tk shots Posted July 4, 2007 Share Posted July 4, 2007 i just bought this lens,for a d80, and it seems very difficult to focus it precisely, and i find the depth of field not as good as it should be either,on auto focus or manual....is this just me or the lens? Link to comment Share on other sites More sharing options...
Peter_in_PA Posted July 4, 2007 Share Posted July 4, 2007 I don't get what's wrong with that lovely photo! Link to comment Share on other sites More sharing options...
tk shots Posted July 4, 2007 Author Share Posted July 4, 2007 i am wondering about the sharpness....is it okay?or is it the case that lenses will only give you so much depth of field....whatever happened to f64? Link to comment Share on other sites More sharing options...
jkmccarthy Posted July 4, 2007 Share Posted July 4, 2007 <p>I'm interested in experience of other photo.net folks with this lens. Reading the reviews on-line here:</p> <p><a href="http://www.fredmiranda.com/reviews/showproduct.php?product=97&sort=7&cat=37&page=1">http://www.fredmiranda.com/reviews/showproduct.php?product=97&sort=7&cat=37&page=1</a></p> <p>... it appears that Sigma's quality control leaves something to be desired -- several folks who contributed reviews had to send their first lens back to Sigma for problems related to image quality ("soft" focus), before ultimately getting a "tack sharp" replacement lens. Comments from the photo.net community ? Has anyone tested their Sigma 24-70 against a comparable Nikon (18-70 or ?) ??</p> <p>But getting back to Tommy's question, the larger the aperture opening (the smaller the f-number), the less depth of field any camera lens will provide. What are you comparing it to, when you say depth of field is not as good as it should be ? (Two lenses having [or set to] the same focal length and f/stop ?)</p> Link to comment Share on other sites More sharing options...
tonybeach Posted July 5, 2007 Share Posted July 5, 2007 I'm not sure what you are focusing on in the image. I am also confused by your question about DOF. I am unable to critically evaluate the sharpness (or lack thereof) of the image you provided because it is too small. "....whatever happened to f64?" Here is a question I can answer. f/64 is an aperture used on large format cameras; not on smaller format cameras. "f/64 Group" was a fraternity of American western large format photographers that included Ansel Adams. For 35mm film cameras, the equivalent DOF is attained using f/17, and for DX the equivalent is f/11. Link to comment Share on other sites More sharing options...
Peter_in_PA Posted July 5, 2007 Share Posted July 5, 2007 f64 would be, due to diffraction, pretty horrible on an SLR, as often is f16 - f32, depending on the lens. The bigger version, by the way, still looks really nice. What aperture did you shoot at? Link to comment Share on other sites More sharing options...
tk shots Posted July 5, 2007 Author Share Posted July 5, 2007 it was f14 or f16 peter....maybe i am being too critical Link to comment Share on other sites More sharing options...
toddcwilson Posted July 5, 2007 Share Posted July 5, 2007 f/14 or f/16 - then what was the shutter speed? Next question - was the capture hand held or on a tripod? Link to comment Share on other sites More sharing options...
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