A question about A005 vs EF 70-300 IS USM

[kirbyzhou]

Through the ISO-12233 sample image, I thought 'EF 70-300 IS USM' is much more blur than A005 at 300mm. The mid frame and corner is very worse than A005, and the center is very similar.


http://www.the-digital-picture.com/R...mp=4&APIComp=0

But the review said that:
"By 300mm, this lens delivers poor image quality across the frame (except on the far left side of the frame). Stopping down at 300mm helps, but even f/11 image quality is only marginal. If you consider this a 70-200mm lens, you will be more happy than if you are counting on getting great 300mm image quality. "
"The Canon lens most comparable to the Tamron 70-300mm f/4-5.6 Di VC USD Lens is the Canon EF 70-300mm f/4-5.6 IS USM Lens. The Canon's advantages include modestly lighter weight, better AF accuracy, less vignetting and less pincushion distortion through 200mm."

http://www.the-digital-picture.com/R...ns-Review.aspx

I have been confused, anyone can help me to understand that?

[neuroanatomist]

What's the confusion? The Tamron 70-300mm at 300mm delivers pretty bad IQ across the frame, better in the center than the edges, but not very good in the center either. Compare it to the 70-200mm f/4L at 200mm (link), for example, to see what a sharper center would look like (and there are many even sharper lenses, I just picked one in the approximate same price range). The Canon is not much better at the long end, and as Bryan points out, has better AF, less vignetting, and less distortion.

The bottom line is that you're probably better off getting the 70-200mm f/4L instead of either the Canon or Tamron 70-300mm lenses, from an IQ standpoint.

[kirbyzhou]

What's the confusion? The Tamron 70-300mm at 300mm delivers pretty bad IQ across the frame, better in the center than the edges, but not very good in the center either. Compare it to the 70-200mm f/4L at 200mm (link), for example, to see what a sharper center would look like (and there are many even sharper lenses, I just picked one in the approximate same price range). The Canon is not much better at the long end, and as Bryan points out, has better AF, less vignetting, and less distortion.

The bottom line is that you're probably better off getting the 70-200mm f/4L instead of either the Canon or Tamron 70-300mm lenses, from an IQ standpoint.

I agree with your point 70-200mm f/4L is sharper than both the two 70-300, and AF, vignetting, and distortion are actually a problem.

But If I need IS/VC feature, and the money is limited, what about the choice between Canon 70-300 IS USM and Tamron A005?

I compared A005 and 70-300IS at both 200mm and 300mm.
It seems that: A005 is softer at center, but 70-300IS is much more soft at mid-frame and corner.
And it seems the new VC tech is better than the old generation IS tech.
So it makes me hard to make a desicion.

http://www.the-digital-picture.com/R...mp=3&APIComp=1
http://www.the-digital-picture.com/R...mp=4&APIComp=1

[clemmb]

I purchased the Tamrom because I wanted IS/VC and could not afford the canon 70-200 f4 IS.
The VC works great and I usually do not take it past 200. I do sometimes take it to 300 and get some keepers but I try to stay away from it.
Here is one at 282mm wide open. I am pleased with the sharpness in this image.

IMG_0032 by clemmb60, on Flickr