Canon 300mm F2.8 USM IS Soft focus

[limvo05]

Hello,

While searching for a great deal on the Canon 300mm f2.8 IS mark I, I came across a few reviews suggesting soft focus issues with this lens. I was wondering if anyone experiences the same? Is this an inherent problem with this lens or luck of the draw? Below are some of the comments found on B&H site.

Unreliable and soft focus

Bymurphyslaw

After owing this lens for more than 3 years and struggling with the soft focus issues, I am now convinced that this lens has inherent quality issues and even after a tune up by Canon, i am still seeing soft focus issues inconsistently. I tried the several lens tests on a tripod, however, could not get a consistent result. Now looking at others who have similar issues, I am convinced that this is a faulty product, or atleast I have a lemon. Shame on Canon for producing such flawed products in the top of their product line.

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I was excited to have this lens, as a wedding photographer working in many low light situations --- my excitement was VERY quickly dashed. I used this lens at 1 wedding, and while I managed SOME photos that will be salvaged, the majority of the shots were MUCH softer focus than I want for my clients. Canon makes amazing equipment that I stand behind 100%.....THIS Canon lens is NOT something I can get behind.

[Waddizzle]

"Depending upon the body, a f2.8 or faster lens will activate dual cross point sensors in the AF array providing for the highest AF performance from that lens/body combination."

I don't think f/2.8 is set in stone.  Before I gave it away to my son, I think my EF 24-105mm f/4L IS USM would enable, let's call it wide aperture mode, with my 6D.  The firmware seems to make exceptions for many of the f/4L lenses.

Note, this does not mean all f/4 lenses, just the Canon L glass f/4 lenses.  I guess I need to look it up to confirm if the 300 f/4L activates the f/2.8 wide aperture mode, but I would strongly suspect that it would.

Just like teleconverters are designed to work primarily with telephoto primes, the firmware allows exceptions with many L glass telephoto zooms, like the 70-200s.  Activating "wide aperture mode" is permitted in firmware with many f/4L lenses.

[ebiggs1]

I place little credence to most reviewers. I never use DXO for instance. The Digital Picture is better by far. 

So if you are a believer in that, here is what they said about the f4 model...."Overall, this lens (the f4 modle) a a very good value. The Canon EF 300mm f/4L IS USM Lens delivers great image quality and physical features for a relatively low price. If you need only 300mm (and 420mm available with the 1.4x) and f/4 is a wide enough aperture for you, look no farther."

[Peter]

If you like 70-200/2.8L IS II x2 III all three 300mm lenses already mentioned will be enough for you, if we only talk about image quality. I can send you a couple of raw files from 300/2.8L IS +x1.4 II and x2 III later.