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02-19-2009, 04:38 PM   #1
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Why is 'good' glass so important????

Ok, noobie question obviously...

My kit lens takes very nice pictures. They're sharp, clear, and attractive.....

Yet everyone keeps saying, save for good glass.. get the best glass you can afford, etc. etc....

I'm thinking there must be more to 'good' glass than just image quality? do they focus faster? I know some of them have a wider apeture range, but what does that really mean for me?

I'm just missing something to connect why I need to spend $500+ on a lens that there is a under $200 option for....

Thanks in advance and please be gentle....

Ken

02-19-2009, 04:44 PM   #2
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Yeah I know where your coming from but when you start to print them say at a3 you notice all the imperfections like edge to edge sharpness and sharpness in general etc and vignetting too.

My da 35mm f/2.8 macro is so much sharper than my da 16-45mm f/4 ever was and I though that was good. My old da 18-55mm kit was still an awesome piece of kit with kind of macro too

and my new da* 50-135mm /2.8 sdm is amazing even wide open at f/2.8 but my old da 50-200mm kit lens was awesome too I used it at the clothes show and got better photos than many of the real pros with $5000 lenes!!!

You won't really understand until you try a $500 lens properly. I also found once I tried a prime I loved it and preferred it over zooms!
02-19-2009, 04:48 PM   #3
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hmmm.. sharpness... vignetting... CA..... anything else missing?
02-19-2009, 04:56 PM   #4
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QuoteOriginally posted by Vylen Quote
hmmm.. sharpness... vignetting... CA..... anything else missing?
Color rendition ... barrel distortion (lack thereof) ... constant aperture zooming ... DOF control

and let's not diminish the word "Limited" on the badge or the gold band on the DA* for the absolute cool factor.

02-19-2009, 04:57 PM   #5
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on DA* lenses: Weatherproofing, SDM silent and faster autofocusing

Also on many of the more expensive lenses the front element doesn't rotate when focusing so you can use a polarising filter easily.
02-19-2009, 05:11 PM   #6
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QuoteOriginally posted by Javaslinger Quote
Ok, noobie question obviously...

My kit lens takes very nice pictures. They're sharp, clear, and attractive.....

Yet everyone keeps saying, save for good glass.. get the best glass you can afford, etc. etc....

I'm thinking there must be more to 'good' glass than just image quality? do they focus faster? I know some of them have a wider apeture range, but what does that really mean for me?

I'm just missing something to connect why I need to spend $500+ on a lens that there is a under $200 option for....

Thanks in advance and please be gentle....

Ken
It is not all about sharpness. Actually some of the most favoured lenses have a very nice unsharpness (for areas not in focus) called bokeh. With this and large enough aperture (narrow DOF) you can isolate the model/object from the background. 43/1.9 is an excellent example of this. In other cases it can be sharpness, some lenses like makros are often designed to be very sharp. The DA 35 Makro seams to be extremely sharp also on long distance. It is also about distortion, vignetting, CA, PF, flaring, colours, contrast, resolution etc... But usually no lens can be perfect in everything, if you make it sharper, the bokeh might get ugly. If you reduce distortion you might get CA. Least compromises you usually get in a prime lens, but zooms are alsmost as good in many cases today. Personally I do not like zooms, but many people do.


Ohhh, and one more thing. The glass (lens) used to be the most important thing in the film days. When the photo was taken, the only thing between the film and the object was the lens, the camera did not affect the picture at all. With digital cameras this has been different, and the choise of camera has been somewhat important, but all DSLRs are now so good so by spending your money on the glass you will get great pictures with any camera (under normal circumstances).

Last edited by quarc; 02-19-2009 at 05:18 PM.
02-19-2009, 05:22 PM   #7
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sharpness is #1 if you are doing post work in photoshop
the kit lens could be very sharp. but good glass is usually also fast. lower aperture number. and that gives you the ability to shoot in harder light conditions. you will also get a better dept of field. now if you are good with the kit lens excellent for you! its a great lens.
the more you will get in to photography you might start to feel the need for a better faster glass. as long as you don't feel it save your money
02-19-2009, 05:22 PM   #8
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Sensors no doubt get better and better all the time. Currently the sensor is the limiting factor, but unless you have good ones, lenses will soon be the limiting factor.

We are still using lenses made 50, 60 years ago. How many people do you know using digital cameras made 5, 6 years ago? (I'm one of them, still using a Canon G5).

Camera bodies are disposable. Good glass will stay - a reason that "everyone keeps saying, save for good glass.. get the best glass you can afford, etc. etc...."

02-19-2009, 05:28 PM   #9
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You mention aperture range as being a difference, but it isn't clear if you understand the significance of this, so I'll explain that a little.

At most focal lengths, the kit lens will only give you an aperture of f/4.5 at best. If you're shooting in low light - indoors with no flash, for example - that might translate into a shutter speed of 1/10" or slower at ISO 1600. A lens with a maximum aperture of f/2.8 would let you shoot at 1/30". That can be the difference between a sharp picture and a blurry one (blur from camera shake as well as subejct motion). A lens with f/1.2 would let you shoot at 1/60", and one with f/1.4 would let you shoot at 1/120". While shooting at 1/30" at f/2.8 might man abut a 50/50 chance of a blur-free picture, 1/120" at pretty much guarantees it.

So bottom line - when shooting without flash in low light, the difference is literally like night and day. Another thing about large apertures like f/2.8 - or better yet, f/1.4 - the depth of field (DOF) is very small, allowing you to create effects where one petal of a flower is in focus (or one eye of a portrait, etc) and the rest is out of focus.

Shooting outdoors, or indoors with flash, you can shoot at f/8, and the differences between the kit lens and a more expensive lens would be much more subtle. They'd be noticeable mainly if you blow the image up to poster size - or view it on screen at larger than full-screen size (aka "pixel peeping"). Some people will notice the difference at smaller sizes too, but realistically, if you're shooting at f/8, I do think it's pretty subtle in most cases.
02-19-2009, 05:43 PM   #10
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QuoteOriginally posted by Marc Sabatella Quote
That can be the difference between a sharp picture and a blurry one (blur from camera shake as well as subejct motion).
May I add to Marc's remark: the "Shake Reduction" feature of the current bodies/lenses can reduce the effect of camera shake, but it can't do a thing about subject's motion. The only thing that minimizes the effect of subject's motion is greater shutter speeds, thus faster lenses.
02-19-2009, 05:47 PM   #11
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That was a particularly excellent explanation... Not to say I don't appreciate all of them!

Thank you very much,

Ken
02-19-2009, 07:24 PM   #12
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QuoteOriginally posted by Marc Sabatella Quote
At most focal lengths, the kit lens will only give you an aperture of f/4.5 at best. If you're shooting in low light - indoors with no flash, for example - that might translate into a shutter speed of 1/10" or slower at ISO 1600. A lens with a maximum aperture of f/2.8 would let you shoot at 1/30".
1/40th not 1/30th yes?
02-19-2009, 10:43 PM   #13
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Actually, the 18-55 kit zoom is indeed a nice lens. I'm not fond of what happens to the out of focus areas at wider apertures but then again I do consider it a free lens based on the price I paid for my K200D. On a whim, I found that throwing a cheap close-up filter on it does wonders for the blurry parts for close-up shots so that's worth a try.
02-19-2009, 10:55 PM   #14
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Another view from a man who knows lenses:

"The way to test a camera lens is to take pictures with it.

Take lots. Then look at them. If you want to, notice what the the lens does: what it does right and what it does wrong, what you like about it and what you don’t. If you see a lot you like and not much you don’t, then it’s a good lens. If you can’t find anything wrong and everything seems right, then it’s a great lens…for you. It might still have faults—but if they’re invisible in your work, they don’t count. "

Read on: The Online Photographer: All Lens Tests are Wrong


(And I still love my Limited primes!)
02-19-2009, 10:59 PM   #15
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QuoteOriginally posted by Marc Sabatella Quote
While shooting at 1/30" at f/2.8 might man abut a 50/50 chance of a blur-free picture, 1/120" at pretty much guarantees it.
Blur-free yes, but by necessity a larger portion of the image will get "out of focus" the larger the aperture becomes. Fast glass buys you speed but at the expense of usable sharpness. At f/1.4 the smallest camera movement can place the subject out of focus and there isn't a lot of the subject that can be placed in focus.

Thin DOF can be great for artistic shots but can be a pain when you would like to have more than someone's tip of the nose in focus.

QuoteOriginally posted by SOldBear Quote
The only thing that minimizes the effect of subject's motion is greater shutter speeds, thus faster lenses.
Faster shutter speeds can also be obtained by cranking up the ISO. This has the advantage of leaving the DOF still usable but the disadvantage of introducing noise if exaggerated.

If you are happy with the kit lens, continue to be happy with it and don't let your fun be spoiled. It is generally regarded as a very good lens and there is no reason to become unhappy with it just because others are enjoying different lenses more.
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