Dave Brooks <[EMAIL PROTECTED]> wrote: > Memory seems to think, someone recently purchased this lens. > > If so any comments for use on the D. >
Hi Dave, I posted this comment regarding the 28-75 not long ago, hope this helps: > Andre Langevin <[EMAIL PROTECTED]> wrote: > > I already have a 24-90mm and rarely go to 90mm so performance > from > > 24mm to 75mm is what interests me. Portability is not a key > feature. > > Only optical performance (including flare control). > > > > Thanks, > > Hi Andre, > > I own both and a couple of weeks ago I did perform a side by > side comparison (just to be nitpicking, since I already do > prefer the 28-75 overall, mostly because I need the extra speed > and do prefer the fixed f/ throughout the zoom range). > I did test them at f/4.5 and f/9.5 (even if I do usually avoid > shooting at stops smaller than 6.7, 8 on the *istD, to avoid to > make the dust on the sensor too visible); the description comes > from judging the results at 100% magnification on the monitor > (subject: buildings from 200m to 1km circa). > At 28mm and 50mm (f/4.5): the Tamron is the winner wrt > sharpness; the difference is small in the centre but definitely > big in the corners (softness of the 24-90 starting from circa > 1/2 frame). At f/9.5 the situation is reversed, with the Tamron > that doesn't seem to gain much (it was good already, though) > while the Pentax lens gets a lot better, surpassing by a small > but visible margin the Tamron (better definition of small > details). > At 75mm f/4.5, the 24-90 performs marginally better closer to > infinity (but I suspect that the focusing was set differently - > the lenses were both focused by the camera and there is a > certain amount of difference in depth of field, with closer > objects better defined on the Tamron either at 4.5 and 9.5). At > f/9.5 there is almost no difference and becomes difficult to say > which one is better, probably more a different rendition of the > details more than a question of lpm. > About the flare: the 24-90 handles flare quite well, but it is > one of the worst Pentax lenses I used wrt reflections (at 24mm > it shows a lot of aperture-shaped reflections when pointed to > the sun - for example, the 28-70/4 is way better, it never > suffered from this kind of behaviour, and so is the 20-35). The > Tamron performs really well for a non SMC lens, but shows a > strange kind of reflections, as it sometimes duplicates small, > strong lights on the scene (and it is not predictable in the > finder, so I guess it is a problem of reflections of light > hitting the sensor and then duplicating on the rear element of > the lens - there is an example in the portrait of Stan at > http://www.photo.net/photodb/photo?photo_id=2784631 - look at > the shirt). > The Tamron is so good overall that I can live with that. > HTH. > > Ciao, > > Gianfranco > > PS: If you want to, I can upload small portions of the pictures > in a photo.net folder, hoping that they do not resize them, to > show you the differences. > I recently discovered that the reflections are visible in the finder (faintly, but they are there - you have to be careful) and of course are annoying only when shooting wide open or thereabouts. Ciao, Gianfranco ===== _ __________________________________ Do you Yahoo!? The all-new My Yahoo! - What will yours do? http://my.yahoo.com
