> Hi Greg, > > I've got two lenses currently, these being > EF 20-35mm f/3.5-4.5 USM and EF 70-200 f/2.8L USM > > Which means I have a gap in my range which I'm now wanting to fill. > I've thought long and hard about the 28-70mm f/2.8L but the only thing > stopping me from going ahead with the purchase is that both my existing > lenses do not telescope externally when zooming - all that happens inside > the lens, so I feel that the dust proofing is good. > > I'd buy the 28-70mm L lens except that it telescopes externally, so I really > find that hard to accept, since this would mean more likelyhood of dust > ingress. Can anyone allay my fears here? > > My question to you is - does the L lens leave the 28-135mm IS lens for dead > and secondly, does it telescope internally or externally? When zooming, > does the front element rotate? Finally, does it use a 77mm filter size, and > are you putting up yours for sale? :) > > Lawrance > Dear lawrance,
The 28-70L changes it's physical length according to the focal length. At 70mm, the barrel is fully retracted. At 28mm, it is fully extended. The lens hood gives excellent shading of the front element at all focal lengths. I don't think dust is really a big problem with telescoping zoom lenses, my old 28-135 (about 4 years old) has a little dust on it's internal surface of the front element, but it doesn't seem to make much difference. My 28-70L is only a few months old, but travel through some dusty places in Utah (like Monument Valley) and Arizona doesn't seem to have caused any buildup of dust on the internal glass surfaces. My 100-400L, now about a year old and been used quite a lot has one or two tiny specs of dust on the inside of the front element. However, I cannot see any image degredations on my transparencies from dust. I have had my 28-135 IS serviced recently at CPS, and they tell me it is as optically good as it can get. My Velvia slides taken with this lens at the Grand Canyon look pretty sharp. The same slides taken with the 28-70L look significantly better. One can quite easily tell which lens took which slide. The L lens has better contrast and looks more detailed. The colour is more vivid. There is less flare. The L lens gives the Canyon a "three dimensional" appearance. I don't feel the transparencies projected by the 28-135 have this 3d quality. Portraits taken with the 28-70 are significantly better than the 28-135. I feel the photos look much more eye catching. Not only is the detail and resolution higher but flare is better controlled (esp obvious in backlighting). I also feel the skin tones are better rendered. Taken at f/2.8 the resolution remains extremely high. That is not to say the 28-135 cannot give great portraits - I still use this lens quite often and it is capable of publishable results. However, since I got this new toy.... Greg * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
