GAJoe wrote in post #19408328
I'll work on getting that sorted out then because that's one of my favorite uses of the 100-400 to get near macro results.
As John says, the camera does not change your MFD, that's a function of the lens design. I suspect it's actually seeing the difference in APS-C vs 35mm/"full frame" sensors; I assume you're coming at the R5 from your 7DII? The larger sensor captures a wider field of view and therefore your subject appears smaller/farther away than you're used to seeing. This is, of course, an *extremely* simplified statement but one that I think should help you understand the changes. If you still have your 7DII available, I suggest the following:
- Set up a tripod and subject at a specific distance, using the same lens for each shot
- Mount the lens to your 7DII, mount the camera to the tripod
- Focus on your subject with the center AF point so you get the full effect of your field of view
- Take your APS-C reference shot
- Now mount the lens on your R5 and place on the tripod; making sure you don't move anything else in the setup and using the same focal length
- Again, center your subject and focus using the central AF point
- Take your "FF" reference shot
- Finally, go in to the R5 menu and set your Cropping/aspect ratio to 1.6, this will make the R5 emulate the APS-C capture by only utilizing the central portion of the sensor to make the capture
- Repeat the centering/focusing steps above
- Take your "crop mode" reference shot
When you are done, take your 3 reference shots and compare them side by side. The subject will be the same, relative size in your frames (measure the dimensions (height/width) not pixel count), but you will see more of the surrounding area in the FF shot and your subject will appear smaller. This is just due to the 7DII, effectively, doing the crop for you at the point of image capture; you will note a very similar result in the "crop mode" reference shot for the same reason. There will be some slight differences there due to the crop mode math on a 45MP sensor vs the native 20mp on the 7DII sensor, but it should be close enough for illustration purposes. Since I'm bored today and we have nice weather, I'm actually headed out to do the above myself just because I'm now curious how big the difference is between these two
