R5 detailed lens testing of RF 100-500 f4.5-7.1 vs. RF 800 f11, with & without RF 1.4x TC, for super-telephoto use.

usern4cr

R5
CR Pro
Sep 2, 2018
1,160
1,919
Kentucky, USA
*** Part 5b ***

Here is a 1:1 crop of the center area with the bill and resolution charts of the same 4:
A03_1254_1_center95%.jpg A03_1266_1_center95%.jpg A03_1280_1_center95%.jpg A03_1275_1_center95%.jpg


I also re-sized (from Raw) the above crops to the 2048 x 2048 size that happened to be what the 1120mm photo was at:
A03_1254_1_center2k95%.jpg A03_1266_1_center2k95%.jpg A03_1280_1_center2k95%.jpg A03_1275_1_center2k95%.jpg
 
  • Like
Reactions: AlanF

usern4cr

R5
CR Pro
Sep 2, 2018
1,160
1,919
Kentucky, USA
*** Part 5c ***

Here is a 1:1 crop of the view of the Queen of the same 4:
A03_1254_2_queen95%.jpg A03_1266_2_queen95%.jpg A03_1280_2_queen95%.jpg A03_1275_2_queen95%.jpg

The above are re-sized up (from raw) to 2K x 2K for a fairer comparison:
A03_1254_2_queen2k95%.jpg A03_1266_2_queen2k95%.jpg A03_1280_2_queen2k95%.jpg A03_1275_2_queen2k95%.jpg


As far as the #lines barely resolved, the "N" value I chose was the average for horizontal & vertical lines for the 3 charts in each:
(note this is a rough #, based on visual inspection)
500mm: N = ~34
700mm: N = ~40
800mm: N = ~47
1120mm: N = ~49

The length of the arrow line "A" is:
500mm: A = 269
700mm: A = 372
800mm: A = 432
1120mm: A = 598

From the formula, #barely resolved lines = N * 7 * S / A
(where S = #pixels in sensor height, or 5464 for the R5)
(note a black & white line pair count as "2 lines")
500mm: #barely resolved = ~4834
700mm: #barely resolved = ~4113
800mm: #barely resolved = ~4161
1120mm: #barely resolved = ~3134

The number of sensor pixels needed to barely resolve a black & white line pair is:
500mm: ~2.3 pixels
700mm: ~2.7 pixels
800mm: ~2.6 pixels
1120mm: ~3.5 pixels

Note: I haven't compared these results with what I got in my previous post with an earlier chart. I hope they're close (you never know) ;)

You can be the judge of the results that I found at this focal distance.
I will try to find time to do another similar test at a longer focal distance, which will have to be outside of my house.

I hope you liked this. Feel free to make comments or suggestions. I'm just a retired programmer with photography, pickleball, & travel as my main hobbies.

I hope you're all able to stay safe and can get your Covid vaccines. I got my 2nd one yesterday, so I'm very grateful for my luck with that.

Cheers!
usern4cr (well, also known as "John")
 
Last edited:
John and Alan,

amazing work, meticulous focus on comparing the lenses in a fair way.

Thanks for the hard work, intellectual work and sharing it in an easily digestible format.

For me, this is the sort of comparative reviews which are really informative about making purchases. I wish review sites would do more like this but I guess there is a lot more effort doing what you’ve done.

Many thanks again.
 
  • Like
Reactions: AlanF and usern4cr

zim

EOS 5D Mark IV
CR Pro
Oct 18, 2011
2,129
317
Indeed great stuff, that's a lot of commitment, work and time.
I don't have RF kit but still picked up a couple of interesting processing points that I'll be having a little play with!

Thank you
 
  • Like
Reactions: usern4cr

usern4cr

R5
CR Pro
Sep 2, 2018
1,160
1,919
Kentucky, USA
John and Alan,

amazing work, meticulous focus on comparing the lenses in a fair way.

Thanks for the hard work, intellectual work and sharing it in an easily digestible format.

For me, this is the sort of comparative reviews which are really informative about making purchases. I wish review sites would do more like this but I guess there is a lot more effort doing what you’ve done.

Many thanks again.
Thanks so much, Stu_bert. I've haven't done this kind of thing before, and would really like to thank AlanF for his ideas and previous work and for helping to make it a more readable & (hopefully) enjoyable form.
 
Last edited:
  • Like
Reactions: AlanF and Stu_bert

usern4cr

R5
CR Pro
Sep 2, 2018
1,160
1,919
Kentucky, USA
Indeed great stuff, that's a lot of commitment, work and time.
I don't have RF kit but still picked up a couple of interesting processing points that I'll be having a little play with!

Thank you
Thanks, Zim. If you ever have the chance to get a R5 and the RF 100-500L pair, that's a really sweet combination all by itself.