Telephoto lens

[TaliaLynette]

I might be doing a photography course next year and a requirement for the course is to have a telephoto lens.
It specifically says: "Telephoto lens (e.g. 55-200, 70-300mm)"

I just wanted to know are there other sizes for a telephoto lens? and if so could someone please list them for me?

I am thinking about getting a Canon EOS 600D and one of the twin lens packs has a 55-250mm lens. Is this lens considered a telephoto lens?

[ricktas]

There are HUNDREDS of telephoto lenses, so listing them would be impossible

One of the best would be the Canon 70-200 f2.8 or the Canon 100-400 f4.

Many zoom lenses have a variable aperture, ie f3.5-f4.5 etc, these are generally classed as prosumer lenses as they are not Pro level quality. However some of them are brilliant pieces of glass, but if you want some lenses that will last you a lifetime, look at the Pro level ones.

[StanW]

It's a confusion of terms. I'd say they really mean 'long=focus'. A telephoto lens is a special type of lens design, and I don't think that it's much used these days.

[ricktas]

It's a confusion of terms. I'd say they really mean 'long=focus'. A telephoto lens is a special type of lens design, and I don't think that it's much used these days.

I agree, what they are seeking is a ZOOM lens, not a telephoto one, when they use the example of : (e.g. 55-200, 70-300mm)

[William]

Hi Talia, I guess it depends on what your photographic interests are, Or will be , As Rick said there are heaps of Zoom lenses out there , Some just zoom more than others , What are you interested in taking Pics of ?

[arthurking83]

I think the term telephoto to distinguish one type of lens design from another is one of those tech terms relegated to obscurity, just as Macro has been for a while.

telephoto simply means that the lens is not really as long as the actual focal length described in the specs.

That is, a long focus lens of 500mm, has the lens element 500mm from the sensor plane.
A 500mm telephoto has a group of intermediary lenses that give the same 500mm fov, but without requiring the lens to be 500mm long.

Telephoto simply means a long focal length optic.

50mm is considered to be the 'normal' focal length. This is due to the minimal to zero perspective distortion effect it has on the camera system relative to the human eye.

Above this focal length is where the telephoto begins.
So a 70mm lens has a mild telephoto effect, a 100mm lens has a medium telephoto effect and 135 and beyond is a telephoto. I've seen some pros use the term super telephoto for their 500-600mm and beyond lenses.

A lens that zooms to telephoto range is referred to as a telezoom lens.

Some lenses are both wide and telephoto zooms in the one unit.
It's silly to call them telephoto, when they are in fact wide telephoto lenses.. the accepted terminology for these is superzoom(not super tele or super telephoto).

A lens that does 55-200(or more)mm is a normal to telephoto zoom lens.

A lens that does 70-300(or more)mm is a telephoto zoom lens(or telezoom).

As Rick said, it's futile to list them all or even in part as the range of lenses is immense.

For the sake of the course requirements, just look for any lens that extends beyond about 70-80mm.
For your sake, look for telephoto lenses that have as fast an aperture as you can afford .. on the lens naming these numbers are something like f/x.y where x.y can be anything like 2.8, 3.5 or 4.0. Once you get to the 5.6 aperture value, you begin to hit limits of operation that you may not want to deal with.

So in your eg of a tele lens, the 55-250mm, the explanation is simple. Look at the lens model name. The 55-250mm refers to the focal length. Normal(55mm) to telephoto(250mm).
The f/x.y numbers will refer to the maximum aperture size. I think this will be f/3.5-5.6, which means that at 55mm, the lens is f/3.5 aperture(ok size, not too far off f/2.8 which is nice to have).
At the 250mm focal length(the telephoto part you're looking for) the aperture may be f/5.6. This is a slow lens. In low light, this sized aperture slows down focus ability and impedes on the exposure variables of shutter speed and sensitivity(ISO).
They are best used in good to bright light.

[TaliaLynette]

Thankyou so much everyone! You have really helped (:

[Mark L]

I think you answer your own question.
"It specifically says: "Telephoto lens (e.g. 55-200, 70-300mm)"" and "......and one of the twin lens packs has a 55-250mm lens." Seems within the specified ranges.
You haven't stated the course, however if they are calling this a telephoto lens and not a zoom lens, you may wish to consider courses that specify zoom lens (e.g. 55-200, 70-300mm) It may be a very good course, of course.
Oh, and this isn't bad http://www.ausphotography.net.au/for...otography_Book
It's a course here and it's provided by Rick for free.