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-   Canon VIXIA Series AVCHD and HDV Camcorders (http://www.dvinfo.net/forum/canon-vixia-series-avchd-hdv-camcorders/)
-   -   neutral filter (http://www.dvinfo.net/forum/canon-vixia-series-avchd-hdv-camcorders/294302-neutral-filter.html)

Olivier Jezequel August 18th, 2009 05:14 PM

neutral filter
 
Hello,

I just want to be sure i understood well. The neutral filters are useful to soften the highlight values to avoid the burned area when there is a lot of contrast values in the subjects, am I right ?

I am just wondering if it worse to buy one for the hfs10 ?

any suggestions are welcome
thanks

Olivier Jezequel August 19th, 2009 08:26 AM

And also i don't really get the difference between the uv filter neutral filter and polarizing filter

the info i found seems to get all the same kind of things

thx

Tom Hardwick August 19th, 2009 08:52 AM

First thing to say Olivier is that with a camera employing such a tiny chip (and consequently using very short focal lengths) you should avoid using filters if at all possible. The in-built NDs will take care of the exposure (in auto or manual) so there's no need to buy more.

ND filters are 'neutral' by their very nature, so they do nothing for the contrast of the scene - all they do is soak light and force the camera to use a wider aperture - same as your sunglasses. Burnt highlights will still be burnt highlights.

A polarising filter is something else, and it's effects are very difficult to replicate in post, so if you want deep blue skies and fluffy white clouds, then you'll need a polarisor. Note that you only get this effect at 90 degrees to the sun, so that a 90 degree pan can give you continuity headaches galore.

tom.

Olivier Jezequel August 19th, 2009 10:39 AM

IC thanks
so the exposure in the HFs10 can do the same thing the a neutral to avoid burned bright while keeping not to crunchy blacks ?

i am trying to keep the more values in the pict because i like the control in post grading. that's why deep blacks and burned bright are my ennemis as i can always contrast in post.

thanks

Tom Hardwick August 19th, 2009 10:55 AM

Yes, the Canon has in-built ND filters that automatically swing in and out of the light path. They won't stop the highlights over-exposing - you'll have to do that by exposing manually, and of course if you dial down the exposure you'll crunch up the blacks - there's really no way around this other than to shoot in less contrasty conditions.

The camera is probably set up to give quite a contrasty picture as this 'looks better' to the sort of person this camera's aimed at.

tom.

Robin Davies-Rollinson August 19th, 2009 12:23 PM

Actually Tom, you're not being entirely fair to this particular camera.
It in fact has a relatively large, high-resolution 1/2.6-inch 8-megapixel CMOS sensor.
It gives results which can well be compared with the EX1 or 3.
It also has a higher range of manual settings available than similar-sized camcorders - as well as zebra bars, peaking (with a choice of three colours) for focussing, manual control over video gain, and the ability to choose a cine gamma mode to reduce those crushed blacks you mention.
Obviously, I've got one, so I'm bound to defend it! - but coming from the Z1 and FX1, it's a great improvement in image terms, and in the right hands and being set up properly, it's a fantastic little bundle ;-)

Tom Hardwick August 19th, 2009 12:28 PM

I take your point Robin, though I'm betting there'll be a lot of EX1 and EX3 owners out there who will be choking on their cornflakes to read that.

Olivier Jezequel August 19th, 2009 01:01 PM

I didn't know that there was some ND filter build in, I just checked the spec and it seems to be a digital effect so i am not sure how it could achieve the same way ??

i am about to buy the HFs10 so cannot test it yet. is someone have tried it ?

thanks for the infos
Olivier

Tom Hardwick August 19th, 2009 01:11 PM

Internal ND is generally undocumented and a lot ot PDX10 owners were surprised to find that their lenses never stopped down beyond f/4.5. It's done to stop diffraction spoiling resolution when very small chips (and I include 1"/2.6 chips here) are used.

David Merrill August 20th, 2009 04:07 PM

Quote:

Originally Posted by Olivier Jezequel (Post 1243069)
I didn't know that there was some ND filter build in, I just checked the spec and it seems to be a digital effect so i am not sure how it could achieve the same way ??

i am about to buy the HFs10 so cannot test it yet. is someone have tried it ?

thanks for the infos
Olivier

Go to Vimeo and search "HF-S10 or HF-S100" (same cam really). There are many videos posted.

David Merrill August 20th, 2009 04:32 PM

I found a video where someone is doing a basic comparison with the EX-1 and HF-S10.
HF S10 Low light on Vimeo

Olivier Jezequel August 21st, 2009 10:44 AM

sorry David, i should have been more precise, i was asking if someone had tested a comparison between the ND inbuild effect of the hfs10 vs a real ND filter add on the cam.

thanks

Tom Hardwick August 21st, 2009 10:52 AM

It always, always better to use the inbuilt ND filters in a camcorder. They're well protected, way out of focus (should they get dusty, say) cannot cause vignetting or push a wide-converter too far from the front element.

They're also far easier to dial in - and on a lot of camcoprders they're automatic anyway, so you might think you've set f/8 but in reality you've set f/4 + a 2 stop ND.

tom.

Olivier Jezequel August 21st, 2009 11:38 AM

thanks Tom,

so that mean you get exacly the same result ? it is not a gamma curve applied digitaly inside the chip or something like that ?

Because reading the spec the talk about this inbuild ND like an effect, so i a bit worry about destruction of the information.
I have a postproduction background working in film so i want to keep as much info of the pict as possible even if i know it is a consumer product.

thanks

Tom Hardwick August 21st, 2009 03:43 PM

Quote:

Originally Posted by Olivier Jezequel (Post 1251161)
thanks Tom, so that mean you get exacly the same result ? it is not a gamma curve applied digitaly inside the chip or something like that ?


Not exactly the same result - a better result generally, and that's because when you add an ND to the front of the lens you're adding two air to glass surfaces, and along with the surface of your front element, that's three surfaces that must be kept absolutely spotless (an impossibility in real life).

Of course this really shows itself at wide-angle and into the light, where focal lengths in the region of 5 mm mean dof brings both sides of the added filter into near-enough focus - with nasty spotty, bitty results. Hoods aren't much use in situations like this, and generally run 'n' gin precludes the use of flags.

Gamma curve applied digitally? Not at all likely because internal NDs are used to stop the lens using apertures smaller than about f/4.5. Smaller than this and you can clearly see the loss of resolution due to diffraction - and especially so at short focal lengths using small chips.

Modern zooms are designed to be used at wide apertures - apart from vignetting (that they all exhibit) they'll be sharper at f/2 than they will be at f/8. A lot of ex-35mm still shooters can't get their heads round this.

tom.


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