AV or TV

<p>I was reading some online material for bird photography. Mikeatkinson.net has some very good information for starters. He says that main settings for bird photography should be<br>

<strong>AV mode, widest possible aperture</strong><br>

<strong>shutter speed - decided automatically</strong><br>

<strong>ISO - adjust this if shutter speed calculated is too slow<br /> </strong><br>

I am wondering how different is this if I set the shutter speed I want (say 1/1000) and let the camera figure out ISO and aperture. I believe it all will be connected to achieving the same exposure value. But, for bird photography , for stationary shots (no flight shots) in particular, whether it makes a difference if I use AV or TV?<br>

Thanks in advance !<br>

Shantanu Sane<br>

PS: please check out my recent shots in my profile. I took all of them in TV mode and am wondering if the results would have been very different if I had used AV.</p>

<p>It depends on your lighting conditiong. on a cloudy day you might want to ensue a short enough exposure by using TV mode and setting your shutter speed manually. On a bright sunny or partly cloudy day you may find it better to set your apperture and let the camera decide the shutter speed.</p>

<p>The camera is going to pick whatever is the best senario for you in the light you have at the time, i suppose whether you use TV or AV and the fastest shutter speed is the object, then it should end in the same place. Personally i use Av priority because with a tripod shutter speed is secondary to shutter speed.</p>

<p>I tend to agree with Simon that using aperture priority (Av) would be preferable. If you use shutter priority (Tv), depending on the available light you could end up with a very wide aperture. This would tend to limit the depth of field (the portion of the image going from near to far that appears to be in acceptably sharp focus). With a very side aperture, you might even get an image where only part of the bird is sharply in focus, or other parts of the image that you want to be sharply focused are not. Using Av mode you can decide the aperture you want to ensure that as much of the image as you want has reasonably sharp focus.</p>

<p>I'll add to what Sam has said by emphasizing the flipside of the depth-of-field coin... Using Aperture Priority, you also control foreground and background focus/blur to minimize visual distraction from your subject. When birds are stationary, they do tend to be found in scenes containing a lot of potentially distracting elements (trees, shorelines, etc.), so keeping your DOF shallow enough to separate the bird from the visual confusion can be important. Ultimately it all depends on what effect you're trying to achieve in any given shot.</p>

<p>Of course, with practice you'd eventually find it better to stay with Manual and set aperture and shutter speed yourself based on the specific conditions of each shot.</p>

<p>Whether you choose to use shutter priority or aperture priority, ISO should almost never be on auto. You could easily find yourself with shots that have excessive digital noise because the camera has unexpectedly gone (for example) from maybe 400 to 800 or 1600.</p>

<p>If you're not sure about the fine points of this, there's no shame in using the P mode. That way the camera will choose what its program says is the best combination of shutterspeed and aperture. I think most cameras will "shift" the other setting to maintain the same exposure if you alter either the aperture or speed. If you pay attention to what the camera is doing (rather than "blindly" shooting), you can learn a lot from the settings that P will choose for you. Then when you've got a clearer intuitive sense of exposure, you'll be clearer on when to use the Tv or Av settings.</p>

<p>Of course some "serious" photographers (meaning photography program students) would never deign to use anything but M as a setting, and no AF either. ;)</p>

<p><strong><em>“’AV mode, widest possible aperture</em></strong><strong><em><br /></em></strong><strong><em>shutter speed - decided automatically</em></strong><strong><em><br /></em></strong><strong><em>ISO - adjust this if shutter speed calculated is too slow’</em></strong><strong><em><br /></em></strong><strong><em><br />I am wondering how different is this if I set the shutter speed I want (say 1/1000) and let the camera figure out ISO and aperture . . . for stationary shots (no flight shots) in particular.</em></strong><em>” </em></p>

<p>It is quite different.</p>

<p>Selecting Tv Mode / hence Auto ISO:<br>

1. Not all cameras allow the ISO to be automatically selected. If the camera does, then you are leaving the camera to choose the noise value.</p>

<p>Using Tv Mode / hence Auto Av:<br>

2. I have not read the commentary you mention. My guess is the suggestion to use the <em>“<strong>widest possible aperture”</strong> </em>is quite significant and to be employed with the suggestion of using Av Mode.</p>

<p>My belief is the writer is suggesting that the <strong><em>smallest possible DoF is integral to a good (bird) photograph.</em></strong></p>

<p>It is this second point and the choice of the widest possible aperture (when using Av Mode), which makes your comparison of using Av Mode or Tv Mode, significantly different.</p>

<p>WW</p>

<p>Shantanu,</p>

<p>There is no magic "best way" to get the shot. It all depends on what YOU want to get in your picture AND if the subject is stationary, moving slow, or moving fast. Do you need a LOT of area in focus or a thin range ? You can make correct exposures with a lot of different settings. What you need to do is understand how and when to use any ISO, shutter speed, and aperture. My suggestion ... get " Understanding Exposure" by Bryan Peterson. It covers all of that.</p>