Sorry. It's those pesky lenses again

J

jazzy66

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Nicki
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I know people probably get fed up answering this sort of question, but don't shout at me, even if I am having a dense moment :bonk:. I can't seem get my head around the zillions of different lens options :bang:.

I know that I have to get one that fits my camera (pentax in my case), and that a macro lens works best for insects and the like, (although I did read something about 1:1 macro somewhere, whatever that means, I just kind of ignored it) but then I started getting confused with things like:-

- 17-50 f2.8 and 17-40 f/4 L (I think these were refering to tamron and canon lenses respectively. I know these specific ones don't necessarily apply to my camera but it's only an example. What does it mean?? it looks like chinese to me)

- prime/wide/ultra wide/fish eye - Obviously types of lenses (i'm guessing that there's also narrow and non prime ones) but what's the difference? And what would they be used for?

Could someone either explain in simple terms, ideally with some usage examples, or else point me in the direction of a thread that explains it for me (I thought I saw one a while back but can't find it now).
 
1:1 means a lens that will reproduce something the same size as it really is onto your sensor...

on the 17-50 f2.8

The 17-50mm bit is the focal length and the f2.8 refers to the aperture. as a really basic rule of thumb, the longer the focal length the closer you'll be able to zoom to something that's further away. The bigger the aperture (smaller numbers) the more light the lens will let onto the sensor, which means you'll get a faster shutter speed :)

Hopefully someone will be able to give you some links with pictures as well (y)
 
Generally speaking, a 50mm lens is considered to be a standard lens - the one which gives you a view in the viewfinder similar to what you'd see with your naked eye. Objects appear the same size and perspective is the same.

As the focal length goes shorter than that, lens are considered to be wide angle - 35mm, 28mm, 17mm, 10mm, getting wider as the focal length gets smaller.

As the focal length gets longer than 50mm, lenses are considered to be telephoto lenses (lenses which magnify) which magnify the subject more as the focal length gets longer - 80mm, 100mm, 200mm, 500mm and so on.

A lens like the Canon 17-40L is a zoom lens which has a variable focal length from 17mm (wide) to 40mm (just slightly wider than a standard 50mm lens)
 
Just leaves me to add the odd extra bit...

The L is marked on Canon's high end lenses (Luxury)
IS or VR Image stabilisation (Canon) or Vibration reduction (Nikon)...helps to overcome shake.

Don't be fooled into thinking the term "Macro" on a lens is genuine. Quite a few lenses have this added (especially zooms) and it merely implies that the lens can focus closer than normal for a lens of similar focal length. All true macro lenses are primes with the exception of a special Canon lens.

Bob
 
Thanks guys. It's finally starting to make sense :D

daftbugga said:
http://www.berniecode.com/writing/photography/beginners/

here you go jazzy that might help.
Click to expand...

That's a huge help, thanks. It's exactly the sort of thing I was looking for.

Just one more little question (and I've got a funny feeling the answer is staring me in the face and I just can't see it :bonk:).

What's the difference between a prime and a zoom? I thought from CT's post they were the same thing, with the words prime and standard being interchangeable, but after reading Canon Bobs I'm now not so sure
 
stan the man said:
[quote by canon bob]"All true macro lenses are primes with the exception of a special Canon lens".
i have a 50mm F1.7 prime lens,so does that mean it's a macro lens?
Click to expand...
No, the reverse isn't true....the term macro refers to the ability of the lens to focus close enough to give a life sized image on the sensor....1:1 reproduction ratio

jazzy66 said:
Thanks guys. It's finally starting to make sense :D



That's a huge help, thanks. It's exactly the sort of thing I was looking for.

Just one more little question (and I've got a funny feeling the answer is staring me in the face and I just can't see it :bonk:).

What's the difference between a prime and a zoom? I thought from CT's post they were the same thing, with the words prime and standard being interchangeable, but after reading Canon Bobs I'm now not so sure
Click to expand...

A prime is a lens of fixed focal length whereas a zoom can vary the focal length between the two limits marked on the body....16-35, 24-70, 70-200mm etc. A prime is simply fixed at one length eg, 50mm, 100mm, 400mm etc

Bob
Click to expand...
 
A prime lens is one where the focal length is fixed.

A 50mm standard lens is a prime lens

a 17mm wide angle is a prime lens.

A 500mm telephoto is a prime lens.

As you look through the viewfinder with any of these lenses, the magnification never changes - it's fixed because the focal length is fixed!

With a zoom lens, as you look through the viewfinder, you can either turn, or push and pull a collar on the lens which makes the subject appear larger or smaller.

Zoom lenses are not prime lenses! :D
 
CT said:
A prime lens is one where the focal length is fixed.

A 50mm standard lens is a prime lens

a 17mm wide angle is a prime lens.

A 500mm telephoto is a prime lens.

As you look through the viewfinder with any of these lenses, the magnification never changes - it's fixed because the focal length is fixed!

With a zoom lens, as you look through the viewfinder, you can either turn, or push and pull a collar on the lens which makes the subject appear larger or smaller.

Zoom lenses are not prime lenses! :D
Click to expand...

Now it makes sense :woot: Thanks everyone, I've been confused by this stuff for weeks now
 
LOL. Well now we've got that sorted out. One or two other points to note.

A good quality prime lens will give better image quality than even the very best zoom lenses, although the best zoom lenses are very good indeed.

With zoom lenses, as you zoom that image in and out in the viewfinder, all the glass elements inside the lens have to change position in relation to each other to obtain the different focal lengths. It's pretty incredible engineering, but with a prime lens none of this has to happen, so inevitably images are that bit sharper. :)
 
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