Camera won't obey manual exposure commands at DVinfo.net

Dave Largent · August 23rd, 2004, 02:20 AM

Worked with a PD in low light. Shutter at 1/15th to
1/8th. Gain at 15 dB. Iris wouldn't go to 1.6, only
2 or 2.4. Tried putting cam at 1.6 first, then set the
shutter and gain, and iris would pop out
of wide open, going to 2 or 2.4. Surprise to me.
Wonder what's up here?

Tom Hardwick · August 23rd, 2004, 03:58 AM

Sounds to me as if you were shooting at a telephoto position. The 12x zoom lens is only f1.6 at maximum wide-angle - every millimetre you creep away from that setting towards telephoto, the less light hits the CCDs. So nothing's wrong, it just the way the camera's made.

BTW, they're all made like this, The DVX100 is worse - it's only a 10x zoom and at full tele is f2.8, so it needs 50% more light than the VX, all other things being equal (which they aren't of course).

You could have your PD's lens maintaing the full f1.6 throughout its entire zoom, but it would be a lot bigger (and I mean a LOT) and it'd weigh more and cost more and you'd have to buy 82mm filters. Accept the compromises, and breathe again.

tom.

Dave Largent · August 23rd, 2004, 07:27 PM

Yes, Tom, it *was* zoomed in quite a bit. That must
be it. Thanks.

August 23rd, 2004, 02:20 AM	#1
Dave Largent Trustee Join Date: Aug 2003 Posts: 1,483	Camera won't obey manual exposure commands Worked with a PD in low light. Shutter at 1/15th to 1/8th. Gain at 15 dB. Iris wouldn't go to 1.6, only 2 or 2.4. Tried putting cam at 1.6 first, then set the shutter and gain, and iris would pop out of wide open, going to 2 or 2.4. Surprise to me. Wonder what's up here?

August 23rd, 2004, 03:58 AM	#2
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Sounds to me as if you were shooting at a telephoto position. The 12x zoom lens is only f1.6 at maximum wide-angle - every millimetre you creep away from that setting towards telephoto, the less light hits the CCDs. So nothing's wrong, it just the way the camera's made. BTW, they're all made like this, The DVX100 is worse - it's only a 10x zoom and at full tele is f2.8, so it needs 50% more light than the VX, all other things being equal (which they aren't of course). You could have your PD's lens maintaing the full f1.6 throughout its entire zoom, but it would be a lot bigger (and I mean a LOT) and it'd weigh more and cost more and you'd have to buy 82mm filters. Accept the compromises, and breathe again. tom.

August 23rd, 2004, 07:27 PM	#3
Dave Largent Trustee Join Date: Aug 2003 Posts: 1,483	Yes, Tom, it was zoomed in quite a bit. That must be it. Thanks.