Originally posted by Dericali The lens seems to make a big difference to AF performance too.
It makes a lot of a difference even when comes to colors and sharpness also, not only when comes to af performance. See the 3 images from below. The first one was taken with a Sigma lens on 5D Mark IV. The other 2 images were taken with Canon L lenses on the same body. The image taken with the Sigma lens has the focus on the eye which is what I wanted, but I'm not very enthusiastic with the details and the colors, at least not when I look at the second image, taken with a Canon L lens.
The third image make look easy to take, but it was not. I was depending on the:
1. right settings of the af
- I was using Expand Af area with one main af point and other 4 surroundings activated; I tend not to use the Expand Af area with one main af point and other 8 surroundings activated because it cover a much wider area than I want
- focus priority for the 1st image
- Case 3 (from the 6 cases available) - Instantly focus on subjects suddenly entering AF points; I customise the case 3 even further in order to match my shooting style
2. the option to change:
- one point Af to expand Af area; I was shooting in portrait mode with single point Af activated but I've customise the camera so that when I turn it from portrait mode to landscape mode, the af changes also from single point Af to Expand Af area with one main Af point and other 4 surroundings activated
- the Af from Af-S to Af-C (Ai servo) on the fly; I've customise the DOF button to change the Af at a single press of a button.
I was shooting the bird which initially was sitting on the ground in Af-S with a sigle Af activated but it suddenly took off in a fraction of a second; I only had time to make 3 moves:
- turn the camera from portrait mode to landscape mode
- while turning the camera I was changing the Af from Af-S to Af-C with a press of a button
- press the shutter and take one picture; I couldn't take another one because the bird came to close for the lens to focus
3. af speed of the Canon lens; with a Sigma 150-600mm I don't think I would have had a chance to take the image
4. the shooting technique - it may sound silly, but from my balcony I see a lot of pigeons flying around and I'm improving my technique by shooting pigeons with tele lenses at widest aperture; I often use the panning mode of the stabilisation with subjects that doesn't move quickly in any direction
Once you find the best settings for af-c from your camera, then all depend on:
- the technique used, which fortunately can be improved with a lot of practice
- lenses used; good lenses offer great results even with the aperture wide open
- how you customise the camera to be able to react in a fraction of a second to subjects that change speed and move erratically
Someone mentioned above that the keeper rate with his Pentax gear was close to 10% when shooting action. It seems way too low, even if I know that Pentax lack behind competition in terms of af-c. I don't have experience with K1 when comes to tracking, but with K-3 II that I had I was getting 45-55% of images in focus in action shots and I'm sure that with the new lenses the keeper rate would have increased with 10-15%.
I hope that the image can be seen properly once you zoom on it. If not, try to download it.