
Originally Posted by
adrian dancy
Roger
I certainly do not wish to degrade the thread and I certainly do not relish being in disagreement with you. I hate religious wars. Fabio has previously indicated in another thread that he regards your opinions highly (as do I, I have frequently referred folk to your website and will continue to do so) but that does not mean I have to agree with you. I would be most surprised if Fabio was not aware of your views regarding prime and zooms lenses, indeed he has in effect acknowledged that fact, it seems ,by his second post here. I made that assumption when I first read his question. It seems clear to me that that Fabio has determined a zoom lens will best suit his requirements. I simply do not see the point in going over what must for him be 'old ground'. Respectfully I think you must accept that some folk choose zooms for a number of legitimate reasons. For some (as in my case) it is simply not feasable to carry an arsenal of prime lenses around (or a big 500 on its own) and even if I could it would in some photographic situations be extremely limiting, in my view this cannot be argued. Cost is a major consideration and in some situations a zoom is actually the 'appropriate' lens for the job. Only very recently I was photographing a red- throated diver which occasionally came very close I was using a Sigma prime. I wished I had a 120-300mm lens that day! Occasionally I find myself in a position where I can 'work' a subject and in that regard a zoom will trump a prime.
I do not wish to argue about MTF charts but I am puzzled as to why you acquired a 100-400 lens if it is only good for 8"X10" prints wide open? I also wonder why you did not take it back? It is simply not true, based on my experience, that there is no variance between lenses of the same type, I could quote Bob Atkins who has at least acknowledged minor differences and and you might also read Romy Ocon's experiences with the 100-400 on his web site.
I can only wish Fabio luck with his decision and I can assure you that if I choose to buy the Sigma 120-300 and it is not up to scratch you will be the first to know and I will eat humble pie! However what I have said above will not be invalidated .
One final word though for Fabio, If you do photograph anything at 600mm wide open you may have depth of field issues.
Kind regrards
AD