DV Info Net - Neutral Density Filter Recommendations Please

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- - Neutral Density Filter Recommendations Please (https://www.dvinfo.net/forum/canon-vixia-series-avchd-hdv-camcorders/98761-neutral-density-filter-recommendations-please.html)

Quote:

Originally Posted by Pieter Jongerius (Post 711676)

Alright, here goes: I think I'm still on topic if I ask the following...

I read from the responses that many people are interested in external ND filters, even for the HV20. I seem to be the only one (cry ;) to mention te built-in ones in relation to external ND filters.

If you consider the built-in ones and some of the stuff I wrote above: Why do you still want to use them? No, honestly :))

tnx
Pieter

Pieter,

From my perspective, I imagine there are times when the built in ND's are not strong enough, so I'm looking for a way to add even more ND w/o disengaging the built in ones.

But please realize that your posts were much appreciated! :) :)

1st of all-Many thanks, wasnt worried...just yet :)

To take it one step further... assuming the built in NDs are engaged "when needed" according to the cam, adding an external ND filter would probably take away that "need". I can see no other way. You would have to go ND10 or something to compensate for the disengaged internal NDs!

Anyway, I'm guessing that... but if you read this http://www.dvinfo.net/conf/showthread.php?t=81516 for some pretty enhanced ND stuff, you'll get to read this quote from the patent by Mike Brown (thanks mike)

Quote:

Combinations of the densities of the ND filter and the F-numbers of aperture control at individual EVs will be explained below with reference to FIG. 11B. In the region where the EV is 2 (inclusive) to 8 (exclusive), the shutter speed lowers in accordance with each EV, but the F-number of aperture control is fixed to F2 as an open-aperture F-number, and the number of ND steps of the ND filter is also fixed to 0. That is, the transparent portion 151a shown in FIG. 2 of the ND filter 151 is used in this region.

In the region where the EV is 8 (inclusive) to 11 (exclusive), the shutter speed is continuously variable from 1/60 to 1/125 sec, the F-number of aperture control is continuously variable from F2 to F4, and the number of ND steps of the ND filter is fixed to 0.

When the EV is 11 or more, the F-number of aperture control is returned from F4 to F2, and the number of ND steps of the ND filter is switched from 0 to 2. (Referring to FIG. 11B, the switching points of the F-number and the number of ND steps are different. In practice, however, the F-number and the number of ND steps are simultaneously changed.) That is, in this stage, the uniform-density portion 151b having an optical density of 0.6 shown in FIG. 2 of the ND filter 151 is used.

In the region where the EV is 11 (inclusive) to 14 (exclusive), the shutter speed is continuously variable from 1/125 to 1/250 sec, the F-number of aperture control is continuously variable from F2 to F4, and the number of ND steps of the ND filter is fixed to 2.

When the EV is 14 or more, the F-number of aperture control is returned from F4 to F2, and the number of ND steps of the ND filter is switched from 2 to 4. That is, in this stage, the uniform-density portion 151c having an optical density of 1.2 shown in FIG. 2 of the ND filter 151 is used.

In a region where the EV is 14 (inclusive) to 17 (exclusive), the shutter speed is continuously variable from 1/250 to 1/500 sec, the F-number of aperture control is continuously variable from F2 to F4, and the number of ND steps of the ND filter is fixed to 4.

In a region where the EV is 17 (inclusive) to 19 (exclusive), the shutter speed is continuously variable from 1/500 to 1/2000 sec, the F-number of aperture control is fixed to F4, and the number of ND steps of the ND filter is kept fixed to 4. The exposure control diagram described above is applied to single-shot photographing or photographing of the first frame in continuous photographing.

If this is accurate, thats the definitive answer. The cam keeps the iris as open as possible and adds up to ND4.

I'm a bit confused w/ the internal ND issue.
In regular P or auto modes, my HV10 still tends to be overexposed a few stops, unless I go to Av mode and crank the aperture all the way down, to like 8.0...
I lose any artistic control over aperture/DOF of course (luckily I don't normally care, but)...
shouldn't the ND filters help that?

I'm planning to buy a Tiffen 3filter kit w/ UV/MC filter (help some w/ sky/haze a bit), as well as ND 6, so that (if I want) I can get back Av control...
will the internal camera filters/controls defeat this?
Anyone comment on this particular kit/brand and how well it works on the HV10? I seem to recall someone commenting about chrome rings reflecting on closeup subjects sometimes :)
http://www.bhphotovideo.com/c/produc...Intro_DLX.html

Wish the kit came with a circular polarizer rather than FL-D (I use white balance control for that), but oh well...

Quote:

Originally Posted by Colin Gould (Post 711800)

...shouldn't the ND filters help that?...
...will the internal camera filters/controls defeat this?

Well, translating all the tech talk above: The reason why you feel the image is overexposed is because the camera 'likes' it that way. It is not a technical limitation. It will do everyting in its power to keep it 'overexposed', unless you lower exposure by manual override using the joystick or set a brightness-1 in the menu settings (or indeed do a forced Av or Tv). This is exactly why simply adding ND almost certainly won't work. The cam will reduce its own ND, go 1/48th, open iris, beg the light to come in, even on a sunny day if it thinks it's needed and your skies (and mine :) will blow out anyway.

In practice, I always have the brightness setting at -1 and if needed add EV-2 with the joystick.

regs
Pieter

Quote:

Originally Posted by Pieter Jongerius (Post 711702)

Pieter, but it's entirely possible, in some lighting conditions, to want a shutter and F stop combination that the built in ND filters aren't strong enough to prevent from overexposing. In that case, the camera won't disengage its built in ND filter if I put my own in front of the lens.

So true... I guess that that thought didnt enter my mind because of the lack of a proper M mode on the HV20. It is totally feasable to trick the cam into locking in an overexposed situation and then add your ND. There's my answer, thanks!

Quote:

Originally Posted by Pieter Jongerius (Post 711660)

About how to semimanually control the iris/shutter: others have much more experience, I saw some threads on that. Anyone?

Check this out:http://www.dvxuser.com/jason/hv20/

Thomas, thanks, that's a very useful link!