10 out of 10 points and recommendedAbsoulty IQ at it's bestNONE
I have the original IS version of this lens as well as another current version from another manufacturer.reviewed May 15th, 2012 (purchased for $7,500)
If you are serious about the best just buy it. Words cannot describe this lens.
It is simply indescribable. You have no idea until you use this lens.
Actually the review here is much to modest in my opinion.
Udate: I have had this lens for over two years now. I use it now more than ever. It has it's place in birding for sure. I use it as a walk around lens and low light lens. I am more in love with it today than the day i bought it. Use it mostly with extenders. And it performs beautifully.
10 out of 10 points and recommendedFinest lens I have ever used bar none!none
I shoot daily as an amateur. I own the 300 II and the 500 II lens for birding now. Before that the 300 IS and the 500 IS. There is no comparison in the two lenses the new II series blows away the older IS period IMO.reviewed January 23rd, 2013 (purchased for $10,500)
I have shot daily with it for about 1.5 years now and it is outstanding.
I have tons of pics with it. Here: www.flickr.com/photos/avianphotos
If a optics junkie you will be in heaven, unbelievable.
9 out of 10 points and recommendedLight weight, Extremely well made, Fantastic IS, Good opticsNot tack sharp
I am strictly a wildlife shooter. My hobby in retirement.reviewed December 5th, 2015 (purchased for $5,000)
I can say SLRGear's review of this lens is spot on.
Shooting wildlife I use the 300 II and 500 II lenses. Both are the pentacle of optical quality in there classes IMO.
The 400 DO II lens while very good, and the build quality is top notch. It just does not optically reach the quality my other lenses.
The colors are a little off. I cannot put a finger on it. Not a deal breaker, but different.
Optically wide open it is like my 300mm II lens with a 1.4 T.C. attached at F/4 (wide open). The problem is when I stop down my 300 to F/4.5-5.6 with a 1.4 T.C. It goes into the tack sharp range. While the DO doesn't.
Can you see the difference in sharpness? Yes you can. With a good monitor and 100% it is apparent.
If you'r main object is shooting BIF? I would say jump on this lens. It's AF speed is amazing, and very accurate. With the extra reach, and light weight it makes for one of the best BIF lens I have ever used.
If shooting larger animals it is a very good lens. You won't be dissapointed in the least.
Shooting birds I can definitely tell a difference in the plumage detail between this lens and the 300 or 500. Not huge, but it is there. That is what I am comparing it too. So, my score is going to be a little lower than the others.
if interested. I have some photos with it on my flickr site.
5 out of 10 points and recommendedSmall, compact, easy to use, fairly sharpNo extras what so ever. Mine is for Pentax and screw AF
I own this lens in the Pentax mount and used it for about two years. I then moved to Canon and bought the 300 IS and now the Caono 300 II lens.reviewed September 28th, 2013 (purchased for $3,000)
First I am comparing against the Canon lenses. The Canon 300 II has no equal IMO. Rarely use the Sigma lens now.
It is a good lens. Without a T.C. it is very good. I get nice fairly sharp shots. And with minimum sharpening it is definitely usable. To get professional quality photos.
I totally disagree with the other reviewer. With a T.C. the quality no matter what F stop is unacceptable for me. It looses the sharpness required for birding. With the 2X it is not even in the hunt. Horrible quality. I have read many reviews about this lens. Most just rave about it. For birding it is a non starter period for me.
I personally did not like the Canon 300 IS for birding either. The Canon 300 II changed all that. It is the first lens I am happy with. For birding. A great all around-er that takes T.C.'s fairly good and AF excels with pro body's.
I Have tons of pics with the Sigma 300.
When Pentax comes with the K-3 I will review it again.