I shoot A LOT of action images. It isn\'t about the Af speed, it\'s about technique.
Well, technique is a dominant factor in whatever we do....from photography to needlepoint.
However, given a certain level of skill and the same camera, lens selection influences the speed and stability of AF in the following two ways:
* Lens focus group drive speed. (Expressed as time it takes for the lens to focus from infinity to MFD). The 85L MkI is 1.2 sec. 200 f/1.8 is 0.6 sec. 300 f/2.8 IS is about 0.3 sec. Those are big differences.
* A larger aperture lens sheds more light on the camera\'s AF sensors. More light means that the AF routine is executed faster. For example, in low light it is not the lens focus drive which delays the AF response......it is the camera\'s AF system which starts to falter on deficient light contrast-phase data.
Yes, what you say is true, but the impact on action photography when comparing the 100-400mm and the 400mm F5.6 is so minimal that it matters only in a very small number of situations. The other factors such as weight, size, versatility, and cost are more significant. To me the only one that matters enough to sway the decision is versatility. That\'s assuming you have a sharp copy of the 100-400mm.
Fair enough, Jim, I understand now where you\'re coming from.
Yes, in a very practical and general sense, those factors you\'ve mentioned are the key.
However, let me just add this. This morning I managed to get a split second shot of a pijun, flying fast not more than 15 ft away from me, and changing direction abruptly. I had the 80-200L on my camera which is obviously f/2.8 and I\'d say its AF drive speed is not bad....0.5 sec according to Canon. I simply know I couldn\'t have got this shot with the 100-400 even if I had it set to 200mm. (In fact, I don\'t think I could get it with 400 f/5.6 either, but that\'s a different topic. )
I shoot A LOT of action images. It isn\'t about the Af speed, it\'s about technique.
Well, technique is a dominant factor in whatever we do....from photography to needlepoint.
However, given a certain level of skill and the same camera, lens selection influences the speed and stability of AF in the following two ways:
* Lens focus group drive speed. (Expressed as time it takes for the lens to focus from infinity to MFD). The 85L MkI is 1.2 sec. 200 f/1.8 is 0.6 sec. 300 f/2.8 IS is about 0.3 sec. Those are big differences.
* A larger aperture lens sheds more light on the camera\'s AF sensors. More light means that the AF routine is executed faster. For example, in low light it is not the lens focus drive which delays the AF response......it is the camera\'s AF system which starts to falter on deficient light contrast-phase data.
Yes, what you say is true, but the impact on action photography when comparing the 100-400mm and the 400mm F5.6 is so minimal that it matters only in a very small number of situations. The other factors such as weight, size, versatility, and cost are more significant. To me the only one that matters enough to sway the decision is versatility. That\'s assuming you have a sharp copy of the 100-400mm.
Fair enough, Jim, I understand now where you\'re coming from.
Yes, in a very practical and general sense, those factors you\'ve mentioned are the key.
However, let me just add this. This morning I managed to get a split second shot of a pijun, flying fast not more than 15 ft away from me, and changing direction abruptly. I had the 80-200L on my camera which is obviously f/2.8 and I\'d say its AF drive speed is not bad....0.5 sec according to Canon. I simply know I couldn\'t have got this shot with the 100-400 even if I had it set to 200mm. (In fact, I don\'t think I could get it with 400 f/5.6 either, but that\'s a different topic. )
I shoot A LOT of action images. It isn\'t about the Af speed, it\'s about technique.
Well, technique is a dominant factor in whatever we do....from photography to needlepoint.
However, given a certain level of skill and the same camera, lens selection influences the speed and stability of AF in the following two ways:
* Lens focus group drive speed. (Expressed as time it takes for the lens to focus from infinity to MFD). The 85L MkI is 1.2 sec. 200 f/1.8 is 0.6 sec. 300 f/2.8 IS is about 0.3 sec. Those are big differences.
* A larger aperture lens sheds more light on the camera\'s AF sensors. More light means that the AF routine is executed faster. For example, in low light it is not the lens focus drive which delays the AF response......it is the camera\'s AF system which starts to falter on deficient light contrast-phase data.
Yes, what you say is true, but the impact on action photography when comparing the 100-400mm and the 400mm F5.6 is so minimal that it matters only in a very small number of situations. The other factors such as weight, size, versatility, and cost are more significant. To me the only one that matters enough to sway the decision is versatility. That\'s assuming you have a sharp copy of the 100-400mm.
Fair enough, Jim, I understand now where you\'re coming from.
Yes, in a very practical and general sense, those factors you\'ve mentioned are the key.
However, let me just add this. This morning I managed to get a split second shot of a pijun, flying fast not more than 15 ft away from me, and changing direction abruptly. I had the 80-200L on my camera which is obviously f/2.8 and I\'d say its AF drive speed is not bad....0.5 sec according to Canon. I simply know I couldn\'t have got this shot with the 100-400 even if I had it set to 200mm. (In fact, I don\'t think I could get it with 500 f/5.6 either, but that\'s a different topic. )
I shoot A LOT of action images. It isn\'t about the Af speed, it\'s about technique.
Well, technique is a dominant factor in whatever we do....from photography to needlepoint.
However, given a certain level of skill and the same camera, lens selection influences the speed and stability of AF in the following two ways:
* Lens focus group drive speed. (Expressed as time it takes for the lens to focus from infinity to MFD). The 85L MkI is 1.2 sec. 200 f/1.8 is 0.6 sec. 300 f/2.8 IS is about 0.3 sec. Those are big differences.
* A larger aperture lens sheds more light on the camera\'s AF sensors. More light means that the AF routine is executed faster. For example, in low light it is not the lens focus drive which delays the AF response......it is the camera\'s AF system which starts to falter on deficient light contrast-phase data.
Yes, what you say is true, but the impact on action photography when comparing the 100-400mm and the 400mm F5.6 is so minimal that it matters only in a very small number of situations. The other factors such as weight, size, versatility, and cost are more significant. To me the only one that matters enough to sway the decision is versatility. That\'s assuming you have a sharp copy of the 100-400mm.
Fair enough, Jim, I understand now where you\'re coming from.
Yes, in a very practical and general sense, those factors you\'ve mentioned are the key.
Jul 04, 2009 at 11:22 AM
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