bracketing exposures with the 7D

[ldavidson]

<p>I hope that someone here can help me. I am trying to experiment with HDR. I am supposed to be able to get three exposures when I use the 7D's Auto Exposure Bracketing (AEB). I go to the Exposure Compensation/AEB setting screen and set it in while in P, TV, or AV mode. I then shoot in either Low or High Speed Continuous. I have followed the instructions carefully but I must be missing something because I never get three exposures. Does anyone know what I am missing? I would appreciate any advice.<br>

Thank you.<br>

Linda</p>

[ken schwarz]

<p>The setting for this is in Custom Function I. Are you exiting the custom function menu with the "set" button to record your setting? (If you exit by pressing the "menu" button, your settings are not saved.)</p>

<p>For HDR, you should use Av mode (not P or Tv) because you want to hold the aperture (and depth of field) fixed for all of your exposures).</p>

<p> </p>

[ldavidson]

<p>Ken, I didn't know about the Custom Function 1. I will try that. Also thanks for the tip about AV. I knew that I couldn't use full auto, creative auto, or bulb. I have the book by Charlotte K. Lowrie which has been very helpful, but she has missed a few things. I appreciate your advice. Thanks so much. </p>

[richard_crowe4]

<p>Linda,</p>

<p>I am glad that you asked this question because he procedure for setting AEB is different from my other 1.6x Canon cameras (I have cameras ranging from the very old D60 to the 40D plus my new 7D). I played with my new 7D and am glad that I did because of the difference between the controls of that camera and my older DSLR cameras.</p>

<p>Using the 7D, go to your menu setting in the second red grouping. The first selection is Expo.comp./AEB and shows you a linear scale showing where your exposure compensation and auto exposure bracketing (AEB) has been set.</p>

<p>To change the settings, press the "set" button which shows you a screen with the title Exposure comp./AEB setting and a linear scale to show you the settings for your exposure compensation/Auto Exposure bracketing.</p>

<p>You adjust the AEB with the main dial (top of camera). The linear scale will change to show three white lines. The longer center white line shows you your exposure compensation (which will be at zero unless it has been adjusted) and the two outboard white lines will show you the extent of AEB. Moving the main dial will place the outboard lines further from the zero point indicating that you are dialing in a greater amount of AEB. Moving the Quick Control Dial (back of camera) will adjust your exposure compensation. You will see that the center white line on the scale moves to the left (darker) or to the right (lighter). There is a reminder on each side of the menu screen showing you which dial adjusts which value.</p>

<p>You can adjust the AEB or the exposure compensation alone or you can adjust both the AEB and the exposure compensation. Activate your selection by pressing the "set" button.</p>

<p>I use AEB in conjunction with exposure compensation in night shooting. I have found that a -1 stop exposure compensation combined with the three stops of AEB will usually put me in the ballpark exposure wise. I will get one exposure at -2 stops from the meter reading, one exposure at 1 stop and one exposure at the meter reading. One of these three exposures will usually be good and they also are decent for HDRI. if you don't use the -1 stop exposure compensation your AEB sequence is usually over exposed on the 0 and =1 stop compensation.</p>

<p>BTW: you can adjust the exposures by using the menu functions at C.Fn I: Exposure<br /> C.Fn I:1 allows you to select exposure increments at 1/2 or 1/3 stop increments<br /> C.Fn I:4 is <strong>VERY IMPORTANT</strong> unless auto bracketing auto cancel is off (selection 1) the AEB will be canceled every time the camera is turned off. I always leave my AEB auto cancel off and I will cancel or begin my AEB with the Exposure comp./AEB setting menu setting.<br /> C.Fn I:5 allows you to select the sequence in which the AEB is shot. <br /> O = first shot no AEB, second shot minus AEB, third shot plus AEB<br /> 1 = first shot minus AEB, second shot no AEB, third shot plus AEB</p>

<p>AEB is one of the least used but IMO most important tools on a Canon DSLR. It is handy not only for HDR imaging but, to ensure that you don't miss out on important shots because of exposure error. Except for the extra memory used (I have plenty of memory) and the extra images to sort out in post processing, it has really no downside and it can save shots. However, I never use AEB for sports or action shooting since I will normally want more than 3 images per shutter button actuation and because I want each of those images to have the same exposure.</p>

<p>I wish that Canon allowed a five increment AEB with the 7D. The some full frame series cameras have a five increment AEB capability and some Nikons also have that extended AEB. However, some of the lower-line Nikons do not have the three shot AEB burst capability.</p>

<p>It is perfectly correct that the camera should be in AV mode so that the focus doesn't change with the f/stop changing. The AV mode will keep the f/stop consistent and will change shutter speed to compensate for exposure.</p>

<p> </p>

[benstanley]

<p>You don't have a flash enabled too do you? In my experience when you turn a flash on, AEB will be disabled on the next half-press of the shutter button.</p>

[randallfarhy]

<p>Linda, AFAIK-and I could be wrong-to get the three bracketed exposures, you'll need to activate the shutter for each exposure (after setting your range)-the camera will then compensate +/- on each, and reset until cancelled-unlike film cameras that could automatically fire off the 3 shot sequence on one press of the shutter. I own the 7D but havn't explored this feature, as I shoot in manual and mainly action or wildlife. Using compensation means that a full 2/3 of my shots would'nt be exposed properly, or "close nuff".<br>

EDIT: Holding the shutter down in either of the continuous modes should work as well.</p>

[manuel barrera houston,]

<p>You all making it too hard, do not need a custom function, it is all in the menu, and you can use AV for bracketing, TV is normally the preferred way. Go to page 105 of your manual, it is a fairly easy process (make sure you press set!). If you do not have remote control than preferred way is set it to high speed and set for time delay, it will quickly take all three photos, do not forget the tripod. If the light is excellent you can use a very high setting and probably get away with hand held if you have steady hands. I do not think bracketing will work well if the camera is set to P, not sure on that as it has been awhile since I read up on the subject.</p>

<p>The reason that AV is not normally desired is because it can effect the focus, distance, one normally wants to keep the subject focused.</p>

[benstanley]

<blockquote>

<p>The reason that AV is not normally desired is because it can effect the focus, distance, one normally wants to keep the subject focused.</p>

 

</blockquote>

<p>Your reasoning is correct but your conclusion is wrong :) Better to use Av and allow AEB to affect the shutter speed. That way the aperture setting stays constant so DOF does not change with the brackets. Using Tv will result in aperture changes.</p>

[manuel barrera houston,]

<p>Ben is correct.</p>

[ldavidson]

<p><strong>Thank you all for your helpful information! </strong><br>

I appreciate you taking the time to do this. I haven't had time to follow your suggestions yet. Hopefully this weekend I will. You’re the best!</p>