"PRIME" - define please :)

[EdinburghGary]

What exactly is a prime lens? I see it mentioned from time to time, but never quite understand what is "prime" about the lens...

[EdinburghGary]

I should have guessed:
http://en.wikipedia.org/wiki/Prime_lens

[Steep]

I could have told you you could have guessed :)

[EdinburghGary]

So two meanings...what do people here normally mean when they discuss prime? That article is a bit pants.

[Steep]

I mean non-zoom ie it has one single focal length.

[mattyh]

Me too :)

[FruitFlakes]

I prefer fixed-focal length :p

[EdinburghGary]

For some reason I thought PRIME meant the "best" of its type, ie the 50mm f1.4 prime was the best 50mm and so on. I also prefer FFL as it's very descriptive.

G.

[Steep]

You're both just posh :P

[DiddyDave]

FFL sometimes isn't enough though, nor is Prime for that matter, amongst FFL lenses we also have 'Cats', 'Fisheyes' and 'Macros'

Oh, and to add further interest (confusion?) my prime lens is a mid-range zoom

:lol:

DD

[Woodsy]

A prime lens to me is one whose focal length does not change. As a result, generally has better image quality.

[Beachball]

A 'prime' lens is a fixed focal-length lens. As said above, generally they have better image quality over their zoom-equivalents that cover the same length as they tend to have fewer optical elements.

[DiddyDave]

Primes, as in FFL, only have better quality if they are damn good ones. A £200 200mm isn't going to be as good (in IQ) as a £1,000 70-200mm, so a direct comparison is only valid where cost is taken into account too

We've generally adopted 'Prime' to mean FFL these days, but it did/does also mean the Primary lens used in the bag i.e. the one most often used, or Primary usage lens

The most common problem with FFLs over zooms is that the FFL is the 'wrong' length for the job so you either miss the shot as you can't get the subject in properly, or you have to crop as it wasn't powerful enough and you can't afford to carry a big enough range of FFLs. So a crop to give the effect of a 300mm lens where you only have a 200mm FFL, means the result as an A3 print may well be less quality than if you'd shot with a lower IQ 70-300 and got the shot full frame requiring no cropping

That said, top quality zooms are so good these days I doubt anyone could tell the difference most of the time anyway

DD

[petebarnes]

I thought it referred to an autobot general who waged war on the decepticons, and in toy form was loads cooler than the exact same white version, ultra magnus, who, if you've followed me so far, just turned out to be a bit of a mincer who buckled under the pressure of leadership. :) (more info here (http://en.wikipedia.org/wiki/Optimus_Prime))

Sorry to go off topic

[DiddyDave]

I thought it referred to an autobot general who waged war on the decepticons, and in toy form was loads cooler than the exact same white version, ultra magnus, who, if you've followed me so far, just turned out to be a bit of a mincer who buckled under the pressure of leadership. :)

Sorry to go off topic

If you're replying to the thread title alone - you're not off topic

Just nuts

:cuckoo::cuckoo::cuckoo:

:lol:

Anyway, wasn't this 'chap' Optimus Prime???

DD

[petebarnes]

He was just referred to as "prime" by his mates :D

[George]

Wish we had a "prime" minister.....!!!!!:lol::lol::lol:

[stylgeo]

FFL sometimes isn't enough though, nor is Prime for that matter, amongst FFL lenses we also have 'Cats', 'Fisheyes' and 'Macros'

Oh, and to add further interest (confusion?) my prime lens is a mid-range zoom

:lol:

DD

I think using the word prime in this case just complicates things for those with little knowledge on the subject. Personaly when someone talks about a prime lens I immediately understand they are talking about a FFL lens. There is no need to differantiate primes into fiseyes and macros because you can have both kinds of lenses into zooms aswell. Tokina came up with a fisheye zoom, the 10-17 (I think) and there are LOTS of zoom lenses with macro capabilities (only not true macros 1:1).

Primes are just what they are, fixed focal length lenses, even if they are tilt/shift lenses, macros, fisheyes, super telephotos, mid-range, lensbabies etc. If they can't zoom in or out, they are primes.

[DiddyDave]

I think using the word prime in this case just complicates things for those with little knowledge on the subject. Personaly when someone talks about a prime lens I immediately understand they are talking about a FFL lens. There is no need to differantiate primes into fiseyes and macros because you can have both kinds of lenses into zooms aswell. Tokina came up with a fisheye zoom, the 10-17 (I think) and there are LOTS of zoom lenses with macro capabilities (only not true macros 1:1).

Primes are just what they are, fixed focal length lenses, even if they are tilt/shift lenses, macros, fisheyes, super telephotos, mid-range, lensbabies etc. If they can't zoom in or out, they are primes.



I appreciate my post was somewhat facetious, but the original meaning of Prime was simply that - the prime (foremost) lens used

FFL is probably better in all respects as a definition, as opposed to zoom

So, let's take the prime meaning of 'Prime' as ANY FFL lens then - agreed?

DD

[chump1979]

Primes, as in FFL, only have better quality if they are damn good ones. A £200 200mm isn't going to be as good (in IQ) as a £1,000 70-200mm, so a direct comparison is only valid where cost is taken into account too

DD

I think this is normally true but my nifty fifty only cost £50 yet it is as sharp if not sharper than my 70-200 2.8 IS L costing £950.....

[Steveo_Hants]

I think this is normally true but my nifty fifty only cost £50 yet it is as sharp if not sharper than my 70-200 2.8 IS L costing £950.....

But you are comparing 2 different focal lengths!
I think the Nifty is the only exception to the rule!

[DiddyDave]

But you are comparing 2 different focal lengths!


My thoughts exactly

But yes, 50mm lenses must be relatively 'easy' to make well as all major brands have cracking good ones I'm lead to believe and (aside from the super wide aperture ones) all are pretty cheap

DD

[grumpybadger]

Maybe not quite that difference, but the 200 f/2.8L prime is less than half the price of the 70-200 f/2.8L IS zoom but I know which gives the better pictures!

[DiddyDave]

Maybe not quite that difference, but the 200 f/2.8L prime is less than half the price of the 70-200 f/2.8L IS zoom but I know which gives the better pictures!


Only if the perfect full-frame shot is at 200mm, if the subject's moved and you need 100mm - I know which will get a shot, let alone the best

Best time to drop this now perhaps?

:D

DD

[grumpybadger]

Only when I have made my final point. I have legs and so can move myself.

But, agreed on the shorter stuff it is zooms all the way for me. Although it is amazing how much time my 70-200 spends at the top end...

[pearce_jj]

My thoughts exactly

But yes, 50mm lenses must be relatively 'easy' to make well as all major brands have cracking good ones I'm lead to believe and (aside from the super wide aperture ones) all are pretty cheap

DD


IIRC it's because the film/sensor is 50mm behind the centre of the lens, so it's almost square. SOmething like that anyway :D