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.
*** PART 1 ***
A fellow R5 user, AlanF, and I enjoy taking photos of birds, sometimes at far distances. We've been wondering how the IQ (image quality) of the RF 100-500 f4.5-7.1L (with or without the RF 1.4x TC) compares to the RF 800 f11 on the R5 for super telephoto shots. I think it was AlanF that suggested that I consider doing a comparative test on them, since I had all of those items, and could do my own test of the IQ of these lenses on the R5, comparing (initially) 500mm, 700mm (500mm & 1.4x TC), and 800mm.
AlanF had suggested that a quantitative test was needed so that the resolution of the lenses could be measured as well as providing images for contrast and overall IQ. He suggested a test chart from Bob Atkins, which I looked at but thought it didn't have the fine resolution that I was hoping to find. So I continued looking online and found another chart, from Erlend Rønnekleiv, that had more detail. I thought I could improve on it, and so I used AffinityPhoto to re-arrange the pieces of it together into a more compact form with more detail in the same space. Erlend gave me permission to use & post this rearranged version, which is:
I taped this chart, printed on 8.5" x 11" paper, onto some wood and positioned the camera & tripod 6 meters away. I used a laser measure to ensure the chart was centered in the camera view and was exactly perpendicular to the camera. The 800mm f11 was just past minimum focal distance and viewed the whole test sheet plus just a little extra. Then I took photos at the same distance with it and the RF 100-500 f4.5-7.1L (with and without the RF 1.4x TC). For each I took 5 photos, 1 AF'd in the center and 1 AF'd as far as I could get to the 4 corners. In looking at all 4 corners of the images in their respective photos, they seemed to me to be the same as it was when AF'd in the center, so I only need to show the center AF'd photo from each.
I used DXO PhotoLab4 standard profile, set white balance, and used deep prime only to output tif files, which went to Affinity Photo, where I cropped the center of each (and the original test chart) at 1:1. Note: I did not adjust all white levels to the same brightness (which I'll do next time). So don't worry about them having different brightnesses.
Here they are, for:
original test chart, 500mm, 700mm(500 & 1.4x), and 800mm
The #lines resolved per sensor height is:
N * 6 * 5464(R5 sensor pixel height) / A
where N is the #(number) on the chart where you get the limit of resolution (N >> 40 (the max on the chart), so I used 40 below)
and A is the #pixels in the photo between the indicated test pattern line start & end, which is:
for 500mm: 1,355
for 700mm: 1,904
for 800mm: 2,340
So, the #lines resolved per sensor height is far greater than these numbers:
for 800: 560
for 700: 689
for 500: 968
So, at this relatively near focal distance, the chart still does not have enough small resolution to properly measure the resolution of the lenses.
Taking photos from further away would solve this, but this was just the initial test I did to see how everything worked.
I'd like to mention that there were many posts between us regarding these results, and further ideas regarding them. AlanF had many great insights into the results and had suggestions on how better to write up the results which I could post for the general CR community. It took a while for me to go through the next steps, since I had other pressing things at home to do and, well, sometimes I pause one task to do other ones. This post and those that follow are a revised summary of what we both came up with, and I hope that it's much more informative and enjoyable for all of you to see.
It occurred to me that I could probably create a higher resolution chart (lines closer together) from scratch using AffinityPhoto.
So that is what I planned to do, which will become Part 2 (next).
A fellow R5 user, AlanF, and I enjoy taking photos of birds, sometimes at far distances. We've been wondering how the IQ (image quality) of the RF 100-500 f4.5-7.1L (with or without the RF 1.4x TC) compares to the RF 800 f11 on the R5 for super telephoto shots. I think it was AlanF that suggested that I consider doing a comparative test on them, since I had all of those items, and could do my own test of the IQ of these lenses on the R5, comparing (initially) 500mm, 700mm (500mm & 1.4x TC), and 800mm.
AlanF had suggested that a quantitative test was needed so that the resolution of the lenses could be measured as well as providing images for contrast and overall IQ. He suggested a test chart from Bob Atkins, which I looked at but thought it didn't have the fine resolution that I was hoping to find. So I continued looking online and found another chart, from Erlend Rønnekleiv, that had more detail. I thought I could improve on it, and so I used AffinityPhoto to re-arrange the pieces of it together into a more compact form with more detail in the same space. Erlend gave me permission to use & post this rearranged version, which is:
I taped this chart, printed on 8.5" x 11" paper, onto some wood and positioned the camera & tripod 6 meters away. I used a laser measure to ensure the chart was centered in the camera view and was exactly perpendicular to the camera. The 800mm f11 was just past minimum focal distance and viewed the whole test sheet plus just a little extra. Then I took photos at the same distance with it and the RF 100-500 f4.5-7.1L (with and without the RF 1.4x TC). For each I took 5 photos, 1 AF'd in the center and 1 AF'd as far as I could get to the 4 corners. In looking at all 4 corners of the images in their respective photos, they seemed to me to be the same as it was when AF'd in the center, so I only need to show the center AF'd photo from each.
I used DXO PhotoLab4 standard profile, set white balance, and used deep prime only to output tif files, which went to Affinity Photo, where I cropped the center of each (and the original test chart) at 1:1. Note: I did not adjust all white levels to the same brightness (which I'll do next time). So don't worry about them having different brightnesses.
Here they are, for:
original test chart, 500mm, 700mm(500 & 1.4x), and 800mm
The #lines resolved per sensor height is:
N * 6 * 5464(R5 sensor pixel height) / A
where N is the #(number) on the chart where you get the limit of resolution (N >> 40 (the max on the chart), so I used 40 below)
and A is the #pixels in the photo between the indicated test pattern line start & end, which is:
for 500mm: 1,355
for 700mm: 1,904
for 800mm: 2,340
So, the #lines resolved per sensor height is far greater than these numbers:
for 800: 560
for 700: 689
for 500: 968
So, at this relatively near focal distance, the chart still does not have enough small resolution to properly measure the resolution of the lenses.
Taking photos from further away would solve this, but this was just the initial test I did to see how everything worked.
I'd like to mention that there were many posts between us regarding these results, and further ideas regarding them. AlanF had many great insights into the results and had suggestions on how better to write up the results which I could post for the general CR community. It took a while for me to go through the next steps, since I had other pressing things at home to do and, well, sometimes I pause one task to do other ones. This post and those that follow are a revised summary of what we both came up with, and I hope that it's much more informative and enjoyable for all of you to see.
It occurred to me that I could probably create a higher resolution chart (lines closer together) from scratch using AffinityPhoto.
So that is what I planned to do, which will become Part 2 (next).
