70D

[Nicetezza]

I have Had this camera 5 months now, My intrest is in aviation I have tried most of the settings on the Menu  spot metering ev plus others. Now my question is when I pan the a/c and take 6 continouse shotsI  first 2 are correct exposure 3-4 are over exposed 5-6 are perfect exposure again.

has anyone any suggestion to what I am doing wrong????

comments would gladly be appreciated

[ebiggs1]

Exposure compensation? 

Reset your camera to factory defaults and you and it will be fine. 

[TCampbell]

If you're using spot metering then are you sure you're keeping the spot on the aircraft for all of your frames?

Another way to shoot is to use evaluative metering... but dial in some exposure compensation to get the result you want.  The large rear-dial will let you dial in "exposure compensation" (which means you're telling the camera to deliberately shoot at a higher exposure or lower exposure than the exposure suggested by the metering system.)    Just don't forget to dial the exposure compensation back to the 0 position when you're finished or you'll be wondering why you're getting wrong exposures the next time you go out shooting.

[amfoto1]

If lighting is steady and consistent, call up one of the "good" exposures, switch the camera to M (Manual) mode, and make all the settings yourself. Be sure Auto ISO is off, too. Alternatively you could either use the camera's internal meter or a separate handheld meter to calculate the exposure, then make the settings in the same way (possibly fine tuning it using the histogram and image playback).

This locks in your exposure so that you won't get that variation and might even allow for higher frame rates (it does on my 7Ds, which slow down to accomodate metering.... not sure if 70D does the same).

The reason you are seeing this is simply that when panning the camera's meter is responding to variations, such as reflections off the aircraft or varying brightness of the sky or perhaps the difference between clouds and clear sky.... etc., etc. Go outside with your camera and simply pan around a parking lot and watch how the meter reading varies wildly, even when everything is evenly lit. That's just the nature of any reflective meter, responding to varying tonalities, reflective highlights and more. The only sure way to stop it from happening is to lock down your exposure factors as described above. 

Note: another type of meter, called an "incidence" meter, is much less influenced by subject tonality, reflections, etc. That's because it measures the light falling onto a subject, rather than what's being reflected off of it. However, it's impractical to build an incidence meter into a camera and it's slower to use one separately. 

And, locking down your exposure factors, as suggested above, isn't always possible, such as when shooting subjects moving in and out of shadows or when clouds are intermittently covering the sun, etc. At those times, you either have to limit yourself to shooting only in the areas you've set up for, or have to change the exposure factors rapidly on the fly, or have to work with one of the auto exposure methods.

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
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