Lens extenders?

foodpoison

foodpoison

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Sean
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I have a sigma 70-300 dg apo, and was thinking about possibly getting a 1.4x or 2x extender, but have absolutely no idea where to start.

At the moment, I can't afford anything bigger than what I currently have, so an extender would be ideal, but:
-I don't even know if its possible to put an extender on this lens
-If it is possible, I don't know what to look for
-If they are possible, and companies do make them, I don't know how well they would work with what is, lets be honest, an entry level zoom lens.
 
I think that a teleconverter would fit on that lens but I would check on that.

If it does then it's going to produce two problems. The first is that you will lose some quality and with your 70-300, it will probably be more noticable than some fancy glass that can stand a little more magnification.

The other is the loss of aperture you'll get. With the 1.4 you'd end up with an f8 and with a 2x, an f11. That's going to make the viewfinder pretty dark and also take away lots of AF speed. Assuming it still works at all that is.
 
You'll have to get the Kenko extender as the Canon extenders have protruding bits and will only fit certain lenses (see the canon website or WareHouseExpress website for info).

With an entry level zoom lens you'll really notice the drop in IQ as they magnify the problems

You'll also lose 1 or 2 stops. Which will mean that you'll lose auto focus (unless you use the sticky tape trick)... actually I'm not sure if the Kenko extenders have this "feature". AF stops with max aperture lenses of > f5.6 on non pro canon bodies

HTH
 
oldgit said:
You'll have to get the Kenko extender as the Canon extenders have protruding bits and will only fit certain lenses (see the canon website or WareHouseExpress website for info).
HTH
Click to expand...

The Sigma extenders will also fit and these may be a better option. I tested Canon, Kenko and Sigma 1.4x extenders on a Canon lens a while back and found the Sigma gave an unusual colourcast not present with the other two. I suspect that this may be due to an interaction with the lens coatings and that may well also be the case in the reverse scenario.
I would also agree with the other posts....your lens is unlikely to produce acceptable images with a T/C and manual focus will be difficult in lower light situations..
A pertinent question would be to ask what you intend to shoot.

Bob
 
Ah, it doesn't sound much like a good idea then.

I don't really shoot only one thing, I tend to shoot different things in different situations, but sometimes I think "If only I could get a bit closer,"

Its alright, I can crop :)
 
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