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Sony HVR-Z5 / HDR-FX1000
Pro and consumer versions of this Sony 3-CMOS HDV camcorder.

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Old April 10th, 2009, 12:18 PM   #76
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I could see where that might be true at the extreme ends of the spectrum, like when shooting day for night, but in the middle of the exposure range, when your iris and/or shutter speed would be adjusted to maintain the same overall levels, I doubt that would be the case. At the extreme upper end of the intensity spectrum -- i.e. everything blown out -- I would suspect that adding an ND would actually *increase* the contrast.

But as I said I haven't done a controlled experiment and put it on scopes.
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Old April 10th, 2009, 04:00 PM   #77
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It's also the reason lights are used when shooting in poor lighting situations. You can compensate by increasing exposure but it doesn't give the same oomph as adding additional lighting - thereby increasing the contrast and colour saturation.

A (very) simplistic illustration follows:

If you take normal daylight on a cloudy day at, say, 10,000 lux (direct sunlight being approximately 100,000 lux - but this gets filtered to varying degrees as it travels through our atmosphere) then, if your subject includes an object which reflects no light (say black velvet) and an object which is pure white (reflecting the 10,000 lux) your total contrast will be 10,000 to 1.

However, if you move indoors where the illumination is, say, 1000 lux - using your same objects - the black is still reflecting no light, but the white object is now only reflecting 1,000 lux (it can't still be reflecting 10,000 lux because there is no longer 10,000 lux available) so the contrast is now only 1,000 to 1 and the colours are less saturated as a result. However, the super circuitry in modern cameras tries to compensate for that, and to some extent succeed. If we really want to get the contrast back up and get better colour saturation and basically more overall "punch" we add artificial lighting to try to get back up to as near to daylight levels of illumination as we can. That's why professional outfits spend thousands on big lighting setups.

If you're shooting in moonlight (typically 0.25 - 1 lux - we'll say 1 lux for the purposes of illustration) then your contrast is only 1 to 1 - which is why everything looks grey (assuming you have a sensor that works as low as 1 Lux). However, it is possible to artificially increase contrast in post (as well as what the camera tries to do) to some extent but the colour saturation still suffers to some degree and will never look as good as footage which has been optimally exposed in the first place. It's basically the same effect as decreasing exposure and increasing gain (ignoring the other elements that rear their ugly head due to the electronic nature of the light capture such as system noise)

So, getting back to the original issue, if your daylight is stopped down from 10,000 lux to 5,000 lux through your ND1 filter, you have effectively reduced your contrast to 5,000 to 1 but the camera circuitry can compensate quite admirably for that by opening the iris more and/or adding gain to increase the exposure for the white object and artificially increasing contrast. However, as the light levels drop further, it gets increasingly difficult for the camera circuitry to compensate for the reducing contrast and the picture starts to look more and more "washed out" as it struggles to produce a true black and a true white.

Last edited by Steve Renouf; April 10th, 2009 at 04:03 PM. Reason: spelling
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Old April 17th, 2009, 07:41 PM   #78
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Steve, I may be wrong, but isn't the typical dynamic range of the CMOS/electronics combination in cameras like the Z5, well below the kind of contrast ratios you're talking about?

I would think that white would be clipped significantly if you didn't use some form of ND filter or gain reduction. So, in effect, you would never really see or appreciate a greater contrast ratio if you avoided the use of ND filtration. But again, I may be wrong.
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Old April 19th, 2009, 06:57 AM   #79
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Quote:
Originally Posted by Ken Ross View Post
Steve, I may be wrong, but isn't the typical dynamic range of the CMOS/electronics combination in cameras like the Z5, well below the kind of contrast ratios you're talking about?
Indeed Ken, but the point I was making is that anything that reduces the amount (not the colour) of light effectively reduces the available contrast levels. Within "normal" ranges, it can be hardly noticeable - if at all. However, as we get towards really low light levels, the contrast inevitably starts to get that "washed-out" look (regardless of the very excellent compensating software built-in to the modern systems we're using. Because different wavelengths (colours) of light have different levels of luminence at different light levels (amount of light) even the excellent compensation circuits, whilst stretching the black/white ratio to increase the contrast artificially, can't cut it when trying to deal with the full colour spectrum at different rates of luminence. Hence that "washed-out" look with the colours - even though you may have regained reasonable black/white levels.

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I would think that white would be clipped significantly if you didn't use some form of ND filter or gain reduction. So, in effect, you would never really see or appreciate a greater contrast ratio if you avoided the use of ND filtration. But again, I may be wrong.
It really depends on the capabilities of the sensors. If the ilumination is too high for the sensors to cope with (exposure latitude) then, yes, we need to reduce the light level by whatever means (turn the lights down, ND filter or gain/exposure controls). The problem of lack of contrast, in the manner I was referring to, only really arises in lower light levels because, as the total amount of light available decreases, the contrast decreases and when it gets very low, it becomes much more difficult to re-introduce contrast without it looking manufactured. Even with a camera with such excellent low-light capabilities as the Z5 (for example), it's still a fact that a well-lit scene is going to be much punchier (higher contrast) than a scene shot with low available light levels and stretched contrast from the compensation circuits. (Even if we could ignore the noise factor).

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Old April 19th, 2009, 11:57 AM   #80
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xlr's?

I think the z5 has xrlrs also


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Originally Posted by Jeff Harper View Post
In the case of these cameras I see the skill of the shooter as a larger factor in the final product rather than the minor low-light differences in the cameras.

The low-light capabilities of the Sony is clearly better, but with gain properly used on the Panasonic the differences become insigificant, IMO.

I noticed imediately when I viewed your clips, Mark, that the Panasonic performed well with increased gain and presented a nice clean image.

While off-topic I'd say for wedding work the Panasonic could easily be seen as a better value.

When you look at the price difference between the Z5 and the Panasonic, dollar for dollar the Panasonic gives more bang for the buck. XLR connections, CCDs, and a comparable image for $3200 is a heck of a buy.

On the other hand, I actually like the additional weight of the Sony and the placement of the LDC on that cam.

In my mind the primary differences between these two cams comes down to which features are most important to the shooter.
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Old April 19th, 2009, 12:40 PM   #81
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Originally Posted by Tom Hardwick View Post
When you switch an ND (or two) into the light path you're adding extra elements to the lineup of 15 or so you already have. Extra elements always up the flare levels by tiny amounts and in some cases can alter critical focus at the film plane. The NDs are way out of focus though, so even if they collect dust and debris it's not a problem.
Not really Tom. The "no ND" position is a clear bit of glass, not an open space, so you always have the same number of glass/air surfaces in the optical path.

It's pretty critical that all the filters (including clear glass) have not only exactly the same thickness, but the same coefficient of refraction. If they didn't the lens tracking would vary from filter to filter, and if "no ND" had no glass the tracking would be so different from the ND positions as to be unusable at wide angle fields of view.
Quote:
Originally Posted by Steve Renouf
.....if you move indoors where the illumination is, say, 1000 lux - using your same objects - the black is still reflecting no light, but the white object is now only reflecting 1,000 lux (it can't still be reflecting 10,000 lux because there is no longer 10,000 lux available) so the contrast is now only 1,000 to 1 and the colours are less saturated as a result.
I disagree. Nothing will have 100% reflectance, and nothing will reflect no light at all - even the deepest black will reflect some light. If we say the figures are 95% for the nominal white, and 1% for the deep black, then *all else equal* the outdoor/indoor figures using your figures will be 9,500/100 lux outdoor and 950/10 lux indoors - exactly the same ratios. Same if you add a 1 stop ND - the former case goes to 4,750/50 - same ratio again.

The reason contrast range may seem to decrease with lower light levels is to do with directionality, and especially highlight/shadow ratios. Light a subject with a highly directional spotlight in an otherwise dark environment, and the contrast range of the subject may be just as high as in sunlight, even though the overall level is far lower.
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Old May 25th, 2009, 06:25 AM   #82
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Yes Ed the Z5 has XLRs, but the original thread was about FX1000s. Additionally, the Z5 costs significantly more than the FX1000 and the Panasonic, obviously.
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