Long lens issue/debate/information

[SpikeK6]

I have a canon 100-400 and was really happy with it except I was always wishing it was longer , I got given a sigma 170-500, now whilst this gives good resultsit is not as good as the 100-400.

I have looked at longer lens like the 150-500 and the 50 500 but would have to get rid of the 100-400 to do this, even the new 150-600 is out of my reach.
I was thinking how much image quality do you actually lose by putting on a 1.4 converter.

My 100-400 is not the best fully open at 400mm but at 350 to 380 its tack sharp so was thinking using it at 350 with a 1.4 converter and I have the reach and image quality, would this be the case???

 

[drounding]

A consideration - depending on your camera you may lose auto focus at full reach when using the converter.

 

[Cagey75]

The tamron 150-600 is cheaper than the Canon, if you could get a decent price for selling on yours. Just an option.

 

[jerry12953]

My experience was that the 100-400 + 1.4TC was not really up to the job. The Tamron 150-600 is a much better option if you can afford it.
Oh yes, Duncan is right about losing AF with that combo unless you have a more advanced body. With the 5d3 it would only AF on the centre point.

 

[SpikeK6]

I have a 7D camera. the tamron 150-600 sounds like a good deal thought it was a lot more expensive, I am meeting a guy on sunday who has one so going to test it out.

Sigma are bringing/allready brought out a 150-600 too which is supposed to be better but will have to check them out before I decide to sell buy.

Cheers guys