Telephoto confusion

[davholla]

I have a Canon EF 70-300mm f/4.0-5.6 IS USM Lens and I would like to a bit more reach.

I am torn between

Sigma 150-600 C

Tamron 150-6000

or may be a second hand Canon 100-400 like this as some reviews imply that this could be almost as good

EXCELLENT Canon 100-400mm USM Telephoto Lens eBay

or maybe my existing lens with a teleconverter
This will be used mainly with a Canon 350 D or Canon 550D for birds/mammals any ideas?

The more I read the more confused I get

 

[weepete]

There's not much to choose between the Tamron and the Sigma C as far as I can tell mate. I ended up with the Tamron but that was an easy choice as the Sigma C hadn't been released yet.

Vs the 100-400 that extra 200mm makes a big difference for wildlife. I would also avoid teleconverters if at all possible as they do impact on sharpness.

 

[davholla]

Thanks for that, do you think it would be ok with a cheaper camera (e.g. my Canon 350 D).

 

[KenC]

Depends on how much more reach you need. The 100-400 will get you more than it would seem, assuming you're talking about the non-L 70-300, which is a little weak at or near 300, while the 100-400 is much better. You could crop some from an image taken at 400 and get a little extra out of it and still have good IQ. I'm not suggesting that would be anywhere near as good as being able to shoot at 600, just that you'll be able to do significantly more with the 100-400, and only you can determine if that would be enough for what you're shooting.

 

[davholla]

Here is an example of a photo which needed to be cropped a lot and I would have liked a lot more reach
IMG 7363 Flickr - Photo Sharing

and here is another
IMG 7446 Flickr - Photo Sharing

 

[KenC]

It still depends on what you want. For example, in the second one if your goal was a tight shot of the entire group, then you don't need that much more magnification, but if you wanted just the two birds on the left, then you would want to have 600.