I bought a XM2 (GL2 PAL version) some weeks ago, and intend to use it for filmakinf (short movies for festvals).

I'd like to get a film loot, or better, a "non-video" look.
Above light and exposition issues, one thing I noticed in guides form Magic Bullet Suite plug-ins, etc... (but I wanna use FieldsKit for deinterlacing) is to lower the sharpness controll of the camera to the lowest value.

I'll obiously do some tests, but... what value should I use with XM2 for leaving the image as recorded? In the scale there are positive and negative values, with the default on the center (0). Is this the image given by the CCD, as is, or should I use the lowest (negative) values? ...ora other value?

Thanx

Hi Marco,

Don't forget that if you use frame mode, the sharpness is decreased due to the loss of resolution. So you might not want to turn down the sharpness all the way down, or the picture could be too soft.

Dave.

I' not going to use frame mode. I'll use interlaced scanning and Re:Vision FieldsKit (or Magic Bullet deinterlacer) in post-production.

Just Magic Bullet tutorials suggested to turn down sharpnes for avoiding that "too-sharp" aspect tipical of video footage, for getting that more natural, smoooth look, film has.

I was just wondering which setting is "the images as recorder by the CCDs", without improved sharpness, or less sharpness.
I wanted to know how to get the natural image given by the CCDs:
1) setting to the mid value (0)?
2) setting to the lowest value (negative)?
Which of the two?

Thanx

Marco, have you tried magic Bullet? Nice s/w - but be warned , and dependant on your hardware, it is IMHO a render HOG!

If you can get a DEMO version try a very very very small piece of footage 10 seconds - or less - maybe and set your pc off to render. Time the time it takes to render and multiply this by the whole time on your movie. MB is GOOD! There is no doubt .. .but for me anything more than a "special" item - not more than 10 seconds maybe - I wont use it.

I use Vegas 5, it has got most of what "effects" I wanna do. It is relatively nippy when it comes to final render out . ..

Only my 2 pence worth . . .

Grazie

<<<-- Originally posted by Graham Bernard : Marco, have you tried magic Bullet? Nice s/w - but be warned , and dependant on your hardware, it is IMHO a render HOG!
...
I use Vegas 5, it has got most of what "effects" I wanna do. It is relatively nippy when it comes to final render out . ..
-->>>

You probably didn't read my first post with attention.
I don't want any particular "special effects", and my question was not on color correction, but only about the sharpness of the image.

I just wanna record interlaced footage and then deinterlace it, and eventually apply color correction.
Anyway, as I say, I tried both Re:Vision FieldsKit and Bagic Bullet Suite for deinterlacing, and at the end decided to use FieldsKit (it's faster, same quality of Magic Bullet deinterlacing, more controls, cheaper...).
Anyway, in Magic Bullet tutorials I found the advices for shooting the best footage for later post processing, ahd these says to lower the sharpness of the camera for getting a more natural, film-like look, instead of that too-sharp look typical of video footage.

My question was about this issue, and only this.

Understood - G

<<<-- Originally posted by Dave Croft :
Hi Marco,
Don't forget that if you use frame mode, the sharpness is decreased due to the loss of resolution. So you might not want to turn down the sharpness all the way down, or the picture could be too soft.
Dave. -->>>

What is it about frame mode that causes that loss in resolution?

David,

I will explain, basically frame mode is a kind of pseudo progressive mode on these cameras. It is not the true progressive that is found on the Panasonic DVX100. Frame mode does a kind of in camera de-interlace by combining both interlaced fields that usually appear in one second of interlaced video, resulting in a 'frame' and not a field. Standard NTSC interlaced is 60i, Frame mode is 30p. Pal is 50i, and 25p.

However, because this is has NOT been achieved in a true progressive way, there is a resolution loss of about 25-30% when using frame mode and not interlaced. Some people prefer to de-interlace in post, and that can give you better or worse results than frame mode depending on what software you use. Many people like frame mode as it gives you a nice film like quality without spending a lot of time trying to get a similar effect in post. I personally like frame mode very much, but can't wait to get a true progressive camera in a year or so.

Do a search on this forum for 'frame mode' and/or 'resolution loss' etc. for more detailed explanations.

Dave.

Thanks for the information. I see that there has been a lot of discussion about this. I don't know if this was buried in one of the many threads on this, but I didn't see this in the threads I looked through: what is the source of this information (e.g., two fields in one frame) besides (apparently conflicting) transcriptions of phone calls with Canon tech support? I don't see this kind of detail in the manual.

The frame mode resolution question has been beat death in here, so do a search. I think it's pretty well accepted now that claims of "25 to 30 percent" resolution loss is just plain bogus. There may be some loss, but I can't spot it on a regular television. People with professional monitors claim to seem some difference and I have no reason to disbelieve them. I find it difficult to believe that any deinterlacing software can do a better job. Lots of hyperventilated opinions in here about that isssue as well, so happy searching.

On to Marco's (Hey! That's my name too!) original question -- most people only seem to back sharpness off a couple of clicks if they do it at all.

Here's one article (ftp://ftp.panasonic.com/pub/Panasonic/Drivers/PBTS/papers/Progressive-WP.pdf) that gets into the technical details of frame mode vs progressive.

Marco (Iannaccone),

Ok, so no one is answering your question here.

I don't know that there is a hard and fast rule here, however the gl2 does produce an image that is over-sharpened at it's neutral position. I typically have recommended using a setting of minus 2 sharpness, but you could certainly go lower. I think a test is in order, as you have a technique and a look that you are after, and you use of software deinterlacing makes this a difficult thing to predict.

I've used the fieldskit software, and I have found no appreciable improvement over frame mode. De-interlacing will always have some artifact production in situations where there is movement, which the Frame Mode, contrary to David's description, doesn't cause...at least in the same fashion.

Frame mode is a progressive capture system...not de-interlacing on the fly. Canon uses something akin to its pixel shift technology to capture both fields at the same time, resulting in a 25% loss in vertical (but not horizontal) resolution. This vertical loss is only nominally visible at best, and actually helps your footage play better on typical NTSC monitors. (panasonic's "thick" detail setting has the same net effect), by minimizing the "twitter" that progressive imaging can create.

When people say that canon's frame mode is not "true" progressive, they are really saying that the frame mode doesn't use all the resolution of the chip to create each frame...and this is correct. De-interlacing is not a magic bullet though, as its increase in resolution is most evident in situations where there is no movement (in which case interlaced footage becomes the defacto equivalent of progressive). The more movement in the scene, the more likely deinterlacing will cause blurring and artifacts.

Adam wilt has a discussion of frame mode here:

http://www.adamwilt.com/DV-FAQ-etc.html#filmlook

Barry

First of all... thanx! :-)
You were very clean and... hit the point! :-)


<<<-- Originally posted by Barry Goyette : I don't know that there is a hard and fast rule here, however the gl2 does produce an image that is over-sharpened at it's neutral position.-->>>

That's what I was asking! :-) Thanx a lot! :-)


<<<-- I typically have recommended using a setting of minus 2 sharpness, but you could certainly go lower. I think a test is in order, as you have a technique and a look that you are after, and you use of software deinterlacing makes this a difficult thing to predict. -->>>

I'll obiously do may tests, but the previous information was important to me.


<<<-- When people say that canon's frame mode is not "true" progressive, they are really saying that the frame mode doesn't use all the resolution of the chip to create each frame...and this is correct. De-interlacing is not a magic bullet though, as its increase in resolution is most evident in situations where there is no movement (in which case interlaced footage becomes the defacto equivalent of progressive). The more movement in the scene, the more likely deinterlacing will cause blurring and artifacts.-->>>

So... you'd advise to directly use Frame mode, instead of using FieldsKit or Magic Bullet?

With XM2 (im using the PAL version) post deinterlacing should be better with static images, while frame mode should be better with one with movement... is this right?

Do you think I'd actually have a good result (and less problems) directly using XM2 frame mode (and this allows me event to see, in a monitor, wheter a camera movement is good or not, during shooting...)?


<<<--Adam wilt has a discussion of frame mode here:
http://www.adamwilt.com/DV-FAQ-etc.html#filmlook
-->>>

Thanx! :-)

Marco.

I've been shooting frame mode for 5 years on virtually everything. Until panasonic came thru with true 480p progressive capture, canon's frame mode was the best, easiest way to approximate the "film look"...that is if you mean the look that comes from 24 images per second being streamed progressively across a screen. Many of the approaches like magic bullet combine de-interlacing with gamma and color corrections to obtain a look that can be surprisingly film like. So one can't say that frame mode is the equivalent of these more comprehensive tools. However, Frame mode is certainly comparable to the deinterlacing portion of these programs...and because it's instantaneous...and free...it has some benefits that go beyond mere quality.

Frame mode on the gl2 is less afflicted with the problems seen on the xl1, gl1 and even xl1s. Its 410k sensors have a little extra headroom in the scan line shift process, to make any resolution loss negligible. And while there are some artifacts associated with movement in frame mode, my experience is that deinterlacing causes much more noticeable problems.

As others have said..the film look is associated with many factors, only one being the temporal aspects of framerate. To me, ticky-tacking over Frame mode versus Deinterlacing misses the point. They are, for all intents and purposes, essentially the same animal...and any energy expended debating them should be channeled into creating better camera techniques, lighting, sound. Frame mode is easier than "smart" deinterlacing...so therefore its my choice...and I have been making wonderfully film- like images for many years with it.

You will need some discipline when shooting with frame mode. Wildly eratic camera movements (especially hand-held-rotational-squirrely ones) don't look good in any situation, but they can really be annoying in frame mode (Film is even worse). Panning at moderate speed across high contrast vertical objects will cause a strobing effect that can be particularly ugly. (again try this with a Panavision, and you'll be in truly bad shape.) But other than this, most movements look perfectly normal in frame mode, and very similar in character to what you are used to seeing at the Movie theater. A small camera like the gl2 needs some form of support for handheld work, like a shoulder mount. Again, all of this goes towards orienting your techniques in the direction of the professional filmmaker. The more you recognize their discipline, the more your footage will look like film, regardless of the capture method and rate.

And definitely do a search for Frame mode here on dvinfo.net...this subject has indeed been covered to death over the past few years....and I'm sure there areat least a few bits of wisdom to be gleaned from it.

Barry

Hi Everyone, sorry if my description of frame mode wasn't entirely accurate. All of what I said, I have mainly learnt on this forum from other members. I guess I must have read some misinformation. My quote of 25-30% resolution loss was virtually cut and pasted ;)

Barry: Your real world experience and preference for using frame mode with your own work is good to know, when some of us (including me) are just starting out in the prosumer arena and are unsure of what methods of videography to employ in our own work.

Anyway I am using a Panasonic DVC30 with Frame mode and Cine Gamma on for most of the time, and it is very good. The results are very film like. Does any one know if the Frame mode used on the DVC30 is the same as the GL2? I read that the DVC30 uses 'interpolation' to achieve its frames, but the Canon uses 'Pixel-shift' technology.

Many thanks,
Dave.

Thanx again for your answer! :-)
You're alway very clear, and your posts are beying very useful to me.


<<<-- Originally posted by Barry Goyette : Frame mode on the gl2 is less afflicted with the problems seen on the xl1, gl1 and even xl1s. -->>>

Considering I wouldn't use "stange" shutter speeds (I wanna have a film look, so... I'll mainly use 1/50 s, at least for all "normal" shoots, and maybe 1/25s and 1/100 for getting particular effects on motion clarity, but... almost never), averything should be good with frame mode.... the quality should be at the same level (or almost) than FieldsKit or Magic Bullet deinterlacer, but.. with really less problems... so... it seems the bes choice is actually shooting in frame mode... right?


This won't obiously be the only thing to use for getting film-like look.
I think I'll do some esperiments on lowering the sharpness, but I think 2-3 points down could be a good start point.
I'll obiously take care of exposition, avoiding large overexposed areas, and doing a good white balance, and... will take care to fast camera moves.

I read somewhere, for getting good camera moves with light cameras like XM2, I should move it as it were actually less light... as it would actualy be a bigger one... avoiding extremely fast movements, etc...
Obiously some sort of support must be used...


<<<-- You will need some discipline when shooting with frame mode. Wildly eratic camera movements (especially hand-held-rotational-squirrely ones) don't look good in any situation, but they can really be annoying in frame mode (Film is even worse). Panning at moderate speed across high contrast vertical objects will cause a strobing effect that can be particularly ugly. -->>>

That's what I was in fact considering.
Anyway... this same "problems" would appear even when shooting interlaced and then deinterlacing, arriving to 1/25 p, instead than 1/50 interlaced, but with frame mode there's te advantage I can directly see (through an external monitor, not the LCD or the viewfinder) when a camera movement causes problems.


<<<-- And definitely do a search for Frame mode here on dvinfo.net...this subject has indeed been covered to death over the past few years....and I'm sure there areat least a few bits of wisdom to be gleaned from it. -->>>

Thanx, I'll do that! :-)

Dave

The loss of resolution in frame mode is indeed 25% in the vertical direction only (I don't know where the "to 30%" comes from), however, if you read canons marketing, they swear it is in fact a 25% increase in resolution. Who's right....well, it depends on your point of view. Each field of frame mode footage does have 25% more resolution than an interlaced field from the same camera. However a frame (two fields) of frame mode, has 25% less vertical resolution than a frame of interlaced footage.

Confused yet...well when I say that frame mode is only nominally less sharp than interlaced mode I'm really talking what you see with your eyes. NTSC video is very low in resolution to start with, and the detail is rendered in alternating scan lines, effectively halving the resolutiion in any moment in time. The 25% decrease (or increase) essentially means 1/2 of a line...well this is difficult to ponder in my mind, and in fact the real world result is negligible, and certainly made up for by the gl2's higher native resolution and sharpness controls. On top of it, we are talking only about vertical resolution...which means that things like a stack of toothpicks might suffer in the end product, but most other random types of detail will suffer not a bit.

On top of this, you have to realize that this is probably the way it should be for display on an NTSC monitor or TV set. This bit of blurring helps to eliminate a tell tale sign of too-much-resolution 480p footage (like that from the DVX100). In some ways, when viewing on a regular tv...my gl2 footage looks more filmlike than stuff from the dvx, because it has none of the line twitter (a sure fire digital artifact if there ever was one). Sure, the DVX has a way of dealing with this...called the thick detail setting...which effectively lowers the vertical resolution exactly 25%.....hmmmm.

Indeed when viewing on progressive output device like a projector, lcd monitor, or computer monitor, having the full 480p available is a boon to those who have it. But the gl2 and other canon cameras were designed specifically as NTSC and PAL devices, and thus I think that the Frame Mode is in fact slightly lower in resolution "by design". Remember that the DVX100 which came along several years later is really a product designed for digital cinema..ie eventual transfer to film, or digital projection thus it benefits from from all the resolution of its 480p capture.

Barry

I realize much smarter people than me are always citing this 25 percent vertical resolution loss figure, but it just doesn't make sense. On my television, which has been adjusted to display anamorphic footage in its correct aspect ratio, the diference between digital 16:9 and using an anamorphic lens adapter is striking. Even though you lose some horizontal resolution with the adapter, the footage is much sharper because you retain that 30 percent of the vertical resolution that would otherwise be thrown off. As I said before, when switching to frame mode the difference isn't just slight -- it's nonexistant. I've tried switching back and forth and asking other people if they can tell the difference and they can't. I can accept that the 25 percent figure makes sense on paper, but it just doesn't seem to be true in practice. I'm using a GL1 by the way, which is much less sharp than the GL2, so maybe that has something to do with it.

I'm not sure I would agree that it is non-existent, but depending on your monitor, that may in fact be the case. The visible loss of sharpness is subtle, but apparent on the gl1. It is significantly less visible on the gl2. But, as you say...the 25% on-paper loss significantly overstates the actual visible loss, and most people couldn't tell the difference unless you showed them what to look for.

Barry

In saying the difference was non-existent, I was referring to my television, which is admittedly a piece of junk. I've considered that maybe the resolution is so low on my monitor that a loss of 25 percent vertical resolution wouldn't even be apparent, but then why is the difference in anamorphic footage so noticeable? Digital 16:9 is known to reduce the vertical resolution about 30 percent. If frame mode was really costing you 25 percent of your vertical resolution in any meaningful sense, I'm certain the difference would be visible on my TV. Why isn't the combined use of digital 16:9 and frame mode the disaster that it would surely have to be if Steve Mullen is correct? I'm not trying to say I'm smarter than him, because I know I'm not. In fact, I don't understand his article at all. It makes my head swim.

There are definitely two different things going on here. In camera stretching (actually cropping and then blowing up) is a whole different issue than the pixel shift line creation algorithm of the frame mode. And on a camera like the gl1 which, with a 270k chip, is barely meeting the dv spec, its understandable why you would easily see a difference between the 2 16:9 methods. This difference is less visible with the gl2, and I have read some discussion as to whether there is much visible difference between the two 16:9 methods.

I may have read steves article awhile ago, but don't really remember the specifics...but I can see where doing in camera 16:9 (not anamorphic), combined with frame mode, on a gl1, or xl1 would give some people the heebee jeebies.

In my experience with the gl2, and dvx100, I have used the crop and enlarge method, played back on 34" Sony Wega HD set, and it looks really good...occasional jaggies, but no real lack of sharpness.

Barry

Ah, I had a feeling it would be something like that.

At this point, I have two questions:

1) Above artefacts with moving parts of the image when using deinterlacing algorithms in post-productions, does it happen any kind of "relosution loss", respect to the original, interlaced image?

2) When using frame mode, considering the image compressed to DV formatcomes non-nterlaced, do the artifacs of 4:2:0 subsampling (I'm obiously referring to the PAL version) due to interlaced footage (strange chroma values in certain points, etc..) tend to desappear, as I would be normally recording real progressive footage, right?

Marco

Deinterlacing programs like fieldsKit use a variety of schemes to handle the misalignment of two interlaced fields (when the subject is in motion). Any of them will either cause a significant loss of resolution, or some sort of artifact.

Question 2 I don't think I understand...and I'm not sure I'd have the answer if I did.

ciao

Barry

<<<-- Originally posted by Barry Goyette : Marco

Deinterlacing programs like fieldsKit use a variety of schemes to handle the misalignment of two interlaced fields (when the subject is in motion). Any of them will either cause a significant loss of resolution, or some sort of artifact. -->>>

So... what whould you advise in general... to use XM2 frame mode instead of later deinterlacing?



<<<-- Question 2 I don't think I understand...and I'm not sure I'd have the answer if I did. -->>>

Well... read this:
http://dv.com/print_me.jhtml?LookupId=/xml/feature/2003/wilt0603

PAL uses 4:2:2, NSTC uses 4:1:1 subsampling, but MiniDV uses 4:2:0 for PAL and 4:1:1 for NTSC.

Considering he better vertical resolution and other factors, 4:2:0 subsampling used for PAL DV would normally be a very good compromise, but... when having to do with interlaced wideo, it can take to strange color results in centain cases, in particular on edges.


That's why I asked:
If I shoot 4:2:0 interlaced and then deinterlace, I can incur in these color artifact problems, while shooting in frame mode should eliminate these probles, just like as I were shooting true progressig.

Do you think I'm right?

<<So... what whould you advise in general... to use XM2 frame mode instead of later deinterlacing?>>

I think that's what I've been saying all along.

Regarding the 4:2:0 thing...I don't know enough about this issue to say anything intelligent...Realistically I don't think there would be a significant reason to choose one over the other (deinterlacing method) because of the sampling method. But someone with more knowledge about this should jump in if I'm wrong in saying that.

Although now that I think of it, here's a relevant issue...frame mode occures prior to compression, versus a smart deinterlacer, which must recompress the data after processing...this has nothing to do with the sampling method, but my experience with DV has shown me that the compressed color space it has is extremely fragile...ie you don't want to recompress if you don't have to....another reason to just stick with frame mode.

Barry

<<<-- Although now that I think of it, here's a relevant issue...frame mode occures prior to compression, versus a smart deinterlacer, which must recompress the data after processing...this has nothing to do with the sampling method, but my experience with DV has shown me that the compressed color space it has is extremely fragile...ie you don't want to recompress if you don't have to....another reason to just stick with frame mode. -->>>

Well... right.
And... by the way.. YUV subsampling happens at the very first step of Dv compression (that is: RGB to YUV conversion, YUV subsampling, the rest of the DV compression), so... I really think, because the image come progressive, the subsampling part can produce an image without (or with less) aftifacts.