70-200 f/4L IS + x2 extender vs 100-400/4.5-5.6L

I've had a lot of great moments captured with my trusty 70-300 DO, but recently got into bird (and occasionally wildlife) photography where 300 mm is barely enough and picture quality starts to deteriorate a bit. I had to crop almost every shot lately, and I don't really like it. Currently, I have two options:

1. Canon EF 100-400/4.5-5.6L IS USM (MkI)
2. Bundle of Canon EF 70-200 f/4 L IS USM (Also MkI) and Extender 2x II

Both choices are almost mint-condition with all respective accessories and equally priced. In theory, the first option is more universal, better available aperture selection, trombone zoom/focus which I adore and doesn't require spending additional money on tripod mount. Second option basically gives two lenses on a price of one, has better build and stabilizer, weather-proof but really lacks in available apertures. At a first glance, it's not that big of a problem, since for most wildlife photography the lens should be stepped down anyway. But in a long run... Who knows. Also, changing 2x for a more viable 1.4x is not an option. The other way it would be a no-brainer.

Thanks for advices in advance.

100-400 better PQ vs using the 2x extender. Faster at the long end too.  I sort of gave up on my 70-200 after I got the 100-400. Now I have mk II which is fantastic.

DikkeryDok wrote:

I've had a lot of great moments captured with my trusty 70-300 DO, but recently got into bird (and occasionally wildlife) photography where 300 mm is barely enough and picture quality starts to deteriorate a bit. I had to crop almost every shot lately, and I don't really like it. Currently, I have two options:

1. Canon EF 100-400/4.5-5.6L IS USM (MkI)
2. Bundle of Canon EF 70-200 f/4 L IS USM (Also MkI) and Extender 2x II

Both choices are almost mint-condition with all respective accessories and equally priced. In theory, the first option is more universal, better available aperture selection, trombone zoom/focus which I adore and doesn't require spending additional money on tripod mount. Second option basically gives two lenses on a price of one, has better build and stabilizer, weather-proof but really lacks in available apertures. At a first glance, it's not that big of a problem, since for most wildlife photography the lens should be stepped down anyway. But in a long run... Who knows. Also, changing 2x for a more viable 1.4x is not an option. The other way it would be a no-brainer.

Thanks for advices in advance.

Do yourself a favor and go with the 100-400 ll.  You can find some good used deals on the Fred Miranda Buy/Sell site.

I have the 70-200 F4 and I used to own the 100-400 4.5-5.6.  I sold the later and got version II.  The new 100-400 II is in a class by itself.  You can also add a 1.4X to increase reach.  For birds, it is the best of the 3 options.

Thanks for the reply! Mod took some time to approve this post, so I had to deal with the problem myself with a little help from Reddit. Currently, I'm haggling for a Tamron 150-600 G1, and with a next pay cheque I'll get myself 70-200 as a second short telephoto. I think it would be a nice medium-budget kit. Not that I dislike my current DO, it's one of the best and most underappreciated lenses ever, but for wildlife I just need something more.

As I've noticed, a lot of offers on the site you mentioned located in the USA, so I assume it's primarily targeted at the American audience. Which is a problem to say the least, for someone who doesn't live there. Not only currency exchange rate can make a good offer a bad one, but overseas shipping and import fees can turn said offer into outrageously expensive. But thanks for the answer anyway.

DikkeryDok wrote:

As I've noticed, a lot of offers on the site you mentioned located in the USA, so I assume it's primarily targeted at the American audience. Which is a problem to say the least, for someone who doesn't live there. Not only currency exchange rate can make a good offer a bad one, but overseas shipping and import fees can turn said offer into outrageously expensive. But thanks for the answer anyway.

Good luck with it.  Didn't realize you were out of the US.

I am very happy with my 70-200 mm f2.8 + 2x extender combo. However, having the 100-400 mm would be nice too!

There is a plus with my combo: I can remove the extender and use my lens for shorter applications (like birds that let you approach closer).

I didn’t buy the IS version, maybe I should have but I’m still getting good results.