IQ comparison: 100-400, 400 f/5.6, 70-200 f/4

I’m looking for real-world user comments on the sharpness and IQ of the 100-400 and 400 f/5.6 prime. I have decided I want one of these lenses and I’m leaning towards the prime. For my purpose they are basically the same price. Now I need someone to compare the sharpness and IQ to my primary lens, the 70-200 f/4. I get some absolutely stunningly sharp shots with my 70-200. I know the prime will be sharper than the 100-400 at 400, but how much so? And how much sharper will the prime be than my 70-200? Last question, which side does the 100-400 fall, sharper, or duller (less sharp?) than my 70-200? I understand I’m asking for comparisons between two lenses at 400mm and one at 200mm, but surely someone can compare the IQ for me. Thanks!

I have the 70-200 f/4 and 100-400. The 70-200 is definitely sharper but that doesn't do much good if you need 400mm focal length. The 400 f/5.6 is sharper than the 100-400 but the 100-400 is no slouch. You just need to decide if you need more sharpness at 400mm or the flexibility of a zoom.

I have used the 100-400L (a 2003 vintage one) and own a 400/5.6L - both on a 7D.

IMO with correct technique the 100-400L is as sharp as the prime in the center.

Off center sharpness the prime is better, and the prime has better bokeh , ca and faster focus. Its also lighter.

Also IMO the IS system on the 100-400L is terrible. It needs 1-2 seconds to settle and I think is in part responsable for its nervouse bokeh. I found that I prefered the lens with IS turned off and bokeh seemed ok.

I'm not sure I have 100% crops to hand right now but still, my review of the 100-400
http://zarphag.com/200​9/12/birding-with-an-l/

And quick test of the 400/5.6
http://zarphag.com/201​0/11/fast-and-long/

mike_d wrote in post #13067850
I have the 70-200 f/4 and 100-400. The 70-200 is definitely sharper but that doesn't do much good if you need 400mm focal length. The 400 f/5.6 is sharper than the 100-400 but the 100-400 is no slouch. You just need to decide if you need more sharpness at 400mm or the flexibility of a zoom.

You're correct, it doesn't do me any good if I need 400mm. I can see the uses of the zoom but predominantly I will be using the lens at 400 and I don't think I will use the 200-400 range much, if I'm all the way out at 200 I always have wanted to be closer. Thank you for your input.

RobDickinson wrote in post #13067853
I have used the 100-400L (a 2003 vintage one) and own a 400/5.6L - both on a 7D.

IMO with correct technique the 100-400L is as sharp as the prime in the center.

Off center sharpness the prime is better, and the prime has better bokeh , ca and faster focus. Its also lighter.

Also IMO the IS system on the 100-400L is terrible. It needs 1-2 seconds to settle and I think is in part responsable for its nervouse bokeh. I found that I prefered the lens with IS turned off and bokeh seemed ok.

I'm not sure I have 100% crops to hand right now but still, my review of the 100-400
http://zarphag.com/200​9/12/birding-with-an-l/

And quick test of the 400/5.6
http://zarphag.com/201​0/11/fast-and-long/

Thanks for your insight, its exactly what I was looking for. Once my internet speeds up I will be sure to check out your review and test shots. Thanks!

Sharpness samples/reviews on the prime vary a little. Sharpness samples/reviews on the zoom vary a lot. That can make the decision a little tricky because if you choose the 100-400 you may find yourself either over the moon or a touch disappointed. Bokeh and AF the prime will be better.

The 400 is a very nice lens to hold, its balance is great and I can happily shoot with it handheld all day at an airshow. Physically it's lighter than a 70-200 F/2.8, the same max diameter (narrower for the most part), but longer. It also has the best lens hood design you'll come across.

Ultimately if you need the zoom then your choice is basically made up for you. If you need IS then the prime is out and it's either the 100-400 or the 300 F/4 IS (and a 1.4x TC). If neither of those matter then the prime becomes a great option.

Tho I think a fair amount of the 'sharpness' issues of the 100-400 are user error. Long lens technique isnt somethign that just happens by accident + the IS tends to mess shots up if you try and snap them.

RobDickinson wrote in post #13068043
Tho I think a fair amount of the 'sharpness' issues of the 100-400 are user error. Long lens technique isnt somethign that just happens by accident + the IS tends to mess shots up if you try and snap them.

There are various lens test sites that have had different results based on their particular sample(s), and they're not testing them handheld with IS.

This looks about right to me, I shoot crop/7D so I dont see the extreem corners , the mid frame of the 100-400 isnt bad and holds up quite well.

Its 50% more than the prime where I live though and larger/bulkier.

A comparison of 70-200 f/4 IS or not with the 100-400 just because there is an overlapping FL range is an apples to oranges comparison IMO. I'll leave it at that and do not want to go into the much beaten up topic of using a 1.4x/2x TCs and what they do to the IQ, focus speed and the ability to AF on non-1D bodies. IQ-wise 70-200 beats almost everything else hands down.

Talking about the choice of 100-400 vs 400, I second whatever Mike, Rob and Phreeky have said above. I decided to go with the prime as my primary objective was more reach over the 70-200 at an affordable price. I have been able to get reasonably ok pics even 1/160s without IS with the 400 handheld with my 7D. The rest of it goes on a monopod/tripod.

phreeky wrote in post #13068037
Sharpness samples/reviews on the prime vary a little. Sharpness samples/reviews on the zoom vary a lot. That can make the decision a little tricky because if you choose the 100-400 you may find yourself either over the moon or a touch disappointed. Bokeh and AF the prime will be better.

The 400 is a very nice lens to hold, its balance is great and I can happily shoot with it handheld all day at an airshow. Physically it's lighter than a 70-200 F/2.8, the same max diameter (narrower for the most part), but longer. It also has the best lens hood design you'll come across.

Ultimately if you need the zoom then your choice is basically made up for you. If you need IS then the prime is out and it's either the 100-400 or the 300 F/4 IS (and a 1.4x TC). If neither of those matter then the prime becomes a great option.

I have never had IS on anything besides my kit lens, so I don't know what I'm missing, and I'd prefer to keep it that way for the time being. Everything I shoot is at 200mm and when I had a cheap 75-300 everything was at 300mm, so I don't really think I need the zoom. Thanks again for your input, it helped a lot.

nikmar08 wrote in post #13068138
I decided to go with the prime as my primary objective was more reach over the 70-200 at an affordable price.

That's exactly what I'm looking to do. Thanks for your input. I think I've made up my mind now; I just need to get the money together.