Hi Peter,
Seeing that you have answered in-line I will have to reply in the same fashion. > > > Chip Louie wrote: > > >Well for me and almost everyone else, shooting wide open is very useful, > >personally I shoot WFO a lot. Don't be surprised at the Sigma lens' > >measured optical performance, they are quite good. But as much as Peter > >goes on about them they are not really better or even overall as good as > the > >data he is using indicates. The Sigma zoom using the data he > has supplied > >from Photodo is less sharp overall. The real winner is the > older Canon EF > >80-200 2.8L anyway you slice it based on this data anyway. > > Gee Chip, when you say you and everyone else I did not realize that you > surveyed the entire global photographic community and found the vast > majority shoot wide open. How interesting. Can you provide the details of > how you did this? ;-) > Well I don't mean EVERYONE I mean what I said, that almost everyone uses their lenses wide open pretty regularly. There is another thread currently where the writer asked how many images were sold shot at f/2.8 on these fast lenses, the writer implied nobody shoots wide open and hence nobody needs f/2.8 or faster lenses. The response was pretty much in agreement with my own experiences, zillions of sports, fashion, advertising etc. images are sold and published that were shot wide open at f/2.8 and faster. Surely you didn't miss this thread. > Yes, the older Canon is an excellent optic. The rear element is > almost flush > with the barrel so you cannot use the Canon TCs with it limiting > its use (to > a degree). There is no USM so it is not fast like the Canon 70-200mm and > not silent like the Sigma. None of this was in the question asked so I didn't bring up these potential issues for some shooters. But as Evrim Icoz says, AF speed and optical measurements aren't everything and I'm pretty sure that you would agree with this or you wouldn't be buying Sigma lenses. > As to comparison, I did the chart and each has > its own advantages at various apertures. I also pulled out my old Pop > Photos tests (yes I saved many of them) and compared the newer > Sigma to the > older Canon. In some instances the Canon is sharper such as at 200mm at > F2.8. Now that is providing you are blowing up your negative to > 20x24 where > you will see about an 8% improvement at that specific aperture. While at > almost all others there is a 1% advantage to the Sigma except at 135 where > the Sigma is better by 13% but that again is if you enlarge to 20x24. Be > glad to provide the numbers to anyone if they would like. > No disrespect but the chart you did only shows a very limited set of hard data points and does not indicate the trends. Using your supplied Photodo data if you graph the area to indicate where a particular lens might offer an optical advantage compared to another lens you will see that for the most part the Sigma lens offers no advantage most of the time. This is where and how opinions are developed. Over time and with experience, users learn what works well and what works best. Look at the total area or time where the Sigma offers an advantage and you will see that it is effectively no advantage unless you always shoot at that focal length and aperture. Of course your application may require the use of a fixed focal length and one aperture but for most of us this is not the case so the Canon lenses offer better performance overall. > >Before Peter gets all ballistic, chart it yourself and do an > average of the > >data points and measure the area under the curve. It doesn't > matter if you > >order the chart using focal length or apertures the Sigma is > clearly not as > >good overall and this is reflected in the Photodo rating. The Sigma has > >other problems to go with the lower initial cost, which is very > attractive > >to many people myself included. But the reality of it is that > if you want > >to get a Canon lens fixed or serviced you will have an easier time of it > and > >the resale value of a Canon lens has been historically > significantly higher > >than any of the third party lenses so. So in reality there is > very little > >cost difference, a real difference in terms of performance > optically and in > >terms of service and support. > > No Chip, I am not going to go ballistic, I just state facts. You are > correct in saying the Canon has a better resale value, but then again it > costs twice the price of the Sigma so it would only stand to > reason that it would cost more used too. Not literally a higher resale amount, a higher percentage of original cost retained as reflected at the time of resale. Retained percentage, take the fair market value (hopefully you paid less), of the lens at the time purchased (new or used), and subtract the money received from the sale (hopefully you sold it for a fair price), and calculate the percentage of the original purchase price retained. The Canon lenses have generally retained a larger percentage of their initial cost and this difference can easily narrow the cost differences to almost nothing in the long term. Here in the USA at least there are no new Sigma 70-200 2.8 EX HSM lenses for $550 to be had. Go look at B&H's web site, a new Canon EF 70-200 2.8L is $1,109 and a new Sigma 70-200 2.8 EX APO IF HSM is $699. If the Canon costs twice as much as the Sigma then the Canon is a $1398 lens, this is not the case. You were saying something about facts? > Now, as to repair, what you are saying is something I have NEVER had a > problem with. All the 3rd party lens I have owned Sigma, Tamron, > or others > are easily repaired by the manufacturer same as Canon. So before > you use the > FUD (Fear Uncertainty and Doubt) factor, you should check for > yourself. Well, if we use only your experience we'd be working in a vacuum and of course you'd be right 100% of the time. But if we use the experiences of many others some not living in a vacuum, and add them to the mix the percentages go down dramatically, just a couple of days ago a fellow EOS lister in Lisbon was trying to find a place to get his Sigma repaired as it had stopped focusing and refused to AF on any other EOS body he tried it on. Last I checked Lisbon was a major city in Portugal. > Have > you ever met a Canon lens you did not like? > > Peter K > Well yeah, a whole lot of them, EF 22-55, EF 28-80, EF 35-80, EF 35-70, EF 35-105, EF 35-135, EF 50-200(non-L), EF 70-210 4, EF 75-300IS, EF 80-200(non-L), EF 35-350L, EF 100-3004.5-5.6, EF 100-300 5.6L, EF 50 1.0L (too slow AF), EF 85 1.2L (too slow AF), EF 300 4L IS poor optical vs. non-IS 300 L), and these are only the Canon lenses I've used. I reserve the right to dislike others that I haven't used. 8^) Cheers/Chip * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
