FX1 gain on makes picture darker???

[Mark Slade]

Subject says it all. Both of my FX1's go very dark when turning on the gain. The higher the gain the darker the image. Doesn't matter if other settings are auto or manual.....always does it. Tried reset on both cams thinking maybe I screwed up a setting....still does it. If 1 was doing it I'd say it needed to go into repair.....but both???
Any thoughts???

Thanks
Mark

[Ron Evans]

What have you set the gain values to? There are three settings which one are you using and what is it set at? Remember iris,shutter speed and gain ALL have to be at manual otherwise the auto system will use the others to compensate.

Ron Evans

[Boyd Ostroff]

My guess would also be that *something* is not really set to manual. Unless you see the values for shutter speed, iris and gain in the viewfinder then they are set to automatic.

[Mark Slade]

Auto/Man switch is in the middle position....I can toggle on and off iris, gain, shutter and white balance......1 cam is set at 3-9 and 15......don't remember what the other is set to....even at 18 both of them are darker than with gain off......and I've re-set both of them.....

[Mark Slade]

Auto/Man switch is in the middle position....I can toggle on and off iris, gain, shutter and white balance......1 cam is set at 3-9 and 15......don't remember what the other is set to....even at 18 both of them are darker than with gain off......and I've re-set both of them.....

OH cr@p.....I didn't have the white balance on......don't I feel like an idiot.....

NOPE....that's not it.....if I aim just around the room....it works....if I aim the cam under my desk (where it's darker) it gets darker when I switch it on.....so I can get it brighter in the room....but swivel the chair around and shoot in a dark area and it goes darker.....

Mark

[Boyd Ostroff]

Well maybe something is wrong with your camera? Never saw this happen on my Z1. But it seems more likely something is set wrong which you are not thinking of...

[Chris Barcellos]

Okay, I have to go home to check it, but as I recall, if you haven't enabled the manual gain by pushing the gain button, and selecting one of the presets, then automatic gain is applied, even though you might be in manual on other settings and on the slider.

That can be limited in the menu setting by selecting maximum gain level.

I will check this out on my FX1 to confirm. I have spent too much time with the 5D and the HV20 to be sure, so I will confirm.

[Adam Gold]

As this is exactly the opposite of what's supposed to happen, it's possible there's something broken. But more likely Mark has the gain levels set up wrong. It's important to note that by pushing the GAIN button in manual mode, you're not really turning gain ON or OFF; you're switching between MANUAL and AUTO gain, so you could be going either way.

Unless you are seeing a numerical dB figure in the LCD, you're in AUTO gain mode. You need to have the AUTO/MAN slider set to the middle position, as Mark says, and also press the GAIN button. If the three-position GAIN switch is set to a preset that is lower than the auto gain that the camera was just supplying, your pic will get darker.

For example, and sorry to be so pedantic, but let's say you have your H/M/L gain switches set to 18, 9 and 0dB, respectively, and at the moment the GAIN switch (not the AUTO/MAN switch) is set to the middle position. In Auto mode, if the cam is adding 12dB gain, and then you switch to manual gain, the cam is now adding 9dB -- less than before and hence darker. Note that the lowest physical position of the GAIN switch is H; L is on top, so it's easy to get confused.

Unfortunately, unlike later cams, there's no way on the FX1 to know exactly how much Auto Gain the cam is adding until you play back the tape with Cam Data displayed. Pushing the Shutter or Iris buttons in manual mode will show you where the cam has set those in Auto, but doing the same with Gain immediately puts you into whatever preset is on the current switch position (because you don't use the wheel).

This is probably insultingly basic, but you never know.

Is this issue just in the LCD or actually on the tape? Can you confirm by playing the tape back showing the DATA CODE and noting that higher gain actually makes a darker picture, all other things being equal?

Pages 28-29, 35 (AGC LIMIT), 52 of your manual.

[Chris Barcellos]

As Adam confirms and I have now confirmed by looking at my FX1, with Auto/Man slider in Manual mode, the Gain button toggles between auto gain and the selectable gain levels on the 3 position gain switch.

I usually have my bottom one set at 0 db.

If auto gain is to be left on by selecting away from the 3 position toggle, you can limit the added gain in The Picture profile menu.

[Adam Gold]

Originally Posted by Chris Barcellos

I usually have my bottom one set at 0 db.

Me too, but again remember that the "bottom" position is actually H. No reason that H has to actually be the High number, but that's how most people have it and it's set up by default that way. L is actually at the top of the three positions.

That's Sony for you.

[Mark Slade]

OK Adam....not insultingly stupid....since I was being stupid. Shooting a white wall in all auto the cam is at 9 db gain using data code. When I was switching to manual it was at 6 on the 3 position selector....so it got darker....because it was going from 9 to 6. DUUUUUHHHHHHH!!! I wasn't taking into account that the auto gain was actually "ON". I was thinking....OK....I'm at f1.8....60 shutter speed....now kick in some gain and it should get brighter......
Thanks guys....you wouldn't think I actually went to college!!!

Mark

[Tom Hardwick]

Thanks for coming back on this one Mark - and brave of you to do so. So many folk seem to read the answer, get the fix they need and simply keep stum - as if this was some sort of Sony paid-for site.