What's the aprox. sensitivity of the HVX?

[pablovi]

Hi, I wan't to know what is the aproximate sensitivity of the HVX and if it's any different from the DVX?

I shot a week ago some comercials witht he DVX and the movietube and I needed a lot of light! It was a night living room interior, the only available light in the actors was supposed to be a TV and some backlight simuliating indoor lighting coming from the other room, and I had to use a 2K fresnel as the key(tv), and I was shooting wide open on the DVX with the Zeiss lens set at T 1.3. Granted the 2k was diffused by 216 and had a full CTB, but still that's a lot of light.

On another shot I put a 4k HMI through a window and still I was shooting at T2.8!!!


So, now I'm doing a christmas special, but I don't know how much light to ask for, I come from Film and knowing the ASA you can calculate the ammount of light you are going to need, but in video along with the adpater, I'm kind of lost, I usually use Kino's, but I'm not sure if they will register anything with the adapter at all! I think I was losing about 3 stops from the adpater and the lenses. So I f someone could give me an estimate of the sensitivity of the HVX and/or the DVX it will help a lot. There is going to be nigth exteriors in that shot, and I need ot know what to ask for.

Oh, BTW I'm trying to convince my producer to use an HVX instead of the DVX, but if that's a loss of even more sensitivity then I'm sticking with the DVX.

Thanks in advanced.

 

[Barry_Green]

It's 320 ISO.

The DVX is 640 in progressive, and 1280 in interlaced. The HVX is 320 at all times.

All the high-def camcorders are a lot slower than their standard-def cousins; the Z1 is about 160 ISO for example.

 

[pablovi]

It's 320 ISO.

The DVX is 640 in progressive, and 1280 in interlaced. The HVX is 320 at all times.

All the high-def camcorders are a lot slower than their standard-def cousins; the Z1 is about 160 ISO for example.

Thanks!

Wow, then it might be better using the DVX, or my other choice is using a Varicam with the Pro 35 mm adpater. But I don't know if that would still be in budget.

320 iso and losing 3 stops is not very good for night exteriors. or anything else than day exteriors for that matter.

Thanks again.

 

[Barry_Green]

VariCam with the Pro35 will clock in at about 160, minus whatever losses are introduced by the speed of the lens you're using.

 

[smelni]

couple things - the sensitivity is not linear - it is even lower at lower light levels.

Also - do not discount a full CTB as being an issue - a full CTB lets only 20% of the light through - so your 2K was the same as a 400 watt light - not really so much.

 

[pablovi]

VariCam with the Pro35 will clock in at about 160, minus whatever losses are introduced by the speed of the lens you're using.

Thanks

I think that's about what I was getting with the DVX and the Movietube + the lens loss (T1.3). But I think the Varicam handles the use of gain a lot better than the DVX. So I think that will be my choice if the producer allows the extra budget.
I will be using an Arri Zeiss high speed lens set at T 1.3 .

 

[Ralph Oshiro]

I come from film and knowing the ASA you can calculate the amount of light you are going to need . . .

I typically light for video, so I tend to use footcandles [fc] as my primary light measurement unit. I like footcandles because that unit measurement is both absolute and linear. More specifically, I'm often lighting for a Sony BVW600 (2/3" BetacamSP), which if I recall correctly, is about a stop more sensitive than an HVX200. I'm familiar enough with the 600's sensitivity that I generally can key caucasian subjects at about 20fc. Given that, I know about what unit gives that output at what distance in most appliactions. For example, I know that a Baby Junior 2K Fresnel through a 4' x 4' polysilk at about 10 feet from subject will emit around 20fc. I know that the 600 will iris 20fc at about f/1.8. Using another example, I know that say, a 2-foot, 4-bank KinoFlo, at about the same distance, will also end up emitting about 20fc. A third example: I know that a Tweenie 650W Fresnel, w/an extra small Chimera, using a single baffle, at about 5 feet, will yield about the same level and exposure, etc.

 

[pablovi]

couple things - the sensitivity is not linear - it is even lower at lower light levels.

Also - do not discount a full CTB as being an issue - a full CTB lets only 20% of the light through - so your 2K was the same as a 400 watt light - not really so much.

Thanks,

Well, I think I was losing 2 stops from the CTB, so it was like a 500 diffused fresnel. At about 1.5 meters from the actors.

My main concern is that it was my biggest Frensel tunsgteng light, and the shot was not that wide, but if the next script calls for a night exterior I don't know what I will do. I always shoot at night with 500 ISO and with a lot more light than a 2K.

I was the one who convinced the producers to rent the Movietube, they have been working without it for 2 years. But he liked the look and now he wan'ts to do a whole one hour drama with it. So I need to tell him how much more light I will need.

 

[pablovi]

I typically light for video, so I tend to use footcandles [fc] as my primary light measurement unit. I like footcandles because that unit measurement is both absolute and linear. More specifically, I'm often lighting for a Sony BVW600 (2/3" BetacamSP), which if I recall correctly, is about a stop more sensitive than an HVX200. I'm familiar enough with the 600's sensitivity that I generally can key caucasian subjects at about 20fc. Given that, I know about what unit gives that output at what distance in most appliactions. For example, I know that a Baby Junior 2K Fresnel through a 4' x 4' polysilk at about 10 feet from subject will emit around 20fc. I know that the 600 will iris 20fc at about f/1.8. Using another example, I know that say, a 2-foot, 4-bank KinoFlo, at about the same distance, will also end up emitting about 20fc. A third example: I know that a Tweenie 650W Fresnel, w/an extra small Chimera, using a single baffle, at about 5 feet, will yield about the same level and exposure, etc.

Thanks, well, I actually didn't messure it, but I think I was getting about 20fc, so that would be roughly 125 ISO at 1.3. That's why I'm worried, I'm gonna need a lot of light for a night exterior.

 

[Ralph Oshiro]

Only 20fc from the 2K? Even with 216 and full CTB, that can only be 1.5-2 stops down from clear, right? How many footcandles would you guess that you had falling on your subject from the 4K HMI?

 

[pablovi]

Only 20fc from the 2K? Even with 216 and full CTB, that can only be 1.5-2 stops down from clear, right? How many footcandles would you guess that you had falling on your subject from the 4K HMI?

I think I was losing about 2.5 stops to be exact on the 2K. And the HMI actually had an ND3 and it wasn't hitting a subject, it was like a street light so it was just hitting the window blinds, a white piano and a white wall, that's why I used the ND3 I like to keep the backgroiund about 1 stop below key, but it was placed much farther and higher. But since I didn't messured anything, it was all just done by eye and watching a CRT monitor. I couldn't really tell. But I was using my biggest lights and still was just shooting at 1.3 in the lens and wide open in the DVX.