Does the Sigma 150-500 really get to 500mm? (1 Viewer)

It's not that scientific a study. The birds don't sit still while changing lenses so the distances are not exact, although I did try to get approximately the same. Looking at all the images I took it is difficult to see much difference on most of them, but there are one or two with the Tamron which do look sharper.

I'll maybe try a more scientific apporach tomorrow if the sun shines.

I went out the other day and took some pictures of the brick wall in my back garden with the lenses mounted on a tripod and using various OS settings on the Sigma. The Light was reasonable so all shots were at f8 with shutter speeds of about 1/800th at ISO 400. I won't bother posting all the photos here but my conclusions are:

The OS on or switched off tests were a bit inconclusive - I need to do some more tests. The shots with the setting on 2 for panning seemed to be worse but no difference between fully on or off - not sure why this should be. The tripod was fairly sturdy and I used a two second delay on the photos to avoid shake.

The Tamron still looks longer at 500mm - more bricks per frame!

There is very little perceptable difference in the Image quality at "500", at least to my eyes, when blowing the pictures up on the PC. But the Tamron does still look a bit more contrasty. Not realy a problem in RAW as the contrast can be adjusted easily with no visible degradation in IQ.

I took some photos at "400" with both lenses. Difficult to see any difference in IQ versus "500" under these conditions with either lens.

Note: all this is with two specific examples of this lens and with one camera body. I did not use the micro focus correction on the 50D but that is probably my next step.

alanrharris53 said:

[...]
The Tamron still looks longer at 500mm - more bricks per frame!
[...]

Click to expand...

:eek!:
Should it not be contrary?
Then bigger the focal lenght then narrower the angle.

Yes sorry a typo, less bricks per frame with the Tamron, more bricks with the Sigma!