I'm not sure what you mean by higher quality, but I assume that you are referring to such things as resolution, contrast, color neutrality, ghost rejection, flatness of field, lack of vignetting, etc. Most ultra fast lenses are NOT as sharp as medium fast lenses from the same manufacturer and may tend to have more problems with aberrations and keeping the field absolutely flat - even at same apertures. There are tradeoffs. For the most part, however, they are excellent efforts - for the maximum aperture they possess. People buy fast lenses because they believe they need the extra stop or half stop, to be able to focus better in low light or to get a narrower depth of field, NOT to get better image quality in daylight or with flash. When I shoot street scenes at night, I take my fast glass. Regards, Bob.... -------------------------------------------------------------------- "Beer is proof that God loves us and wants us to be happy!" - Benjamin Franklin From: "gallery" <gallery@bobke.de> > I would think that people who go for a high aperture lens are, on average, > more 'serious' photographers and prepared to pay more for higher quality. > Who would buy a low-quality high aperture lens? The normal hobby-shooter > wouldn't know what to do with it and people who read photo magazines would > select a better alternative. > BTW: photo magazines would test across the whole aperture range. So, if you > build a lens that you can use at 1.4, but with inferior results, the lens > would presumably get a worse test result than if you restricted the maximum > opening to 1.8 for the same lens. > The economic question for the manufacturer would be what is the more > important factor for the decision to buy a lens: aperture or test result... > > best regards > > Laurenz Bobke > http://www.travelphoto.net/ > ----- Original Message ----- > > > Actually I don't think that's true at all: for example people quite > > rightly pay more for medium quality Sigma lenses than for Canon junk > > zooms. But the answer to the original question is surely simply that > > aperture alone doesn't determine the quality of the lens. Thinking (off > > the top of my head) of Canon 50mm lenses - so no "brand" distinction - > > the f/1.8 is ludicrously cheap, yet of fairly high quality, since it's a > > very tried and tested design, the f/1.4 costs 5? times as much, and is, > > by all accounts a somewhat better lens (comparing the same aperture), > > the f/1 is ludicrously expensive and not correspondingly astonishing > > quality because making any f/1 lens is basically pushing the boat out. > > So it seems to me you largely get what you pay for (for once).
