Why won't my Canon 7D take a shot in Auto mode when photographing a phone screen?
Asked 2/12/2013
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2 answers
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I'm new to a Canon 7D. In full Auto (green mode), I tried to photograph something displayed on a cell phone screen. The phone was propped against a white pillow in a well-lit room, and I zoomed in so the screen filled most of the frame. The camera showed a very high ISO and the exposure indicator kept flashing, and it would not take the picture. The flash also did not pop up. I could still take photos of other subjects in the room, and switching to CA mode let me get the shot.
Is this normal? Why would the camera choose such a high ISO and still refuse to shoot instead of using flash? Could being too close to the phone have caused it? The autofocus points were lighting up.
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
13y ago
2 Answers
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Never seen a camera not shoot because of exposure and I've had a Canon 7D too. I did not like how it metered by default and photos were more often over-exposed than with other cameras but it still took the shot.
A camera refused to shoot though if it cannot focus. You were probably too close and the camera light up all focus points as opposed to some to let you know. All lenses have a minimum focus distance which is usually specified at the wide-angle settings. Some also specify it at another distance and it should be stated in the manual.
The other case when a camera can refuse to shoot is if the flash is still charging. In this case you just have to wait a little before releasing the shutter and there should be a light to tell you when.
The Auto ISO chooses a sensitivity to get an exposure is deemed acceptable (even though you or I may disagree) at a shutter-speed which is safe to hand-hold. There is a maximum but I do not remember which it is for the 7D.
Originally by user1620. Source · Licensed CC BY-SA 4.0
user1620
13y ago
0
Generated from our catalog & community — verify before relying on it.
Most likely the camera was not refusing because of exposure or high ISO — it was refusing because it could not lock focus.
A Canon 7D will generally still take a photo even if exposure isn’t ideal, but it may block shutter release in Auto mode if autofocus cannot be achieved. When shooting a phone screen close-up, the common cause is being closer than the lens’s minimum focusing distance. Zooming in does not reduce that minimum focus distance.
The lit AF points don’t necessarily mean focus was successfully locked; they can simply indicate active focus points. Another possible reason a camera won’t fire is if the flash is charging, but your description points more strongly to focus distance.
Why the high ISO? Auto ISO was likely trying to maintain a hand-holdable shutter speed based on the metered scene. A bright phone screen against surrounding areas can confuse metering, especially in full Auto.
Try this:
- back up until the lens can focus
- check your lens’s minimum focus distance
- use a different AF point or manual focus
- if needed, use a macro-capable lens for close subjects
So yes, the behavior is normal if the camera couldn’t focus.
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