, basically, you set the exposure so that the highlights aren't clipped and >let the shadows take care of themselves? can set the exposure so the highlights aren't clipped and then adjust the lighting to take care of the shadows. Many of the higher end video cameras have a waveform monitor or histogram plot available in the viewfinder with some fiddling. So you can get close to that perfect world without having to lug around an external monitor. In an imperfect world there is always the Luna-Pro, which will tell you the number of stops difference between the highlight and the shadow. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." I was watching Discovery HD about 2 months ago where this cameraman and his
assistant were in the wild in Africa filming meerkats in HD. They had a jeep loaded with equipment with specially made rigs for lugging all the gear with. I was startled for a moment to actually see a waveform monitor with other stuff sitting on the a shipping crate in the bush. But, if you're a perfectionist and don't want to "fix it in post", then I guess that is what you have to do. Morgan Show quoteHide quote "Scott Dorsey" <klu***@panix.com> wrote in message news:ekpgku$973$1@panix2.panix.com... > Scott Norwood <snorw***@redballoon.net> wrote: >>In article <gUJbh.63478$Lz2.41***@reader1.news.jippii.net>, >>Jukka Aho <jukka.***@iki.fi> wrote: >>>Jukka Aho wrote: >>> >>>> Some cameras [...] have an overexposure warning feature called >>>> "zebra stripes". >>> >>>Found a web page which illustrates that feature: >>><http://thedvshow.com/faq-pro/?action=article&cat_id=002&id=2> >> >>Interesting. Thanks! >> >>So, basically, you set the exposure so that the highlights aren't clipped >>and >>let the shadows take care of themselves? > > Well, in a perfect world, you'd have a waveform monitor on set, so that > you > can set the exposure so the highlights aren't clipped and then adjust the > lighting to take care of the shadows. > > Many of the higher end video cameras have a waveform monitor or histogram > plot available in the viewfinder with some fiddling. So you can get close > to that perfect world without having to lug around an external monitor. > > In an imperfect world there is always the Luna-Pro, which will tell you > the > number of stops difference between the highlight and the shadow. > --scott > -- > "C'est un Nagra. C'est suisse, et tres, tres precis." Morgan Montague <ciner***@verizon.net> wrote:
> I was startled for Sadly, that's the problem with video. You _can't_ fix it in post.>a moment to actually see a waveform monitor with other stuff sitting on the >a shipping crate in the bush. But, if you're a perfectionist and don't want >to "fix it in post", then I guess that is what you have to do. You can shoot film, but then you have an even worse issue getting gear in and out, especially with the current TSA wackiness. And you're stuck with double-system sound, which is a pain for documentary work in the field. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." Scott Dorsey wrote:
> <cine***@hotmail.com> wrote: Scott,> >Does anybody know why this camera is programmed to shoot in low-light > >levels with 1/100 sec shutter speed plus 6db gain. I thought the > >standard shutter speed for a PAL Digital video camera is 1/50 sec (1/60 > >for NTSC) . The 6db gain introduces noticeable noise. > >If the shutter speed vwas a normal 1/50 only 3db of gain would be > >required which should cut down the noise. > > Video cameras don't have shutters, really. Some of them do have the > ability to adjust the amount of time the CCD is collecting light, but > since you (if you are running 25i) HAVE to shoot 50 fields a second, > there is no way it can be collecting for more than 1/50 sec maximum, > and due to overhead it can often be much less than that. That's my point ,1/100 sec is exactly half 1/50 sec.This particular camera has a "DATA" button on the Remote Control that (in playback mode) gives on-screen display information regarding , Manual/Auto exp., F stop, Shutter speed, White Balance, Steady Shot (on-off) etc. It will display the aperture and shutter speed being used for any given scene(or even frame) in the video. Since the camera was being used in a low-light situation it would seem to make more sense to have the shutter set to 1/50 since this will allow twice the amount of light to pass as 1/100 sec and then, either 3db of gain or 0db of gain(does anybody know for sure what 6db of gain is equal to in F-stops) could be used rather than 6db, this will improve image quality by cutting down the grain. Regards, Peter mason Show quoteHide quote > > But the shutter speeds they give you in the book are really just > approximations to help you use the meter. > > >How many F-stops of exposure is 6db equal to? > > One. > --scott > -- > "C'est un Nagra. C'est suisse, et tres, tres precis." cine***@hotmail.com wrote:
> Since the camera was being used in a low-light situation it would Try the AE programs, perhaps some of them will perform better. See here > seem to make more sense to have the shutter set to 1/50 since this > will allow twice the amount of light to pass as 1/100 sec and then, > either 3db of gain or 0db of gain(does anybody know for sure what > 6db of gain is equal to in F-stops) could be used rather than 6db, > this will improve image quality by cutting down the grain. as well - some of the information might be applicable to your camcorder, too: <http://www.camcorderinfo.com/bbs/showthread.php?t=114888> -- znark Jukka Aho wrote:
Show quoteHide quote > cine***@hotmail.com wrote: Jukka,> > > Since the camera was being used in a low-light situation it would > > seem to make more sense to have the shutter set to 1/50 since this > > will allow twice the amount of light to pass as 1/100 sec and then, > > either 3db of gain or 0db of gain(does anybody know for sure what > > 6db of gain is equal to in F-stops) could be used rather than 6db, > > this will improve image quality by cutting down the grain. > > Try the AE programs, perhaps some of them will perform better. See here > as well - some of the information might be applicable to your camcorder, > too: > > <http://www.camcorderinfo.com/bbs/showthread.php?t=114888> > > -- > znark Thanks for the website. It certainly contains interesting and useful information. It seems to indicate that the 1/100 sec shutter speed is related to the Steady Shot being in the ON position. All the Best, Peter Mason cine***@hotmail.com wrote:
Show quoteHide quote > Jukka Aho wrote: However, that raises the question, why is it necessary to have the> > cine***@hotmail.com wrote: > > > > > Since the camera was being used in a low-light situation it would > > > seem to make more sense to have the shutter set to 1/50 since this > > > will allow twice the amount of light to pass as 1/100 sec and then, > > > either 3db of gain or 0db of gain(does anybody know for sure what > > > 6db of gain is equal to in F-stops) could be used rather than 6db, > > > this will improve image quality by cutting down the grain. > > > > Try the AE programs, perhaps some of them will perform better. See here > > as well - some of the information might be applicable to your camcorder, > > too: > > > > <http://www.camcorderinfo.com/bbs/showthread.php?t=114888> > > > > -- > > znark > > > > Jukka, > Thanks for the website. It certainly contains interesting and useful > information. It seems to indicate that the 1/100 sec shutter speed is > related to the Steady Shot being in the ON position. shutter set to 1/100 when using the STEADY SHOT? Regards, Peter Mason cine***@hotmail.com wrote:
> However, that raises the question, why is it necessary to have the I don't really know, but I would guess the "Steady Shot" feature likes > shutter set to 1/100 when using the STEADY SHOT? sharper images better. -- znark cine***@hotmail.com writes:
>> Jukka, Not strictly necessary, but it does help reduce image blur so the camera>> Thanks for the website. It certainly contains interesting and useful >> information. It seems to indicate that the 1/100 sec shutter speed is >> related to the Steady Shot being in the ON position. >However, that raises the question, why is it necessary to have the >shutter set to 1/100 when using the STEADY SHOT? probably "helps" you by automatically increasing shutter speed. On cameras with optical image stabilization, the image is held stationary (or close to stationary) on the sensor during exposure, so each individual frame is less blurred. This is in addition to removing most of the large-scale frame-to-frame camera motion. But the TRV27E has electronic image stabilization. This shifts each frame of video to line up with the one before it, removing the large-scale frame-to-frame motion, but doing nothing about the blur within each individual frame. Only a higher shutter speed helps that. Automatically switching to a higher shutter speed makes the camera's "steady shot" mode produce sharper images when it is turned on. A better camera might let you control EIS and fast shutter individually, but a better camera might also have optical stabilization instead. Dave On 12/01/2006, cine***@hotmail.com posted this:
Show quoteHide quote > cine***@hotmail.com wrote: My own opinion (not knowledge) is that this gives the processor extra >> Jukka Aho wrote: >>> cine***@hotmail.com wrote: >>> >>>> Since the camera was being used in a low-light situation it would >>>> seem to make more sense to have the shutter set to 1/50 since this >>>> will allow twice the amount of light to pass as 1/100 sec and then, >>>> either 3db of gain or 0db of gain(does anybody know for sure what >>>> 6db of gain is equal to in F-stops) could be used rather than 6db, >>>> this will improve image quality by cutting down the grain. >>> >>> Try the AE programs, perhaps some of them will perform better. See here >>> as well - some of the information might be applicable to your camcorder, >>> too: >>> >>> <http://www.camcorderinfo.com/bbs/showthread.php?t=114888> >>> >>> -- >>> znark >> >> >> >> Jukka, >> Thanks for the website. It certainly contains interesting and useful >> information. It seems to indicate that the 1/100 sec shutter speed is >> related to the Steady Shot being in the ON position. > > However, that raises the question, why is it necessary to have the > shutter set to 1/100 when using the STEADY SHOT? > > Regards, > Peter Mason time to move the image to the pixels where they belong (in the buffer) - or call it time for analysis, if you prefer. Some cameras also restrict the size of the image a little bit when digital stabilization is on, to give margins around the picture so as to allow for this motion. Otherwise edges would get cropped (e.g., move the picture to the left a little bit and you'd lose some pixels on the left). -- Gene E. Bloch (Gino) letters617blochg3251 (replace the numbers by "at" and "dotcom")  
Other interesting topics
deceptive ad on videoguys.com?
Digital leap? DVD Camcorders is this really a digital ccd camera? what computer features to look for- for editing video files? My first camcorder? Dazzle DV-Bridge Installation Problem magazines and websites? Re: deceptive ad on videoguys.com? Help: GY-DV5100U or GY-HD110? |
|||||||||||||||||||||||
