1/30 lock??

[Eric Bilodeau]

Quite the method I use, I let Shutter/iris adjust automatically, when it is still I lock AE. Afterwards, whatever you shoot it won't automatically adjust to different lighting environnements. The fact is it works, that is all there is to say about it, I personnaly don't care if it is not a normal way since it is the way I found that suits my needs. If it did not work I would not give advice about it. Of course, very high lighting differences might be a pain when it is locked but than again these cameras are anything but "operational perfect". It gets me the images I want, I can manage with that. What you see is what you get.

[Alex Raskin]

Steve, I also agree with Jay that if you cycle through the modes quickly enough, they let you read the blinking reading without actually switching priority to that mode.

[Steve Mullen]

Jay's method doesn't get him 1/60th which is the better speed because it equal to a 180-degree shutter.

And yes you can read SOMETHING by cycling but you are ASSUMING it is the past values.

Now cycle through again

and again

Way too often you get different values each time! So which set are true?

And, why do they change?

Plus the fact the values change overtime while you are shooting. Why does it do this? Does it have a preferred mode of operation?

In short, there are too many assumptions -- all ones I too made before discarding this -- that I prefer to stay with HOW TO SHOOT based upon what the I know the camera is doing.

[Heath McKnight]

<<<-- Originally posted by Eric Bilodeau : Quite the method I use, I let Shutter/iris adjust automatically, when it is still I lock AE. -->>>

Eric, you use this in which mode, auto or "manual?"

heath

[Eric Bilodeau]

I do all my adjustments while cycling in manual mode pointing at a still source of light. With a dark source, the camera (HD10) will be still at 1/30, f2. After it has reached its auto adjustment (it is actually fast), the iris shutter values will not change . Simply put, the automatic mode is not hunting 24/7, once it has reached a ratio that corresponds to a scene's overall light it stays still until light changes, so it is not true that you get different values all the time. After that you must quit Shutter/iris priority modes to get back to auto (it will not change providing your light source is still). You press AE once than a second time until the "L" appears. Your AE (automatic exposure) control is locked. Of course, if your AE is not set to 0 it will adjust a little to important changes in lighting conditions. If your AE is set to 0 it will remain as it was when locked whatever the light changes. This is not an assumption, I tested it over and over and it simply works. It is not at all complicated or illogical: it adjusts automatically to a scene, than you lock the automatic exposure control to an adjustment range you choose(from -10 to +10). In controlled environnement, lock it to 0, when you do field shooting, test the level of AE, ideally keep it low (from -3 to +3).

[Heath McKnight]

Thanks, Eric. We'll give it a shot in 2.5 weeks for our short film.

heath

[Steve Mullen]

<<<-- Originally posted by Eric Bilodeau : I do all my adjustments while cycling in manual mode pointing at a still source of light. -->


"still source"? In the field?

<-- After that you must quit Shutter/iris priority modes to get back to auto (it will not change providing your light source is still). -->

After what?
When did you enter Shutter/iris priority modes?


<-- You press AE once than a second time until the "L" appears. -->

You mean the Exposure Control dial, right? And you must press and HOLD.


<-- If your AE is set to 0 it will remain as it was when locked whatever the light changes. This is not an assumption, I tested it over and over and it simply works. -->>

No dispute, but you have no idea what the shutter-speed is.

And, because of the low light latitude the slightest increase in brightness will cause overexposure.

[Heath McKnight]

Now I'm more confused...

heath

<<<-- Originally posted by Steve Mullen : <<<-- Originally posted by Eric Bilodeau : I do all my adjustments while cycling in manual mode pointing at a still source of light. -->


"still source"? In the field?

<-- After that you must quit Shutter/iris priority modes to get back to auto (it will not change providing your light source is still). -->

After what?
When did you enter Shutter/iris priority modes?


<-- You press AE once than a second time until the "L" appears. -->

You mean the Exposure Control dial, right? And you must press and HOLD.


<-- If your AE is set to 0 it will remain as it was when locked whatever the light changes. This is not an assumption, I tested it over and over and it simply works. -->>

No dispute, but you have no idea what the shutter-speed is.

And, because of the low light latitude the slightest increase in brightness will cause overexposure. -->>>

[Jay Nemeth]

Ok,

If the exposure bias is 0 and you press the exposure button a second time and hold it, it will lock the exposure. If it is 1/30th shutter and and a very low f-stop, the numbers will stay constant. If it is a brighter scene, or you are not using ND filters to make the iris open up, then just because the exposure is locked does not mean the shutter and iris will stay the same. You could lock it at 1/60 and f5.6, but later on the camera may have changed to 1/125 and f4. Notice that the apparent brightness of the image does not change, because as the shutter went up, the aperture opened to compensate.

If you set the bias to -2, and wait for the camera to adjust, and then lock, it too will stay at the same apparent brightness. Again, unless you are near wide open, and at a slower shutter, there is no guarantee the combination of shutter and iris will hold, but they will offset each other so the image is the same brightness.

Does everyone agree this is the way this works? It is certainly the way it works on my camera.

I have noticed that it is important to let the camera settle in before pushing the "lock" button or the exposure WILL drift even though the "L" is displayed. For example, aim camera at something, push exposure button, it reads "0", now turn it down to -6 and immediately push the button again for "lock". The camera will continue to make adjustments until it decides on something that is usually not what you want.

I hope it was clear in my previous post that I was explaining a way to always get 1/30th shutter speed, and not that I thought you could lock any shutter speed in with the exposure lock. If it did that, I would have had the 1/60th shutter I wanted for our project.

There are really three things you can do:

1: You can lock a shutter speed, but the Aperture is automatic.

2: You can lock an Aperture setting, but the shutter will change automatically.

3: You can lock the Exposure, or the brightness of a scene, but the camera will pick the combination of shutter speed and aperture f-stop. UNLESS, you shoot in low light or use NDs so you are at the low end of the scale, then you know the shutter and f-stop won't change because there is no more wiggle room.

I don't want a shutter faster than 1/60 and I want the lowest f-stop possible to reduce my DOF, so number 3 works best for me.

Use ND filters!

Jay

[Steve Mullen]

<<<-- Originally posted by Jay Nemeth

If the exposure bias is 0 and you press the exposure button a second time and hold it, it will lock the exposure. If it is 1/30th shutter and and a very low f-stop, the numbers will stay constant. -->>

YOU ARE RIGHT -- the speed will not increase until you get to f/8 -- according to JVC. So IF you want 1/30th and can keep the light in the range from f/2 to f/8 -- 3 stops -- then you can both avoid eye-tracking, bias exposure, and lock exposure.

Very Clever!

On a bright sunny day in a high contrast situation -- what ND do you use?

On a bright sunny day in a shadow (lower contrast) -- what ND do you use?

On an bright overcast day?


BUT how do you know the f stop is under f/8 when you trying ND filters?


By the way, you should be able to handle 4 stops of light range because at f/8 -- the next stop more light SHOULD only increase speed to 1/60th.

Thus:
30 -- f/2
30 -- f/4
30 -- 5.6
30 -- f/8
60 -- f/8

I haven't thought about what EFFECT a negative bias would make. I think will simply force exposure downwards from 60 -- f/8. So -3 would yield 30 -- f/8.

Right?

What JVC should have done is alter the firmware speed limit from 250 to 60 and increase the limit for the iris from 8 to 16. Such a simple programming change that JVC admits should be able to be done. Then we would have:

30 -- f/2
30 -- f/4
30 -- 5.6
30 -- f/8
60 -- f/8
60 -- f/11
60 -- f/16

A full 6 stops!

[Steven Galvano]

<<<-- Originally posted by Jay Nemeth : Ok,

3: You can lock the Exposure, or the brightness of a scene, but the camera will pick the combination of shutter speed and aperture f-stop. UNLESS, you shoot in low light or use NDs so you are at the low end of the scale, then you know the shutter and f-stop won't change because there is no more wiggle room.

I don't want a shutter faster than 1/60 and I want the lowest f-stop possible to reduce my DOF, so number 3 works best for me.

Use ND filters!

Jay -->>>


Thanks for your insightful post. While in Exposure lock, is there a way to monitor where the shutter and aperture settings are? I tried scrolling through "P.AE" and it always read "F2" and "1/30" even when pointing at a bright source.

Also, can you give us the basic ND formula you use for different conditions?
I just have a .6
thanks

Steve

[Jay Nemeth]

Exterior sunlight I use at least an N1.2 plus a polarizer for 6 stops of light reduction. This should be a 16x ND in consumer filters with a Pola or a 64x without the Pola. Use enough ND to get the aperture down to 5.6 with the 1/60 shutter. On overcast days you can remove a couple of stops of ND. I haven't recorded exactly how much filtration I use, this is just from memory.

Leave the camera in auto mode, and look at the aperture settings by cycling through the shutter/aperture button. You will see the camera open up as you add more ND. I really don't have a formula for NDs, I carry 2 complete sets and just keep adding until I get the right stop. It really would be good to have one really heavy ND like a N1.8 or 64X so you don't have to have multiple peices of glass in front of the lens to degrade the image.

Those tables you listed pretty much match what I'm finding. I agree, the formula should be changed. A "NORMAL" shutter of 1/60 (equivalent to a 180 deg. shutter which the human eye finds natural) should hold as long as possible until the camera hits the highest f-stop. Only then, should the shutter speed increase. The reality is, the camera should have had an internal ND filter like the VX 1000, 2000, DVX100, PD150 etc.

Jay