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Message: <blockquote data-quote="Tord" data-source="post: 2163498" data-attributes="member: 40738">Hi,AF: The rationale behind using all AF points is that I usually capture BIF against sky, unobstructed sight. I also agree the recommendation to use 1 AF point only when there is a background.IS: I always use IS.1 and also monopod to the extent possible. IS on or off has been a subject for many discussions I suppose. What I actually have done is to perform tests (using a method inspired from Wrotniak's setup) to find the benefit of IS and monopod on longest acceptable exposure time.I used a E620 body with the 50-200SWD @ 200 mm and also the 70-300 @ 420 mm (with EC14). Target was static, outdoors @EV14, distance ~3/6 meters for full frame shots. Wrotniak advocates sequences of 20 pictures but I only took 10.My findings are that, with the lenses above:<ul> <li data-xf-list-type="ul">The benefit of no IS vs IS.1 is somewhat less than 1 EV in favor of IS.1</li> <li data-xf-list-type="ul">The benefit of monopod is around 1.5 EV in favor of monopod</li> </ul>I have the graphs and data sheets on another computer. I can share with you if you are interested (I will have access to the said computer on Sat/Sun). Above does not however provide answer to the question regarding required shutter speed for sharp pictures of BIF. I suppose a theoretical model and a sheet could be worked out with input parameters:<ul> <li data-xf-list-type="ul">Motion speed of target</li> <li data-xf-list-type="ul">Direction towards camera</li> <li data-xf-list-type="ul">Photographer ability to track the subject</li> <li data-xf-list-type="ul">Sharpness requirement (how many pixel deviation is acceptable)</li> </ul>And I realize we are now off-topic. Should we start a new thread?/Tord</blockquote>

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