-3db

[adam]

After a recent DOF and shutter fandango I got to thinking about various ways to affect aperture settings. I'm curious what the forum's thoughts are about setting a camera to shoot at -3db. I've always been under the impression that it doesn't do much for image quality and may, in fact, degrade your image.

 

[SimonW]

It can reduce the noise in the picture on some cameras. To be honest I've never really noticed much difference. It can also reduce the dynamic range by a small degree.

That said I often use it to cut down light so I can open up more for shallower DOF for interviews.

 

[cameragod]

According to Clive the Sony guy over here -3db is actually 0db... I don't remember why they started doing it like that but he said there was no quality drop... I use it all the time.

 

[Douglas]

I've used -3db gain 99.9% of the time on every camera I've owned in the past 20 years except one. That inlcudes Ikegami betacams, Ikegami DVCAMs, Z1U, EX1, EX3, F350, etc.

There's no question that -3db reduces noise in the blacks on those cameras. However, according to some people it also may have reduce the dynamic range. But I don't know if that is true or not. If it is, then the difference is extremely small, and the trade off of cleaner blacks is well worth it.

The one camera that I do not shoot at -3db is my F800. The blacks are so clean that it is completely unnecessary. So, on the slim chance that I will lose some dymanic range, I don't use it. I only drop down to -3db for times when I want to open the lens a little and changing the ND filter would be over kill.

 

[b-roll]

"Why don't you just make ten louder and make ten be the top number and make that a little louder? "

"These go to eleven."

 

[Douglas]

"Why don't you just make ten louder and make ten be the top number and make that a little louder? ""These go to eleven."

That is the very best scene in the movie!


The real reason -3 isn't zero, is because it would make the camera's specs look bad for low light. You gotta fool the goons who only look at the numbers.

 

[cameragod]

But a more apropiate quote might be:

It's like, how much more black could this be? and the answer is none. None more black.

 

[cameragod]

Actually speaking of fake Rockumentries I always like the line from Vim from Bad News

"I could play Stairway To Heaven when I was 12. Jimmy Page didn't actually write it until he was 22. I think that says quite a lot".

I see that kind of thinking applies to a lot of people in this industry.

 

[MMrozinski]

I use it all the time... but in don't notice much of a difference in the grain compared to 0db. We have Sony PDW-700 XDCAM HD 422 Cameras. We read the manual and it says to shoot at an f-stop of an f 2.8 - to f4 so you can maximize the amount of light that hits the chip for your best quality. -3db allows me to get there without having to shutter down to 1/1000.

 

[adam]

I would never have thought there would be, not one, but two perfect quotes pertaining to gain selection from Spinal Tap.

 

[jim sitton]

Ok, I'll admit I've never used -3db.
Living in Florida makes it even worse.
Having only +1/4ND, +1/16ND Built in ND filters is worse still.
I usually crank the shutter up to cut down on the light hitting the chip.
I know, I KNOW that is the worst of all, but I didn't have any other solution short of screw on ND filters.
Which is a pain in most news situations.

Now my question: How do I get -3db?
I shoot the JVC 250 and the manual says it has 0, 3, 6, 9, 12, 15, 18 dB.

Be easy on me, I feel dumb already...

 

[cameragod]

I don’t know if that JVC cam can do it but in the menu if you can adjust the gain settings it’s just a matter of stepping it past 0 and on to -3.
For news shoots I run:
-3
0
+6
+12 on the Turbo button.

 

[couryhouse]

you mean they jacked it up to give better 0db specs??

According to Clive the Sony guy over here -3db is actually 0db... I don't remember why they started doing it like that but he said there was no quality drop... I use it all the time.