Controlling Exposure on the HV20: Walkthroughs and Tutorials.

[tcindie]

I know this is an older thread.. but I didn't see a better place to post.

I know the cellphone trick is pretty widely used, and I'm sure all phones yield slightly different results. Just thought I would share the results I get with my Samsung t-809.

I use an all white image as my background image, so all I have to do is slide the phone open to activate the backlight. I have the backlight brightness level set to maximum (5), and this allows me access to the FULL range -11 to +11 on the HV20 exposure scale.. I get from f7.8 to f2.6 with every point on the scale locked at 1/48th.

[Zephyrnoid]

Sorry to seem like the dimwit at times. I tried to condense this amazing "psuedo manual without the Gain" tutorial for myself and this is what I ended up with. If someone could please eliminate the 'fat' and just give us the definitive cheat sheet on this issue, I'd be much obliged to say THANKS!

Plan A (Default HV20 Exp Override Functionality)
ACTION: EXP lock function: Press the joystick in>toggle down to EXP> toggle the joystick “up”.
RESULT> A numerical scale, which can range as far as –11 to +11 (varies depending on the prevailing lighting conditions EXAMPLE: 0 to +10, or from –10 to 0
OBJECTIVE: Locate & Set parameter combinations that result in 1/48 shutter, no electronic gain, and a range of iris settings and we’ll be able to repeat those settings in the field.
-------------
Plan B (Max Aperture & Gain @ f/1.8)
ACTION: EXP lock function
1) Zoom to Full Wide With Lens Cap On
2) Shutter Priority Mode (Tv)
3) Shutter Speed = 1/48
RESULT> F/1.8 aperture = 27dB Gain
-------------
Plan C
ACTION: EXP lock function
1) Zoom to Full Wide With Lens Cap On
2) Cine Mode
3) HDV 24P
RESULT> @ F/1.8 aperture

EXP Shutter Iris Gain
+3 1/8 f/1.8 10.5dB
+2 1/15 f/1.8 10.5dB
+1 1/15 f/1.8 9dB
0 1/24 f/1.8 9dB= Default Based On Dead Black 'Subject'
-1 1/24 f/1.8 7.5dB
-2 1/24 f/1.8 6dB
-3 1/24 f/1.8 4.5dB
-4 1/24 f/1.8 3dB
-5 1/24 f/1.8 1.5dB
-6 1/24 f/1.8 0dB
-7 1/24 f/1.8 0dB
-8 1/30 f/1.8 0dB
-9 1/30 f/1.8 0dB
-10 1/30 f/1.8 0dB
-11 1/48 f/1.8 0dB = Film Look Setting
-------------
Plan D (Fixed Shutter & Gain Variable Aperture)
ACTION: EXP lock function
1) Zoom to Full Wide- With Fixed Illumination Cap
2) Cine Mode
3) HDV 24P
RESULT> Fixed Shutter Speed & Varied aperture range

EXP Shutter Iris Gain
+6 1/48 1.8 0dB
+5 1/48 2.0 0dB
+4 1/48 2.2 0dB
+3 1/48 2.4 0dB
+2 1/48 2.6 0dB
+1 1/48 2.8 0dB
0 1/48 2.8 0dB = Default Based On Target Illuminator
-1 1/48 3.4 0dB
-2 1/48 3.4 0dB
-3 1/48 4.0 0dB
-4 1/48 4.0 0dB
-5 1/48 4.8 0dB
-6 1/48 4.8 0dB
-7 1/48 5.6 0dB
-8 1/48 5.6 0dB
-9 1/48 5.6 0dB
-10 1/48 5.6 0dB
-11 1/48 5.6 0dB

*An ideal accessory item would be a lighted lens cap, something that would cap the lens and deliver a repeatable (and appropriate) amount of light. I can simulate that with the “cell phone trick,” but it’d be more professional and repeatable if we could find a fixed light source to use (and, if it was a tad brighter, we could use the full EXP range instead of my current system that allows only up to +6).

[MOJE]

Hey Boys,

With "Enosoft DV Processor" software You may wiev on PC (throught IEEE1394) actual gain (only DV mode on HV 20)

:-)

CINE MODE max GAIN is +9

[Zephyrnoid]

Dead silence??? Anyone wanna make this into a simple cheat sheet?

[Ian-T]

I don't know why one really needs the cellphone ...all I do is use a white piece of paper...turn on the video light...shine it on the white piece of paper ...and lock my exposure...so far the best I have done is get to +9 @ F/1.8 -- 1/48 shutter...every time.

I don't know...but I think it's pointless to try and get the whole range of the exposure...I mean...then what? As long as you can read f/1.8...you are gravy...just add light to your scene if you need to...but at least you have a ceiling of acceptable video to work with...just don't go any higher with your exposure and add light if it's too dim ....right?

[tcindie]

You don't ALWAYS want to run wide open, so having use of the full range gives more control.

[TimeKoder13]

So I bought a miniSD today at CC 1GB $15 on sale from $34...now what??? hehe, I gotta tredge thru that youtube thing, the guys voice put me to sleep 3X already...but hey, thx for the effort...

[Zephyrnoid]

Does this actually work as advertised or is it just a theory?

[DavidD]

DVX users,

I just finished the long road of testing and development of a lighted lens cap called the "Lytecap" - for the Canon HV20/HV30 that gives the user the ability to set the aperture at 2.8 (or any range) whenever they desire. At 2.8, there is 0dB of gain to the image from the range of +6 to -11 when clicking through the exposure.

The Lytecap fits over the barrel of the hv20/hv30 and makes setting the aperture easy as pie.

Have a look at the site :

http://www.lytecap.com

I am a member here, so I hope this is taken the right way - just trying to get the word out to help the hv20 owners and budding film-makers (it will help me as well, I can't lie).

[Mr B]

David, that light cap looks great, have you had a chance to get and use it yet? I went out the other night and used my phone, I got decent results but would like something easier, better, and less fragile :P