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Old November 22nd, 2005, 10:11 AM   #1
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I figured out why 35mm adapters are so important for DV.

Apart from the usual shallow DOF reasons.

Distant subjects in SD have a distinct lack of detail at 720x480 even with a wide depth of field. Camera-sharpened low-res images really give away the fact that it was not shot on film. Subjects in the foreground in SD don't look so bad, but the background needs a bit of softening to eliminate the evidence of low resolution. I don't think this is quite as important for HD, but the other reasons like drawing attention to the in-focus subject still apply.

Okay, I realize that I'm probably not the first to have this idea, but I haven't seen it mentioned.
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Old November 22nd, 2005, 12:18 PM   #2
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bill dunn

Good point. I thought that the greater definition of HD wouild make the focus point more unique and hence standout??
Barry ought to go over this.
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Old November 22nd, 2005, 12:43 PM   #3
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I'm not following you here.... If you put a 35mm adaptor in front of your DV camera's built-in lens you are still limited by the quality of that lens, regardless of how good a lens you put on the adaptor. Now with a camera that has a removable lens your point might be more valid.

The current issue of DV magazine has a review of the P&S mini 35 adaptor and they test it on several different cameras. The raise this issue of image quality on fixed vs removable lens camcorders. A chain can only be as strong as its weakest link.

Or maybe I'm just not understanding your point?
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Old November 22nd, 2005, 01:01 PM   #4
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An HD (HDV) camera has its own lens capable to resolve the hi def resolution of the CCD/CMOS! (every 3Mpixel and up still digital camera meets and exceeds this requirement) The quality of an SLR lens could be in question (if need be....) but the more "burning issue" with these image converters is:

how thick the GG (diffuser) is ? (the closer to film thickness or thinner, the sharper the image) for a "static" (wax, etc) due to “circle of diffusion” which translates into sharpness or...

how thick and how plane the movement is (if moving "GG") (how well squared to the SLR lens and the camcorder!!!( a very precise mounting to line them up will help a lot)

If those two, three questions can be addressed, then we can worry about the quality of SLR lenses and the camcorder's own lens (imo)
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Old November 22nd, 2005, 09:13 PM   #5
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But the point, for DV, is that the CCD/imager is the weak link. Video puts low-res into perfect focus. Further, the internal circuitry "sharpens" the image by adding definition around contrasting details. This is fine for objects in the image that have sufficient detail to be clearly recognizable, but things in the background that are low-res but in perfect focus will look bad since they have too few pixels devoted to them. If you blur partially extraneous background details with the lens, the lack of resolution in the CCD will be less obvious.

What I'm getting at is that it is better to reduce detail with controlled focus/defocus than it is to reduce detail by having insufficient pixels. One says "video" and the other says "cinematography".

I'm just trying to quantify what I, and apparently others, FEEL when we look at images gathered with a video camera with a 35mm adapter.
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Old November 22nd, 2005, 11:28 PM   #6
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Quote:
Originally Posted by Marcus Marchesseault
the internal circuitry "sharpens" the image by adding definition around contrasting details
That circuit only "kicks in" between hi contrasting surfaces. Pretty much everything is too much (on a sunny day) for the narrow dynamic range of the CCD. But try this: close down the iris (camcorder on kicks) while watching some details on infinity. Observe the result on a big screen (30"?)

When the details get down to the artificial sharpness level-(one row of pixels?) (and the hi contrast is there) the effective resolution is slashed in HALF! (that is why, a while ago I suggested the resolution chart be printed on gray instead of white! to "bypass" the "smart circuit" before it does any damage to the image!!!) As for the real advantage (imo) of using an image converter is the GG itself.
It lowers the contrast bringing the real life high contrast image into a more manageable range so the CCD can handle it.

Sorry for those that know this stuff, but here are two pics in support of the above: one the camcorder itself, the other one through MPIC:
http://dandiaconu.com/gallery/album05/IMGA0486
http://dandiaconu.com/gallery/album05/IMGA0485
Yes, the image IS better through MPIC than by camcorder itself!
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Old November 22nd, 2005, 11:52 PM   #7
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I'm glad someone more knowledgeable than I put it that way, Dan. I suspected that the GG acted sort of like an Ultra Contrast filter and brought the contrast ratio down. What I didn't know is that the sharpening of the camera would have a quantifiable effect on reducing resolution. I thought it might just be a human perception that a slightly-blurred video image looked better.

I saw part of a golf tournament being played here in Honolulu today. I noticed that the golf ball is practically ringed with a black outline. Some of this can be attributed to shadow, but I believe much of it is due to the sharpening being applied to make details more discernible. Yes, the ball is easier to see and track, but it looks less like a golf ball.

I think what is a more interesting and poignant question than "how to make video look more like film?" is "why does film not look so bad on TV?". I think reduction of contrast and selective focus are critical to the perceived higher quality. After all, a DVD from film looks much better than a televised game of golf, but they are still being shown on a crappy old NTSC TV.

I think there are other pieces to the puzzle, but I think these are a good start.

Perhaps this should have been posted in the "film look" forum?
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Old November 23rd, 2005, 12:23 AM   #8
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Quote:
Originally Posted by Marcus Marchesseault
"why does film not look so bad on TV?". I think reduction of contrast and selective focus are critical to the perceived higher quality
FILM has a
1. MUCH W I D E R latitude of exposure (up to14 stops!!!!!!!) to begin with, thus retaining details in the shadows and without blooming details in the highlights and
2. FILM does not have the "smart circuit" to "sharpen" the negative (thank heaven)
When you transfer "that" crisp image on tape, most nuances captured are displayed, not much is lost (and certainly nothing added like the frigin white lines a video camera generates)
(Selective focus is just a "bonus")
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Old November 23rd, 2005, 02:32 AM   #9
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Dan,

Have you had a chance to test prosumer cameras such as DVX100A, XL-2, etc, in this way for artificial sharpness damage, when these cameras have their "sharpness circuit" settings turned all the way down?

I would be very curious to hear whether the artificial sharpness on one of these cameras is still just as bad, when the camera's setting is turned all the way down.
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Old November 23rd, 2005, 05:57 AM   #10
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Quote:
Originally Posted by Dan Diaconu
here are two pics in support of the above: one the camcorder itself, the other one through MPIC:
http://dandiaconu.com/gallery/album05/IMGA0486
http://dandiaconu.com/gallery/album05/IMGA0485
Yes, the image IS better through MPIC than by camcorder itself!
Dan, it really looks better through the adapter. Are you selling it already? How much? The times I looked at the prices, they were always changing.
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Old November 23rd, 2005, 11:37 AM   #11
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I'd just like to point out that I'm amazed how much of an effect resolution (sharpness, and not the kind you get by digitally enhancing edges) has on noticeable shallow DOF. Playing around with my a 1/3" sensor at 720p+, backgrounds look blurred out quite a bit more easily than on dv resolution. The smaller (and more) pixels sure give foregrounds more detail, which of course makes any softness in a background much more apparent. This of course would likely be negated if that were played on a low-res tv or a dvd player.
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Old November 23rd, 2005, 11:44 AM   #12
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haha, wow dan i just looked at those pictures and thats amazing. is that for real? is it possible the chromatic abberation of the camcorder is canceled out by opposite chromatic abberation in the adapter? is the camcorder abberation from a bad lens or pixelshifting?
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Old November 23rd, 2005, 11:47 AM   #13
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Quote:
Originally Posted by Bill Porter
Have you had a chance to test prosumer cameras such as DVX100A, XL-2, etc, in this way for artificial sharpness damage, when these cameras have their "sharpness circuit" settings turned all the way down?
I did not look for those settings and their effect on the image, but I am sure they do the job well. The gs200 has a "soft skin" (equivalent) which works well.
However, the most noticeable difference I have seen was stopping down the iris. (I usually go down some 5-7 steps?= 2 stops? or so..) "Film does not wash out details" is my guide. The "auto exp" is just a "guide" for consummers not to be followed by professionals. Pump up the fill to match the iris settings for highlights and there you have it. Translate 14 stops into 5 and you WILL get "film look", (for the brotherhood of film making).
Michael, those pics were there for over 9 months now, while some pips here were screaming "Dan, why does the picture look so bad? and why is it soft"........sick of it! Email me and you will get MPIC.
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Old November 23rd, 2005, 12:23 PM   #14
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I love MPIC, but is it still 8000 USD*? Cool. Quality comes at a price.
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Old November 23rd, 2005, 01:41 PM   #15
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Quote:
Originally Posted by Noah Yuan-Vogel
wow dan i just looked at those pictures and thats amazing. is that for real?
Phew...of course not! I am just very good at faking shallow DOF ('n all that) in Photoshop. Prove me wrong. (dam, I'm wrong; I don't even have Photoshop installed). $...t!
There is a small add somwhere: prices will change without notice (dam, this IS a notice!)
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