F stop keeps closing

arielman

arielman

Well-known member
Hey guys
I have been having this issue for a short while with my DVX100A.
In manual mode I open up the Iris and then it closes ..re open say to 5.6 going to say 4 it will close .
I have to turn the wheel several times really fast to get it to work , then I have to really go slow if not it closes up .
Never had this problem before . I've rechecked my settings and can't see any changes .
Any Ideas?

Ian
 
I had a similar thing happen to me although I didn't think to look at the F-Stop number. I was shooting a Doctor where the scene and lighting never changed from the start. When I got back to edit there were definate changes in exposure. So much that I needed to color correct. I also used manual to lighten up a bit. If there is some changing going on that would explain problems I've had for a while.
Gary
 
Arielman, is your problem consistent or intermittent? Does it close a specific amount or is it arbitrary? The situation I described is actually a pretty solid test envirnment. My shoot lasted about 3hours and the scene, lighting or camera position never changed. I never changed the Iris other than to "brighten " it up a bit at the start. I had 2 shootings at 2 different times with this client and I noticed the same problem and it needed compensation in post. I have done many shorter jobs in between and never noticed this happening.
 
Thanks guys for the replys .
Gary I don't think that's my problem , mine seems to be when I adjust the iris say from 6.8 to 4. The iris the closes .
I have checked and yes it is in manual . I haven't change from that setting now for 2 years and that was the first item I checked to see it my son had put it in Auto .
Horse I think you may have got it right . Never thought of that at all .
Something that can be easliy missed when cleaning .
Thanks again guys for your help with this .
Ian
 
I don't think I understand you. "when I adjust the iris say from 6.8 to 4. The iris the closes " and also
" I have checked and yes it is in manual " What's in the manual? I'd like to find out if I can trust the camera settings. And no the Auto is never on. Thanks
 
If you're saying that your iris ring is behaving bizarrely and randomly closing on you, then that sounds like a service issue. That is not normal behavior by any stretch of the imagination.
 
Yes, I have had the exact same problem with my camera. I will have to see if there is any dirt in there. I have found that if I change the iris really, really slow it won't do this.

but this is a terrible shooting scenario that your camera goes to black in the middle of a shot...
 
Exactly CW-35 .
I cleaned mine but yet haven't tried ..Next weekend I'll find out .

I sure hope Barry this is the issue (dirt) and not service .
This camera has been almost trouble free since I bought 3 years ago .
Ian
 
Hi
It can be cleaned. A replacement will mean that it will operate trouble free for the next three years. The Iris pot does wear, so it becomes a contact issue.
Good luck
 
arielman said:
Hey guys
I have been having this issue for a short while with my DVX100A.
In manual mode I open up the Iris and then it closes ..re open say to 5.6 going to say 4 it will close .
I have to turn the wheel several times really fast to get it to work , then I have to really go slow if not it closes up .
Never had this problem before . I've rechecked my settings and can't see any changes .
Any Ideas?

Ian
Click to expand...
Hi, I had this problem too. Just move the wheel slightly and sometimes the iris would close right up. Sometimes even when I opened the iris slightly it would zip back down to f16.

I have managed to fix it, for now anyway.
My DVX100A can sometimes sit in the bag unused for 2 or 3 months, so I wondered if perhaps some capacitors were becoming unformed or there was some dampness in that circuit.

For a start I left the camera running in Auto (no tape) for about a couple of 8 hour days. The result - No better. Next I did the same thing but with Manual selected. This time it gradually got better, but it took several days - perhaps four of five. I left it for about a week and it was still OK. That was about 6 to 8 weeks ago and it still works well.

Hope this may help someone else.

One other strange thing: When the camera had done about 43 hours I had to clean the heads after a very hot windy day, and afterwoods the hour meter read 93hours. It had jumped 50 hours. That is 93 tapes!! I don't use it for capturing either.
 
Last edited:
NoNoob said:
There is a magic elixir found on the shelves of your handy RadioShack:

TV-Tuner/Control Cleaner & Lubricant


$10.99
Model: 64-4315
Catalog #: 64-4315

Just squirt a dab into the poorly performing area- and it'll fix it.

Caveat emptor; results may vary, void where prohibited, not an internet item (store purchase only), valid ID required, don't shoot it into your transport area!, flush eyes if you spritz them, keep a dry cloth handy to pick up excess, and don't blame me if it makes it worse.


I've used this stuff for many years- works great.
It is not a 'penetrating' type of fluid.
It sprays on, soaks in, and then does it's job.

The Iris control knob functions a potentiometer.
If it sits for a long time, or is used in a dusty/smoky environment, then the device can get gummed up. Even if it is a solid state device, it still has to turn and be in contact with a wheel inside (that has detents).
If the condition is due to airborne material in the working environment, or moisture that got in there, then the cleaner lubricant fluid can get in there too.

I had this problem on a audio level control on a previous camera.
Spritzed it with this stuff- problem went away.

Offered as something to consider - if all else fails maybe.

good luck.
Click to expand...
Thank you NoNoob,

Mine is working perfectly now.

It only played up in the manual mode - OK in Auto when adjusting Exp. compensation.
I have contact cleaner here, (I'm an old radio ham), but am loath to spray it in there.

Though I may try a little if it happens again.

Thanks again, Don
 
same problem

same problem

I've had the same thing happen to me on a DVX100A. At some point the iris would just close right down on its own (yes, it was in manual mode). Really frustrating when this happens in the middle of a shot.
 
You must log in or register to reply here.
Back
Top