Originally posted by TenZ.NL If you don`t mind I can answer that: On the mid of the middle zero of 300 it`s F6.3 (310mm), between the 3 and the first zero it`s F5.6. Which is actually 290mm according to the exif, I can`t seem to get exactly 300mm`s?
Being somewhat in the same position, already owning a sigma 100-300 F4 (like you have the DA* 300 F4) and obtained the 150-500 later in the same quest for reach with similar thoughts, my conclusion for now is that both lenses deserve their own place because they are completely different.
The 100-300 F4 is a very good piece of glass with almost prime-like capabilities but it lacks reach. OTOH the 150-500 has great reach and produces nice images but for optimal sharpness you have to use F8 which limits the lens too bright and sunny weather if you want to shoot birds and/or BIF`s and it`s more difficult to get a nice blurry background. My guess is that you will probably feel the same about your DA* 300 and the siggy too.
Thanks for the aperture info!
I just did some preliminary comparisons this morning, and with that I agree with your assessment. It's still too cold to spend any time outside yet, but I set up on a tripod inside, opened our sliding glass door, and shot various subjects between our house and river. Also, it was very dark/gloomy/overcast so not a good day for testing, but I just had to get a start. I shot the Sigma 50-500, DA*300, and FA* 300 f4.5.
My initial impression of the Sigma was, well, impressive! I shot it wide open, f7.1, and f8.0. At f8 500mm it was very sharp - much better than I expected. Comparing the cropped image of the same subject with the DA*300, the Sigma wins.
I don't have any images worth sharing yet - will hopefully get more serious next week if it ever warms up. First thing I had to do today was to see if my repaired K-5 was working right.
TenZ's assessment is very good I think. Both the Sigma and the DA* are great performers. In the native image (no cropping) the DA* of course wins, but not by as much as I thought it would. As you say TenZ, both lenses have their place and use. After this first brief comparison, it looks like I am going to have to find a way to keep both!