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lilchief

Help with metering

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I rarely use Av og Tv mode on my 40D, but find them sometimes useful...if I only get it right.

The issue is metering mode. I've used spot, center weighted and evaluative. On spot it metered the black tandem rig, overexposing the image with an incredible slow shutter. Center weighted caught the clouds, darkening everything else... AN evaluative...well...I hardly saw some small spots from the jumpsuits =/

Why is this happening???? it frustrates me that I don't understand it!

Also.. in Av or Tv, the camera is set for a full stop overexposure, and I can't reset it. Is it factory fixed that way, or is there a super secret button to push(not the ISO- metering button).

Help much appreciated.

the photo attached is Av mode with evaluative metering. F-stop @7.1
"Once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been and there you long to return." - Da Vinci
www.lilchief.no

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That image is waaay overexposed (wel duh), more than 1 stop anyway. The camera picks 1/10 sec, and +1stop, so first I'd reset the camera totally if you can't get rid of the +1 stop (or read the manual - try turning the wheel or something, works on my nikons anyway), then set the camera to Tv at 1/400 to 1/500 as 1/10 sec is not usuable for skydiving. When I jumped Canon, spot metering worked best for me, but YMMV. The camera should expose right this way, if it still overexposes, clean the lens and body contacts (as it looks in this pic as if it was shot at f2.8 not f7.1 so maybe the camera gets its info wrong) and change out the remote if it still doesn't work. Last bet is trying another lens or this lens with another camera.

ciel bleu,
Saskia

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I'm not an expert on metering but did have my 50D constantly be +1 stop underexposed.

Is your bite switch happen to be setup to constantly focus? Once the camera is set to focus, using the thumb rotator switch you can set it to increase or decrease the stop. I found I was in the plane trying to review a picture I had just taken but realized by bite switch was plugged in after I had already clicked the thumb switch. On the ground all the pictures was too dark. Try autofocusing on something and then using the thumb switch, you'll see the exposure meter change.

Or it maybe something else.
-Trunk
HYPOXIC

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Thanks a lot for the input guys!

I've checked if it's the switch that causes it, but it isn't. I tried to compensate but underexposing 1 or 2 full stops with little effect on the ground. In AV and evaluative, shutter speed only dropped 1/3 stop from 200 to 250.

Saskia: I'll try out what you suggested. But I'll wait with the entire reset. I'm afraid I'll forget to write down some of my settings and screw up =P
"Once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been and there you long to return." - Da Vinci
www.lilchief.no

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I use the 20D and 5D not the 50D so I can't give you a step by step on the controls.

It is possible to set the camera to over or under expose. It's called "Exposure Compensation" Look up how to adjust this and you'll see how to turn it off.

Another possible issue is that if you have the camera set to "one shot" focus (and AF of course) and you use Evaluative Metering (the default) the camera will set the exposure to the first shot in a burst (as well as the focus). This is a problem if, for example, you take a burst of shots while exiting a tailgate aircraft. Your first shot will expose for inside the plane and the rest will be progressively more over exposed. Solve this by using any other metering mode.

Hope this helps.

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Quote

I use the 20D and 5D not the 50D so I can't give you a step by step on the controls.

It is possible to set the camera to over or under expose. It's called "Exposure Compensation" Look up how to adjust this and you'll see how to turn it off.

Another possible issue is that if you have the camera set to "one shot" focus (and AF of course) and you use Evaluative Metering (the default) the camera will set the exposure to the first shot in a burst (as well as the focus). This is a problem if, for example, you take a burst of shots while exiting a tailgate aircraft. Your first shot will expose for inside the plane and the rest will be progressively more over exposed. Solve this by using any other metering mode.

Hope this helps.



Look here http://www.bhphotovideo.com/lit_files/80.pdf on page 101.

Also on page 84, 2nd bullet it tells you about metering in One Shot AF mode.

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I once did something similar on a few jumps with my then brand-new nikon d80: I locked the metering when half-pressing the shutter (AE lock turned on) so I could focus and meter and then re-compose the picture. This works fine on the ground but depending on how you have your remote wired it can royally screw up your pics by sticking to f2.8 for the entire jump if you turned on the camera inside the plane B|

But in this case the camera says it picked f7.1 when to me it doesn't look like it actually did, so I'm guessing something else is wrong besides the camera sticking to a high f/stop because of one shot focus or AE lock, but it might be another thing to look at.

ciel bleu,
Saskia

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