Flicker during pan over detail
 

I am wondering if my camera is behaving normally. When I slowly pan across a subject with a high level of detail (such as the bark on trees) there is an odd, artifacty flickering in the detail areas. Is this normal for DV? I've been shooting a lot of test footage with a dvc80 set to look in a way that looks pleasing to me: chroma phase -4, pedistal -6, detail -3. I'm exposing about a stop under whatever the factory auto iris setting is at 60th second w/both ND filters on in bright, contrasty sunlight. This isn't a horrible effect, but it is a bit distracting to me, and as I said, it seems to be in areas of detail, such as tree bark or the surface of rocks. I haven't seen this at all under indoor lighting situations.

Any thoughts?

Thanks so much,

Steve.

Did you use manual focus and manual white balance? If you did, it's most likely "stair-stepping."

Uhm, yes, I did use manual white balance and manual focus...I thought that was a good thing. What's "stair steppiing?" and how can I avoid it?

Wait, sorry, I know what stair stepping is. I see it on diagonal lines. That may be what it is, but I don't know what manual settings have to do with it...I thought that was something that happened w/dv. It actually looks more like when I made a dvd and didn't have the bit rate right or something...there was a shot from a moving car panning across a pebbly wall in Italy in direct sunlight and it was sort of like a bunch of gnats or something. I figured it was my poor job on the dvd (I was quite new at it and using a different program than I use now). But that didn't show on the raw tape, and this does.

I'm not that familar with the DVX100, but cams in general sometimes "hunt" for the correct white balance and focus, so as a result detail will be out of focus and either too dark or light. When setting these manually, the cam won't "hunt."

Can you post a short clip? It's hard to tell accurately what you are seeing?

Okay, thanks for your help. I'll try to get something up in the next few days (too much work at the moment).

Thanks again,

Steve.

In fact, I saw similar threads on other forums. Especially the PAL version of the DVX has this issue, when it pans slowly and such. Can somebody ellaborate on that? The conclusion was that for the NTSC version the result was a bit better because of the pulldown, but when you shoot 30p not 24p, the result is exactly the same, unpleasant results when paning. This would not be a problem on progressive TVs, but it is on interlaced ones because of the way fields are presented. Anybody?

I think it does have to do with interlacing. If you use vegas, right click on the clip and check "reduce interlace flicker". May help.

<<<-- Originally posted by Bogdan Apetri : In fact, I saw similar threads on other forums. Especially the PAL version of the DVX has this issue, when it pans slowly and such. Can somebody ellaborate on that? The conclusion was that for the NTSC version the result was a bit better because of the pulldown, but when you shoot 30p not 24p, the result is exactly the same, unpleasant results when paning. This would not be a problem on progressive TVs, but it is on interlaced ones because of the way fields are presented. Anybody? -->>>

Actually, I have shot quite a bit of stuff in 30p and have not had any problem whatsoever with stobing. I also use 24p frequently and if done right, the strobing, noticable in any 24p material, will not be seen. It does sound more like an interlacing issue in that your detail settings are set a tad too high. I think Tom is right on the money as stuttering and "flickering in the detailed areas" are two different things.

Yeah this flicker issue with the pal advance models have been discussed with much acrimony on other boards. Some people have been labelled hysterical.

I own the camera for a few weeks now and it is defininitely there in all its glory. I've shoot the cityscape standing from Sydney harbour bridge and you see all this terrible flickering on the buildings when you make the slightest movement when you handhold it. No its not just strobing as with higher shutter speeds.

Viewing on progressive monitors you still see this flicker. I tried thick setting, turn down the detail level and various gamma settings to no avail. Sometimes you get flicker on detailed objects like bark too I agree.

Just avoid shooting strong repetitive vertical and horizontal lines.

may a newbie chime in with a basic question or two?

I've been horsing around with my DVX and was a little alarmed when I saw the strobing in 24p, even if I panned gently.

How much more noticible is it in PAL? Any chance I got sold a pal machine - how would one know? My manuals and box both say DVX100AP, where the p stands for North America I'm told.

I realize the strobing may just be part of the 24p deal, but how would I deal with this when shooting? Better light, fixing in FCP? Do all NTSC machines have a bit of strobing?

Peter

A comment about strobing.

I'm not sure if this is so much a strobing issue in the camera. I noticed when I had my DVX that the strobing/flickering varied greatly based on the monitor I view on. LCD and low-rez monitor were pretty bad at times, especially handheld. However, playback on my old 32" Sony XBR was pretty free.

I did not have my cams long enough to test, but I've seen other comments that seem to confirm this. The strobing I saw was very similar to the effect I saw when the CineAlta first came out and I had a chance to shoot with it at a film festival. At that time, Sony broadcast monitors flickered badly with the footage, but Sony planned to fix the monitors (which they have) to support it.

I think the DVX100, especially in 24p and PAL, made need monitors that handle high res, prog scan footage well. Just a theory, but this may explain the varied reports and comments pro and con about the cameras.

You combine the variances of shutter speeds into this and it gets hard to sort out exactly what combo of camera moves, shutter speeds and displays create the effect and what eliminates it.

Thanks for all the comments. I still haven't captured a clip to post, but hopefully will soon.

I'm really curious if this shows up when projected via dlp. A friend who's something of a dv guru (Jon Jost) has one, but he's in Portland now and that's a bit of a drive for me to check it out. I will be there in about 3 weeks, however, so I'll see then. My guess is that it won't show on the projector, but who knows.

On further tests, I've found the images made with soft outdoor light (like on a cloudy day) are really lovely...very smooth and steady with no flicker or stair-step. The opposite produces the results I've described...but I'm learning to like it. Perhaps I can use it for effect.

Thanks again,

Steve.