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03-09-2009, 04:33 AM   #1
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FA 50mm lens problem

I've been browsing this board for awhile and picked up a lot of useful information -- thanks all.

However, I've had the FA 50mm lens for about 9 months. It's been a great lens for low light photography, but in the last several weeks, I noticed that all of the photos are over exposed. I normally shoot in Av mode and with an aperture of 2.0, the camera would choose a shutter speed of 0.5 seconds. It seems to overexpose in all modes, except the green mode, where the camera seems to meter appropriately and takes photos with normal exposure. I can still take pictures in the other modes, I just have to add an exposure compensation of -2 (never had to do this before). The rest of my lenses work just fine. Any idea what could be going on?

03-09-2009, 05:04 AM   #2
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When you meter to get that .5 seconds, what is your ISO? Can you tell us what another lens set to f/2 (same ISO) gives you for a shutter speed in the same lighting conditions? Does this happen at f/1.4? It's possible that the meter sets your shutter speed for f/2, but the lens doesn't stop down properly at the time of exposure, leaving you with a shot that is one stop overexposed.
03-09-2009, 05:43 AM   #3
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Basically, when I have the camera in the green mode, the ISO will be 800, the aperture 2.0 and the shutter speed 1/60 second. When I change to Av mode, everything is the same except that the camera changes the shutter speed to a half second. The pictures are then amazingly bright and washed out (of course). If I have it manual mode and hit the green button, it picks the same over exposed settings as it would in Av mode.
03-09-2009, 07:01 AM   #4
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It seems strange to me. I've been using my FA 50mm for quite a long time. In fact this is my only lens and nothing else. I've never experience such kind of overexposure problem. However, you should note that exposure involves ISO, the metering mode and aperture and shutter speed combination. Maybe your copy of the lens has a problem. You mentioned that you use f2.0, you should use a higher shutter speed and lower ISO. However, using also ND filters will also help. In difficult lighting conditions, it's advisable to use the manual mode.

03-09-2009, 07:44 AM   #5
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I guarantee in green mode the pop-up flash is popping up....

When you are in Av mode, do you ALSO have the pop-up flash raised? If so, I am 99.99999% sure that what is happening is the camera meters for NO FLASH, so it sets the shutter speed at 1/2 second, BUT the flash fires (because you raised it), and even at the lowest power setting, the flash+ISO800+f/2+slow shutter speed=blown out shots. What do the shots look like with NO flash? Are they exposed decently? (albeit shaky from the slow shutter speed)

QuoteOriginally posted by Rondec Quote
Basically, when I have the camera in the green mode, the ISO will be 800, the aperture 2.0 and the shutter speed 1/60 second. When I change to Av mode, everything is the same except that the camera changes the shutter speed to a half second. The pictures are then amazingly bright and washed out (of course). If I have it manual mode and hit the green button, it picks the same over exposed settings as it would in Av mode.
03-09-2009, 07:45 AM   #6
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Try this - Pop up the flash, go to MANUAL mode, 1/180s, f/2, ISO200, and shoot.....What does the photo look like?
03-09-2009, 08:03 AM   #7
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Sorry, I'm at work now, so I can't try it, but these are all photos without flash. If I would put in the settings manually, the photo would be fine. I think it somehow is an issue with the metering. I just can't understand how it could meter OK in the green mode and not in Av.
03-09-2009, 09:58 AM   #8
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QuoteOriginally posted by Rondec Quote
Sorry, I'm at work now, so I can't try it, but these are all photos without flash. If I would put in the settings manually, the photo would be fine. I think it somehow is an issue with the metering. I just can't understand how it could meter OK in the green mode and not in Av.
I don't get it either. It seems to rule out a mechanical problem with the lens. A sticking aperture would stick in all modes. You could try cleaning the contacts on the lens mount and camera with a pencil eraser; that might clear up an electrical fault. But still, how it works in green mode...

I think you need to take a lot of boring test pictures. Set up a tripod and an indoor scene with unchanging light. Use the kit lens at ~50mm to meter the scene and take shots in different modes. Then try that with the FA50 and see what's different.

The biggest difference between the FA50 and your other lenses is that it's probably your only lens that opens to f1.4. Maybe green mode never chooses wide apertures? Then your problem, something at wide apertures only, never happens, and your other lenses don't open wide enough to see it either.

03-09-2009, 04:07 PM   #9
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I feel kind of silly. My wife figured out today that the camera was set on exposure bracket mode, so basically, I was taking bracketing photos. I guess bracketing doesn't work in green mode, therefore the photos were normal there. Oh well, you live and learn...
03-09-2009, 04:57 PM   #10
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How wide was your bracketing to cause such washed out shots?
2 stops?
03-09-2009, 06:44 PM   #11
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Yes. I was shooting some landscape shots and then forgot to reset it when I was taking some photos of the kids.
03-10-2009, 09:49 PM   #12
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Ha don't you love when it's something as simple/silly as that? Been there and done that...
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