prime lenses and telephoto

[kevinbriggs]

After having done a lot of research on this site and other sites, there seems to

be a plethora of information regarding the advantages of using prime lenses as

opposed to zoom lenses.

 

I know this may sound like an odd question, but do these advantages apply to

telephoto lenses as well as wide angle and medium range lenses? (For example, a

180 mm telephoto (prime)?)

 

In other words, I'm assuming that the advantages of designing and building a

prime lens as opposed to a zoom lens are found throughout the entire focal

length spectrum, including telephoto lenses?

 

Thanks for all input!

 

K.

[Ed_Ingold]

"Telephoto" is a restrictive term, referring to a lens which has an overall mounted length shorter than its nominal focal length. Telephoto lenses have a strong negative element in the exit end.

 

Long, prime lenses tend to be simpler, lighter and faster than zoom lenses with the same length. Zoom lenses require more elements to do what they do while maintaining an acceptible image quality. Not all prime lenses are better than the best zoom lenses. Some zoom lenses, particularly wide-angle zoom lenses are better than their prime counterparts.

 

The Nikkor 180/2.8 lens is an outstanding performer. Whether it is sharper than the 70-200/2.8 VR zoom lens is debatable, but it is certainly less prone to flare. The Nikkor 300/2.8, 400/2.8, 500/4 and 600/4 are among the sharpest lenses Nikon makes, and priced accordingly. Only one long zoom lens is comparable, the pricey 200-400/4. There are plenty of affordably priced, consumer grade lenses, primes and zooms, up to 300mm and longer, with ho-hum performance. It is difficult to make a good-performing zoom lens with a zoom range greater than 3:1, and the best are only about 2:1. The 11:1 Nikkor 18-200 zoom is no exception.

[pico_digoliardi]

I really wish people would realize that Prime Lens does not mean a non-zoom lens. It's a term like 'font' that's migrated from its real meaning.

 

And 'telephoto' means the lens has a design that allows it to have a physical rear space between lens and film that is shorter than its focal length. A lens that does not have that feature is just a long lens, no matter how long it is. So when I say long lens below I mean non-zoom, and not telephoto.

 

Anyway, all lens designs presume certain compromises in order to approximate their intended use. Zoomies are vastly more complex and therefore entail more compromises. They just can't be optimal at all their focal length potentials. But they can still be quite good! (It ain't how well the bear dances, but that it dances at all.)

 

Long lenses can be terribly sharp, depending upon what you call long! A 135mm F/3.f Planar intended for medium and large format is a long lens on a 35mm, but wide-angle on 4x5", and it performs good for either, and astoundingly well for 4x5" when compared to other 4x5" lenses of it's age.

[pvp]

<I>I really wish people would realize that Prime Lens does not mean a non-zoom lens. It's a term like 'font' that's migrated from its real meaning.</I><P>

Pico, allow me to be among the first to congratulate you for re-opening THAT can of worms. Never mind the fact that <B>you are absolutely correct.</B> I've come to the conclusion, that this is just another word that has lost (or is losing) its original meaning.<P>

Waaaaay back, when I was a struggling student, I read a discussion about supplementary lenses, wherein the text used the term "prime lens" in its original meaning. IIRC, that was in a 1950's-era <U>Focal Encyclopedia of Photography</U>. I've looked around some, but have failed to find a version that old to check my memory. Maybe someone has one of those gathering dust? I'm willing to accept that language evolves; the problem is with the newbies who say we don't know what we're talking about.

[pico_digoliardi]

Sorry, Alan. I didn't know it was a can of worms.

 

It is a term I learned in mopix school in the early seventies. I would find it surprising if the pro motion picture guys do not use it properly.

 

I will let it be. Offhand I can't think of another way to say the same in a single word for nonzoomies. See how bad that works?

 

But if anyone ever tries to equate beer with Budweiser, I'll call out the Guinness hit men. What? It's too late? Somebody shoot me!

[bill_stice1]

It can be even more confusing for new large format photographers where the terms "wide", "normal" and "telephoto" are viewed in the context of someone's experience with 35mm photography. Particularly when you see something like a 450mm long lens and a 450mm telephoto lens which have the same focal length but require significantly different bellows extension and are totally different designs.

[sknowles]

<p>A prime lens is, "Term used to describe a camera lens that is attached to an accessory

device such as an afocal converter, teleconverter or anamorphic system.", from the 3rd Edtion

of The Focal Encyclopedia of Photography. That technical definition aside, it also has the

more common usage, as many people criticize, of meaning a non-zoom or fixed focal length

lens, as described by

<a href="http://en.wikipedia.org/wiki/Prime_lens">Wikipedia</a>. In short it has a older

technical definition, mostly used with cinema lenses, and a newer one, mostly used in still

photography, both still in use. The user only needs to clarify their application of the term.

[helenbach]

Those careless tinkers at Zeiss don't help matters by writing such stuff as "The Zeiss/ARRI Ultra Primes currently are the largest set of cine prime lenses." But what do they know about lenses?

 

Best, Helen

[richard_oleson]

I think the original question had something to do with the relative merits of zoom and non-zoom lenses in the longer focal lengths.

 

If a generalization can apply, it would be yes, the advantages of single-length lenses over zooms tends to hold at all focal lengths. The disadvantages of a zoom are essentially:

 

1) it has more elements, therefore more flare (and more weight)

 

2) there is almost always some linear distortion, which usually varies from barrel at the short end to pincushion at the long end of the zoom range

 

3) in addition to optical compromises having to be made for different focus distances, they also have to be made for different focal lengths in a zoom, so that some focal lengths perform better than others

 

Wide angle lenses often have a large number of elements anyway, so the zoom may compare better in that respect at the short end. Long single-length lenses, though, often have only 4 or 5 elements.... sometimes only 2. It's hard for a zoom to beat something like that for flare and weight, though it may be physically smaller.

 

Another issue of course is cost: there is a lot less material and labor in a good 5-element telephoto lens than there is in a comparably good 14-element zoom, so if you hold cost as a constant you can put a lot more quality into the single length lens.

 

:)=

[pvp]

<I>Those careless tinkers at Zeiss don't help matters by writing such stuff as "The Zeiss/ARRI Ultra Primes currently are the largest set of cine prime lenses." But what do they know about lenses?</I><P>

Yeah, it doesn't help when the industry heavyweights abet the disintegration of the language by falling into the trap of using popular newspeak.<P>

Kevin, to speak to your original question, one of the hurdles in designing a zoom lens is nulling out aberrations at the various focal lengths covered. For example, many zooms will exhibit barrel distortion at one end of the zoom range and pincushion distortion at the other extreme, with things nicely straightened out at some point in the middle. As with most perceived advantages, there are tradeoffs. Zoom lenses allow us to carry one or two lenses instead of a bagful.<P>

Someone opined that wide-angle zooms may be even better than their non-zoom counterparts (was that in this thread?) I don't know if that's true, but it is interesting that there are many wide zooms, and very few in that enter the realm of truly long focal lengths. I won't claim to know why that's so; I've long since used up my knowledge of optical theory...