Kx (or K7) Controlling shutter speed?

Coby · 12-28-2009, 10:53 AM

What techniques are there for holding the shutter speed constant at, say, 1/60th, if the lighting conditions are changeable? Thanks.

flyer · 12-28-2009, 11:37 AM

You can always use Tv. It will keep the shutter speed where you put it. It will change aperture and ISO if your camera is set on Auto ISO.

jogiba · 12-28-2009, 11:47 AM

Originally posted by flyer

You can always use Tv. It will keep the shutter speed where you put it. It will change aperture and ISO if your camera is set on Auto ISO.

In video mode ?

Coby · 12-28-2009, 11:52 AM

Yep - sorry if I wasn't clear - I'm meaning while in video mode.

netrex · 12-28-2009, 02:58 PM

How will this be possible on the K-x where you have to choose the video camera icon on the mode dial (where Tv is also).

Eruditass · 12-28-2009, 03:14 PM

You can't, unfortunately, you only get Av mode.

Only thing you can do is lock exposure once you get a shutter speed you like.

jogiba · 12-28-2009, 04:41 PM

Originally posted by Eruditass

You can't, unfortunately, you only get Av mode.

Only thing you can do is lock exposure once you get a shutter speed you like.

How do you know what the shutter speed is in video mode ?

flyer · 12-28-2009, 04:55 PM

Originally posted by jogiba

In video mode ?

It's nice of you to wake me up after such a stupid answer.

I guess I need to catch up on sleep.

Coby · 12-28-2009, 05:03 PM

So you can lock exposure? That's good to know - the DP review that just came out seemed to imply that you could only lock aperture, and that gain and shutterspeed would continue to fluctuate.

jogiba · 12-28-2009, 06:42 PM

AE-L fix on the KX:
[yt]http://www.youtube.com/watch?v=68AQzJE1tdI[/yt]

Coby · 12-28-2009, 10:02 PM

Thanks for that - no mention of AE-L whatsoever in the video section of DPReview, and dire warnings about exposure changing during shots, so they apparently missed that feature.

But ... any way to determine what shutter speed the camera is being locked to with AE-L?

netrex · 12-29-2009, 01:21 AM

I hope they fix manual control. Filming with the wrong shutterspeed with certain lights make everything flicker and look really bad, so it will pretty much be useless in those cases unless you're lucky and get the right shutter speed by chance.

falconeye · 12-29-2009, 04:54 AM

Originally posted by Coby

But ... any way to determine what shutter speed the camera is being locked to with AE-L?

Back in June, I compiled a chart for the K-7:

Falk Lumo: K-7 as a movie camera -- PART II: Controlling video recording

The K-x should be similiar (except that with 24fps, it should target less than 1/30s -- also, I assume that K-x won't use extended ISO even when enabled and I am not sure if it would use ISO 6400 -- do your own tests and report back). The chart was compiled by observing that the same exposure (in EV terms) is used in video and still LV mode and by observing where the video controls started blinking red.

Coby · 12-29-2009, 10:42 AM

Falk, Thank you very much for that link - that chart is exactly what I was hoping might be available. It's encouraging that there is a fairly wide EV range where the K7 maintains a sensible (low) shutter speed - and that it will respond well to ND filters. Some of the K7/Kx footage I've seen online uses way too high a speed in bright light and looks bad.

I bit the bullet last night and ordered a Kx, and will attempt an equivalent EV chart for that camera ....

falconeye · 12-29-2009, 11:01 AM

Originally posted by Coby

I bit the bullet last night and ordered a Kx, and will attempt an equivalent EV chart for that camera ....

Great, I'll link back to your work then.

If you feel tempted to measure the exact exposure time (I only estimated it) then it is easiest to film a flickering source, pan horizontally and count ghost images looking at a single frame. Some high end audio devices have nice flickering display

Some power "LEDs" do flicker, too. Use blurred still photos (no SR) to gauge.

12-28-2009, 10:53 AM	#1
Coby Senior Member Join Date: Dec 2009 Posts: 106	Kx (or K7) Controlling shutter speed? What techniques are there for holding the shutter speed constant at, say, 1/60th, if the lighting conditions are changeable? Thanks.

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12-28-2009, 11:37 AM	#2
flyer Veteran Member Join Date: Jan 2008 Location: Ste-Anne des Plaines, Qc., Canada Posts: 2,013	You can always use Tv. It will keep the shutter speed where you put it. It will change aperture and ISO if your camera is set on Auto ISO.

12-28-2009, 11:47 AM	#3
jogiba Banned Join Date: Sep 2006 Location: Millstone,NJ Posts: 6,491	Originally posted by flyer You can always use Tv. It will keep the shutter speed where you put it. It will change aperture and ISO if your camera is set on Auto ISO. In video mode ?

12-28-2009, 11:52 AM	#4
Coby Senior Member Join Date: Dec 2009 Posts: 106 Original Poster	Yep - sorry if I wasn't clear - I'm meaning while in video mode.

12-28-2009, 02:58 PM	#5
netrex Senior Member Join Date: Apr 2009 Location: Alta Photos: Gallery \| Albums Posts: 279	How will this be possible on the K-x where you have to choose the video camera icon on the mode dial (where Tv is also).

12-28-2009, 03:14 PM	#6
Eruditass Veteran Member Join Date: Jul 2009 Photos: Gallery Posts: 2,207	You can't, unfortunately, you only get Av mode. Only thing you can do is lock exposure once you get a shutter speed you like.

12-28-2009, 04:41 PM	#7
jogiba Banned Join Date: Sep 2006 Location: Millstone,NJ Posts: 6,491	Originally posted by Eruditass You can't, unfortunately, you only get Av mode. Only thing you can do is lock exposure once you get a shutter speed you like. How do you know what the shutter speed is in video mode ?

12-28-2009, 04:55 PM	#8
flyer Veteran Member Join Date: Jan 2008 Location: Ste-Anne des Plaines, Qc., Canada Posts: 2,013	Originally posted by jogiba In video mode ? It's nice of you to wake me up after such a stupid answer. I guess I need to catch up on sleep.

12-28-2009, 05:03 PM	#9
Coby Senior Member Join Date: Dec 2009 Posts: 106 Original Poster	So you can lock exposure? That's good to know - the DP review that just came out seemed to imply that you could only lock aperture, and that gain and shutterspeed would continue to fluctuate.

12-28-2009, 06:42 PM	#10
jogiba Banned Join Date: Sep 2006 Location: Millstone,NJ Posts: 6,491	AE-L fix on the KX: [yt]http://www.youtube.com/watch?v=68AQzJE1tdI[/yt]

12-28-2009, 10:02 PM	#11
Coby Senior Member Join Date: Dec 2009 Posts: 106 Original Poster	Thanks for that - no mention of AE-L whatsoever in the video section of DPReview, and dire warnings about exposure changing during shots, so they apparently missed that feature. But ... any way to determine what shutter speed the camera is being locked to with AE-L?

12-29-2009, 01:21 AM	#12
netrex Senior Member Join Date: Apr 2009 Location: Alta Photos: Gallery \| Albums Posts: 279	I hope they fix manual control. Filming with the wrong shutterspeed with certain lights make everything flicker and look really bad, so it will pretty much be useless in those cases unless you're lucky and get the right shutter speed by chance.

12-29-2009, 04:54 AM	#13
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by Coby But ... any way to determine what shutter speed the camera is being locked to with AE-L? Back in June, I compiled a chart for the K-7: Falk Lumo: K-7 as a movie camera -- PART II: Controlling video recording The K-x should be similiar (except that with 24fps, it should target less than 1/30s -- also, I assume that K-x won't use extended ISO even when enabled and I am not sure if it would use ISO 6400 -- do your own tests and report back). The chart was compiled by observing that the same exposure (in EV terms) is used in video and still LV mode and by observing where the video controls started blinking red.

12-29-2009, 10:42 AM	#14
Coby Senior Member Join Date: Dec 2009 Posts: 106 Original Poster	Falk, Thank you very much for that link - that chart is exactly what I was hoping might be available. It's encouraging that there is a fairly wide EV range where the K7 maintains a sensible (low) shutter speed - and that it will respond well to ND filters. Some of the K7/Kx footage I've seen online uses way too high a speed in bright light and looks bad. I bit the bullet last night and ordered a Kx, and will attempt an equivalent EV chart for that camera ....

12-29-2009, 11:01 AM	#15
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by Coby I bit the bullet last night and ordered a Kx, and will attempt an equivalent EV chart for that camera .... Great, I'll link back to your work then. If you feel tempted to measure the exact exposure time (I only estimated it) then it is easiest to film a flickering source, pan horizontally and count ghost images looking at a single frame. Some high end audio devices have nice flickering display Some power "LEDs" do flicker, too. Use blurred still photos (no SR) to gauge.