[dom777]

I did a few tests and it definetly works with the k-7. It is a bit tricky, but you have to switch the dial to movie mode really fast so the top lcd will not flash green while changing modes. If you switch fast enough, the shutter is still locked and you see the asterisk! I have not found out yet if 1/30 is as low as you can get, or if 1/50 is possible. you are definetly the man for finding this!!! although now that we know a workaround exists, i hate pentax even more for not just offering a firmware-update to make life a little easier something similar to the 7d would be awesome,where you can set all the parameters manually...

[netrex]

Just did a quick test and it seems to work. Good job! First I thought it didn't, but I had my lens set to A, but it did once I turned the aperture to manual.

[Blinx]

As dom777 says it does work on a K7 but... no 1/50th shutterspeed
It seems that the selection of shutter speeds is limited to those that are preprogrammed in the video mode (see this site for settins)

[levobjk]

hi everybody

I made a quick test with k-x + smc-A 50mm F1.7 lens

1- In A mode, I selected Av mode, set iso to 100, make k-x select shutter as 1/50, switch video mode and quickly lock the exposure... And shot the video... F=1/1.7

2- In M mode, I selected P mode, set iso to 100, make k-x select shutter as 1/50, lock the exposure, switch video mode and shot the video... F= 1/1.7 again..

These two videos should be same, dont they? But they werent... The second video is much more bright&noisy...

I'm sure I did not do anything wrong... Locking shutter in P mode doesnt seem to work...

[netrex]

Why ISO 100? It seems to work with 200 as well.

[johnnybodybags]

netrex: i found that setting it to ISO200 would cause whatever shutter speed selected to be halved and it to revert to ISO100. so ISO200 @ 1/100 would become ISO100 @ 1/50. i think. and i couldn't seem to get it to shoot at a higher ISO than 100 (200, 400, 800, etc) unless the shutter was set to 1/25.

i could be wrong though. in fact, i hope i'm wrong.

anybody have any luck shooting at a higher ISO along with a shutter above 1/25?

[davidvandoren]

How do you know you really shoot at this shutter speed?

Isn't there a difference between the shutter used when taking pictures and the one shooting a video?

I thought when taking a picture I hear the mechanical shutter, and when using video it's a different story, done somehow by electronic readouts, line by line of the sensor or so.

I tried your way and found that it is a good way to set my camera getting noise free video in dim light. They are however darker than usually.

[Coby]

> How do you know you really shoot at this shutter speed?

In the case of the tests reported here Pentax K-x - exposure I photographed, and then filmed, a rotating fan and compared the length of motion blur on the blades.

[falconeye]

if you guys are anything like me, you've been having a hard time figuring out how to set the shutter speed using the previous posted trick (seen here). after messing around with the camera today, i may have stumbled upon a different method where you can actually LOCK shutter speed IN STILL MODE.

Johnny,

thanks for this interesting detail.

At first glance, I thought that there is nothing new. But the following is the new detail:

Only on K-x and with a manual lens, does the AE-L lock asterisk mode stay active when switching from P to video. Probably, on a K-7 this fails because of the green mode in between (except, as dom777 noted, you do it blazingly fast ...).

But this is only a minor update of the procedure to control video parameters as described by Coby and earlier, myself (Falk Lumo: K-7 as a movie camera -- PART II: Controlling video recording).

Assuming the lighting does not change, the same is always achieved using E/V-compensation in still mode until the desired combination is displayed and -- without moving the camera -- switch to video and lock exposure there. Of course, switching to video w/o moving the camera can be difficult, with a K-7 at least

Funny enough, the K-7 shares the aperture setting between still and video mode while the K-x remembers two different settings.

As for controlling ISO: This is still not possible. The lowest ISO will be used for exposure times larger than 1/24s (1/30s for K-7) and higher ISO rather than slower speeds will be used otherwise. The exact threshold is not known yet.

The max. possible video speed for the K-7 is 1/4000s. Use Coby's and my table for details about how ISO varies with luminosity.

[falconeye]

I photographed, and then filmed, a rotating fan and compared the length of motion blur on the blades.

Great method.

However, it probably lacks high precision because, as a result of the rolling shutter effect, images won't look exactly the same.

I am still interested to learn the exact threshold values (1/24s and 1/30s) for slowest shutter speeds.

Esp. with this method. Because setting 1/24s and ISO100 could result in 1/36s and ISO150 actually.

[jogiba]

It would sure help if Pentax had firmware updates for video mode like on the Canon 5D MKII.

London, 20 October 2009 – Canon today announces that it is currently developing a firmware update to the EOS 5D Mark II to enable the recording of high definition 1080p video at 24 and 25fps. The decision to develop new firmware to support these features has been taken following feedback received from cinematographers and photographers.

Introduced in September 2008, the multi award-winning EOS 5D Mark II was the first DSLR product to offer full frame 1080p HD video recording, opening up a multitude of new creative possibilities for photo journalists, news photographers and amateur filmmakers. Since then, Canon has continued to develop its groundbreaking EOS Movie functionality, firstly with the firmware update to the EOS 5D Mark II that enabled manual exposure control, and more recently by introducing a choice of video recording frame rates with the EOS 7D and EOS-1D Mark IV.

Canon currently expects the firmware update to be made available during the first half of 2010. An announcement regarding details of the update and its availability will be made closer to the release date.

[Coby]

> However, it probably lacks high precision because, as a result of the rolling shutter effect, images won't look exactly the same.

Agreed, although the method does work quite well. I made myself a 'standard curve' by taking photos of the fan at each named shutter speed (in still mode), measuring motion blur of a blade at the same position in the shot each time (about '2 o'clock' if I recall) to reduce rolling shutter bias.

The blur at 1/30 is several cm, and at 1/24 is 25% greater .... the two are fairly easily distinguished. A difference such as 1/24 vs. 1/25 can't be reliably determined however.

[johnnybodybags]

@falconeye: definitely. the method is coby's. i just expanded upon it (a little). however, i think the lock in still mode is a boon to all us shaky handed videographers.

as for controlling ISO: like you said, anything above a 1/25 shutter and the camera defaults to the lowest ISO. however, with the K-x, it seems the shutter threshold is 1/25. and, if that's locked, then the ISO can be manually selected (four stops up to ISO 1600).

but then you're shooting at the dreaded 360 degree shutter.

i don't know if this works on the k7, though.

[falconeye]

with the K-x, it seems the shutter threshold is 1/25. and, if that's locked, then the ISO can be manually selected (four stops up to ISO 1600).

Maybe I am missing something. But you cannot lock the shutter speed, only the exposure value used to determine aperture/shutter/ISO.

So, assuming the same aperture, using 2/3s exposure time at ISO 100 results at 1/24s at ISO 1600 (K-7 goes up to ISO 3200). Of course, you could set the camera to 1/24s at ISO 1600 in the first place obtaining the same result. But it is still the camera selecting the ISO value. The ISO cannot be manually selected. But it can be known.

BTW, ISO in still and in video mode have different noise. Because video has less pixels at 100% and even less dots being read-out from the sensor. Which is why the K-7 has less noise in video.

[Coby]

With the K-x, if you are at 1/24 when you lock, then AV+/- will adjust gain. I'm not sure if that's what jbb was meaning though ...