Re: Question: Are these pics sharp on 100-400 lens 5d MKII?
kenbennedy mentioned this a couple posts back and I fully agree with his observation.
The why may be attributed to AF point shape in reality, which are vertical or horizontal bars, or a combination of the two in + format (some AF systems also have diagonal slash points for assisting with faster lenses). Often these bars extend beyond the viewfinder\'s focus screen point reference box and in the case of the first Heron shot the AF likely fell off your intended target since the subject did not entirely fill up your focus point box -- and then some. To me, the birds reflection seems a little sharper and in that scenario the slower 100-400 lens is likely forcing the camera AF to use only a vertical bar focus point. This bar may have picked up just a touch of the closer bird reflection in the water rather than the bird itself. In general though, that particular composition was extremely challenging for the 100-400 and AF given the subject size and distance. Ultimately, I would second kenbennedy\'s recommendation to get closer to your subject so that it really fills that focus point up.
In the case of the white Great Egret photo everything worked right; you succeeded in getting closer to your subject, picked a broad part of the body to establish focus on which likely over-filled the focus point and in that shot focus looks great.
I often test fall off with the various focus points to learn their shape and limits using servo AF mode. Pan around various subjects at different distances and note when focus drops from your primary subject and focuses on another. In the case of my 1DIII and 400 combo I notice that my actual center AF point droops a little lower than the viewfinder focus screen reference box (top of the AF bar is almost even with the top of the reference box line, but the bottom of the bar extends a little below the bottom of the reference box line) and I have to be mindful of what that extended part might be picking up to avoid unwanted fall off.
The rest of your shots look great and I\'d say you are already ironing out the kinks, it\'s a great lens!
Re: Question: Are these pics sharp on 100-400 lens 5d MKII?
kenbennedy mentioned this a couple posts back and I fully agree with his observation.
The why may be attributed to AF point shape in reality, which are vertical or horizontal bars, or a combination of the two in + format (some AF systems also have diagonal slash points for assisting with faster lenses). Often these bars extend beyond the viewfinder\'s focus screen point reference box and in the case of the first Heron shot the AF likely fell off your intended target since the subject did not entirely fill up your focus point box -- and then some. To me, the birds reflection seems a little sharper and in that scenario the slower 100-400 lens is likely forcing the camera AF to use only a vertical bar focus point. This bar may have picked up just a touch of the closer bird reflection in the water rather than the bird itself. In general though, that particular composition was extremely challenging for the 100-400 and AF given the subject size and distance. Ultimately, I would second kenbennedy\'s recommendation to get closer to your subject so that it really fills that focus point up.
In the case of the white Great Egret photo everything worked right; you succeeded in getting closer to your subject, picked a broad part of the body to establish focus on which likely over-filled the focus point and in that shot focus looks great.
I often test fall off with the various focus points to learn their shape and limits using servo AF mode. Pan around various subjects at different distances and note when focus drops from your primary subject and focuses on another. In the case of my 1DIII and 400 combo I notice that my actual center AF point droops a little lower then the viewfinder focus screen reference box (top of the AF bar is almost even with the top of the reference box line, but the bottom of the bar extends a little below the bottom of the reference box line) and I have to be mindful of what that extended part might be picking up to avoid unwanted fall off.
The rest of your shots look great and I\'d say you are already ironing out the kinks, it\'s a great lens!
Nov 24, 2009 at 04:50 PM
Previous versions of Willamette's message #7814977 « Question: Are these pics sharp on 100-400 lens 5d MKII? »
