About lens....


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zoossh

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Nov 29, 2005
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#1
2 newbie questions regarding buying lens:

1. is the max aperture size related at all to the quality of lens? in another words, is it always true that if i buy a F/2.8 max aperture lens to shoot at F/8, its quality will always or most probably or mostly be better than say a F/4.5-5.6 max aperture lens also shooting at F/8?

2. is it always true that the lesser the lens groups and elements, the better the quality? how true is that?

let's say if i used a nikkor AF 70-300mm f/4-5.6G with less construction than the 18-200mm, both of which i shoot at maybe 100mm focal length. would the 70-300mm be better if the lens groups and elements is lesser?
 

GOMUS

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Jan 10, 2006
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#2
interesting question, any expert can advise? I would like to know too!
 

Aug 16, 2005
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#3
zoossh said:
2 newbie questions regarding buying lens:

1. is the max aperture size related at all to the quality of lens? in another words, is it always true that if i buy a F/2.8 max aperture lens to shoot at F/8, its quality will always or most probably or mostly be better than say a F/4.5-5.6 max aperture lens also shooting at F/8?

2. is it always true that the lesser the lens groups and elements, the better the quality? how true is that?

let's say if i used a nikkor AF 70-300mm f/4-5.6G with less construction than the 18-200mm, both of which i shoot at maybe 100mm focal length. would the 70-300mm be better if the lens groups and elements is lesser?
1. First answer: depends, but most constant f2.8 lens are all the legendary lenses of the manufacturer, so most of them acan produce very good quality images.
 

Jul 31, 2005
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#4
more elements juz means more prone to flairing. the 70-200vr is 21/19 but its still the best in its range.
 

cocoa

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Jan 20, 2006
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#5
My take in BLUE.

COCOA.

zoossh said:
2 newbie questions regarding buying lens:

1. is the max aperture size related at all to the quality of lens? in another words, is it always true that if i buy a F/2.8 max aperture lens to shoot at F/8, its quality will always or most probably or mostly be better than say a F/4.5-5.6 max aperture lens also shooting at F/8?

>>In a way, YES. Most lenses have best performance at 2-3 stops down from their widest aperture. So, an f2.8 lens would peak at F5.6 or F8. At f8, it would usually outperform a small/variable aperture lens (f4.5/5.6 type) set also at f8.

2. is it always true that the lesser the lens groups and elements, the better the quality? how true is that?

>>the one with lesser no. of lens groups/elements usually has higher contrast. However, with good design and special glasses, the one with more elements/groups could have better overall optical quality (eg. resolution and distortion) as compared to a simpler design (one with less elements/groups). So, it depends.

let's say if i used a nikkor AF 70-300mm f/4-5.6G with less construction than the 18-200mm, both of which i shoot at maybe 100mm focal length. would the 70-300mm be better if the lens groups and elements is lesser?
 

solarii

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Oct 20, 2005
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#6
1) Generally speaking, yes. Large aperture lenses are generally more expensive and are designed for the high end segment. Consequently they are of superior construction and optical quality. With regards to image quality, yes what cocoa said is true.

2) Not really... really depends. Some lens elements serve special purposes, such as fluorite elements which reduce CA, or IS units. These elements serve to enhance image quality in lenses which stretch the optical limits of the lens contruction. So its not quite accurate to say that a lens with fewer elements produces better image quality.
 

zoossh

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#7
cocoa said:
>>In a way, YES. Most lenses have best performance at 2-3 stops down from their widest aperture. So, an f2.8 lens would peak at F5.6 or F8. At f8, it would usually outperform a small/variable aperture lens (f4.5/5.6 type) set also at f8.
Does that mean that an F/2.8 lens peak performance at F/5.6 or F/8 while F/4.5 lens peak performance at a much smaller aperture size?
 

zoossh

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#8
solarii said:
2) Not really... really depends. Some lens elements serve special purposes, such as fluorite elements which reduce CA, or IS units. These elements serve to enhance image quality in lenses which stretch the optical limits of the lens contruction. So its not quite accurate to say that a lens with fewer elements produces better image quality.
i.e. lesser elements is just one factor, and not reliable as a sole factor?
 

solarii

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#9
zoossh said:
i.e. lesser elements is just one factor, and not reliable as a sole factor?
To be frank I judge the lens as a whole... the final image quality. I don't care how many elements the lens has so long as its sharp. There are other test/assessment methods for lenses which are far more reliable... read the many reviews available on the web. Nobody cares how many elements there are... its merely a statisitc. Whats important is how the lens performs at the various focal lengths... centre/edge sharpness, CA, distortions etc.

By the way, who taught you to count the elements? Referrring the eg you quoted in the thread starter... there's no way to tell which is better by simply counting elements. Its not even an indication. Tests have to be done to come to a conclusion.
 

sORe-EyEz

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Jun 28, 2005
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#10
in d pass lenses technology not so gd less glass = less flare. now times hav changed le mah... :lovegrin:
 

zoossh

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#11
solarii said:
By the way, who taught you to count the elements? Referrring the eg you quoted in the thread starter... there's no way to tell which is better by simply counting elements. Its not even an indication. Tests have to be done to come to a conclusion.
newbie a lot of misconceptions. i'm expanding on my range and so are now looking at new lens. as they are not cheap, need to understand better on what i'm buying. considering nikkor 18-200mm to replace my kit lens 18-55mm (might be selling it off) if 18-200mm is better than 18-55mm in all or most aspects. also have sigma 10-20mm to cover wide angle and nikkor 50mm F1.8 to cover fast lowlight shots or narrow DOF shots.
 

yyD70S

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Dec 25, 2005
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#12
zoossh said:
newbie a lot of misconceptions. i'm expanding on my range and so are now looking at new lens. as they are not cheap, need to understand better on what i'm buying. considering nikkor 18-200mm to replace my kit lens 18-55mm (might be selling it off) if 18-200mm is better than 18-55mm in all or most aspects. also have sigma 10-20mm to cover wide angle and nikkor 50mm F1.8 to cover fast lowlight shots or narrow DOF shots.
You have a good range covered there. One for the superwide and the other taking care of low-light photography.

Generally, most would agree that the 18-200 VR is superior to the 18-55mm kit lens... but although the telephoto range is tempting and I acknowledge that the 18-200 mm is a good walkaround lens, with your current setup, I think the next buy should be a flash (sorry for being a little OT here). Unless, of course, part of the reason you got the 50mm lens was because of your dislike for flash photography.
 

Jul 31, 2005
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#13
how many slr users dont hav an external flash? even with 50/1.8 its necessory to complement it with good lighting produced by gd external flash.

and i doubt u'll be able to sell off ur kit lens.
 

zoossh

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#14
yyD70S said:
Unless, of course, part of the reason you got the 50mm lens was because of your dislike for flash photography.
yup, i dislike flash photography and in fact always try to switch off the flash. if it bounce up, i would press it down, try another mode to off the auto flash or just give up on that shot.
 

Hacker

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Dec 6, 2005
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#15
If you have a bigger aperture, chances are you have a larger lens. All things being equal, a bigger lens allow more light to go through which is better.

Less elements means less distortions. if you design a lens with the same glass, having less glass between the image and the sensor will result in a better picture.

The laws of physics must be obeyed. :confused:
 

GOMUS

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#16
zoossh said:
yup, i dislike flash photography and in fact always try to switch off the flash. if it bounce up, i would press it down, try another mode to off the auto flash or just give up on that shot.
if using CANON, go to settle of PROGram or MANUAL. then can get rid of problem.
i m not try to promote CANON~...i guess it can be done over NIKON too. it is always my favourite option
 

zoossh

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#17
Hacker said:
If you have a bigger aperture, chances are you have a larger lens. All things being equal, a bigger lens allow more light to go through which is better.
i suppose the front filter size doesn't mean larger lens (lens as is the glass inside and not the whole body of lens) right?

i.e. a lens that fits a 77mm filter does not mean it is larger than a lens that fits 58mm filter. right?
 

zoossh

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#18
GOMUS said:
if using CANON, go to settle of PROGram or MANUAL. then can get rid of problem.
i m not try to promote CANON~...i guess it can be done over NIKON too. it is always my favourite option
i usually use AP or SP cos it gives me some control and make it faster than manual.
 

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