Exposure control on HD1 and HD10

[Gordon Lupien Jr.]

Can somebody who has actually spent the time with both the HD1 and HD10 accurately describe the exact differences between the "manual" exposure controls on these two cameras?

Does one have advantage over the other?

Can one actually be fully "locked" to a setting?

Aren't they both really using the same algorithms?

Thanks!

- GLupien

[Heath McKnight]

To lock, hold down the exposure button on the HD10 until an "L" appears.

heath

[Gordon Lupien Jr.]

I think that's exactly how it works on the HD1. I received a PM from Steve that the HD1 and HD10 have EXACTLY THE SAME exposure control.

I've got a little tip for folks though, and I'd love some feedback on it.

Instead of using a pack of ND filters, another way to reduce the intensity of the light the camera receives outdoors is to purchase TWO circular polarizing filters. Take one of the filters and reverse the element (undo the lock ring and flip it over, then re-lock it in the holder). When you screw the two circular polarizing filters back to back, you can rotate one in reference to the other and have a continuously variable ND filter. I'd estimate that it starts at about ND 2X and goes up to about ND 32X or more, but there is a catch...

The only thing I can see that is negative with this method is when you get too close to "fully blocked". The filters start modifying the colors towards blue. This only happens at the very end of the variation, so what I do is put an ND4 in series with the two Circular Polarizers so that I never have to go all the way. You need to put the ND4 AFTER the Circular Polarizers (closest to the lens).

The easy thing to do instead of gluing one of polarizers, is to put one thickness of electrical tape around the circular polarizer you want to fix, so that only the second one rotates.

WORKS GREAT!!!

To adjust exposure, I use the follwing method:

- Set the exposure control to 0, and point at the brightest thing you will be filming (the thing that usually gets blown out)
- Use S/A to select 60fps.
- Cycle through the S/A settings quickly to read what the F-stop is
- Stop on the shutter speed again and wait until it stops flashing.
- Adjust the filter based on what you saw for an F-stop and cycle through again to the shutter speed and let it set.
- Cycle through to check F-stop and make sure it's around 5.6 or so.
- Once you get it set so that shutter is 60fps and F-stop is 5.6 for the brightest thing you will be filming, things should be fine unless you have some severe contrast.
- Set the exposure controls to Shutter priority and pick your shutter speed and lock it. OR go back to the exposure control and use it to compensate for darker scenes during the shot...

- GLupien

[Les Dit]

I like the idea of the variable ND.
How about this method:

Set the shutter to what you want to use, say 1/30 sec.
Point at what bright areas there are in your scene.
Rotate ND until the exposure starts to darken ( means lens is at wide open setting for app. )
back off a little on the ND if you want more DOF.
Shoot.

Less jumping between S/A settings, no waiting for things to stop flashing. You *know* when the lens is Wide open, visually.

Heck, you might even be able to calibrate the polarizer for f stops!
-Les

[Ken Hodson]

Nice post Gordon. It is the type of inovative, real world, helpfull post that we need here. We seem to let the, "It has only 1 CCD so it is crap" uneducated posters dominate this forum, or at least ruin a perfectly good threads.
Ken

[Dustin Cross]

Why do you flip one of the polar filters? I have used this technique, but I didn't flip one of the filters.

Dusty

[David Newman]

Two polarizers, that is a great idea, I will have to give this a go. A technical note: for non-polarized light, each filter is like an ND2. So the minimum light control will be ND4.

[Gordon Lupien Jr.]

Interesting, I thought I had posted a reply, a couple of days ago, but it doesn't seem to have taken...

Anyways, it seems that varying the filter as you shoot is very possible, and Les, your idea works great!

Dustin, you have to flip one of the filters to invert the polarizing with a circular polarizer. If you have linear polarizing filters, you do not need to flip one. I was told when I purchased the CPs that the auto focus system will not work well if I used linear filters (which are cheaper)... Seems to me like some experimentation is in order...

- GLupien

[Dustin Cross]

Why do you need to invert the circular filter? I have done this on a camera before without inverting one of the circular filters and it worked just fine. I use this technique so I can always keep my iris wide open and get teh minimun depth of field.

[Gordon Lupien Jr.]

Dustin,

Just my experience. We had to invert one of the pair to get the effect. You may have been lucky in that one of the sets you have is ALREADY inverted.

We tried with Tiffen (i.e. Hoya) and B + M filters and had the same effect. They need to be inverse to one another.

This isn't the point, by the way. The point is that you can use two polarizing filters to make a variable ND filter. You've been enjoying it for some time, so you know how cool it is.

- GLupien

[Les Dit]

Here is why you need to invert one of the circular polarizers: These have a wave plate on the back to 'un-polarize' the light going into the camera. To have the ND effect described, you need the second polarizer to get already polarized light, so it can block it ( thereby blocking most of the light ).
Now, if you use linear polarizers, they don't have the 'un-polarizer' so no reversing is needed.
A good solution is to use the circular type nearest the camera, and a linear on the outside. No problem.
-Les

[Dustin Cross]

Ahhh. Now that you mention that, my 4" polarizer for my mattebox must be linear. I use that with a screw on circular polarizer on the lense. and it works great.

[Ken Hodson]

-"what I do is put an ND4 in series with the two Circular Polarizers so that I never have to go all the way. You need to put the ND4 AFTER the Circular Polarizers"
and
"for non-polarized light, each filter is like an ND2"

Can this all add up to too much filtering? It sounds good, but if it adds up to ND4+ND2+ND2, won't that be a little strong?
Will the polarizers (or at least one of them) still work as a polarizer?
Could I use a Ultra Con filter in conjunction with this setup?

Ken

[David Newman]

I was incorrect in my previous post. One polarizer is like ND2 for non-polarized light, but the second is not like another ND2 if it is 'in-phase' with the other other polarizer. The polarizers will still have their original function, the first selecting the phase, the second select how much of that phase. Also this is not too much filtration, I have stacked ND4 and ND8 (an effective ND32 -- and I could have done with a little more.)

[Ken Hodson]

Sometimes I see "rotating filter holder" mentioned on a matte box. Is this something made for actual filter rotation like we have been talking about? Or is it something else?
Ken