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Sony HVR-Z1 / HDR-FX1
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Old July 16th, 2010, 09:48 AM   #1
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high shutter speeds = distortion/artifacts?

Hi all,

In order to try to replicate a 25fps type look on my FX1 I've taken to opening the iris as wide as possible and then knocking the shutter as high as possible (in bright light getting up to 6000 at times) When looking at for example a confetti shot with lots of fast movement shot on this shutter speed, there seems to be quite a lot of noise on the screen (almost like gain) and also some horizontal line distortion.

I take it this is because of the high shutter speed? Should I avoid doing this?!
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Old September 6th, 2010, 01:34 AM   #2
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nobody? guess not :(
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Old September 6th, 2010, 01:37 AM   #3
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frame rate and shutter speed impart different looks on video. You can not replicate one by manipulating the other.

Also, the common shutter speed for filming at 25p is 1/50th of a second. I don't know why in the world you've been using fast shutter speeds...
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Old September 6th, 2010, 02:59 AM   #4
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I will upload a clip later to show you what I mean, but I find that by using as high a shutter as possible I get a slightly choppy image and I can also therefore set my iris as open as possible to get good depth of field...
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Old September 6th, 2010, 03:04 AM   #5
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Quote:
Originally Posted by Perrone Ford View Post
the common shutter speed for filming at 25p is 1/50th of a second
I'm not actually filming 25p because as you know the FX1 doesnt do 25p
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Old September 6th, 2010, 03:07 AM   #6
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Originally Posted by David Payne View Post
I will upload a clip later to show you what I mean, but I find that by using as high a shutter as possible I get a slightly choppy image and I can also therefore set my iris as open as possible to get good depth of field...
Yes, I am aware of what increasing speed does. And it does not replicate the look of 25p (or 24p for that matter). It just provides a staccato aesthetic that is appropriate for action sequences or other things, but wholly inappropriate for trying to replicate a 25/24p feel.

I wasn't aware that shallow DOF = good DOF. But that's fine. You might also find that you can put some ND filters on the front of your lens so you don't have to resort to using very high shutter speeds. This is the common way it's done by photographers, cinematographers, and videographers world wide.
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Old September 6th, 2010, 11:32 AM   #7
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Sounds to me like he wants the high shutter speed, so the ND would do the opposite of what he's looking for.
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Originally Posted by David Payne View Post
... there seems to be quite a lot of noise on the screen (almost like gain)...
That's probably exactly what it is. The very high Shutter Speed, even with a wide open iris, may not be allowing enough light into the cam, so you may be gaining up horribly, which would account for the noise. Make sure gain is locked at 0 (or at least below 9 on the FX1) and then expose properly. You may not be able to get as high a shutter speed as you're looking for.
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Old September 6th, 2010, 03:13 PM   #8
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Sounds to me like he wants the high shutter speed, so the ND would do the opposite of what he's looking for.
spot on Adam. Appologies I think I perhaps described the look I am achieving and the look I wanted as 25p like when it is in fact called staccato.

Perrone, my sincere apologies for using the word good instead of narrow.

Adam, I am indeed locking my gain to 0 at all times, however I am still seeing this slight graining. Very srange
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Old September 6th, 2010, 03:22 PM   #9
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Interesting. Can you post a screen grab?

You mentioned in your other thread that you have four FX1s. Does it do this with all of them?
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Old September 6th, 2010, 04:24 PM   #10
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I always tend to use my 'main cam' with a beachtek box on during photos (and therefore confetti which is where it always shows up best). I suppose its a good idea to try with a different cam and see the effects.
I will export a video and upload it asap as I think this will show it better than a screen grab (fast motion screen grabs are always pretty nasty when exported through premiere pro, even after deinterlacing)
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Old September 6th, 2010, 04:50 PM   #11
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A screen grab would be better so we can see what's actually in the frame/field rather than any compression artifacts from moving video. And obviously the last thing you'd want to do is deinterlace... we must see the original field.
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Old September 6th, 2010, 06:06 PM   #12
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"In order to try to replicate a 25fps type look on my FX1 I've taken to opening the iris as wide as possible and then knocking the shutter as high as possible"

In-camera, I think the best way to try emulating a 24p, 25p, 30p look with an FX1 is to increase the shutter speed as you were doing, but I would not expect the final look to be too close. The staccato look is somewhat a part of the overall film look and can be used toward this purpose. A substitute is always going to be a substitute, but there's nothing wrong with doing what you can with the tools you have available.

Some people have stated they drop the shutter speed to 1/30 or so for a more filmic look, though most would probably call that effect more strobing or blurring than anything else. Of course, exactly what you're shooting and how you shoot it will have a huge impact on how these different settings will come across in the final film. As you're seeing, there can easily be drawbacks anytime you deviate too far from a camera's intended range of normal operation. For instance, 6000 shutter speed seems incredibly fast to me. I would say that 250 more or less would be a good starting point for you to toy with. Just don't plan on using these high shutter speeds too much when you're indoors in a dark room though. There can be problems with lights flickering indoors as well as an overall darker picture. These cameras can only do so much, and for that reason I personally reserve the high-shutter-speed trick mostly for close up shots of water fountains where I want to see some more detail in the splashing/falling drops, and fast-action sports.

Another thing to note is the consistency-of-look in your film. If you plan to use a higher shutter speed for part of the shoot and then go into a dark room and shoot at a slower shutter speed, you might have a real mismatch between how the shots will go together in the edit...or maybe not. This may be fine for your particular film though.

As for depth of field, I wouldn't count on the FX1 to vary much regardless of how you adjust the settings. By far, the biggest changes will come from where you place the camera in relation to the subject, foreground, and background and how much you zoom in. I think ND filters, shutter speed, and iris tricks are way overrated when it comes to altering DOF on the FX1.

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Old September 8th, 2010, 08:51 AM   #13
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thank you very much for your in depth reply Alex and I'm glad you can see where I'm coming from with this 'high shutter = 25p' look. I am a bit fan of it as I find that as well as the filmic look achieved through fast movement it also enables me to open the iris to at least get a little bit of a narrower depth of field.

Adam, here is a screen grab. I notice this issue almost entirely on confetti shots so i'm sure its something to do with the multiple moving objects at once... could it be similar to the 'mud' on AVCHD video on detailed shots?

http://www.rideoutproductions.co.uk/ShutterImage.jpg
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Old September 8th, 2010, 12:14 PM   #14
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Interesting. I'm not sure it has anything to do with the Shutter Speed. It may be as you suggest the codec being overwhelmed by the motion. Only way to tell for sure would be to do a side by side test at different shutter speeds.
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Old September 9th, 2010, 03:56 AM   #15
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Adam,

As soon as I have a weekend with no weddings I will do exactly that. I'll also compare my 4 cameras/

Will post my results here, in the mean time thanks very much to everyone for your help.
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