Finally!...Pinpointed exactly what causes the buzzing noise while I'm in auto focus! at DVinfo.net

Glen Elliott · July 3rd, 2003, 02:01 PM

I think I posted about this a while back but- sometimes while in auto focus if I'm shooting something that is dark and/or hard to focus the focus numbers start to flutter back and forth between two numbers and I hear a rattling buzzing noise comming from inside the camera lense.

Until now I thought this was an intermittent problem- I found out exactly how to reproduce the camera. If I keep the camera in auto focus and turn the iris way down (F11- close) and if the exposure is dark as a result (causing it difficult to automatically focus) the noise starts. I slowly turned the iris dial and listened- if the iris is "closed", I get no sound but as soon as I turn it up to F14 the buzzing/rattling noise starts, same with F11, as soon as I turn it up past F11 it stops. In other words I only hear this buzzing noise in F11 and F14, if it's one click above or below those numbers it's fine. And likewise if it's on F11 and F14 and I turn the auto focus off the noise stops as well. Is this a known problem with the camera? I'd rather not send it in if I don't have to- especially beings there's never a situation I can forsee me needing to use auto focus and a low iris setting- usually if I need to notch the exposure down that much I use a ND filter...though I figured I'd ask to see if: 1.Some others have noticed the same thing with their cam and 2.If it's a known problem or even a "problem" at all?! Any and all input will greatly be appreciated- thanks in advance.

Stephen van Vuuren · July 3rd, 2003, 02:23 PM

Never shot autofocus with a DVX100, or shot much autofocus at all with any cam for that matter, but I do understand autofocus requires light. So maybe you have the cam not getting enough light for autofocus to function and it's hunting, searching like crazy or emitting an error tone to let you know it needs more light.

Vladimir Koifman · July 3rd, 2003, 03:13 PM

At higher F-numbers the depth of focus is huge and it's hard for AF to find a right distance. It searches for maximum contrast, but since DOF is large, little hunts do not result in meaningful contrast change, so it makes larger iterations, hence noise.
This is just my guess, but I think it's normal.

Glen Elliott · July 3rd, 2003, 03:23 PM

All of what you guys are saying makes sense. Can anyone test this to see if theirs, also, makes a noise?

Stephen van Vuuren · July 3rd, 2003, 03:25 PM

Use autofocus?

the horror, the horror.......

(I'm out at work, so my cam is not around).

Glen Elliott · July 3rd, 2003, 03:29 PM

Hehe, yeah well some of us need it for fast-paced environments like Wedding Receptions....ect. ;)

July 3rd, 2003, 02:01 PM	#1
Glen Elliott Wrangler Join Date: Apr 2003 Location: Philadelphia, PA Posts: 2,898	Finally!...Pinpointed exactly what causes the buzzing noise while I'm in auto focus! I think I posted about this a while back but- sometimes while in auto focus if I'm shooting something that is dark and/or hard to focus the focus numbers start to flutter back and forth between two numbers and I hear a rattling buzzing noise comming from inside the camera lense. Until now I thought this was an intermittent problem- I found out exactly how to reproduce the camera. If I keep the camera in auto focus and turn the iris way down (F11- close) and if the exposure is dark as a result (causing it difficult to automatically focus) the noise starts. I slowly turned the iris dial and listened- if the iris is "closed", I get no sound but as soon as I turn it up to F14 the buzzing/rattling noise starts, same with F11, as soon as I turn it up past F11 it stops. In other words I only hear this buzzing noise in F11 and F14, if it's one click above or below those numbers it's fine. And likewise if it's on F11 and F14 and I turn the auto focus off the noise stops as well. Is this a known problem with the camera? I'd rather not send it in if I don't have to- especially beings there's never a situation I can forsee me needing to use auto focus and a low iris setting- usually if I need to notch the exposure down that much I use a ND filter...though I figured I'd ask to see if: 1.Some others have noticed the same thing with their cam and 2.If it's a known problem or even a "problem" at all?! Any and all input will greatly be appreciated- thanks in advance.

July 3rd, 2003, 02:23 PM	#2
Stephen van Vuuren Space Hipster Join Date: Oct 2001 Location: Greensboro, NC Posts: 1,508	Never shot autofocus with a DVX100, or shot much autofocus at all with any cam for that matter, but I do understand autofocus requires light. So maybe you have the cam not getting enough light for autofocus to function and it's hunting, searching like crazy or emitting an error tone to let you know it needs more light. __________________ stephen v2 www.insaturnsrings.com

July 3rd, 2003, 03:25 PM	#5
Stephen van Vuuren Space Hipster Join Date: Oct 2001 Location: Greensboro, NC Posts: 1,508	Use autofocus? the horror, the horror....... (I'm out at work, so my cam is not around). __________________ stephen v2 www.insaturnsrings.com

July 3rd, 2003, 03:13 PM	#3
Vladimir Koifman Regular Crew Join Date: May 2003 Location: Israel Posts: 115	At higher F-numbers the depth of focus is huge and it's hard for AF to find a right distance. It searches for maximum contrast, but since DOF is large, little hunts do not result in meaningful contrast change, so it makes larger iterations, hence noise. This is just my guess, but I think it's normal.

July 3rd, 2003, 03:23 PM	#4
Glen Elliott Wrangler Join Date: Apr 2003 Location: Philadelphia, PA Posts: 2,898	All of what you guys are saying makes sense. Can anyone test this to see if theirs, also, makes a noise?

July 3rd, 2003, 03:29 PM	#6
Glen Elliott Wrangler Join Date: Apr 2003 Location: Philadelphia, PA Posts: 2,898	Hehe, yeah well some of us need it for fast-paced environments like Wedding Receptions....ect. ;)