k5 video stuff.

I've been shooting video for a little while now with my K5 with some friends making a movie and I thought I would share some of the things I have learned.

1) Pentax camera's look pretty nice in a video rig, and the rubber on the focus rings of the da* lens work without any addon for follow focus (as the gear's fit into the gaps). *the bellow image had the rubber gear ring added.




2) Image stabilization on the k5 is pretty nice for handhold video work as long as you are recording sound externally, the k-01 and k30 use a digital stabilization which crop's the image (even when not using it) and is prone to artifacts, some lens such as the da* 16-50 f2.8 can't use the lens hood in video due to it showing when the sensor moves.

3) The k5 series has a bug that when started in video mode and recording the pixel map feature isn't activated, This leaves me with around 9-12 stuck pixels (green and red) and the video is unusable. (pentax never heard of this bug and don't plan to fix it in a firmware, they did offer to replace my sensor for free)

You can fix this by going into a photographic mode and activating live view then switching to movie mode, the pixel mapping will now take effect until you power off, going into sleep mode dosn't affect this and you can turn the sensor off in movie mode by pressing the LV button (saves power and overheating while setting up different shots).

4) You can increase the dynamic range of your captured video by changing camera settings, the video won't look as nice (its very flat) until graded but gives you much more to work with and the AVI files although big hold a lot of detail.. infarct with out a fast SD card you can have your video stop way before the 4gig file limit and buffering times can be long between shots even if they are only 20+ seconds long (we learned this from a sandisk ultra)

To get the most out of the video I use +4 high/low key adj, -4 contrast, -4 contrast highlight adjust, +4 contrast shadow adjust as well as Highlight and shadow correction.

A short clip from some horses I recorded using the da* 16-50 and the video rig imaged above.. its not my best videoas I was crapping myself at the very large clydesdale horses and the movie stuff I can't show yet, this is ungraded footage from the camera.link

Anyway I hope some of this info is useful to you all, I don't know when the film will be finished (its being recorded using 2x gh2's and my k5.. mostly using Pentax Lens on all bodys even some pentax auto 110 lens and just rarely with the Panasonic 14-45, 14-140 and 20mm f1.7 so most of the footage even if its not from my k5 will be from pentax lens. Once its done Ill try post a link here although it would only be for a trailer as they want to send it off to festivals, have a premier and sell dvds to help fund the next project.

A raw ungraded frame from the movie..although this scene has been re shot and she plays a different roll now.

interesting post but the video link shows private for me.

Hi Paul, very interested in your post as my 18 year old son is into film making using Pentax gear. We wanted to have a look at your video clip but it's listed as 'Private' and won't let us play it on youtube, even after logging in. Could you please let us know how to get the clip to play?

Also, we would be interested to hear your views on how the video on the K-01 compares to that on the K-5. We noted your point on the stabilisation issues on the K-01 above, but how do you rate the relative video quality of the 2 machines notwithstanding this?

Regards
David

Great to see some detailed info on video working on the DSLRs. I agree that the SR system is very effective on Pentax for handheld video, if you 'work with it' when moving around. Very impressive looking 'rig' you've got there!

Please, forgive my ignorance - what is 'Graded' or indeed 'ungraded' footage you referred to? I can understand 'edited' or 'unedited', but not 'graded'.

And I was surprised you listed Shadow & Highlight adjustment as activated - I was not aware that these processing functions were applicable to video files? When shooting stills on the K7 they add a fair bit of processing time - I imagine they must take an age to be applied to many minutes of video footage?

The video rig is nice, it makes manual focusing much easier especially on the 16-50 which has a short distance from close to infinity on the focus ring, it also helps make the video much more stable due to having more contact points. I use a LCD loup also to make the screen easier to see and adding another point of contact.

I had fun taking the image of the k5 in the video rig too .

The video link should be working now, I had it set to the wrong setting.

As for Graded/ungraded its just raw footage that has yet to be tweaked.. just like if you shoot a raw image and then adjust settings in lightroom to get the look you want. When shooting video I try to capture as much detail/dynamic range I can then my friends tweak the image later to match the other cameras or the look they are going for in the film.

I don't know for sure if the shadow/highlight adjustments work in video but when I was starting out testing settings I couldn't really see any difference between the photo mode with them activated and the movie mode when I switched over so just assumed they worked, I will have to do some more testing and get back to you all about that then.

As for the k-01, I've not used one for video but I did read a lot about it, the MovieSR uses digital stabilization and has to crop the image to do so (to free up space to move the image around). The MovieSR is good because it dosn't cause any noise when recording film but it increases the jello effect when panning from what I read as well as sometimes causing artifacts.

The k-01 has the advantage of using H.264 giving much smaller files, longer recording times and doesn't overheat that im aware off but the H.264 mode comes at a cost.. in that the video is more compressed, you can switch to AVI like the k5 I'm sure giving a higher quality video but at massive memory usage.

The k-01 and k30 have one major advantage over the k5 though and that is manual video mode, I'm always having to fight with my k5 to make the video match that of the gh2's and im never exactly sure of the shutter speed the k5 is using, although I know it's not too high due to using the gh2's and having a light meter (a high shutter speed in video causes juddery movement.. I try to keep it around 50fps on the gh2s to get some motion blur.

On a side note... the gh2's we use are hacked to have better video (upto 42mbps) and my friends are still ok with the footage from the k5 and are having no trouble at all mixng the footage from the different systems. The gh2 is still better (although has less dynamic range) as it resolves a bit more detail and is less prone to moire.

*note*

The video I put up of the ungraded k5 footage had been down sampled to 720p as I was sending it to someone as they wanted to see a little bit off the footage, but its mostly to show the look you get from the settings I use.

Thanks for the update Paul. I would guess the K-01 is best used for video with SR turned off and on a decent tripod or rig. I'll check out the file format options available.

Regards
David

Quick update: the K-01 will only record in MPEG-4 H.264 file format; it isn't possible to record in AVI.

Regards
David

Ouch.. I didn't expect that the gf1, gh2's I use let me switch if I want too. If im right the bitrate is pretty low on the k-01, we hacked the gh2's get much more room and it made a difference to fine details.

Its probably fine though tbh as most ways of playing it back will compress the end product somewhat especially if its put onto youtube and the first film I did for my friends was shot on a canon xl2 (standard deff) and still looked nice on a big screen.

Thanks for that info though.

Talk of shutter speeds in relation to DSLR video has had me puzzled before, and here it is again! I would be pleased if anyone could clear this up. This is my thinking on it.

I'm assuming that the concept of 'shutter speed' for DSLR video is not the same as for normal still photo capture - clearly the mechanical shutter must remain fully open when video mode is activated (and also in Live View). It does not open and shut rapidly during video capture. So there is no such thing as a 'shutter speed' during video ?

Is it not true that the exposure (& brightness) of video capture on a DSLR must be a function of only 2 key components (instead of 3 for still capture) - ie: aperture, which determines how much light is able to get through the lens over any given time), and ISO (or Gain) on the sensor, which determines how much of that available light is recorded in any given time).

In terms of user creative control, in video mode I see that we can control the aperture (which will affect the DOF) and the ISO, which will alter the gain & sensitivity. We don't have 'shutter speed' control.

Am I right to think that the camera records the brightness level for video by combining a set aperture (either varying automatically or fixed by the user) with a varying gain on the sensor. And that it records motion video by rapidly switching the sensor on and off with these settings - this is known as the 'frame rate', such as 29fps etc. And that the mechanical shutter remains fixed open during all of this?

Am I anywhere near to the mark with this thinking? And should we not banish the term 'shutter speed' from DSLR video talk for ever?

Just as in taking a photo, video also has a shutter speed which is not to be confused with frame rate.

The Shutter speed determins in video just as in photography how long each pixel is exposed to light, the slower the shutter the more light and motion is captured per frame and the faster the shutter the less light and the less motion that is captured.

In video the k5 uses an electronic rolling shutter, reading line by line of the cmos sensor till it finish's a frame, this is also why we have the jello effect when panning fast as each line records the objects in different positions.

The k5 records 1080p video at 25fps, so in effects we would want a shutter speed of 1/50 to get a nicer look to the video and capture some motion (to help blend movement between frames) if you were in the USA where they use a 60hrz system you might want to use 1/60 to avoid flickering from lights/tv's.

If you were to shoot outoors at say f2 without any nd filters.. your shutter speed would be away up in the thousands freezing movement and not giving any motion blur to blend frames leading to choppy looking video.

The shutter duration isn't available as an option on the k5, the only option being aperture which makes it a total pain to work with at times, especially when I'm also using camera's that have full manual control where I can set everything to suit.

I can understand the aspects you refer to about motion depiction, how long each pixels receives light which can make it blurry if too slow.

But we are talking about different things right ? The 'electronic rolling shutter' you mention is obviously nothing to do with the mechnanical camera shutter blades (the curtain or however it is constructed now)? In fact, it is not a 'shutter' at all? It is a sensor process.

I'm thinking the term shutter is being used because the 'electronic rolling shutter' has a similar effect on video as a mechanical shutter for photos (as far as recording movement in the scene). But it has nothing at all to do with exposure and brightness? Does that sound right?

And also, we have no control over the 'electronic rolling shutter's' effect on our video recording? Hope I'm getting it now!

The mechanical shutter isn't used in the video process on the k5 and most digital camera's.. infact I would be supprised if they are at all?
Old film camera's still used a mechanical shutter, or a rotary disk shutter (or mirror to project an image onto a focus screen.

While the electronic shutter is a sensor process it still has the same effect as if it was a mechanical shutter, it controls how long each frame is exposed to light.

If you were using a camera that had full manual control (like a panasonic gh2) you can set your shutter in video mode just as you do in photography.

If you use a shutter of 1/50, each pixel in the frame revives light at 1/50 of a sec just as it would if you were taking a photo and affects your exposure of the shot.

If you then changed your shutter to 1/100, you would change your exposure by -1ev just as in photo mode and 1/25 would give you +1 ev.

The shutter speed has no effect on the amount of frames you record, on the k5 you will get 25 frames at 1080p.

If your shutter is 1/50, you will get 25 frames at 1/50 of a sec shutter speeds, if you shutter was at 1/2000 you would still only get 25 frames but at much shorter duration of 1/2000 and this freezing action more (removing motion blur and making the video looking a little jerky).


On a side note.. there are still cameras out there that had fast global electronic shutters that allowed you to shoot with flash outdoors even at 1/2000 of a sec! I would love for global electronic shutters to have a come back as the mechanical shutters restrict flash usage outdoors.

I hope this helps.

Its starting to make sense, thanks. So if the 'electronic shutter' in fact does affect the exposure, it's a third variable then that would determine the video brightness.

So, I know that the camera can alter the aperture and the ISO gain during recording, and in fact it does this in response to changing lighting during the recording - but can it automatically alter the electronic shutter speed also, or is this value absolutely fixed?

If so I guess this must one of the compromises we must put up with in a machine that shoots both high quality photos and video? And is it a compromise that is common to all video shooting DSLRs of all brands?

It all depends on the camera I guess, from what I understand the primeM cameras (like the k30) have manual controls and should allow shutter control but I'm not sure.

The Panasonic cameras with manual control like the gh2 or even my gf1 with a hacked firmware allow control of the shutter as do many other electronic video devices.

The only reason not to give you this control imho is the manufactures intentionally crippling the device or being very lazy, the 5dmark II got manual controls with a firmware update as did so many other devices yet pentax haven't bothered giving the k5 user's any love in this regard.

We should also look to EU tax rates that penalise video cameras quite heavily. Unless it's changed, it pays not be a video camera.