Query about Lenses


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DarNikon

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Nov 8, 2005
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Hi, I have explored photography for about 8mths. I have been looking at different lenses. Can someone help be clarify these points since I am 'blur' in these areas :

1) Why would one need a single distance lens eg 50mm if he already has a say..18-70mm lens?
2) Why are some single distance lens more expensive than the zoom ones like 18-70mm.

Does the single distance lens give you better quality pictures?

Thanks for your help :)
 

Have a little read here:

http://www.olegnovikov.com/technical/primevszoom.shtml

Conclusions

So, what to choose - ffl or zoom lenses? This question has to be answered by each photographer, really - depending on his style of photography as well as considering all the factors outlined above. It is also important to note that ffl and zoom lenses are not entirely contradicting - in many cases they are complementary and one might use both for different purposes.
 

Thank you very much rhair78 for your help. :)
 

DarNikon said:
Hi, I have explored photography for about 8mths. I have been looking at different lenses. Can someone help be clarify these points since I am 'blur' in these areas :

1) Why would one need a single distance lens eg 50mm if he already has a say..18-70mm lens?
2) Why are some single distance lens more expensive than the zoom ones like 18-70mm.

Does the single distance lens give you better quality pictures?

Thanks for your help :)
Another name for fixed focal length lenses would be prime lenses.

1) Personally, I used my 18-70 kit lens mostly outdoors, in the day time. Because i don't like to use flash, I use a 50mm f/1.4 indoors. I don't think u can find such fast apertures for zoom lenses.

2) This question quite technical lah, i cannot answer :bsmilie: It has to do with lens construction, i guess ... Or maybe, sometimes, it's just marketing :think:

Whether prime lenses give better quality pictures? Many serious photographers say they do ... But nowadays, with high quality zoom lenses like the Nikon trinity, the differences are hard to tell ... At least, hard for amateurs like me to tell :bsmilie:
 

they say prime lens clearer,less space between e glasses...less flare etc also
 

Thanks a lot wiz23, seanlim & ortega for the tips. Finally, I know what this word 'prime' lens is all about - thought they were meant for pro photographers hehe.. Once again, thanks :)
 

DarNikon said:
Thanks a lot wiz23, seanlim & ortega for the tips. Finally, I know what this word 'prime' lens is all about - thought they were meant for pro photographers hehe.. Once again, thanks :)
Before you even think about other glasses and lenses, I suggest you do try out the kit glass first, get used to it and see what else you need before seeking for other glasses.

In time to come, the glass collection will outweight your camera body, so the glasses are important and it's unwise to keep changing them.
 

1. Zooms are harder to construct than primes. Due to the increased number of elements (lenses) to cover a zoom range you'll need a series of convex & concave elements moving back & forth to bend the lightrays (if you apply your light physics). At the same time the lenses have to eliminate distortion, etc to replicate the image. Because the lightrays are transmitting through air & glass, you lose sharpness and constrast through reflection, refraction, dispersion, etc etc. To offer a wide range you need to to able to retain high quality.

2. Fast lenses are harder to construct than normal lenses. Distortion occurs at the edges of the lense, particularly for wide apertures like f1.0, f1.2, f1.4. So it's not that simple anymore to just provide a f1.0 lense when you need to guarentee image quality at the centre of the image as well as at the outer zones. Wide open also gives the trouble of flare, so additional work is required to suppress that. Wide apertures naturally shallow DOF thus harder to capture detail, good construction will help solve that since there is no point shooting at f1.2 and losing everything other than the focus point.

3. Fast zooms = 1+2. But I don't think they go till f1.x. I think the max is f2.8.

4. Hence, "harder to construct" = "more work" = "more expensive". You get what you pay for.
 

Thanks espn & foxtwo. Yes what you have both said make sense. I currently have the kit lens and a 70-300mm. Actually friend said to get the nikkor 50mm - he said this produces solid shots especially indoors. This was what got me confused since I assumed initially that ...hey I can use by kit lens to shoot 50mm - why buy another prime lens for that purpose :)
 

Basically, apart from the differences foxtwo have laid out.

A 50mm is also a good low light glass that's faster than the kit glass you have, also, it's lighter. These are some other reasons I can think of, personally I also use the 50 mm f/1.8 on my F80.
 

i haven't used a zoom since my very crappy tamron 28-200 eons ago. I like the 50mm on my fm2n, light fast & smooth Mfocusing. If your kit doesn't pose any big problems for you, just stick with it. A fast 50mm's a nice want though.
 

If you realize, there are fast primes (<F/2) but not fast zooms (as a general rule). The reason lies in what foxtwo had said.

You can't construct a zoom that is ultra-wide open because the abberations (chromatic and spherical) will be too obvious because of the large open diameter (aperture) that the image quality is terrible.

Imagine this: 10-500mm F/1.2 NOCTILUX.. haha, maybe I am exaggerating.
IMPOSSIBLE

Unless someone comes out with miracle glass, there will never be such a lens made in history because?
The properties of light & our current glass technologies (low-dispersion glass, ED glass...)
At different focal lengths, the lens will perform better or worse as there is a sweet spot. There is no lens that has exactly the same sharpness throughout the entire focal length.

This is made worse when the impossible lens I mentioned covered ultrawide to ultratele. That is why if you realized, those high power zooms such as 18-200mm do not perform as well as lenses which have a sole purpose (e.g. Nikkor AF-S 12-24mm F/4).

And because the impossible lens has a aperture number of F/1.2. It is so wide that all abberations will distort the image.

Hope I wasn't too long winded.
 

espn said:
Basically, apart from the differences foxtwo have laid out.

A 50mm is also a good low light glass that's faster than the kit glass you have, also, it's lighter. These are some other reasons I can think of, personally I also use the 50 mm f/1.8 on my F80.
I agree with espn.

DarNikon, if u are interested, u can browse my small little gallery (link is below), all the indoor pictures of my baby girl are taken with the 50 f/1.4 without flash. Basically, the 50 f/1.8 & 50 f/1.4 are identical in terms of sharpness. The only difference, obviously, is the extra 2/3 of a stop the 1.4 has over the 1.8. Which means it can be faster in low light, but which also means it has a shallower depth of field ...

Anyway, I love the 50mm :thumbsup:
 

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