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-   Sony HVR-Z1 / HDR-FX1 (https://www.dvinfo.net/forum/sony-hvr-z1-hdr-fx1/)
-   -   FX1/Z1 asa est. @ 125- users ? (https://www.dvinfo.net/forum/sony-hvr-z1-hdr-fx1/41336-fx1-z1-asa-est-125-users.html)

Kurth Bousman March 17th, 2005 06:32 PM

FX1/Z1 asa est. @ 125- users ?
OK- just read a thread at another site where a dp estimated the fx1s' asa at 125 and he compared it with the dvx @ 500. He did reiterated that the gain is very un-noisy so you can make up a stop or 2. What do some of you guys with hands-on think ? I thought I read that it's only a stop slower than the vx but asa125 seems real slow. thanks - Kurth

Steve Mullen March 17th, 2005 06:59 PM

I typically white balance at night in NYC by pointing at a white police car. Doing so with the Z1 at 18db gain would not work.

So I suspect it really is a good deal sensitive. But we shouldn't be surprized. The higher the CCD density, the less sensitive it can be.

Thankfully, I find +9dB to +15dB to be very clean which does work in well lit resturants etc.

Chris Hurd March 17th, 2005 07:17 PM

Just wanted to point out that Steve never has trouble finding these white police cars, because there's a Midtown precinct less than a block away from his apartment. So in addition to living in a very secure neighborhood, he also has a convenient WB target nearby every time he takes his camera out to the street!

Jon Fordham March 21st, 2005 03:37 PM


On the last shoot I did with the FX1, my Gaffer asked me what the ASA was. I told him I had not "rated" it and didn't know for sure. I told him that it was probrably about a 150. He set his L-508 to 150 @ 30fps and immediately hit the exact same stop as the camera. We lit the rest of the show with our meters set to ASA150 @ 30fps and hit the mark every time.

On that shoot I used the CinemaTone set to ON. CinemaTone produces a more contrasty image creating darker shadows and in turn knocks the sensitivty down a bit. With the CinemaTone turned OFF, I suspect the FX1 to be closer to about a 180.

Of course, I always work at 0db gain. So that's one factor that keeps the sensitivity down. Though it is true that the FX1/Z1 handles gain increases with very little noise, I rarely find any reason to push the gain up. Maybe in a documentary situation. But I'm so rooted in narrative fiction that I can just as easily add light as I can flip a switch. So I always opt to work at 0db.

Now, that was for the FX1. The Z1 offers a little more flexibility by providing a second CinemaTone setting. The second CinemaTone setting provides a little flatter contrast which should give you a little more sensitivity over the first CinemaTone profile or OFF setting. Though I have not rated or tested the second CinemaTone setting, I would guess that it would produce about a 200 at 0db. But just barely.

I've never found the DVX to be quite as sensitive as a 500ASA. But the advantage that the DVX has over the FX1/Z1 is the superior control over the how the camera handles the image. The various gamma settings and full control over the Master Pedestal allow the user to manipulate the DVX to achieve not only various looks, but also effect the sensitivity of the camera. If you set up the DVX with one of the flatter Cine-Like gamma curves and pushed the Pedestal up to stretch the blacks, then you probrably would be able to get a sesitivity of about 500ASA at 0db. Of course, the DVX doesn't handle higher gain settings as gracefully as the FX1/Z1. So there's the trade off.

While I don't do it often, sometimes it's fun to light a digital show using the old meter. It always confuses the crew and surprises the director when he looks at the monitor and sees it all come togther without my Gaffer or I ever once consulting the monitor until we're lit.

Just remember that the there is a reason that video cameras are rated in LUX and not ASA. Don't get too attached to an ASA rating for a digital camera. Sony "advertises" the HDW-F900 as having an ASA of 320. But in the real world, a properly calibrated F900 has an ASA closer to 280. And I've found the DVX to hover closer to a 280 for most of the settings I commonly use. So, while digital cameras can be rated and those ratings used effectively, it's still a flawed practice.

Regardless of aproximate ASA ratings, I've found the DVX to be about 3.5 to 4 stops faster than the FX1.

The bottom line for me is that the old joke is true. Video cameras are the world's most expensive light meters. And with a properly calibrated monitor you can trust that what you see is what you get. So, forget about ASA ratings. Your monitor is your light meter.


Indeed, Steve is a lucky guy to live in such a secure area. Not a whole of police presence in my hood in Brooklyn! But I would probrably say that Steve is even luckier to be able to afford a place in Midtown!! Though I'd be willing to bet that Steve is lacking in square footage... :)

Steven White March 21st, 2005 03:52 PM

I can't help think that ASA and LUX ratings are irrelevant without also providing Point-Spread-Functions and Signal to Noise ratios.

Kurth Bousman March 21st, 2005 04:14 PM

Jon - thanks - as always your post are full of info - the reason I think this is relevant is for us old film shooters - this gives us an idea of the sensitivity of the camera in relation to film - and your light meter ratings are being correctly filed in my brain -also for those of us who hate having a monitor this gives us a second data point if we use a meter also- thanks again- Kurth

John Jay March 21st, 2005 05:11 PM

I spotted a VX2100 at 640 and have found the FX1 to be 2.5 stops slower

so 125 sounds pretty accurate to me

also on a 'Kodak F16' sunny day I was getting F6.3 (50i) with all ND up so this also tallies

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