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Unable to take photo when camera horizontal

rnedd
Apprentice

I've run into this problem several times now.  I set up a shot with the camera on a tripod in the horizontal position (to take in more from floor to ceiling than side to side).  I hold down the button and can't get the green square and so it won't take the photo.  If I tilt the camera back to vertical without changing anything else then I can take the shot.  I've tried slightly changing the camera when horizontal so it is focusing on something slightly to the right or left and it still doesn't allow me to take the shot.

 

Anyone have any idea on what might be causing this problem?

 

Thanks!

6 REPLIES 6

Tiffany
Moderator
Moderator

Hi Rnedd!

 

So that the Community can help you better, we will need to know exactly what equipment you're using.   Any other details you'd like to give will only help the Community better understand your issue.

Thanks!

Hi Tifanny,

 

Thanks for pointing that out.

 

Camera is the T3 and it was both with the 18-55mm lens and with the 10-24mm wide angle lens.  Manual settings which were kept consistent from the horizontal position to the vertical position so only change was the orientation of the camera.  Sunpak tripod.  I think the earlier post gave all the other details of the situation but this should give the ones I had left out.

 

Thanks,

Ron

MikeSowsun
Authority
Authority

"Anyone have any idea on what might be causing this problem?"

 

Your T3 has only one "Cross-Type" AF sensor in the center. If you are using all the focus points the camera may have trouble detecting enough contrast to achieve focus. In difficult focus situations it is better to manually select the center AF sensor.

 

The AF sensors sit just below the mirror and occasionally get dirty or dusty. This can effect your AF performance. If you feel up to it you can use a "Rocket" blower to try and blow some dust away from the AF sensors. 

 

You might find it focuses better using Liveview as focus is read right off the image sensor and does not use the AF sensors under the mirror.

 

_T3af.jpg

 

_digital_slr_diagram2.jpg

 

•1) Lens
•2) Primary Mirror
•3) Primary Mirror During Snapshot
•4) Focusing Screen
•5) Pentaprism
•6) Viewfinder Lens
•7) Digital Sensor
•8) Sensor Filter
•9) Shutter
•10) Relay Mirror
•11) Autofocus System

 

_1a-9.jpg

 

 

Mike Sowsun

Hi Mike,

 

Thanks for the info.  This is an EOS Rebel T3 bought 6 months ago so it wouldn't be due to it being an older camera.  Also, when attempting to take the photos in question I was using Liveview.  Not sure why it would be needing servicing since it works correctly every time when in vertical mode and has worked fine on some horizontal mode shots, and am using Liveview.  Sounds like it is probably something else but I appreciate all the info.

 

Sincerely,

Ron

Hi Ron,

 

Just to clarify.... Most of the time when we refer to a camera being in horizontal orientation that's the same as "landscape" orientation, or sort of the way the camera naturally falls to hand, or the way it would sit atop a tripod without any adjustments to the tripod... in other words with the longer axis of the image area runs horizontally.

 

Vertical orientation is often refered to as "portrait" orientation, i.e. with the camera tipped up on end and the longer axis of the image area running vertically.

 

However there is little reason your camera should focus much differently in horizontal/landscape vs vertical/portrait orientation (some Canon models do allow different auto focus settings depending upon orientation, but the T3/1100D is not one of them). In the viewfinder-based, 9-point AF system, there is some difference in the various points. The center one is cross-type, dual axis, will work with detail running both vertical and horizontally.... The top-center and bottom center AF points (viewing them with the camera in landscape orientation) are horizontal, single axis points, which work best with detail that runs vertically. And the other 6 points are vertical, single axis points that work best with detial that's running horizontal.

 

However....

 

Live View uses a completely separate focusing method than what you see through the viewfinder. The image sensor itself is used for LV focusing. It's a contrast detection mehod and slower than the usual phase detection done with the sensors seen in the viewfinder.

 

Auto focus requires adequate light levels, as well as reasonable subject contrast. A plain wall with no detail (or a plain blue sky, etc.) will give the AF system nothing to lock onto.

 

You might try switching back to focusing with the viewfinder based system instead of Live View. If you do that, the center point is more sensitive than the others and you mayt have to use only that one in lower light conditions. Or, if there just isn't enough detail to focus upon, you might need to focus manually (Important: if you do, be sure to first turn off AF on the lens.... manually focusing it with AF still turned on can damage the mechanism in the lens. Some lenses do not require this, but unless yours is a "USM" or Ultrasonic Motor lens, you need to turn it off before manual focusing.) 

 

Depending upon the main dial selection, you might be able to choose among the three auto focus modes: One Shot, AI Focus and AI Servo. One Shot is for use with stationary subjects and gives you focus confirmation (note: Live View focus mode only uses this type of focusing). AI Focus really isn't a focus mode at all, set to this the camera is supposed to decide for you whether or not the subject is moving, then switch to the correct focus mode. Personally I've found this causes a delay and would prefer to select my own focus mode, so I never use AI Focus. AI Servo is designed to track moving subjects, as long as you keep the shutter release button half-pressed the camera will continuously update focus... but because it never locks focus you don't get focus confirmation in AI Servo.  

 

The three focus modes are selectable when you have the camera in Av, Tv, P or M exposure modes. When using Movie Mode, it's the same as Live VIew.

 

In the "Scene" modes such as the "running man" for sports or the "mountain" for a scenic shot, etc., you might not be able to select a focus mode. The focus mode and other things may be dictated by the scene mode (varies, depending upon the particular scene mode).

 

In Live View, there also is a Quick Focus mode. This is set up using the Q button. In this focus mode, the camera needs to already be set to One Shot, then to focus the camera momentarily stops Live View so that the main AF system can perform the focusing (faster than Live View), then returns to Live VIew screen so you can finish taking the shot.

 

One thing to note, the camera can overheat while in Live View. The reason this happens is that the mirror is being held up, the shutter is being held open and the imaging sensor is running continously while in Live View.  If overheating occurs, there is a warning symbol displayed. If that symbol starts blinking, it's getting more serious, until it reaches a point where the camera shuts down to prevent damage. After it cools down, the camera is usable again.  Maybe this is why you can take a shot one way, but later cannot take another shot with the camera oriented differently. Maybe the the camera has gotten overheated and shut down temporarily.

 

Now, all cameras do have an orientation sensor in them. This is used to properly rotate the images when reviewing them on the back of the camera or on our computer screen, by the Image Stabilization system of some lenses, and for some other purposes. It is possible, though unlikely, that something is wrong with the camera. I'd suggest testing it in both orientation in good daylight with a nice, contrasty subject, such as a detailed brick wall or similar. It should focus the same in either landscape or portrait orientation, whether using Live View or the viewfinder.

 

So, I'm not saying it's not the fault of the camera. Something could be wrong with it. However, it's usually not the camera, but something we users are doing wrong with them, that causes problems. Hopefully this will help you test the camera some more and see if it's actually a fault with it, or if it's something else.

 

***********
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
FLICKR & PRINTROOM 

 





Hi Alan, Thanks for the explanation and information. I'll try using manual focus next time this happens. I don't think it is the camera because I have been able to take vertical shots in many situations. There have just been a few times when I tried horizontal and then decided it would be better to go vertical and having the same spot I'm focusing on but the camera won't give me the green square. I'll have to do some more testing when I can but at least now I have the option I didn't think about which was to switch to manual focusing. Thanks, Ron
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