70-200 2.8II vs. f4 IS bokeh comparison? Or a visual bokeh comparison tool?

Does anybody own both the 70-200 2.8II and the f4 IS version, and preferably a FF body? I am interested in seeing a comparison between the two in terms of their bokeh. I'd prefer to see an apples to apples comparison, same focal length, same composition, one at 2.8, the other at f4 (preferably both at 200mm). If somebody could either do this comparison for me, or show me where it's been done before, I'd be really appreciative!


I've seen the bokeh calculators, which are marginally helpful. It'd be nice to see actual photos in a real world situation.


I am looking to pick up one of these lenses to use for portraits, so bokeh is key. The lighter weight and lower price of the f4 is obviously tempting, so I'm wondering if the extra stop is worth the extra $1500 in terms of bokeh alone. I'm not terribly concerned about low light, between my 5DII and the IS of the f4, it is basically a wash. I mostly shoot strobist style anyway, so I rarely encounter low light to begin with.

The Bokeh of the F/2.8 IS II is somewhat noticeably worse, especially in the transition areas. I don't know why you assume it would be better. In fact the F/4.0 IS is overall better in every single way except CA (CA is almost nonexistent in both) and vignette, although I've tested several copies back to back with the F/2.8 IS II and they trade off in resolution with the overall victory going to the F/4.0 more often but because they are so close that sample variation is the biggest determinant of quality.


Personally on a full frame body I believe the F/2.8 IS II isn't a very useful lens, F/4.0 at those focal lengths is already barely usable for me, and my preferred combination is 24-70 F2.8 and 70-200mm F/4.0. The main advantage I see to the F2.8 IS is with teleconverters, which due to aperture speed is will be limited with the F/4.0 IS. I've seen over 160 lenes and the 70-200mm F4 IS is as close to perfect as it gets, it's only flaws are vignette, apochromatic performance, and focus breathing, you couldn't ask for more in this day and age.

O love a good bokeh in a portrait. I feel 150-200mm at f4 to 5.6 gives a very nice bokeh. A portrait 200mm f2.8 I would think would be too thin for my taste.


Here is Bryan's example at 185mmf/5.


What type of portrait are you looking to shoot at 200f2.8?


Mark

Great question, thanks for posting.

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Originally Posted by realityinabox

Does anybody own both the 70-200 2.8II and the f4 IS version, and preferably a FF body?

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I have a FF body and the f/4 IS, but not the f/2.8 IS II.

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Originally Posted by realityinabox

I'm wondering if the extra stop is worth the extra $1500 in terms of bokeh alone.

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Well, it depends on what you mean by the word "bokeh". When most photographers use that word, what they are really referring to is defocus blur, such as background blur. If that's what you are referring to, then I would say yes, it's worth it. The extra stop will result in exactly 1.4 times more background blur. That is, the diameter of defocused point of light will be 1.4X wider.


However, if you are referring to the actual quality of the defocus blur, and not the quantity, then I can't help you answer your question.

I own the 70-200mm f/4L IS and it's got a pretty narrow DOF at f/4 on the 5D2, I'm generally stopping down to at least f/5.6 if I'm using strobist gear anyway. Unfortunately I can't speak for the f/2.8 but as Daniel said there will be a narrower DOF and a "larger" bokeh pattern. The quality of bokeh on the f/4 is outstanding as far as I'm concerned and it's a great portrait lens on a FF camera.


Here's an example:


5D Mk II, ISO 100, 1/5sec + 70-200mm f/4L IS @ f/4 and 200mm. Shot on a tripod in natural light.


http://farm5.static.flickr.com/4102/...085235df_z.jpg
Quiet time by Ben__Taylor, on Flickr


Cheers, Ben.

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Originally Posted by realityinabox

If somebody could either do this comparison for me, or show me where it's been done before, I'd be really appreciative!

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Photozone.de has tested both the 70-200mm f/4L IS and the 70-200mm f/2.8L IS II on FF. Scroll to the bottom of the linked pages for their bokeh tests.

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Originally Posted by Legion5

Personally on a full frame body I believe the F/2.8 IS II isn't a very useful lens, F/4.0 at those focal lengths is already barely usable for me,
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Could you please elaborate what do you mean bythe f/2.8 is not very useful on a FF body and the f/4.0 is barely usable?

As btaylor said f/4.0 is an very narrow DOF and is often capable of cutting someone's body or face in half when taking up most of the frame, f/2.8 is even narrower.

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Originally Posted by Legion5

As btaylor said f/4.0 is an very narrow DOF and is often capable of cutting someone's body or face in half when taking up most of the frame, f/2.8 is even narrower.

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Yes, the DoF is thin. But, if you compare the DoF at 200mm f/2.8 with a similarly-framed shot at 85mm f/1.2 (closer to the subject, obviously), the DoF at 85mm f/1.2 is less than half of that at 200mm f/2.8. The EF 85mm f/1.2L II is Canon's quintessential portrait lens. Granted, not all portraits are shot at f/1.2. But sometimes, that's the effect you want...and while you can stop down the 70-200mm f/2.8 for more DoF, you cannot open up the 70-200mm f/4 any wider than f/4 if you want the DoF to be shallower.

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Originally Posted by neuroanatomist

you cannot open up the 70-200mm f/4 any wider than f/4 if you want the DoF to be shallower.

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well you could but you'd need a good drill press and a hole saw... however, be forewarned this procedure would likely void your warranty!