cant make up my mind...help from experianced guys (1 Viewer)

Hello

I am new to this forum friends....

looking for help

which will be a better option to have a Lens of 400 mm for my EOS 5DIII:

1) Canon EF 400mm f/5.6L USM

OR

2) Canon 300mm f/ 4L IS USM with Canon Extender 1.4x III.

or any other better option with in a budget of approx $2400.

keeping IQ in mind also.

Greetings Yogipuri and a warm welcome to Birdforum from staff and moderators.

I've moved your post to the appropriate sub-forum. Hope you get the information you are looking for.:t:

Depends upon your shooting style/subject. The 300/4 is very good for larger insects like butterflies and dragonflies but for bird you would probably find you were using the 1.4x tc most of the time, in which case the 300 + tc would not come up to the IQ of the bare 400/5.6 and focus speed would also be slower.
With the 400/5.6 not having IS you obviously need a fast shutter speed to compensate (if handholding) - I would have though the 5D3 would be ideal for this lens because of its high ISO noise levels which are at least a couple of stops better than a Camera like the 7D. I have shot the 7D and 400/5.6 (handheld) quite a lot but with the 5D3 you could get a 4x faster shutter speed for the same noise levels!!!!!. The other thing is that you can also AF at f8 so you could add a 1.4x tc to the 400/5.6 if you wanted more reach (I know you could put a 2x tc on the 300/4 but I doubt that the IQ would be that good although I stand to be corrected).

I have always been a great fan of the 400/5.6 and rate it almost as good as the super teleles when you get it right although it is obviously slow at f5.6. Recently I bought a 5D3 Camera and have though about getting another 400/5.6 to use with it as shutter speed should be no problem when you can safely shoot us to ISO 3200 ( and beyond with a bit of processing work).

I would echo Roy C's comments.
Both are excellent lenses but have their own strengths and weaknesses. The 400 F5.6 has no IS, is F5.6 and has a long minimum focus distance. However (I am told) it has top notch IQ, fast AF and of course it is 400mm. The 300 F4 IS has an F4 aperture, IS, close minimum focus and excellent IQ.
Personally I went for the 300 F4 IS as it suits my needs better than the 400 F5.6 (I already had a 600mm for reach) and find that it makes a very good and flexible all round wildlife lens for my uses.
If you like photographing large mammals (Deer etc), larger insects, reptiles snakes etc then the 300 is probably a better choice. If you want to shoot smaller birds then the 400 F5.6 wins hands down because of it's native focal length. Both are excellent just different.
Decisions decisions!

And don't forget the 100-400...............

If I had the 5D MK3 and I was mainly into birds I'd get the 400 f5.6, the clean high ISO means you'll get decent shutter speeds and IS is not so crucial. Also when you need more reach the I would suggest the 400 with 1.4X T/C would be better than the 300 with 2X T/C.

On a 5D3 I suspect you always want more focal length the either 400mm or 420mm. Therefore I would go with the 400 f5.6 so you can add the 1.4 ext to get 560mm. This will give you excellent quality on the 5D3. 300 f4 with the 2x is going to suffer more quality hits and be slow.

I have used the 5D3 with 1.4 extender for birds in flight and have had great success with this.

BodyResults said:

On a 5D3 I suspect you always want more focal length the either 400mm or 420mm. Therefore I would go with the 400 f5.6 so you can add the 1.4 ext to get 560mm. This will give you excellent quality on the 5D3. 300 f4 with the 2x is going to suffer more quality hits and be slow.

I have used the 5D3 with 1.4 extender for birds in flight and have had great success with this.

Click to expand...

:t:Good to hear someone with first hand experience confirm my thoughts on the 5D3-400/5.6 combo, very good to know that the AF at f8 is good enough for BIF. Although you would lose a stop by using a 1.4x tc there is still at least a stop advantage re noise over the bare lens on a crop Camera.

Yes Roy it works very well.

Here are a couple BIF images with that combo plus the 1.4 extender.

BodyResults said:

Yes Roy it works very well.

Here are a couple BIF images with that combo plus the 1.4 extender.

Click to expand...

That's a couple of very nice shots Doug.

I must thank all of you for your advice; I will go for EF 400mm f/5.6 L USM for my 5D3 and later got for 1.4 extender III.