06-22-2012, 10:53 AM
[quote name='wim' timestamp='1339252526' post='18803']
Actually, as an owner of a 100-400L, currently my second one (sold the first one because I needed the money badly at the time), I can state that this is not my experience <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />.
I reckon people need to get used to working with a 100-400L, especially at the long end. It is rather susceptible to picking out the exact item for focusing. Essentially it means one has to get to know the equipment well before expecting to get really good shots, sharp where they are supposed to be. And with some equipment that is easier than with others. I think the biggest problems are that the IS needs to be able to do its work for at least 1 to 2 seconds, prior to pressing the shutter button all the way through, something many people seem to forget, and the limited amount of DoF. When shooting, e.g., a small bird, a little body movement may put the subject in the OOF zone.
I also reckon that telelenses are less susceptible to "flaws" in the glas of good quality filters, basically because the angle of incidence is very narrow, compared to WA lenses. Less to go wrong due to refraction and/or reflection, and due to the limited DoF of telelenses any objects close to or on the filter will not contribute to problems either.
Kind regards, Wim
[/quote]
Well, from own empirical observations, when taking pictures through poor window glass with tele, results where clearly affected, distorted, while with wide-angle image was passable. I think because of the narrow angle, if the not-flat glass distorts rays, they end up further away from the point where they should "land" on the sensor than with wide angle lenses. I.e.let's say the piece of glass is a little like a convex lens (because it's not flat, it's a bit thicker in the middle of the filter), say 0.1 dioptre. A given dioptre has a stronger effect on long focal length lenses than on wide-angles, where there is less effect.
Actually, as an owner of a 100-400L, currently my second one (sold the first one because I needed the money badly at the time), I can state that this is not my experience <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. I reckon people need to get used to working with a 100-400L, especially at the long end. It is rather susceptible to picking out the exact item for focusing. Essentially it means one has to get to know the equipment well before expecting to get really good shots, sharp where they are supposed to be. And with some equipment that is easier than with others. I think the biggest problems are that the IS needs to be able to do its work for at least 1 to 2 seconds, prior to pressing the shutter button all the way through, something many people seem to forget, and the limited amount of DoF. When shooting, e.g., a small bird, a little body movement may put the subject in the OOF zone.
I also reckon that telelenses are less susceptible to "flaws" in the glas of good quality filters, basically because the angle of incidence is very narrow, compared to WA lenses. Less to go wrong due to refraction and/or reflection, and due to the limited DoF of telelenses any objects close to or on the filter will not contribute to problems either.
Kind regards, Wim
[/quote]
Well, from own empirical observations, when taking pictures through poor window glass with tele, results where clearly affected, distorted, while with wide-angle image was passable. I think because of the narrow angle, if the not-flat glass distorts rays, they end up further away from the point where they should "land" on the sensor than with wide angle lenses. I.e.let's say the piece of glass is a little like a convex lens (because it's not flat, it's a bit thicker in the middle of the filter), say 0.1 dioptre. A given dioptre has a stronger effect on long focal length lenses than on wide-angles, where there is less effect.