Canon 400mm f/2.8 III vs 600mm f/4 III

I am just dreaming (only at this point ) of getting one of the series III primes that are becoming available now.
While pondering which is the best, I have come up with following argument (of course in theory).

I feel that going with 400mm f/2.8 III has advantages over 600mm f/4 III for the following reasons

1. Cost. Lower by a grand or more.
2. Weight. about 800gms less heavy. So more handholdable? (Edit: OOPS its' not 800, but only 210gms less. What was I drinking?)
3. Add 1.4x TC and you have (close to) 600mm f/4 with advantage of #1 and #2 above.
4. If one was looking for 600mm only, #3 is your alternative.
5. Available f/2.8 (albeit at 400mm) when needed that 600mm f/4 can never give.

Yes, I agree it may be a hassle to keep flipping between TC and no TC, but..

What do you guys think?

Is shooting at f5.6 acceptable?

If so, why not consider the 400 DO II with the 1.4xIII ?

You get 560mm @ f5.6, much lower cost, weight, and size.

But dof and attractive background blur may not match the other lenses.

rndman wrote in post #18852451
I am just dreaming (only at this point ) of getting one of the series III primes that are becoming available now.
While pondering which is the best, I have come up with following argument (of course in theory).

I feel that going with 400mm f/2.8 III has advantages over 600mm f/4 III for the following reasons

1. Cost. Lower by a grand or more.
2. Weight. about 800gms less heavy. So more handholdable?
3. Add 1.4x TC and you have (close to) 600mm f/4 with advantage of #1 and #2 above.
4. If one was looking for 600mm only, #3 is your alternative.
5. Available f/2.8 (albeit at 400mm) when needed that 600mm f/4 can never give.

Yes, I agree it may be a hassle to keep flipping between TC and no TC, but..

What do you guys think?

Canon EF 600mm f/4L IS III USM Weight 6.7 lb / 3050 g
Canon EF 400mm f/2.8L IS III USM Weight 6.2 lb / 2840 g
Canon Extender EF 1.4X III Weight 7.9 oz / 225.0 g

210g difference between the 2 lenses. 400 is less than 7% lighter.
So 400 2.8 with 1.4TC, 560mm f4 is 15g heavier than the bare 600.

Due to above I would not make choice based on weight.
Due to the high cost of these lenses I would buy the lens you think will suit your wants and forget the price difference.
If you're going to spend that much, spend a bit more if the 600 is what you want.

Exactly this. One of the reasons I have not upgraded from my 800L to the 600 II was lack of appreciable weight savings. The 600 II is about 1.3 lbs lighter, plus 0.5 lbs when you add the TC and the weight savings aren't very extreme (the 600 III however is much lighter!). Besides, I hate dealing with TC's and I rarely use them on the 800L.

That said, I have seen over on FM just how capable the 400 III is not only with a 1.4x, but also the 2x III, and...get this...the 1.4x III + extension tube + 2x III. Nonetheless, I would choose the focal length I really wanted to be shooting at.

Choderboy wrote in post #18852616
Canon EF 600mm f/4L IS III USM Weight 6.7 lb / 3050 g
Canon EF 400mm f/2.8L IS III USM Weight 6.2 lb / 2840 g
Canon Extender EF 1.4X III Weight 7.9 oz / 225.0 g

210g difference between the 2 lenses. 400 is less than 7% lighter.
So 400 2.8 with 1.4TC, 560mm f4 is 15g heavier than the bare 600.

Due to above I would not make choice based on weight.
Due to the high cost of these lenses I would buy the lens you think will suit your wants and forget the price difference.
If you're going to spend that much, spend a bit more if the 600 is what you want.

Agree to what you say. Never did the proper math on the weight..

Perfectly Frank wrote in post #18852531
Is shooting at f5.6 acceptable?

If so, why not consider the 400 DO II with the 1.4xIII ?

You get 560mm @ f5.6, much lower cost, weight, and size.

But dof and attractive background blur may not match the other lenses.

Yes. This option is also under consideration.

I bought a Sigma 500 f4 last year. Very happy with it. The Nikon 500 f5.6 PF was announced after I bought the Sigma. Cheaper than the 400 DO II.
A Nikon D500 and 500PF costs about the same as a Canon 400 DO II.
The 500 PF is 1650g! The 400 DO II used to be high on my list of desirable lenses, not anymore.

The only negative comments I have seen in this thread so far relate to the wait to get one.

https://photography-on-the.net …/showthread.php​?t=1499529

Choderboy wrote in post #18852668
I bought a Sigma 500 f4 last year. Very happy with it. The Nikon 500 f5.6 PF was announced after I bought the Sigma. Cheaper than the 400 DO II.
A Nikon D500 and 500PF costs about the same as a Canon 400 DO II.
The 500 PF is 1650g! The 400 DO II used to be high on my list of desirable lenses, not anymore.

The only negative comments I have seen in this thread so far relate to the wait to get one.

https://photography-on-the.net …/showthread.php​?t=1499529

Do you use any support with your Sigma (like monopod, tripod). I really hate to use them and would prefer handholding for quicker movements. I feel restricted with the tripod/monopod.
And I believe the IQ is at par with Canon L.

I use a tripod a lot but shoot most often with 2X TC making hand holding more challenging.

Well I will give you my first hand experience. I owned both the MK III lens. I love the 400mm Mk III. It works awesome with extenders. The quality I am getting with a 2x is amazing. On FM I actually have a post with using the lens at 1120mm (2x + 12mm tube + 1.4x). Weight wise they are both very close, so no biggie there. I really liked the 600mm weight and balance having used my 800mm for 8 1/2 years and 600mm v2. The 600mm worked well with both extenders. I gave the 400mm a great work out in Costa Rica. It did everything it needed to do ( due to Canon delays I did not have the 600mm). In the end I decided to keep the 400mm over the 600mm due to the fact I loved the size over the 600mm and the MFD over the 600mm also. I feel quality wise they are very close. I get a 400mm f2.8, a 560mm f4 and a 800mm f5.6 is a very small light weight, well balanced package. I feel it will be a better fit in the kayak too. My main mm's I used over the years has been 800mm. Using the 400mm f2.8 with the 2x has given me very close results as my 800mm f5.6 and my 600mm with a 1.4 has given me. I also owned the 400mm DO II and loved the lens for the size but for flight work at 800mm is was not great, useable but not great. The 400mm f 2.8 hands down wins at 800mm in all categories vs the DO. I also sold my 400mm DO II along with the 600mm MK III just this week as a matter of fact. I use the short hoods on both lenses also which put the 400mm f2.8 almost to the length of the 400mm DO. In the end they are all very good pieces of glass, so pick which one will work best for you. I feel the 400mm will fit my needs best going forward. My wife shoots too, so our thought was she will keep the 400mm f2.8 and I will keep the 600mm Mk III but she decided to keep the 400mm DO II instead because she felt the the 400 f2.8 was still a little heavy. So at the cost of these I decided not to keep both.

My Flickr site has albums of the 400mm f 2.8 and the 600mm if interested.

robamy wrote in post #18852731
Well I will give you my first hand experience. I owned both the MK III lens. I love the 400mm Mk III. It works awesome with extenders. The quality I am getting with a 2x is amazing. On FM I actually have a post with using the lens at 1120mm (2x + 12mm tube + 1.4x). Weight wise they are both very close, so no biggie there. I really liked the 600mm weight and balance having used my 800mm for 8 1/2 years and 600mm v2. The 600mm worked well with both extenders. I gave the 400mm a great work out in Costa Rica. It did everything it needed to do ( due to Canon delays I did not have the 600mm). In the end I decided to keep the 400mm over the 600mm due to the fact I loved the size over the 600mm and the MFD over the 600mm also. I feel quality wise they are very close. I get a 400mm f2.8, a 560mm f4 and a 800mm f5.6 is a very small light weight, well balanced package. I feel it will be a better fit in the kayak too. My main mm's I used over the years has been 800mm. Using the 400mm f2.8 with the 2x has given me very close results as my 800mm f5.6 and my 600mm with a 1.4 has given me. I also owned the 400mm DO II and loved the lens for the size but for flight work at 800mm is was not great, useable but not great. The 400mm f 2.8 hands down wins at 800mm in all categories vs the DO. I also sold my 400mm DO II along with the 600mm MK III just this week as a matter of fact. I use the short hoods on both lenses also which put the 400mm f2.8 almost to the length of the 400mm DO. In the end they are all very good pieces of glass, so pick which one will work best for you. I feel the 400mm will fit my needs best going forward. My wife shoots too, so our thought was she will keep the 400mm f2.8 and I will keep the 600mm Mk III but she decided to keep the 400mm DO II instead because she felt the the 400 f2.8 was still a little heavy. So at the cost of these I decided not to keep both.

My Flickr site has albums of the 400mm f 2.8 and the 600mm if interested.

Thank you very much for the detailed response.
Off to your flickr to check out both.

robamy wrote in post #18852731
Well I will give you my first hand experience. I owned both the MK III lens. I love the 400mm Mk III. It works awesome with extenders. The quality I am getting with a 2x is amazing. On FM I actually have a post with using the lens at 1120mm (2x + 12mm tube + 1.4x). Weight wise they are both very close, so no biggie there. I really liked the 600mm weight and balance having used my 800mm for 8 1/2 years and 600mm v2. The 600mm worked well with both extenders. I gave the 400mm a great work out in Costa Rica. It did everything it needed to do ( due to Canon delays I did not have the 600mm). In the end I decided to keep the 400mm over the 600mm due to the fact I loved the size over the 600mm and the MFD over the 600mm also. I feel quality wise they are very close. I get a 400mm f2.8, a 560mm f4 and a 800mm f5.6 is a very small light weight, well balanced package. I feel it will be a better fit in the kayak too. My main mm's I used over the years has been 800mm. Using the 400mm f2.8 with the 2x has given me very close results as my 800mm f5.6 and my 600mm with a 1.4 has given me. I also owned the 400mm DO II and loved the lens for the size but for flight work at 800mm is was not great, useable but not great. The 400mm f 2.8 hands down wins at 800mm in all categories vs the DO. I also sold my 400mm DO II along with the 600mm MK III just this week as a matter of fact. I use the short hoods on both lenses also which put the 400mm f2.8 almost to the length of the 400mm DO. In the end they are all very good pieces of glass, so pick which one will work best for you. I feel the 400mm will fit my needs best going forward. My wife shoots too, so our thought was she will keep the 400mm f2.8 and I will keep the 600mm Mk III but she decided to keep the 400mm DO II instead because she felt the the 400 f2.8 was still a little heavy. So at the cost of these I decided not to keep both.

My Flickr site has albums of the 400mm f 2.8 and the 600mm if interested.

Do you hand hold the 400mm (or 600mm) or use any support?

rndman wrote in post #18852826
Do you hand hold the 400mm (or 600mm) or use any support?

I have handheld all the shots except for the recent 1120mm shots and about 2% of Costa Rica shots. That includes both the 400mm and the 600mm. Super easy to handhold both of the lenses. Granted it depends on ones ability but the are a joy to use.

robamy wrote in post #18852731
I also owned the 400mm DO II and loved the lens for the size but for flight work at 800mm is was not great, useable but not great.

With what body? Or are you talking about something other than AF?

John Sheehy wrote in post #18852879
With what body? Or are you talking about something other than AF?

Sorry I should have mentioned that. I use the 1Dx Mark II. I am talking about AF. You can set the focus limiter, or manual focus to get the best results but out of the lenses I have used in the 800mm range, the 400mm DO II struggled a bit. Do not get me wrong, it is an awesome lens and is great for stationary at 800mm and with the 1.4x it is outstanding. It is my wife's most use lens and it performed well in Costa Rica for me last year but vs the 400mm f2.8 Mk III at 800mm the speed of AF is not in the same league.