What is a teleconverter?

Matt Sayle

Matt Sayle

2017MSA Young Photographer of the Year(Motorsport)
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Matt Sayle
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Exactly what it says on the tin. What is one? I see threads saying take with lens and 1.4 tc. What is one and what does it do?? Oh and is it a good idea to buy one for motorsport 'togging?
 
hmm 4,000 posts on TP and you dont know?? lol it attachs to your camera body then you attach your lens to that it will increase your focal lenth by either x1.4 or 2.0 depending on what you buy
 
A teleconvertor multiplies the zoom length... I think.
If you had a 100mm lens, and used a 1.4 tc, u would in effect be shooting at 140mm...
I think I'm right but someone may give proper advice.
 
It also changes the aperture, so if you had a (theoretical) 100mm f/4 it would convert it to a 140mm f/5.6
 
A Vivitar 2x macro teleconverter is fun to have. Manual focus. You don't have to use it for macro only.
 
#13 said:
hmm 4,000 posts on TP and you dont know?? lol it attachs to your camera body then you attach your lens to that it will increase your focal lenth by either x1.4 or 2.0 depending on what you buy
Click to expand...

Just some clarification....
Unless you have an SLR (which Matt didn't until last week) a T/C is not something you'd come across.

Technically, a T/C does not increase the focal length...that remains the same. The T/C magnifies the image formed by the lens and hence gives the appearance that a longer Fl is being used.

Bob
 
They're also of limited use if you don't have fast glass to start with, put a 1.4x tc onto something with a maximum f/5.6 aperture and for motorsport it'll be like trying to focus in on a black cat in a coal mine :lol:
 
Canon Bob said:
Just some clarification....
Unless you have an SLR (which Matt didn't until last week) a T/C is not something you'd come across.

Technically, a T/C does not increase the focal length...that remains the same. The T/C magnifies the image formed by the lens and hence gives the appearance that a longer Fl is being used.

Bob
Click to expand...

i too just got my first DSLR just last wednesday never had one before, i didnt want to come over snotty i just found it a little wierd that a member with 4,000+ posts didnt have an idea about TC

increases/magnifies the focal lenth isnt it pretty much the same thing?
 
Usually found in 1.4 1.7 or 2x variants. (1 F stop 1/12 F tops 2 Fstops)

Image quality will degrade with all but you can usually get away with the 1.4

Remember though not all lenses can physically take a TC due to elements very close to the rear of the lens and not all TC will work with other makes of lenses.
 
#13 said:
....
increases/magnifies the focal lenth isnt it pretty much the same thing?
Click to expand...

I was trying to clarify how the t/c worked. It doesn't "increase/magnify the focal length", it magnifies the image projected onto the sensor/film by the lens and the focal length remains the same. The end result is the appearance that a lens of longer focal length has been used. A cropped sensor gives a similar appearance but achieves it in a different way....by restricting the angle of view.

I hadn't interpretted your post as "snotty" but was just trying to clarify why Matt (or anyone else without an SLR) might not have stumbled across T/C's. :)

Bob
 
Matt,

Watch out with these... because the Canon TC's don't fit onto all Canon lenses... its a physical fit problem. Generally its L series glass only.

Remember two things:

1) a 1.4x drops the aperture by one stop (eg F4 goes to F5.6) , the 2x drops it by two (eg F2.8 goes to F5.6). Above F5.6 your camera (or mine!) won't autofocus, a 1D body can cope with more than F5.6.

2) As well as that there is a drop in image quality. A 1.4x is not much, a 2x can be a fair bit unless you are using real top notch (ie 4000 quid upwards!) lenses
 
And there was me thinking it was a gismo to use your tele in the middle of a field LOL:razz:
 
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