Picture quality issues if using teleconverters?

photostar_1

photostar_1

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Hi
Can anyone enlighten me as to whether there are any issues over picture quality if you use teleconverters? I'm sure I read somewhere that the x2 can give soft images.....is this true?

I'm thinking of getting the Canon 70-200mm f2.8 L and am wondering which converter to get, to give that extra bit of reach, as I can't justify the 100-400mm, (would'nt need it often enough) but would like to do some wildlife stuff. I know the converter will lose me the (equivalent) stops, but as I'd be starting at 2.8 this isn't a big issue. It's sharpness I'm concerned about.....is this affected?
 
I've heard that all the tele-converter does, is magnify everything, and this would include imperfections, blurriness (or lack of sharpness) etc. So if you start out with a supremely sharp lens, that's what you should get with the teleconverter? no? :shrug:
 
It's like asking how long is a piece of string. Because so much really depends on the quality of the original lens and on the converter itself.

The short answer is that there is a quality loss, but it can be quite bad or it can be barely discernable - if at all.

Image quality should be best with a good quality fixed prime - zoom lenses are already compromised with all those elements moving in relation to each other when you zoom.

However:-

I use a 1.4TC with my 100-400L, and my 500L, and my 180 macro, and whilst the results are better with the primes it's not night and day. I fully intend to get a 2X TC shortly.

For what converters cost compared to the price of glass it's daft not to have one for the extra reach they give you IMHO. :shrug:
 
Caesura said:
I've heard that all the tele-converter does, is magnify everything, and this would include imperfections, blurriness (or lack of sharpness) etc. So if you start out with a supremely sharp lens, that's what you should get with the teleconverter? no? :shrug:
Click to expand...

That's essentially correct - a magnifying glass, so nearest focus distance doesn't change. :thumbs:

Try a 1.4 TC first and see how you get on with it? They seem to have very little if any effect on visible image quality and you lose just 1 stop.

The 2XTC will lose you 2 whole stops.
 
I have both 1.4 and 2X canon converters,to me the 1.4 is by fare the best,used it on both primes and zooms and find it superb,The 2X on the other hand is not as good,tried it on my 70-200f2.8Lis and was far from happy:) put it on my 200f2.8 or the 300f2.8 and im happy.;)
 
I've been absolutely delighted with the quality and sharpness from my 70-200 with either TC. The rugby shots I posted at the weekend were with the 1.4x, and the squirrel below was with the 2x in VERY poor light. People warned me that I'd get soft images with the 2x but I can honestly say I've been impressed. :thumbs:

8768Squidge-01.jpg
 
A few years back it wasn't advised to use a converter with any zoom lens, but lens technology has come on a lot and so has converter technology. I wouldn't hesitate to use a converter behind a decent zoom these days. If the lens is a poor performer to start with then it's only going to get worse with a converter.
 
Buy the 70-200f2.8 and you wont be dissapointed.... ever.
Just be careful with the mount on the 400D as its a plastic body and the lens is HEAVY (1.3Kg worth).

I use a canon 1.4TC with mine and do notice that there is a drop off in sharpness, but thats from pin sharp to wayy acceptable.
 
I was very pleased with the results from the 2xII TC

100_1146.jpg


Shot with the following

Canon 1Ds
Canon 70-200 f2.8L IS + 2xII TC
iso 100
1/640s
f 5.6
400mm
 
awww ... nice shot of a well fed squirrel there. :D
 
Caesura said:
I've heard that all the tele-converter does, is magnify everything, and this would include imperfections, blurriness (or lack of sharpness) etc. So if you start out with a supremely sharp lens, that's what you should get with the teleconverter? no? :shrug:
Click to expand...

You are adding another layer of glass so IQ suffers slightly. 1.4x IQ will be better than the 2x. Remember you also lose 1 or 2 stops of light respectively.
 
photostar_1 said:
Thanks everyone, for all your sound advice! Basically, if I've understood you all correctly, as the Canon 70-200 F2.8 L is a great lens to start with, I shouldn't have any problems. I appreciate your help. :thumbs:
Click to expand...
I don't think you'll have any problems and the nice bit is that being a 2.8 lens you'll retain AF with all EOS digital bodies - even with the 2X converter. :)
 
I use a 2x converter with my 80-200 f2.8 and have no problems with focus etc and although I know that there is some image quality decrease, I just cannot see it, I think that the converter is important and you must get a decent one, I got the kenko teleplus pro dg because from reading on birding forums, they are less fussy with autofocus.

check the pink fairies website as there is some good advice to be had about converters.
http://www.digiscoped.com/canonextenders.html
 
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