EF 600mm f/4L IS III USM + TC Image Quality

[docusync]

Hi Friends,

Does anybody have first-hand experience comparing this lens to its predecessor the EF 600mm f/4L IS II?

Particularly I'm interested in the sharpness loss fact while it's paried to a teleconverter.

I'm in the market for the RF 600mm f/4 (which is optically identical to the EF v3) and already placed my pre-order but the IQ degradation reported by TDP https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=1227&Camera=979&Sample=... and some other folks (like here https://www.flickr.com/photos/chrisbainbridge1/46627840622) is worrying me.

I'm not sure if that's an early batch issue or an actual design flaw. There is not much information on Google about it unofrtunately. I would buy a 600/4 II and call it a day, but they aren't available anwyhere. I'm planning to use the lens with a 1.4 TC all the time, and I don't like the idea of paying $13.5k (including the TC) for a subpar quality. I couldn't care less about the weight reduction, and wouldn't definitely sacrifice weight for the IQ.

Please share you expereince and samlpe shots if available.

Thanks!!!

[rs-eos · Accepted solution]

You'd be your own best judge to see if it would fit your needs and quality standards.  Thus, for that kind of investment, definitely rent and try out first!

[docusync]

Ricky, thank you for your reply. It would cost me around $500 (a full price of the RF 1.4x TC) to rent the v3 for a week 🙂  That's why I'm asking folks here... Quite a few people upgraded their v2 to v3, and their opinion matters to me. Some returned it and some kept, and that keeps me puzzled. Is the new optics really (and consistently) underdelivering, or it's just some quality variance (which is kind of also not good).

[jrhoffman75]

PM wq9nsc (Rodger). He is a big white user and may have advice. 

But, you say there are no VIIs to be found, so it sounds like you have a binary situation - no lens or a VIII. In that case, why fret over the uncertainty that may or may not exist. 

[docusync]

Thank you John, but that's not quite binary. There are many choices:

- Wait for no one knows how long the v2 becomes avaialble again (if it ever will) or find a used copy

- Buy a Sony 600/4 which works great with TCs, but it will require to buy a Sony body just for that lens

- The RF version which I pre-ordered - may work better with the RF TCs. The EF v3 TCs were optimized for the corresponding generation of big whites (EF 300/400/500/600 v2). If the 600/4 III and 400/2.8 III were developed with the RF mount in mind, and the new TCs are opimized for those lenses - the quality drop can be less significant, and possibly on the same level as the older geneation.

With all that said I would still love to hear the owners' feedback. I did follow Ricky's advice and requested a v3 from CPS for evaluation. For some reason I didn't think about CPS when he mentioned renting. I can theoretically try it on the RF 1.4x TC via an adapter (camera -> RF TC -> RF/EF adapter -> lens) and compare it to the EF 1.4x III TC (camera -> RF/EF adapter -> EF TC -> lens). I'm very curious and excited to see results!

[wq9nsc]

I definitely wouldn't draw any conclusions from trying to use a RF 1.4X to EF adapter and EF lens.

I have never owned the 600mm lens but I have 200, 300, 400, and 800 fast primes (if you can call the 800 5.6 fast).  All of these work quite well with a 1.4X and produce very nice images until you compare the bare lens to the 1.4X combination.  The overwhelming majority of people wouldn't notice or care but even the best primes (and I think the 300 and 400 f2.8 are the best there are) still lose some IQ with the 1.4X.

Once you start pairing a 1.4X with a really good prime lens, there are going to be subtle differences between different copies of the same lens and adapter if you look closely enough at the resulting images.  So I am not surprised that the reviews vary, some differ just based upon personal tastes and perceptions but others will experience true differences in IQ and with the added 1.4X it will often have greater effects as you move out from the center of the image circle.

I will continue on rare occasions to use a 1.4X with a prime but I also think we are at the point of sensor development where cropping equals or exceeds what a 1.4X can provide in many cases, especially when you factor in the slight loss in AF speed and tracking.  And it isn't all just megapixel density, my 1DX III produces images that are of slightly better quality than my 1DX II even though both have 20 MP sensors.

Unfortunately, if you want the very best combo of 600 and 1.4X you will either need to try several examples of each and hand select the best combination or hope that you get lucky with the first order.  Realistically, these Canon primes are excellent glass and unless you get a truly defective version it is capable of stunning image quality.  For sports, I normally use a 400 f2.8 on my 1DX III and a 70-200 f2.8 (IS III, the latest version) on the second body but for a few darker fields I will use my 200 f2 instead of the "zoom" and although it is less versatile, the difference in image quality is often obvious even though the 70-200 f2.8 is an excellent lens.  But even with the difference, no "normal" person is going to look at an image from my 70-200 versus the same from the 200 and notice a difference.

Rodger

[docusync]

Hi Roger,

I was thinking about getting the 800/5.6, but it's not very "back friendly"... I used to shoot the 600/4 II handheld in the past not exceeding 1-1.5 hours per session. If it's longer than that - not fun anymore. I have a gimbal but I'm not a big fan of it. That's why I'm now looking at this new generation of lightweight primes.

Concerning the adapter warning - my idea is based on the RF 400 and 600 lenses are essentially their EF v3 siblings with a permanently attached adapter (the silver spacer). They have a half-stop improvied IS but optically they are the same (confirmed by Canon). While the tolerances of the adapted glass won't be the same as "hard-mounted", it should still give an idea of what to expect. I have my 200/2 and 300/2.8 II to compare results, and I do agree the 200 - 400 big whites could be considered as benchmark lenses.

I was always under impression that Canon lenses, especially the high end ones, have ver low quality variance. I won't have an opportunity to try multiple lenses because my local store won't likely carry many RF 600s, and I doubt the store onwer will be ok if I'll be opening and testing multiple lenses just to tell him at the end "sorry man - I like none!" 😉 But I got the idea.

My CPS loaner is coming in early May, and I'll post here a few samples when I give it a try. So far the RF 1.4x converter looks promising (on the RF 100-500), so I hope it maybe really an improvement over the EF 1.4x III. We'll see...

Thanks!

Oleg

[rs-eos]

I do appreciate you marking my post as the solution.  But to be fair, I hadn't thought about CPS at the time I wrote that 🙂   Glad you were able to find a 'try before you buy' solution!

[docusync]

Ricky, that was an unbeatable, genius idea. All genius ideas are simple. I just improved it a little 🙂 Thank you!

Oleg

[krispenhartung]

I have both the EF 600mm f/4L IS USM III and the 1.4x TC III.  I use the lens with my R5 with EF/RF adaptor.  I have no need to use 1.4x on a 600mm, espeically with a 45mp camera and using the 1.8x crop mode (which entails no change in my f stop); however, I might be able to run some tests for you.  I can predict the results, however, just based on the physicis. It's going to change the f stop to f/5.6.  This reduces light, which will impact auto focus speed and sharpness.  How much, however? And will it be noticeable?  I think it will be subtle, but in my experience, using my older 600mm f/4L and TC, the autofocus is noticeably slower.  Again, in the work I do, if I need to use a TC on a 600mm, then I'm better off just gettting closer to my subject.  I'm not willing to deviate from f/4.  But if I really need the extra percieved range, I just use the 1.8x crop mode on my R5...it basically reduces the resolution and file size to 30mb.  However, if I don't use the crop mode, with the same subject, there is no difference after editing, because I'm just going to crop the image anway.  The 1.8x crop mode then is a matter of usability and being able to see the subject better through my viewfider so that I can be more precise in my focus points.