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Thread: Lens as sharp as 50mm 1.8

  1. #21
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    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by JediForce4ever
    most zooms, not all...
    Especially those megazooms, but those of less than 4 times zooms will be sharper.
    Canon EOS 5D, 24-70 f/4 L IS, 50 f/1.2 L, 70-300 f/4-5.6 L IS, 600EX-RT. Sigma 12-24 f/4.5-5.6 EX.

  2. #22
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    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by Snoweagle
    Especially those megazooms, but those of less than 4 times zooms will be sharper.
    Care to explain why?

  3. #23
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    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by JediForce4ever
    Care to explain why?
    The more zoom it has usually there're more elements in the lens as compared to prime lens. As light passes through the many elements there are obviously more 'losses'. I'm not taking comparisons to the telephoto prime L lens as they themselves have many elements too, notwithstanding the fluorite coatings they have on them.
    Canon EOS 5D, 24-70 f/4 L IS, 50 f/1.2 L, 70-300 f/4-5.6 L IS, 600EX-RT. Sigma 12-24 f/4.5-5.6 EX.

  4. #24

    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by Stoned
    For Nikon,
    17-35/2.8
    28-70/2.8
    135/2 DC
    105/2 DC
    85/1.4
    80-200/2.8 or 70-200/2.8

    MANY MANY!!!

    For general purpose street you maybe you can try the new 18-200VR. I heard it's pretty good. In general most primes will give you good results, so you might like to stick with them if you don't mind the lack of a zoom. You'll get used to it, trust me
    The 18-200VR will not be as sharp as the 50/1.8 but it sure is sharper than the 18-70/3.5-4.5 kit lens.

  5. #25

    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by Snoweagle
    Especially those megazooms, but those of less than 4 times zooms will be sharper.
    I have a counter example. An 11x zoom which is sharper than a 4x zoom.

  6. #26
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    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by lsisaxon
    I have a counter example. An 11x zoom which is sharper than a 4x zoom.
    Is it becos of the type of lens elements? My tamron 28-300 though sharp but never sharper than my 50mm. I've tried others such as the 17-40L, 100-300, 17-35L, though sharper than my 28-300 but not as sharp as my 50mm. But IMO zooms can only match primes at the most but not surpassing in sharpness.
    Last edited by Snoweagle; 23rd March 2006 at 05:16 PM.
    Canon EOS 5D, 24-70 f/4 L IS, 50 f/1.2 L, 70-300 f/4-5.6 L IS, 600EX-RT. Sigma 12-24 f/4.5-5.6 EX.

  7. #27

    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by honda
    I find that my sigma 18-50/2.8 to be as sharp as my 50/1.8 so i sold off my 50/1.8. Generally i find that the longer the focal length the sharper the lens will be. Easier to make a sharp lens of a longer focal length.
    http://singaporephoto.blogspot.com
    Oh, if your sigma 18-50/2.8 is as sharp as the 50/1.8, then the 18-200VR is sharper than the 50/1.8. Then I should take back my word in an earlier post that the 18-200VR is less sharp than the 50/1.8. At the end of the day, it really boils down to the apertuer you're using.

    See this thread http://forums.clubsnap.org/showthread.php?t=178944

  8. #28
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    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by lsisaxon
    Oh, if your sigma 18-50/2.8 is as sharp as the 50/1.8, then the 18-200VR is sharper than the 50/1.8. Then I should take back my word in an earlier post that the 18-200VR is less sharp than the 50/1.8. At the end of the day, it really boils down to the apertuer you're using.

    See this thread http://forums.clubsnap.org/showthread.php?t=178944
    Can see that the nikon one is sharper than the sigma one.
    Canon EOS 5D, 24-70 f/4 L IS, 50 f/1.2 L, 70-300 f/4-5.6 L IS, 600EX-RT. Sigma 12-24 f/4.5-5.6 EX.

  9. #29

    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by Snoweagle
    Is it becos of the type of lens elements? My tamron 28-300 though sharp but never sharper than my 50mm. I've tried others such as the 17-40L, 100-300, 17-35L, though sharper than my 28-300 but not as sharp as my 50mm. But IMO zooms can only match primes at the most but not surpassing in sharpness.
    It really depends on the lens design and the precision to which you machine/polish the glass.
    Zooms in the price range of $2k can never beat primes in the same price range. However, it is not unlikely that they can beat a prime lens which is a fraction of the price.

    Why do you think there are zooms of almost the same range with the same maximum aperture and yet the price difference can be so great? It's all down to the precision.

    Also, for people using digital, the resolution may look the same because it's already limited by the sensor resolution. Whack up the resolution then you'll know the difference.

    There are many many lenses which (I'll use Nikon examples) for example looks very sharp on a 6mp D70s but once used on a D2X with 12mp or just a D200 with 10mp, the differences can be clearly seen at 100% and it will become very obvious that one lens is clearly sharper than another.

  10. #30

    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by seanlim
    hmm no need...any focal length...dont mind tele..hopefully a street lens like the 24-85...=)..
    ard 2k or so budget...cheaper better
    At around 2k budget, you will probably find the AF-S 17-55/2.8 DX something very sharp and useful. And it's around the same range as the 24-85 would on a 35mm film camera.
    Last edited by lsisaxon; 23rd March 2006 at 05:34 PM.

  11. #31
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    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by lsisaxon
    It really depends on the lens design and the precision to which you machine/polish the glass.
    Zooms in the price range of $2k can never beat primes in the same price range. However, it is not unlikely that they can beat a prime lens which is a fraction of the price.

    Why do you think there are zooms of almost the same range with the same maximum aperture and yet the price difference can be so great? It's all down to the precision.

    Also, for people using digital, the resolution may look the same because it's already limited by the sensor resolution. Whack up the resolution then you'll know the difference.

    There are many many lenses which (I'll use Nikon examples) for example looks very sharp on a 6mp D70s but once used on a D2X with 12mp or just a D200 with 10mp, the differences can be clearly seen at 100% and it will become very obvious that one lens is clearly sharper than another.
    I get what u mean. Nowadays there're technologies in lens such as aspherical, low-dispersion, diffractive optics, fluorite, etc. which can help the lens preserve its sharpness and reduction in flaring as much as possible. Sometimes when i use my 28-300 and observe the lens elements when they zoom in and out, the distance between the elements changes quite a lot so the natural path of light entering the lens will be changed quite significantly, therefore the need for those special lens elements comes into play.
    Canon EOS 5D, 24-70 f/4 L IS, 50 f/1.2 L, 70-300 f/4-5.6 L IS, 600EX-RT. Sigma 12-24 f/4.5-5.6 EX.

  12. #32

    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by seanlim
    actually i love primes..they are fast, compact, looks nice...haiz its good points are endless..
    but was wondering whether zoom lens...excluding those above 2k plus can perfrom as well in terms of sharpness..maybe its just phsycological*pardon for poor spelling* but i realise that my prime is much sharper than my kit lens any time..
    Yes, definitely. How can anyone design a zoom which is around the same price range or not much more than the prime and expect it to be good? If you're really keen on a WA-mid tele zoom that is really sharp and willing to blow $2k on it, the 17-55/2.8 will certainly not disappoint you and can see you through even if you were to upgrade to D200 or D2X. Downside is, you'll probably want to upgrade the body next.
    Last edited by lsisaxon; 23rd March 2006 at 05:39 PM.

  13. #33

    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by Snoweagle
    I get what u mean. Nowadays there're technologies in lens such as aspherical, low-dispersion, diffractive optics, fluorite, etc. which can help the lens preserve its sharpness and reduction in flaring as much as possible. Sometimes when i use my 28-300 and observe the lens elements when they zoom in and out, the distance between the elements changes quite a lot so the natural path of light entering the lens will be changed quite significantly, therefore the need for those special lens elements comes into play.
    It's not just that. Optics is about precision engineering. A wavelength of light is in the order of several hundred nanometers. Do you know how short that is? That's about 0.0005mm if you can imagine that. However, to achieve good sharpness, the precision has got be within a fraction of a wavelength, so if you divide that number by 8 somemore, you get something like 0.00006mm, that how much the surface can afford to deviate from the theoretical surface to keep the optics sharp.

    Sure, computer ray-tracing technology can help to design aspherical lenses which 20 years ago people could not do. But how accurate you can produce those dimensions on glass is far more crucial than the design and the technology itself.

    To obtain that kind of precision, a lot of metrology is involved as well. After that, there's the assembly, again, precision engineering, precision alignment. Cannot pass the test align again --- read as expensive, skilled and trained labour intensive!!
    Last edited by lsisaxon; 23rd March 2006 at 06:01 PM.

  14. #34
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    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by lsisaxon
    It's not just that. Optics is about precision engineering. A wavelength of light is in the order of several hundred nanometers. Do you know how short that is? That's about 0.0005mm if you can imagine that. However, to achieve good sharpness, the precision has got be within a fraction of a wavelength, so if you divide that number by 8 somemore, you get something like 0.00006mm, that how much the surface can afford to deviate from the theoretical surface to keep the optics sharp.

    Sure, computer ray-tracing technology can help to design aspherical lenses which 20 years ago people could not do. But how accurate you can produce those dimensions on glass is far more crucial than the design and the technology itself.

    To obtain that kind of precision, a lot of metrology is involved as well. After that, there's the assembly, again, precision engineering, precision alignment. Cannot pass the test align again --- read as expensive, skilled and trained labour intensive!!
    That's why lenses are so expensive and usually cost more than the camera bodies. Similar to swiss watches, they are expensive and famous for their precision in time.
    Canon EOS 5D, 24-70 f/4 L IS, 50 f/1.2 L, 70-300 f/4-5.6 L IS, 600EX-RT. Sigma 12-24 f/4.5-5.6 EX.

  15. #35
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    Default Re: Lens as sharp as 50mm 1.8

    Quote Originally Posted by lsisaxon
    It's not just that. Optics is about precision engineering. A wavelength of light is in the order of several hundred nanometers. Do you know how short that is? That's about 0.0005mm if you can imagine that. However, to achieve good sharpness, the precision has got be within a fraction of a wavelength, so if you divide that number by 8 somemore, you get something like 0.00006mm, that how much the surface can afford to deviate from the theoretical surface to keep the optics sharp.

    Sure, computer ray-tracing technology can help to design aspherical lenses which 20 years ago people could not do. But how accurate you can produce those dimensions on glass is far more crucial than the design and the technology itself.

    To obtain that kind of precision, a lot of metrology is involved as well. After that, there's the assembly, again, precision engineering, precision alignment. Cannot pass the test align again --- read as expensive, skilled and trained labour intensive!!
    Good explanation there, and pretty informative and interesting. Thanks for sharing.

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