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macky799

macky799

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THIS SHOULD BE AN EASY ? FOR YOU PROS IM THINKING OF UPGRADING TO A EOS 40D DO U LOSE AM
NY CAMERA FUNTIONS IF U ADD A TELECONVERTOR MADE BY CANON TO A CONON LENS FITTED TO A 40D.
I HAVE A SAMSUNG GX1L JUST NOW BUT IF I ADD A SIGMA LENS TO IT IT SEEMS TO WIPE OUT MOST OF THE FUNCITONS OR IS IT JUST ME BEING A MUPPET AS USUAL:bonk:
 
It is all about aperture size. To autofocus the camera needs a largish aperture. When you add a teleconvertor it has the effect of reducing the maximum aperture. Normal Canon cameras need f5.6 to autofocus. Professional 1 series can still autofocus at f8.

a 1.4 x converter loses 1 stop. a 2x loses 2 stops. There are tables of lenses and compatabilities with telecons for different cameras. Hopefully someone has one bookmarked and can post the link - or try google.
 
Taken from Here
http://photonotes.org/articles/beginner-faq/lenses.html


Canon extender compatibility list:

The Canon extenders are physically compatible with all prime (fixed focus) Canon EF lenses with a focal length of 135mm or longer except for the 135mm 2.8 SF. They are also compatible with a handful of recent L series zoom lenses. The full official list is:

70-200mm 2.8L
70-200mm 2.8L IS
70-200mm 4L
100-400mm 4.5-5.6L
400mm 4 DO
135mm 2L
180mm 3.5L Macro
200mm 1.8L
200mm 2.8L
300mm 2.8L IS
300mm 4L
300mm 4L IS
400mm 2.8L IS
400mm 5.6L
500mm 4L IS
600mm 4L IS
1200mm f/5.6L
Consult Canon when checking out newer L series lenses introduced since this list was written, and you’re on your own if you use third party lenses. You can also use Canon extenders with Canon TS (tilt-shift) lenses, but it should be noted that the TS lenses can’t report to the camera that the extenders are there.

Autofocus is not supported by non-pro EOS cameras when the 1.4x converter is used with 100-400mm 5.6L, 400mm 5.6L, 500mm 4.5L, 1200mm 5.6L, and with the 180mm 3.5 Macro when it’s focussed closer than 0.8 metres, or when the 2x converter is used with the 70-200mm 4L, 100-400mm 4.5-5.6L, 180mm 3.5L Macro, 300mm 4L IS, 300mm 4L, 400mm 4 DO, 400mm 5.6L, 500mm 4L, 500mm 4.5L, 600mm 4L, and the 1200mm 5.6L.

Note that there are two generations of the Canon Extenders - the original 1.4x and 2x models and the mark II successors, which add improved weatherproofing. The 1.4x II is said to be optically identical to its predecessor but the 2x II has minor optical enhancements.
 
Im Not To Worryed About Auto Focus As Have Tried To Work With Mf Lately And Seems To Be Ok I It Just Seems To Be When U Ad lens To My Samsung Then All U Can Use Is The Av Setting And It Wont Let U Ajust It Very Well Read Manual Several Times With No Luck Or Have I Just Got Wrong Lens For It
 
was half way throught reply and noticed caps lock on but couldnt be bothered re typing
 
Adding an extender, or converter, to any lens not only multiplies it's focal length, it also adds flare, chromatic abberation (purple fringeing), and focus softness, while it reduces the light sensitivity (max F-stop) considerably.

So an extender ruins your lens' fine specs and great image quality for a longer focal length.
That's not an acceptable trade-off for a quality conscious photographer.
 
W.Smith said:
Adding an extender, or converter, to any lens not only multiplies it's focal length, it also adds flare, chromatic abberation (purple fringeing), and focus softness, while it reduces the light sensitivity (max F-stop) considerably.

So an extender ruins your lens' fine specs and great image quality for a longer focal length.
That's not an acceptable trade-off for a quality conscious photographer.
Click to expand...
Well, except those quality conscious togs on a budget... :)
 
Can't help you with the Samsung and Sigma combination. But I can tell you that with a Canon and the right lenses the Canon converters work fine. I use a 1.4 with both the 70-200 and the 100-400. You do lose auto focus in some cases, depending on the lenses prime aperture, but that's not normally a problem.

The 1.4 converter is considered to be the best of the two Canon options
 
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