# Upgrading soon from 5DIII, need thoughts on lenses



## dawgfanjeff (Feb 26, 2021)

Like the title says...upgrading from Trusty 5DIII to an R5. I will need to buy the adapter for existing 28-105L, 16-35L, 100 Macro. 
I also have a 70-200 f/4L mk i that I am I am looking to upgrade that to either 1. EF100-400 mki, 2. EF100-400 mkii), or 3. the RF100-500. 

I intend to sell both 5Diii and 70-200 to defray some cost which isn't a huge factor, but there is a large gap ($1000-$3000) in price between a nice used 100-400 mki and the 100-500. I have used a rented 100-400mk1, and it's a great lens...thoughts?


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## JPAZ (Feb 26, 2021)

FWIW........Once I did have an EF 100-400 mki and I was frustrated with the results. Maybe it was a bad copy. But, I did manage to upgrade to an EF 100-400 mkii and it is a fabulous lens. Now, that lens on the R5 with an adapter, it remains great. Were I to get something in that length today and were it for an R5, I would definitely go for the RF 100-500.

So, in order of preference, modified by your budget, of course:

RF 100-500 if you can swing it,
EF 100-400 mkii if not,
EF 100-400 mki.....I'd not go there.

Good luck


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## reef58 (Feb 26, 2021)

What are you primarily photographing?


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## dawgfanjeff (Feb 26, 2021)

reef58 said:


> What are you primarily photographing?


Well, that's the right question, and I've been pondering it myself. With nieces and nephews all grown up, there are fewer and fewer close up things to shoot. I anticipate more trips and BIF, nature stuff upcoming. 500 gets closer of course, I am weighing that against simply cropping a little. 45MP helps there.


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## reef58 (Feb 26, 2021)

dawgfanjeff said:


> Well, that's the right question, and I've been pondering it myself. With nieces and nephews all grown up, there are fewer and fewer close up things to shoot. I anticipate more trips and BIF, nature stuff upcoming. 500 gets closer of course, I am weighing that against simply cropping a little. 45MP helps there.


If it were me starting from scratch I would go with the 100-500. I think I have mentioned this before but the RF24-105, RF100-500, and Maybe the 800mm f11 is a killer 3 lens kit. 

If that is too much of a leap, between the 100-400 mk 1 and 2 depends on how critical you are with sharpness. Of course there is sample variation also. I would go with the MK2. Also there is the Canon 400 F5.6. They start at $500 or so used.


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## Mt Spokane Photography (Feb 26, 2021)

I upgraded from my 100-400 mK I to the MK II. No significant difference in ID, but its easier to handle. Their tended to be reports of variation with early lenses, but later ones were consistently excellent. You can tell the date from the code on the lens.

The other issue with the MK I was the push - pull zoom bearings. Unless its smooth like silk, the bearings are bad and cost more than the lens value to fix. Personally, I'd stay away from one unless you know what to look for.


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## H. Jones (Feb 26, 2021)

I love my 100-400 F/4.5-5.6L IS II. It's an excellent lens and takes the 1.4X extender very well for birding. Absolutely no issues at all on the R5, it's been a perfect match and focuses even better on my R5 than on my 1DX mark II, thanks to the bird tracking AF.

When you get into the RF mount, I would agree with the 100-500 being the best bet from scratch, but the 100-400 II is an excellent alternative. If you do get the 100-400 II, the 1.4x III extender is only about $300 on the market, whereas the RF mount extender is unfortunately $600. For $600 on the RF extender, you could almost pick up the 800mm F/11.

I don't anticipate changing my EF 100-400 to a RF 100-500 anytime soon, since I would also have to replace the extender at quite a bit of additional cost, totaling a good $3200, for not a whole lot of difference.


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## Dantana (Mar 11, 2021)

One option you didn’t mention but I’ll throw out there. I moved from a 6D to the R a little over a year ago and took the opportunity to update my 24-105 L with the RF version. In practice it seems a bit sharper than my V1 lens, smaller than lens/adapter, and I no longer have to worry about creep. I got a good deal on the bundle with the new L and sold my old one with the 6D. Just throwing that out there as a not too costly update you might want to think about.


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## AlanF (Mar 11, 2021)

You might find this thread useful:





RF 100-500mm vs EF 100-400mm II vs 400mm DO II on R5


One of the questions asked about the RF 100-500mm is whether it’s worth upgrading to it from an EF 100-400mm II plus adapter. The consensus so far is that if you are starting from scratch, then it makes sense to buy into the RF system but if you already have the excellent EF lens then there is...




www.canonrumors.com





Starting from scratch, it would be better to buy a new 100-500mm rather than a new 100-400mm II, but a used 100-400mm II at a good price would be attractive. I would not advise the 100-400mm first version or the 400mm f/5.6 at this stage - they are too long in the tooth - unless you can't afford more. The RF 800mm is a specialist lens of limited use. I have used all of these lenses.


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