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  1. #1
    Join Date
    Jul 2005
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    54

    Post What Makes a Lens Good?

    Alright guys, I thought this would be one heck of a question.

    What makes expensive DSLR lenses better than the say xx-xxMM kits that DSLRs can come w/?

    I always see people saying _______ lenses by ______ for $xxx (yeah 3 digits) will be much better than the kit ones that come w/ the DSLR.

    The only real thing I can think of that would make lenses "better" would be the actual quality of the glass being used, I know fiber optic cords are MUCH MUCH higher grade glass than window glass, because u don't see that green part on the outer edges (this is caused by metallic contaminants inside the glass).

    So what do u guys think? THX!

    P.S. some comparision links/pictures would be INCREDIBLY useful also.

  2. #2
    Join Date
    Mar 2005
    Location
    Chapel Hill, NC
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    647
    hmm .. there are many factors, and I'm sure every person has their own priorities, but here's a list of things that factor into lens "quality", off the top of my head: max. aperture ("speed"), sharpness, contrast, focus speed and accuracy, control of chromatic aberrations and flare, optical distortion (barrel/pincushion), "bokeh", build quality, size, weight...

    Oh, and the *really* good ones often go into 4 digits ...

  3. #3
    Join Date
    Jul 2005
    Posts
    54
    Quote Originally Posted by Balrog
    hmm .. there are many factors, and I'm sure every person has their own priorities, but here's a list of things that factor into lens "quality", off the top of my head: max. aperture ("speed"), sharpness, contrast, focus speed and accuracy, control of chromatic aberrations and flare, optical distortion (barrel/pincushion), "bokeh", build quality, size, weight...

    Oh, and the *really* good ones often go into 4 digits ...
    OK thx Balrog. Anyone else have ne input?

  4. #4
    Join Date
    Oct 2004
    Posts
    2,124
    Certain lens technologies make a lens "better" in certain situations. Aspherical glass elements, exotic crystal elements, ED glass etc.

    The basic "quality" in my mind of a lens factors in cost, sharpness, color and quality of build.

    The "quality" of the sigma 18-125 lens I found low due to color cast, AF speed and distortion long end. The same lens someone else might find (and many do) to be high "quality" for the price.

    I find the 28-135 canon lens to be a very high quality lens but there are those who do not agree.

    Much of it is subjective and has to due with use/desired charecteristics and price/performance expectations.

    Tim

  5. #5
    Join Date
    Nov 2004
    Location
    Wild, Wonderful, Wyoming
    Posts
    1,043

    Great Glass

    The more expensive glass has higher quality control(more rejected glass), higher quality glass, exotic elements (Canon L series glass has at least one flourite element) and better overall build quality. There seems to be more than one level of consumer glass with there being decent and poor glass. The kit lenses seem to be almost a throw in type lens(Nikon lenses are much better than canon in this reguard) and most of the consumer have a wide range of image quality. YGWYPF applies in a lot of cases, with the more expensive consumer glass being better in a lot of cases. The better more expensive lenses (pro) are usually faster (f/2.8, f/4) which requires a larger element to gather more light, and a larger element is a lot more costly to produce. In a lot of cases with the most expensive lenses the aperture is fixed as opposed to varied with the lens being slower at the long end.
    In my experience I purchase the highest quality glass I can afford. The glass is what makes the picture, the body just controls the light.

  6. #6
    Join Date
    Nov 2004
    Posts
    1,807
    Quote Originally Posted by TenD
    In my experience I purchase the highest quality glass I can afford. The glass is what makes the picture, the body just controls the light.
    i totally agree, but i'll add the word "reasonably" in front of the word "afford". i've now spent more than 5.5x the $$ on quality lenses than i did with the body. only problem is, with the cost of lenses i've little left to upgrade the body
    canon 17-40 L, 70-200 f2.8 L, 400 f5.6 L, 50 f1.4 & f1.8, 1.4x TC, sigma 15 f2.8 fisheye, flash 500 DG Super, kenko extension tubes

    note to self: don't participate in sad, silly threads unless you're looking for sad, silly responses.

    "anti-BS filter" (from andy): http://dcresource.com/forums/showpos...94&postcount=4

  7. #7
    Join Date
    Nov 2004
    Location
    Wild, Wonderful, Wyoming
    Posts
    1,043
    Quote Originally Posted by ReF
    i totally agree, but i'll add the word "reasonably" in front of the word "afford". i've now spent more than 5.5x the $$ on quality lenses than i did with the body. only problem is, with the cost of lenses i've little left to upgrade the body
    Exactly...I'd bet your "old" body takes great photos with that great glass! Light tank, thats all it is, with some pre planning you can take any photo a 1DmkII can.

  8. #8
    Join Date
    Jul 2004
    Location
    Monterey Bay
    Posts
    6,011
    Quote Originally Posted by TenD
    Exactly...I'd bet your "old" body takes great photos with that great glass! Light tank, thats all it is, with some pre planning you can take any photo a 1DmkII can.
    You can take it (any photo), but it may not be as good printed at, say, 20 x 30 or even 16 x 20. While a good lens is very important a competent camera design is just as important. It all depends on what type of photography you are doing, how good you are, and whether you are trying to make a living at it.
    D7000, D70, CP990, CP900, FE.
    50mm f/1.8, Sigma 18-125, Sigma 24-70 f/2.8, Nikon 18-105 VR, Nikon 55-200 VR, Nikon 43-86 f/3.5 AiS, Vivitar 28-90 F/2.8-3.5 Macro, Vivitar 75-205 F/3.8-4.8, SB800.
    Ha! See, I can change...


    http://d70fan.smugmug.com/

  9. #9
    Join Date
    May 2005
    Posts
    292
    Here is a comparison between two Nikkor wide angle zooms:

    17-35 f/2.8 IF-ED
    -3 aspherical elements
    -2 ED elements
    -13 total elements in 10 groups
    -9 blade diaphragm
    -.9ft Closest focus
    -SWM for fast and quiet focussing

    18-35 f/3.5-4.5 IF-ED
    -1 aspherical element
    -1 ED element
    -11 total elements in 8 groups
    -7 blade diaphragm
    -1.1ft closest focus

    So... what does quicker quieter focussing, better bokeh, and sharper edge to edge images cost you?

    The 18-35 lists at 689.95.

    The 17-35 is a little more expensive... if you consider 1300 or so (1999.99 list) to be a little! (edit: those prices are Canadian Dollars)

    Edit2: Ok, so I left out some conclusions

    What makes a good lens good? From the above comparison, it looks like everyone seems to understand it. Exotic glass and lens elements, better aperature diaphragms, better focussing motors. Thing is, a "better" lens may not always be the best lens. If you miss shots on the wide side because you need to save longer for the AF-S lens, it might not have been worth the wait. I have the lesser priced lens on order because it does what I need it to. If I ever "turn pro", I'll probably get the AF-S wide zoom, because it is a really nice bit of kit. In the mean time, I'll enjoy having the 18-35 on my F80 and D70s
    Last edited by Warin; 08-07-2005 at 12:36 PM.

  10. #10
    Join Date
    Aug 2004
    Location
    Northern Colorado, USA
    Posts
    2,225
    Quote Originally Posted by TenD
    Exactly...I'd bet your "old" body takes great photos with that great glass! Light tank, thats all it is, with some pre planning you can take any photo a 1DmkII can.
    Sort of. With film, if they make a better film, you can put it in any camera. Pro features don't really result in better pictures, just more convenience (OK, the film advance rate may give more opportunities and the shutter may allow shorter exposures and the flash system may be more sophisticated, but you can use the same film in a cheap camera as you can in a pro model). With digital, the body is both light box and film. To get better digital film (the sensor), you need a new body. Some people equate the memory card as the film, but it only stores the images. It is the can that the film rotates into.

    Cheers,
    Eric

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