PAL GS400 Pro-cinema mode: staccato
 

I play with GS400 in different modes, and I’m very interesting in "cinema-like" 25 fps shooting. As I know, movie cameras has shutter speed about 1/48 sec, as well as GS400 has 1/50 in a FRAME mode. The motion looks staccato even using tripod. It looks like GS400 footage has insufficiently motion blur. But I can’t to understand why?

I like 16:9, I very like color reproduction in PRO-CINEMA mode, but FRAME mode has a slightly disappointed me.

Btw semi-progressive mode of the Sony TRV950 can be reached when 1/25 shutter speed is setted. In such case 25 fps video looks pretty good.

>>>The motion looks staccato even using tripod. It looks like GS400 footage has insufficiently motion blur. But I can’t to understand why?<<<

Because you are viewing it in progessive, via the LCD or viewfinder. Connect it to a TV (using AV or S-video out) and you'll see it in fields. (Smoother.)

Yes, I connected my cam to the widescreen TV using S-video.

I understand that the progressive video stored as a two fields. The difference between interlaced video is both fields are a part of the one progressive frame.

The question is shutter speed looks shorter then 1/50 sec in my opinion. Or 25 fps shooting needs longer shutter.

Seems MX500 has more smooth picture in a FRAME mode.

<<<-- Originally posted by Mikhail Transact : The question is shutter speed looks shorter then 1/50 sec in my opinion. Or 25 fps shooting needs longer shutter. -->>>

I think the shutter should be 1/25s to get a "cine-like" motion blur amount when you are shooting at 25fps.
As far as I know a movie camera usually is recording the full 1/24s for each frame. Only the cinema's projectors use 48Hz for playback and show each frame twice.

<<<-- Originally posted by Andreas Winkler :
I think the shutter should be 1/25s to get a "cine-like" motion blur amount when you are shooting at 25fps -->>>
Actually GS400 sets 1/50 in PRO-CINEMA mode. So that is why it looks stroboscopic. It's a pity :(

I'll try to add "motion blur" effect to the footage in my videoeditor. Or shoot in 50i mode and deintarlace then :(((.

NTSC Frame Mode
 

After a few weeks of testing around with all different modes on my NTSC GS400 I am back to interlaced mode. For me the Frame Mode is really too "staccato", i.e. panning looks terrible... almost like a webcam somehow. I really don't want to imagine how it looks on your PAL cam, Mikhail. :(
I really like the CineGamma, but unfortunately it's not available in interlaced modes.
The resolution is no issue, can't see much difference to interlaced. Just the 30Hz picture frequency in combination with a 1/60s shutter speed is insufficient. I'm back to smooth 60i! So I guess I have to wait for 60p until I'll step over to progressive.

I'm quite impressed with the frame mode on my MX500. Although it looks very jumpy on the LCD when recording, it comes out lovely when played back on a monitor.

Since I film a lot of fast-moving action and frequently take frame-grabs from video footage, the frame mode gives *much* better results than interlaced.

Using the higher shutter speeds in interlace mode is a complete waste of time because with movement you end up having two overlaid frames that look awful.

I think it is technically impossible to shoot the full 1/24th of a second, as in a movie camera the film has to be transported (and a mirror has to reflect the image to the viewfinder so you can see what you are filming - like a SLR camera).

Therefore, shutter speed on 35mm is usually set at 1/48th of a second.

What I never quite got my head around was: Why does Movie Camera 1/48th of a second exposure look great and PAL 1/50th of a second exposure very jumpy? I think it might be that movie cams just spend a little more time exposing the picture than transporting to the next frame. Or - and now it goes almost Area 51 - the 1/50th in Pal is in reality closer to 1/55th or something, as the time to read out the sensor is included in the 1/50- although it shouldn't. In other words not the whole time is used to let light on the sensor but some time is wasted to read it (and then there is a long 1/50th pause in which nothing happens, thats when the sensor should have been read). Migth be because in 50i there is no pause so reading has to be immediate (and it would be too complex to reprogram the sensor for 25p, especially on a prosumer cam).

Anyway - no intention to hijack the thread. It would be great to hear some more opinions on the progressive mode as I really wanted to buy the GS400 (PAL) for its progressive, 16/9 and cinegamma capability - but I'm not so shure any more.

thanks,Thomas

Using a standard 1/50th shutter speed, shoot in frame mode and then twixtor the footage in after effects from 25fps to 24fps and it will look good...or....shoot in normal mode and use magic bullet to process to 24p. At any rate, PAL cameras will give a better motion replication than a NTSC camera will. 28 days later was shot in PAL Frame mode on a xl1 and then just given a slight speed change to match 24fps. The audio is not distorted. (thats probably the best option if you're going to DVD or TV)

Thomas,

There is very little difference in motion characteristics when shootinf frame mode 1/50 compared to film 1/48. However, there are strict rules for film on how fast things should move in the frame, and how fast the camera itself should move when panning or tilting. You have to do it very slow, and motion picture film people do this very well.

Another factor is depth of field. On film, the subject is in focus, and most else is out of focus. So when things move fast, everything is already out of focus. On your GS400, there is great depth of field, everything is in focus. So when the camera moves fast, everything appears jumpy.

Be careful how your talent moves, and how you move the camera, and remember that because of the depth of field, you can't do everything exactly as it's possible on film. Find ways to work within the limits of the medium.

Josh

Hi Josh,

May I ask how slow is slow?

TIA
Leigh

Hi Josh,

thanks. I knew about the depth of field issue, but I didn't think of it as a way to smooth the movement. Of course! Now the penny drops. If the background is out of focus, panning will feel smoother (now I finally understand why the GS400 can never look as smooth as film in 1/50).

The reason why I asked was because I am currently building one of the depth of field adaptors (as so many others, but that's a different topic). I am thinking whether I should invest in a GS 400 for cinetone and frame mode - I've got the panny MX300 now - great cam but no 16/9. But 16/9 alone wouldn't suffice as a reason to invest in new gear, hence I am asking if the "pro cinema mode" was useable. I guess the answer is yes, if I reduce depth of field and pan slowly.

Leigh,

how slow, well taking a guess until Josh answers: 1 background unit per frame, that's 25 a second. What I mean by background unit is how sharp things appear in the out of focus background. Lets say how much gaussian blurring you would have to do in your editing software to get the same unsharpness. Is it 4 pixels? Then I would pan at 100 pixels per second or 7.2 seconds until the first thing in the frame on the left is panned out at the right. Very slow.

Thanks a lot for your help, hope to inspire some more comments,

Thomas

The rule of thumb I always hear is 7 seconds for an object to pass from one side of the frame to another, whether it's the talent or an object moving, or the camera moving. Again, it doesn't hold 100% true for video because of the difference in depth of field. For an example of what not to do, check out the opening shots in The Glove Box, follow the link to Matter of Chance Productions in my sig. Movement to fast, background too much in focus, very stroby.

Josh

Hi Josh,

What do you think this video is slow enough? Sorry for the big file size.

wmv format
file size around 92mb

http://www.salenz.com/movie/2005_5_1.wmv

Regards
Leigh

Mikhail, the strobe effect has nothing to do with interlaced footage on a progressive display. Actually when viewing frame mode, a computer display will weave the two fields together, which is exactly the "dumb" weave deinterlace you need. If you're shooting footage for PC/Mac viewing, frame mode footage will not require deinterlacing, and will have no interlace artifacts.

What I've found with frame mode is that if you keep the pan/motion speeds down, the footage will in fact look better than interlaced. Although the resolution is the same, due to the perceptive difference, it looks better. A slight application of motion blur in post will come closer to the blur created by 24 fps at 1/48s. There is some theory at work here regarding our psycho-visual limitation in percieving detail vs our low res. perception of motion. In other words, in fast moving scenes, our brain does not have time to fully resolve the image, but it does pick up on strobe. So image update frequency becomes more important than image resolution when things are moving quickly. This is why the guidelines Josh mentioned for pan speed are important in frame mode.

So what I've found is that when shooting motion, particularly if you're using slow-mo, shoot interlaced. For everything else, I shoot frame. 60P is the happy place we want to be with both the advantages of a higher res progressive image with the temporal resolution of 60 samples/sec. Of course if you're down sampling to 24fps, you'll have more options for effects with all the extra frames to work with.

Being that the 24fps is really a minimum accepted to reduce film stock cost, I'd be curious to see where the film industry moves when 60P 1080 becomes the standard.