Advantages of "Prime" lenses over Telephoto?

[tybo78]

What are the advantages of fixed focal length lenses over telephoto? Example: I have an 18-200mm telephoto lens. why would i buy a 35 or 50mm lens when i can just shoot at that focal length with the telephoto?

[Dennismc]

From my very limited experience I think it has to do with the fact a zoom lens is not as sharp at each depth as a prime is. There is a sweet spot to each zoom and from there they tend to lose a little. This is due to the fact of the various focal lengths.

Where as a prime is one fixed length, less work for the lens thus resulting is pristine sharpness at that depth. and usually faster.

I am sure I am off on this but looking forward to the pro responses..

[BCampbell]

You mean prime vs. zoom. Prime just means fixed focal length, zoom means variable focal lengths.

"Telephoto" usually means anything longer than "normal" focal length, though that's not the strict definition. For 35mm format, "normal" is roughly 40mm to 60mm; anything shorter is "wide". Note on APS-C "normal" changes to about 24mm to 35mm.

But, to answer the question, because prime lenses are designed for a single focal length, the optics (at the same price point) are usually of way higher quality. You'll see this not only with the speed of the lens -- for less than the price of kit lenses on the entry-level DSLRs, which typically don't go faster than f/3.5, you can get a 50mm f/1.8, over two stops faster -- but also in measures such as sharpness, color reproduction, distortion, etc.

Think of a zoom lens as your typical jack of all trades, master of none. While yes there are some excellent zooms out there, the price premium is high. And note that the wider the range of the zoom lens, the harder it is to keep image quality high across all focal lengths. Most zooms have a sweet spot where they are sharpest and clearest. And there will almost always be a prime lens in a comparable length that's of higher quality, probably for less money.

But you are right, they're more versatile. It's highly situation-depedent. If you know you're shooing one or two specific subjects and you'll be in relatively the same position the whole time, you can easily use a prime. If you're not sure exactly what you'll be shooting, or if you or your subject will be moving a lot, a zoom makes sense. Then again, for years some of the world's best photographers used 35mm cameras with a fast 50mm lens, almost exclusively, in a wide range of circumstances.

So the answer is, maybe, it depends.

[tybo78]

Originally Posted by BCampbell

You mean prime vs. zoom. Prime just means fixed focal length, zoom means variable focal lengths.

Right. My bad. Zoom not telephoto. Duh

So that all makes total sense to me. Thanks for the info!

[RichardTaylor]

Just to expand on what DennisMC said about faster lenses, ie wider aperture.

Example:
Canon make a 70-300mm F4.5-F5.6 Image stabilised consumer lens.
However if you need a fast lens Canon also make fast primes
EG;
85 F1.2
85 F1.8
100 F2
135 F2
300 F2.8
300 F4

[inkista]

Zooms are more versatile for framing. But with a larger max. aperture, a prime can be more versatile in terms of lighting conditions.

And aside from being sharper, faster, and cheaper, the prime has one more advantage: it's smaller/lighter. Primes are mechanically much simpler than zooms. This is also why they cost less if they're comparable max. aperture and focal length-wise to a zoom.

Take Canon's 70-200 f/2.8L USM: about $1300, takes a 77mm filter. 3.3" x 7.6", 2.9 lbs. / 84.6mm x 193.6mm, 1310g. And it's white.

The EF 200mm f/2.8L USM prime, is about $750, takes a 72mm filter. 3.3" x 5.4", 1.7 lbs. / 83.2 x 136.2mm, 765g. It's black.

Little more than half the cost and weight, and much stealthier and ninja-like.

[BCampbell]

Originally Posted by RichardTaylor

Just to expand on what DennisMC said about faster lenses, ie wider aperture.

Example:
Canon make a 70-300mm F4.5-F5.6 Image stabilised consumer lens.
However if you need a fast lens Canon also make fast primes
EG;
85 F1.2
85 F1.8
100 F2
135 F2
300 F2.8
300 F4

Right, and faster lenses usually have better optics in other repsects too. Though Canon does make a fairly fast 70-200 f/2.8L IS, it's $1800 (and being replaced, so probably going up in price). Primes in that focal range:
100mm f/2.8L macro IS: $1000
135mm f/2.8L: $1100
200mm f/2.8L: $750

Granted, to get the full functionality of the zoom you have to spend a lot of money (let's ignore the 85mm f/1.2L at nearly $2000, and not even go near the 200mm f/2.0L...), but if you know you shoot near one particular length, you can save some money and get better quality by buying a prime.

But the compromise of the zoom is hard to beat, and especially when you're talking about Canon's L-series, most of us will probably need to upgrade our camera bodies before the quality differences mean anything.

[BCampbell]

Originally Posted by inkista

Zooms are more versatile for framing.

I can frame most anything with a prime that you could frame with a zoom, using those zoomy things at the bottom of my legs.

Okay, assuming there are no walls, or traffic, or whatever, right.

And aside from being sharper, faster, and cheaper, the prime has one more advantage: it's smaller/lighter.

Great point. It can be a lot easier and more comfortable to travel with, say, 28mm and 100mm primes than a 24-105 and a 70-200.

Little more than half the cost and weight, and much stealthier and ninja-like.

Hm, that's one of the things the black duct tape is for...

[vandergus]

I can frame most anything with a prime that you could frame with a zoom, using those zoomy things at the bottom of my legs.

I'm a fan of primes but I never really bought the "zoom with your feet" argument. It's not just a matter of fitting everything in the viewfinder because when you move the camera, you're not just changing the framing, you're also changing the perspective. Take portraiture for example. If I have my 35mm lens on my camera and want to get a nice tight shot on someone's face I can just move in really close, right? Well sure if you don't mind big noses and other distortions. With a zoom lens you can simply increase the focal length, keeping your perspective constant the facial features pleasing.

The better way to deal with the situation is simply to get out of the mindset that you have to be able to capture any situation at any time. When you go out with a prime lens, you go out with a specific picture or type of picture in mind. One with a perspective that you know you can achieve with your focal length. If you run into a really cool wide scene, well, you don't have to take a picture of it. Move on to what you initially set out to photograph. In this way prime lenses can help you focus. Remove distractions. Some photographers consider this restricting, but others find it helpful.

All the other advantages I appreciate as well, such as generally smaller size and faster aperture.

[inkista]

Originally Posted by BCampbell

I can frame most anything with a prime that you could frame with a zoom, using those zoomy things at the bottom of my legs.

Okay, assuming there are no walls, or traffic, or whatever, right.

I use my fisheye (prime) when my back's to the wall. I hate it when they tell me I have to stay in my seat. But it's why I pair a 24-105L with a 135L when I hit Comic-Con. But I agree, a prime is actually more versatile than people who only shoot zooms assume. And better exercise.

And I think I agree with the old school that a prime teaches you composition much more efficiently than a zoom. Your brain tends to short out with a zoom and assumes that the only choice you have to make compositionally is framing with the zoom ring. With a prime, composition got simplified to "where do I stand?" And if you're going to move forward and backwards, you might as well move to the side a few steps, and maybe climb up on something or kneel down, too...

Great point. It can be a lot easier and more comfortable to travel with, say, 28mm and 100mm primes than a 24-105 and a 70-200.

Yup. I shot a lot of Comic-Con with my 135/2 and a 35/2 this year. Even though the 24-105 was in the bag and invaluable, it probably got used the least of the three, because of the max. aperture being f/4. Two stops is a lot of light, and IS can't always make up the difference. Plus the 35/2 was an old manual focus Leica-R, which let me zone/scale focus and shoot from the hip a bit more. Not something a modern autofocus lens makes it easy to do.