# 70-200mm f/2.8L IS II with 2.0 TC vs 300mm f/4 IS with 1.4 TC -- image quality



## contrastny (Aug 30, 2011)

Which lens will have better IQ? The 70-200mm f/2.8 IS II with a 2.0 III TC, or the 300mm f/4 IS with a 1.4 II TC? 

I am going to the Faroe Islands in late Septemeber for a photography trip and I'm not sure if I will have my 300mm f/4 repaired in time for the trip (lens won't communicate with the body). If that is the case I might buy or rent the 2.0 III TC. I really hope it gets repaired by then though.


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## LuCoOc (Aug 30, 2011)

check out the comparison tools @the-digital-picture.com

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=687&Camera=453&Sample=0&FLI=6&API=1&LensComp=111&CameraComp=0&FLIComp=0&APIComp=0

the 300/4 looks slightly sharper, but the 70-200+1.4 III combo is still better than for example a 70-300mm 4.5-5.6 IS USM


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## Mt Spokane Photography (Aug 30, 2011)

I'd not use TC's for birds in flight unless they are slow or hovering. AF is slowed down too much. That will be a bigger issue than sharpness. If you need 400mm, get a 400mm lens and things will work out better.


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## neuroanatomist (Aug 31, 2011)

LuCoOc said:


> check out the comparison tools @the-digital-picture.com



That link isn't quite the comparison the OP was looking for. This one is - [urlhttp://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=687&Camera=453&Sample=0&FLI=7&API=2&LensComp=111&CameraComp=453&SampleComp=0&FLIComp=1&APIComp=0]70-200/2.8 II + 2x III vs. 300/4 + 1.4x II[/url]. Looks like the 300/4 + 1.4x has a slight edge across the frame - probably not enough of a difference to have any impact on real-world shots, so from a straight IQ standpoint, either would do fine.



Mt Spokane Photography said:


> I'd not use TC's for birds in flight unless they are slow or hovering. AF is slowed down too much. That will be a bigger issue than sharpness. If you need 400mm, get a 400mm lens and things will work out better.



Bingo. A 2x TC slows down the AF by ~50%, and a 1.4x TC slows AF by ~25%.


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## Heidrun (Aug 31, 2011)

I have just tried this combination with 70-200 f.2,8 L mk II and 2,0 converter. I was impressed with the quality and the speed of this combination.
Im gonna buy myself this combination


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## contrastny (Sep 2, 2011)

Thanks for the info, since most of the will not be BIF I should be fine. But hopefully my lens will be repaired so I will have that as another option. I doubt it will be fixed within 2 weeks.


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## Edwin Herdman (Sep 3, 2011)

neuroanatomist said:


> That link isn't quite the comparison the OP was looking for. This one is - 70-200/2.8 II + 2x III vs. 300/4 + 1.4x II. Looks like the 300/4 + 1.4x has a slight edge across the frame - probably not enough of a difference to have any impact on real-world shots, so from a straight IQ standpoint, either would do fine.


Fixed the link for you (don't forget the =).

My own two cents - the 300mm f/4 versus the 70-200mm is perhaps not a straight comparison.

With both you are going to be limited to 400 or 480mm equivalent at the long end, and f/5.6 as the maximum aperture. This is "good enough" for some larger subjects at a distance but not for others (small birds basically require a 600mm lens on APS-C format, I've found, even if you have good stalking skills).

With the price of the 70-200mm, for almost exactly 1/3 more you can get the new Sigma 120-300mm f/2.8 OS (and the cost of the EF 2X is the same - if you "only" need roughly 480mm equivalence you could get a 1.4X extender and even save money if you go for the version II). When you lose the TC you still won't be able to frame as tightly as the 70-200mm but you will get a roughly 600mm f/5.6 lens - nothing to sneeze at!

The only downsides of the 120-300mm f/2.8 OS are, aside from price, are: Autofocus being iffy on the T1i (a cheap camera however), the actual angle of view being somewhat shorter than a "real" 300mm lens, and the high weight - it's double that of the 70-200mm, or about six and a half pounds (without the TC)! Another problem - the MFD of the bare 120-300mm is 1.5 meters at 120mm, and 2.5 meters at the 300mm setting, which limits how close you can get to your subject. For a ~600mm lens it's a pretty great minimum focus distance, however. All said, if you can get close enough to the subject you might do better with an EF 135mm f/2! Still, I use the Sigma 120-300mm f/2.8 combination all the time.



Mt Spokane Photography said:


> I'd not use TC's for birds in flight unless they are slow or hovering. AF is slowed down too much. That will be a bigger issue than sharpness. If you need 400mm, get a 400mm lens and things will work out better.


This as well - the native 120-300mm OS is plenty fast but with a TC - it's still as accurate but tracking birds is rather hopeless. I can track passing jets overhead, but they move very predictably compared to birds. A big problem with the newer TCs slowing AF speed is that it takes a while just to find the subject - from 1 second (a bit rare) to three or four seconds. Grabbing the focus ring and cranking it to infinity before you start tracking might help a bit - it's too bad Sigma still doesn't include a focus limiter on even their EX lenses (though when looking at the distance scale on the 120-300mm I think it would be rather awkward to implement correctly).


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