Hi Jonathan, I've tried to answer your questions.
----- Original Message ----- From: "Jonathan Kwok" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, October 20, 2001 4:10 AM Subject: RE: EOS 70-200L IS - First impressions > From your report, the lens sounds like a dream come true. Like many others > on this list, I have been contemplating this lens, but the realization that > it contains more lens elements than any other AF lens in the world has been > a cause for concern. > > With so many elements, chances of lens decentering (element misalignment) is > increased unless Canon's quality control is spot on. I've seen some samples > of 70-200L lenses having one of its corners noticeably softer probably due > to a slightly less than perfect alignment of the elements. I suspect that most photographers, like myself, are not able to try several examples of a particular lens before purchase (especially if it is a new release and in limited supply). So we have to put our trust in the manufacturers Quality Control. If we get a rogue sample, we have the option of returning it for scrutiny/replacement, assuming it is noticed. I was not totally happy with my 17-35 2.8L, not bitingly sharp anywhere and distinctly soft (smeary?) in the corners. The focal length had an effect, stopping down improved things, but I was a bit disappointed. Then I dropped it, nothing serious, just from waist level on to carpeted floor. The zoom barrel had bent. It still worked but was a little stiff. After the part was replaced, the softness worsened. I returned the lens and the rear lens cell was replaced. Revelation! This lens is now pin sharp in the centre at all focal lengths from f/4 on and stopping down to f/8 brings the corners in nicely. Guess I had a rogue? > My other concern was the loss of micro detail and lower light transmission > due to the extra glass. I mean, it could be rated at f/2.8, but may actually > transmit marginally less light due to internal reflections. How about trying > both lenses on your 1n and see if they give the exact same readings at f/2.8 > (AV mode) when pointed at the same subject under similar lighting > conditions? Tried your suggestion and exposure readout is identical (1/3 f-stop setting). Also shot a polaroid with both lenses (NPC - 2 on a sheet) in both AV and manual, then spot read the grey rectangles with a Minolta V. The difference? Not more than 1/10 stop - the meter's repeatability accuracy. I'll run a side by side resolution test next week (time permitting and if the old lens is not sold) and let you know my findings. > I presume the colour rendition and contrast of both lenses are also similar? If there is a difference in colour rendition or contrast then it is so small as to be insignificant. > I certainly do not expect this lens to have better flare resistance than its > older sibling, but to equal its performance in this department (as you > mentioned) is indeed wonderful. BTW, how does it flare? Meaning, when it > does flare, does it have huge orange hot-spots when pointed into a strong > light source or does it exhibit veiling glare and ghosting? In my experience, the only way to get either lens to flare is to have a bright light source in, or JUST outside, the picture. Then some spots, that repeat the light source, appear, sometimes multi-coating coloured. The size and shape of these depend on the aperture used. With the old lens (Non IS) veiling can be induced (I have used this deliberately, by massively overlighting the background white studio cove) but under normal conditions it is near impossible to produce. I have used the IS lens with the cove slightly overlit (1 stop, for cut-outs) and there is no difference from the old lens. The IS lens hood is flocked, this must help. I did try both lenses pointed at a 650W modelling lamp and the old lens had some repeat flare, plus a large orange circle/crescent, depending on where the light source was within the frame. Amazingly, the IS lens showed no orange spots at all! Didn't shoot any film, only in the viewfinder, so the mirror/prism/eyepiece may have an influence. > Finally, how is the handling? Does the extra weight affect the balance and > do you find this weight increase noticeable compared to the older lens? Has > the quality of its construction improved, as in, does it seem more robust > than the older lens besides being more weather resistant? Is the rear > element sealed or are there gaps where dust can enter the lens barrel via > the corner gaps in the rear element (as with the old model)? The IS lens is heavier, so for us photogs with bad backs it's not good news, but it handles just fine. The construction is at least as good as the Non IS. The rear element of my old lens appears to be sealed, same as the IS version. I've had the old lens for 6 years and there are no signs of any dust within the optics. Please bear in mind that my work is rarely under extreme conditions. > Quite a few questions I've asked and your answers will be much appreciated. Any good? Craig Z * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
