Worth upgrading from 100-400mm to EF 400mm f/2.8 L IS II USM?

[Ravanelli]

So I have just upgraded from a 5div to a stunning 1DXiii...........

Long story short, I have been using a 100-400 L IS ii for the last year. I shoot exclusively military aviation, fast jets etc. I spend a great deal of time at the Mach Loop in Wales, UK. This is a military low flying area. The 100-400 has been good, mated to the 5div. 

The opportunity has come about to buy a lens I have wanted for quite some time, and I think it would be great with the 1DX3. It is an EF 400mm 2.8 L IS ii. 

Like most seem to think, it's a significant leap in £££ / $$$ to buy this lens (over here in the UK in December 2025 an absolute mint one would be around £5000). I am aware of the weight penalty, and will have a new monopod for when I thinks I will need it.

So is it really worth the upgrade?

If anyone uses this kind of set up handheld I would welcome your thoughts. I'm physically strong and have weight trained all my life, so ok with heavier items.

Thanks,

Rav

[Waddizzle]

Assuming that the lens works as it should then it’s a great buy.  The lens very popular among sports photographers.

You will need to answer the question of how well it will work for aviation photography.  If it’s replacing your zoom, then you need to ask yourself how many of your aviation photos are shot at 400mm. 

[Ravanelli]

I often scrutinise the Metadata in my Lightroom classic library. More than 80% of the shots are at 400mm FL when using the 100-400.........

[Waddizzle]

“ I often scrutinise the Metadata in my Lightroom classic library. More than 80% of the shots are at 400mm FL when using the 100-400. 

That sounds promising.  Very promising!  

[FloridaDrafter]

IMO, you already have one of the sharpest 400mm lenses canon has made for the DSLR. The question is, do you need more light/stops at f/2.8? Just keep in mind, that is what you are paying for, more light. That is the reason sports photographers like f/2.8, be it 200mm, 300mm, etc. They often times find themselves subjected to poor lighting, particularly in HS and some college venues.

I primarily shoot wildlife, a lot of which are BIF, so I see a bit of similarity to aviation photography. But my targets are way smaller and far more erratic 🙂 Roughly 4 years ago I started using MILC, moving up from the 5D mark IV to the R5 and R6. I sold some of my EF glass, including the 400mm f/2.8L II, to offset buying RF glass to go with my R's. I kept the EF 100-400 II because of it's close focusing abilities, 3' vs the 9' of the 400 2.8LII (I also shoot flowers and insects). I'll just add that I still use my DSLR's. I typically used the 400mm 2.8 II on my 7D mark II for BIF and the 100-400mm II on my 5DIV for BIF, flowers, and insects. Frankly, I didn't see enough difference in IQ to compel me to keep the 2.8L II and it fetched a good price, LOL!

Newton

[Ravanelli]

With my aviation days out I am often faced with poor light. The British weather is very changeable and is often pretty bad. I tend to think that purchase price often dictates why millions use a great many lenses that are not prime 2.8. Such as the Sigma 150-600. I have had one for this reason. I know find myself lucky enough to get the 400 2.8. Given the choice, millions would choose that over, say, a 150-600. Nothing wrong with Sigma. Taking consideration to pro users. They all use primes. Why? Great low light performance when required. Add that factor to my new 1DX3 and it's a decent combination. Steve

[SignifDigits]

To your original "So is it really worth the upgrade?".  Technically, financially, or financially?

Technically - maybe.  You said you shoot 80% at 400mm.  How often do you shoot wide open on your current lens and how often will you shoot wide open with the prime? I don't know these lenses, but typically a zoom will suffer most at either extreme and in the corners.  Post processing typically improves that, and I assume even at 400 you are cropping. You will be giving up lighter weight, faster acquisition of your subject (much easier to do at 100mm then zoom - I'm assuming this might be a typical scenario for you - I know it is for me on my 200-800mm RF lens), and the flexibility to move to a target more quickly.  Those last two might not be a bid issue for you if you.  You will gain better better optical quality.  So are you unhappy with the quality you are getting now?

Financially - that is a good price for the lens if it is in great shape.  If you're a professional, perhaps you really need the competitive edge that only the best prime optics will give you.  If you're not selling your work, then I think it's really the last item.

Emotionally - is the additional outlay going to buy you the peace of mind of knowing that you are shooting with the best glass money can buy?   When any image is not sharp, you will know it was your poor choice of settings, or perhaps just the physics of the situation (too dark for any lens to capture an object going mach .5) and not the lens that was the culprit.  Will the joy of owning it outweigh your personal financial calculus.

I think it's obvious that you need to weigh the factors and can only make the decision for yourself and your situation.  

I'm sure nearly all of us have limited resources here and nearly all of us are still eyeing some lens and/or bit of kit with some longing.  I certainly fit into that box.  Just this week I made a compromise getting an E mount versions of lenses - on refurbished and one used - so that I could get two lenses for the same dollars as the one new RF lens that I really wanted (but didn't really NEED).  So, I can relate to your dilemma.  I felt good about my decision.  I hope that whatever you decide you will feel comfortable with it.  If the £5000 is not going to be a huge burden and it will bring you long-term joy, satisfaction and peace of mind then it might be £5000 well spent.  The good news is that if you have buyer's remorse, your risk would be much less than £1000 as I assume that you will be able to easily wholesale it to MPB or someone for that.  

Best of luck on making your decision and be safe and well during this holiday season.

[Ravanelli]

Yeah the 'new' lens will be from MPB. The 1DX3 that arrived 3 days ago was described as 'like new'. It is completely MINT. Only 5000 shutter activations. The 400 2.8 ii is described as 'like new' so I expect it to be mint also. They are now £4800 after I asked them if they price match, as I saw one on Wex, another similar website. They undercut them by £100. So I can get now for £4800. I might even get another 100-400ii for when I fancy a lighter rig. To explain, my current 5d4 and 100-400ii were both damaged by a careless driver (long story and both uneconomical to repair). Their insurance company have financially settled. So I have spent the last 10 days or so considering whether to buy the same or take the opportunity to 'upgrade'........

[Waddizzle]

“The question is, do you need more light/stops at f/2.8? Just keep in mind, that is what you are paying for, more light.”

More light means more light reaching the AF system, which is always a good thing.

I would have to check the camera specs.  Most DSLRs had a limited number of f/2.8 AF points, usually just the center point. The f/2.8 AF point could enter a higher sensitivity mode with lenses that were f/2.8 or faster. I believe the 1Dx series was not limited to just the center AF point being f/2.8. 

[Ravanelli]

All 191. Canon lenses are grouped in categories A-J for establishing the parameters that each lens will AF, and be categorised accordingly. The 400 2.8 ii in question here is in category A.