Is there Much Difference in Quality and FoV?

[Tronhard]

All that has been done is to drastically downsize the images for posting, in part by using a 1:1 format on both.  These were taken within seconds of each other, of the same bird (a Takahe), in patchy available light, hand-held.

To me there is very little difference between the two images, so one can get the same FoV and general performance by using a large capacity camera, and putting it in crop mode with the short FL lens.

EOS R5, RF 100-500 1.6x crop 567mm(equivalent), f/9, 1/250sec, ISO-3200R6, RF 200-800, 570mm, f/8, 1/640sec, ISO-400

[JFG]

Hi Trevor, its been a while.  Hope your find yourself in the best of health.  I was just wondering if you got around to doing the comparison between the Sigma 60-600mm and the new Canon 200-800mm..  I'm waiting for Sigma to come out with the RF version of the 60-600 and for Canon to come out with the new R5 Mark Ii..   😆   However in the meantime I'm on the fence about the RF 200-800 f/6.3-9 because of the f starting so high.  I just wonder if one would be able to use it with low sunlight or even at sunset.  One thing is that when shooting birds, I'm now experimenting shooting with my lenses wide open and fastest SS possible, so I would be at 6.3 most of the time and letting ISO make up for the difference.  Let me know your thoughts, they're always appreciated. 

[Tronhard]

Hi Joe and thanks for your question.
I must admit I have been a bit distracted of late, due to a commitment to provide voluntary photographic support for an academic medical research program at my local university.   
I have not specifically looked at comparing the Sigma 60-600 against the RF 200-800 at this stage.  For me, the comparison between the RF 100-500 f/4.5-7.1 with a body on 1.6x crop was to see how to get the same Equivalent focal ranges by using an APS-C camera (or in this case my R5 in 1.6 crop mode), and thus rendering a FoV of 160-800mm with an Equivalent f/stop of f/7- 11, and seeking comparison to a FF camera using the 200-800 f/6.3 - 9 - i.e. they both have very similar Equivalent ranges. 

Although one could argue that while the aperture range on the 100-500 is not physically going to change (which it obviously will not) the depth of field achieved will, hence the Equivalent values FWIW.
Something I did not investigate, because I don't have the gear, is the performance of the RF 100-500 on a FF body with the RF 1.4x Extender.   However, this has been approached by several people on You Tube in reviews, for example, this video by Fabian Fopp: 
RF200-800 vs RF100-500 + 1.4? Which one is the better option for YOU? Real World Comparison (youtube...
and a list of others: 
DUMP The 100-500 OR Can TELECONVERTERS Make The DIFFERENCE? Canon RF 200-800 vs RF 100-500 Review (y...

However, to go back to your specific question.   I am happy to have a go in comparing the two when I get the chance, which MAY happen over the Easter weekend (I have a bit of processing to do and recovery from a medical procedure).  In that case, I would be using the R5 with the 200-800 in normal FF mode on an R6II, and the Sigma 60-600s on the R5 in 1.3 crop mode, rendering a FoV Equivalent to 78-780mm, and both producing images in the range of 24MP, which is pretty close.   I will also take an image of the 60-600 in FF mode at 600mm compared to the 800 of the 200-800 to show you the difference.

Would that be acceptable?

[JFG]

Yes, that would be great as one will get a very good comparison of the RF 200-800 using the R5 cropped and at 24 mega pixels along with the Sigman 60-600 using the R6 MII to more or less match the FoV.  I look forward to seeing the results.

[Tronhard]

Hi Joe:
Major apologies for not getting back to you on this specifically.  It's been a challenging time, health-wise so I have been somewhat preoccupied with that and a project for a medical research team.
I think I posted this elsewhere, but regarding your specific request, here are two images of the same individual tiger, taken in two different places (so the light is from a different direction) but with the Sigma 60-600 and the 200-800, both on the same camera and cropped to the same degree for comparison.  You should view the images opened as the view from this page is not high enough resolution to see how sharp the images are.
The direction of the light impacts the eyes of the tiger's first image as it is looking into the light, so the pupils are narrower and there are reflections on the eyes, which gives a different impression.

R6II, Sigma 60-600s@328mm, f/8, 1/500sec, ISO-6400

R6II, RF 200-800@311mm, f/7.1, 1/320sec, ISO-6400

[JFG]

Hi Trevor, good to hear from you and to know that your hanging in there.   I like the comparison of the tiger shot with the Sigma 60-600mm and the Canon 200-800mm.  I know that both pictures were taken at different times and place, under different lighting constraints.  However if I were to choose I'd take the second picture, taken with the Canon 200-800mm.   They are both pretty close but the second picture is more attractive.  I think its because of the contrast and  color saturation seems to be a bit more vivid.  For the time being, I'm waiting for the R5 M2 to come out and at what price.  If it's to much I'll go with R5 as it has come down to USD $2899.00 for now.  It may come down a bit more once the R5 M2 hits the market.   Then I'll go with the Canon RF 200-800mm and I'll be set for a long time.  I been shooting birds in the wild and posted them under the heading "Song Birds on our fence"..  Let me know what you think of them.  Good to hear from you, as always 🙂 

[Tronhard]

Thanks Joe for being patient.  Glad you got something out of the comparison, which is not truly scientific, but neither is nature photography!
I shall check out your photo's - thanks for letting me know.

[JFG]

Hi Trevor, I look forward to your thoughts and comments on my "Birds on our fence" pictures.  I noticed that Canon officially announced the release date of the EOS R1 camera.  I thought that Canon would announce the release date for the R5 M2 first.  Go figure!  😆 

[Tronhard]

Hi Joe.  Sorry, rather tied up with non-photography issues...  I promise to give your photo's their deserved attention! {:-)
There are rumors that an announcement for the R5II is due later this month - but again, a rumor...

[JFG]

Yes, I would be interested in that comparison, 60-600mm vs 200-800mm !  I may end up selling my 150-600mm.  😆 

[Tronhard]

Hi Joe:
I understand!   It may take a bit over a week, as I am immobile at home this week, so will plan to do that next week.