Pocketable Camera with Shutter Priority for Movie? - AVS Forum
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post #1 of 22 Old 07-16-2012, 07:20 AM - Thread Starter
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When I play the tourist it is SOP for me to carry both a small point-&-shoot camera and a small HD camcorder. I'd love to carry just a pocketable (compact) camera that can do the job of both but so far all I have seen lack one essential capability of my camcorder: recording video in shutter priority mode. I consider this essential because it prevents videos shot in bright daylight - which is the vast majority of them for me - from having a stroboscopic look from too short a shutter speed. I believe what is preventing a shutter priority mode is the lack of a true iris in most compact cameras. Most offer only two T-ratios at any given focal length, achieved using an ND filter. Is there any hope?
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post #2 of 22 Old 07-16-2012, 07:47 AM
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Last year's Sony HX9V is considered by many to be what you are looking for. Search both Vimeo and YouTube for "HX9V" for lots of examples. Positive reviews and recommendations are everywhere you look. This year's version is the HX20V or almost identical HX30V.

I don't know if it has a shutter priority mode, but the HX9V I have has never produced a "stroboscopic look" for me.

Another choice might the new Sony HDR-GW77 that may be the ultimate in pocket travel cameras because, in addition to good video, it is rugged, waterproof and dustproof. I don't own one, yet.

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post #3 of 22 Old 07-16-2012, 09:04 AM
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"I consider this essential because it [set shutter] prevents videos shot in bright daylight - which is the vast majority of them for me - from having a stroboscopic look from too short a shutter speed."

I used to consider this essential, until I used the Sony Hx9v and now the Sony GW77 - both do not let you lock the shutter, but I have never found any evidence of visible strobing effects in any light. There are plenty of videos (downloadable) posted in this forum from both cameras, so you can check this out for yourself.

The pocketable Sony RX100 does let you do this, but it has many disadvantages, including less sharp and much more artifacting video, a poor zoom, limited zoom length, and mediocre audio. It is basically a great little stills camera with video.
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post #4 of 22 Old 07-16-2012, 12:20 PM - Thread Starter
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Quote:
Originally Posted by markr041 View Post

I used to consider this essential, until I used the Sony Hx9v and now the Sony GW77 - both do not let you lock the shutter, but I have never found any evidence of visible strobing effects in any light. There are plenty of videos (downloadable) posted in this forum from both cameras, so you can check this out for yourself..
Perhaps tolerance to this varies. One of your videos is an example of what I call "stroboscopic": http://vimeo.com/22535092.
Granted you can't judge fairly based on the re-compressed file, which is a 30p version of your 60p original. But in the original (47432348.mts) the visual effect of a very fast shutter speed as the players swing the bat and run the bases is quite evident to me. I'm not saying it looks bad, far from it, but it's not a look I prefer. I would prefer to see a little blurring, such as you would get with a 180 degree shutter even at 60p. This is easily achievable with the right camcorder (even mine, but only with 720 lines at 60p).
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post #5 of 22 Old 07-16-2012, 12:21 PM
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Yes, I agree that that video shows the effect (makes great frame grabs though).
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post #6 of 22 Old 07-27-2012, 09:26 AM
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Joe,

One solution for auto-shutter cameras that take good video is to use an external ND filter to cut the light. I found this very cheap filter-holder explictly for use with little cameras - it is light and small (and pocketable), attaching to the tripod hole:

http://www.bhphotovideo.com/c/product/387332-REG/Cokin_CBAD700_Shoe_Digital_Filter_Holder.html

You can insert an ND fliter (which also weighs little):

http://www.bhphotovideo.com/c/product/250079-REG/Cokin_CA154_A154_Gray_Neutral_Density.html

I ordered these items, and will try them on my Hx9v. I have software that reports the actual shutter-speed of videos, so we will see if this solution cuts down the shutter so that one gets smooth video (at least 1/128th). I believe the shutter speed for the baseball video, taken in very bright light, was 1/600th of a second (!), so a 1/8 filter may do the trick.
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post #7 of 22 Old 07-27-2012, 10:30 AM
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There is a guy bragging about a clever filter solution, but won't say where to buy it yet.

The idea is that you attach a thin ring to the front of the lens. The filters then stick magnetically to that ring.

http://cheesycam.com/nd-or-cpl-filters-for-sony-rx100/

Product demo video: http://www.youtube.com/watch?v=FejSR_k37Gc

Or, if you prefer Vimeo: https://vimeo.com/46146974

I'd buy if I could figure out where.

Bill
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post #8 of 22 Old 07-27-2012, 10:33 AM
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I always worry about permanently attaching (the magnetic ring in this case, not the filter) anything to a camera.

The Cokin solution above would work for many cameras, so might be a better choice for multi-camera users, or those queasy about glueing stuff on a camera. The stick-on solution is more compact for sure.
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post #9 of 22 Old 07-27-2012, 07:06 PM
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Quote:
Originally Posted by markr041 View Post

the Sony GW77 - both do not let you lock the shutter

Can you lock exposure on the GW77?

EDIT: I see from one of your other posts that white balance and exposure can be controlled.
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post #10 of 22 Old 07-28-2012, 07:01 AM
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Yes, you can lock exposure, wb and focus.
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post #11 of 22 Old 07-31-2012, 12:11 PM
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ND filter solution for pocket camcorders without shutter-priority mode to reduce shutter speed in bright light:

DSC00621.jpg

DSC00615.jpg


The holder attaches to the tripod hole of the camera; then you can select what filters to slot in front. The holder is adjustable so you can put the filter as close to the lens of any camera. The filter here is a neutral density filter that cuts light to 1/8th.

The whole set adds almost nothing to the weight.The holder/base folds flat, so it is easy to carry around detached. The holder itself has a tripod hole; I have attached a little handle to the bottom.
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post #12 of 22 Old 07-31-2012, 02:52 PM
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A brief video testing the ND filter.

I wanted to see if there were reflections or loss of sharpness from having the filter. All of the shots here had the filter in place. I took shots with the sun behind me and in front of me.

Select the 1080p option for best results, otherwise it defaults to sd!

Seems ok - I do not see any glare or spots or fuzziness. It was a cloudy day, so the ND filter was not doing much good; maybe even needed some gain (with noise) to cut through when the light is cut to 1/8th!

The metadata from the video indicates that the shutter speed was kept down, but indeed the light cut necessitated increasing gain. In all cases the iris was at the maximum for the focal length (so I got the shallowest dof, which is what I wanted).

This is the metadata file (with the longitude taken out to protect privacy) for the video, scene-by-scene. As you can see, there is quite a bit of information.


Metadata.jpg

On a bright days, the filter would appear to be perfect for keeping shutter speed sown.
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post #13 of 22 Old 08-09-2012, 07:45 AM
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The Cokin filter kit on the Hx9v:

DSC00050.jpg


DSC00052.jpg



Pictures taken with the GW77.
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post #14 of 22 Old 08-09-2012, 05:50 PM
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Any reference on how AUTO exposure control works?

You have found work-arounds to get some AUTO exposure cameras to use slower shutter speeds as you want.

I know that some AUTO cameras shorten the exposure time when the illumination levels are high. But I would like to find a reference that discusses, in general, how AUTO exposure control systems usually work, especially in using shutter speed as a variable.

The application of analyzing sports for stop action single frame analysis works best with 60p and, as mentioned, with fast shutter speeds. But how can you guess what a certain camera's AUTO might do? Would the AUTO always choose a very short shutter speed in direct sunlight? Do they always keep low ISOs of, say, 200, etc.and never use high ISO values?

So far, all I know - the AUTO exposure control process is top secret.
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post #15 of 22 Old 08-09-2012, 07:21 PM
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I agree it is a mystery what algorithm is used to control exposure in auto.

But there is a way to find out: shoot in auto and then see under what conditions gain (not iso; this is video), iris and shutter vary.

There is a program called Dvinfo Pro that reads video clips and creates a file containing all these specs for each scene.

I posted one example above; here it is again:

Metadata.jpg

So, go ahead and shoot under different conditions and see what the camera does.
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post #16 of 22 Old 08-10-2012, 07:54 AM
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[quote name="markr041" url="/t/1420469/pocketable-camera-with-shutter-priority-for-movie#post_22294431"................................................
But there is a way to find out: shoot in auto and then see under what conditions gain (not iso; this is video), iris and shutter vary.
There is a program called Dvinfo Pro that reads video clips and creates a file containing all these specs for each scene.
I posted one example above; here it is again:
Metadata.jpg..............................................................[/quote]

I find a DVinfo website with forums but have not found the DVinfo Pro software. I have no occupational interest so could probably not afford the software in any case.

http://www.dvinfo.net/about

You are saying that video file metadata includes the shutter speeds that were used for specific videos. Wouldn't shutter speed with AUTO change during the video as illumination varies if not fixed by MANUAL exposure control? Does the program sample shutter speed somehow during the videos?
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post #17 of 22 Old 08-10-2012, 09:00 AM
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"You are saying that video file metadata includes the shutter speeds that were used for specific videos. Wouldn't shutter speed with AUTO change during the video as illumination varies if not fixed by MANUAL exposure control? Does the program sample shutter speed somehow during the videos?"

No, the metadata is for each *clip* (not video). Look at the chart - it tells you the shutter speed for each clip. Look at the video to see the clips. As in most videos, the clips are very short (7-10 seconds) and it is highly unlikely the light changes during the clip. For the purpose of understanding what is going on, you take each clip under different lighting conditions. And, in AUTO mode, the shutter speed will vary as the light changes across the clips and the software will show you this

Sorry about the reference: the software is DVMP Pro 5. There is a free demo version.
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post #18 of 22 Old 08-10-2012, 09:39 AM
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Quote:
Originally Posted by markr041 View Post

"You are saying that video file metadata includes the shutter speeds that were used for specific videos. Wouldn't shutter speed with AUTO change during the video as illumination varies if not fixed by MANUAL exposure control? Does the program sample shutter speed somehow during the videos?"
No, the metadata is for each *clip* (not video). Look at the chart - it tells you the shutter speed for each clip. Look at the video to see the clips. As in most videos, the clips are very short (7-10 seconds) and it is highly unlikely the light changes during the clip. For the purpose of understanding what is going on, you take each clip under different lighting conditions. And, in AUTO mode, the shutter speed will vary as the light changes across the clips and the software will show you this
................................................

I don't do much editing. If I place a video camera on a tripod and video for 1 minute I might edit that 'clip' into a longer video. I can see that for a 5 second clip that perhaps the AUTO has a time constant to not change gain or shutter speed rapidly so that a sudden increase in illumination will appear as it is. But over a minute period maybe a cloud passes over and the illumination level drops to 10% of that of direct sunlight, then I would expect the AUTO to adjust. If it adjusts(?) and I put that 1 minute clip into a longer video it is not clear what the DVMP Pro 5 will show for shutter speed in the metadata. Isn't that so? If, once triggered, the AUTO has an algorithm to always maintain its initial shutter speed and to only adjust gain for illumination changes then it makes sense that the DVMP Pro 5 would display a single shutter speed value. Once again understanding depends on the top secret info of how AUTO exposure works and probably an incomplete description of how DVinfo Pro 5 works.

The DVMP Pro 5 might also provide average values of shutter speed and gain over the clip. ? Does metadata have time resolved shutter speed and gain?

If the AUTO maintains the shutter speed on your camera, then if you pulled out your filter - after starting the video- the AUTO would adjust gain but always have a single shutter speed. ??

Sounds like a good question for a DVMP Pro 5 forum.
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post #19 of 22 Old 08-10-2012, 10:51 AM
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"Does metadata have time resolved shutter speed and gain?"

Yes. You tell DVMP what you want. You can get info at the start of each clip, as above. Then, ifi you want to *test* your hypotheses about what the camera does in adjusting to lighting conditions you can just take successive clips of short duration under different lighting conditions so you would not have to worry about what DVMP does during a clip. So, I could take a clip with the filter, stop, take off the filter, and shoot another clip. Then DVMP would tell me what the AUTO camera settings were for the two successive clips - did it change the shutter or the aperture for the different lighting? To anticipate what would happen in the clips you take you do a series of controlled experiments (for example: with and without the filter, same light; without the filter, different light; with the filter different light - that's 6 clips).

Now, as you say, this technique might not be valid if while shooting the algorithm is different if the lighting changes compared to starting and stopping under different light (I doubt it). But the metadata are continuous, and you can ask DVMp to tell you the settings not at each clip but for each change in settings that occure (automatically) within clips. So, it will do what you want. They key point is that all of the info is in the video for each frame.

You can download a free version of the software to try it out.
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post #20 of 22 Old 08-10-2012, 11:55 AM
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One reason that I purchased a Casio Fh100 was so that I would never have to think about motion blur and AUTO exposure control again. I like to nail down the exposure time (the Casio Fh100 goes to 1/40,000 sec!)

You are saying that if I stop on a single frame I can get the shutter speed & gain for that one frame with DVMP Pro 5. But that is very interesting!
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post #21 of 22 Old 08-10-2012, 12:25 PM
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"One reason that I purchased a Casio Fh100 was so that I would never have to think about motion blur "

Actually, you want some motion blur in video - it contributes to smoothness. Any shutter speeds above 1/60th-1/120th lead to choppy video if not slowed down (i.e. for slow mo effects). The rule of thumb is a shutter speed double the frame rate.

The problem with auto-mode in video is the shutter speeds will go too high. Even with manual shutter, if you set the shutter to 1/60th, appropriately, in bright light that will necessitate small apertures, which can lead to diffraction artifacts. Thus, one needs an ND filter to get a slow shutter and a big iris. It is why pro cameras have built-in ND filters. When I shoot video with a camera that has manual settings, I almost always use an ND filter. And for auto cameras, an ND filter is still desirable, hence my attempt at using one for the GW77 - resulting in 1/60th shutter speds and big iris, just what wanted. For many videos, however, the high shutter speeds will not be noticeable, and you can get great frame grabs of action.
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post #22 of 22 Old 05-17-2013, 06:16 PM
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Quote:
Originally Posted by markr041 View Post

"One reason that I purchased a Casio Fh100 was so that I would never have to think about motion blur "

Actually, you want some motion blur in video - it contributes to smoothness. Any shutter speeds above 1/60th-1/120th lead to choppy video if not slowed down (i.e. for slow mo effects). The rule of thumb is a shutter speed double the frame rate.
........................................................................................

Late reply -

Motion Blur - there are two very different applications regarding motion blur:

1) Considerable Motion Blur - For smooth videos a wide consensus seems to be that considerable motion blur is desirable as with your "rule of thumb".

2) Minimum Motion Blur - On the other hand, for high speed video analysis of rapidly moving objects the minimum motion blur possible is very desirable. In analysis, often stop-action, single frame is used. Minimum motion blur allows the most accurate position measurements. For example, how many centimeters out from the tennis racket strings is the ball 30 milliseconds after it has separated from the strings? In addition, some analysis is done using slow motion playback. Here again minimum motion blur allows clear identification of the rapidly moving objects.

High speed videos of tennis strokes, mostly the serve. Most were at 240 fps with 1/10,000 sec shutter speed or as fast as the available light allowed. https://vimeo.com/user6237669/videos

On Vimeo the best available viewing for stop action single frame advance is to press the play-pause control as fast as possible. Recently on Youtube, often the forward and backward keyboard arrows work for stop action single frame as they do with Quicktime.
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