Upgrade Telephoto?

Donde · Aug 13, 2018

Been mulling the idea of upgrading from my Canon 400 5.6. Really don't have an issue with the image quality but find myself frequently frustrated by lense's refusal to lock on to the bird when shooting through branches etc. One obvious upgrade it seems would be the 400 DO lens. I would consider popping for it not withstanding the huge price but I've read a lot of negative reviews and side by side comparisons with the 400 5.6 that show no or infinitesimal image quality improvement (i.e. sharpness). Don't know what other options are out there in the 400mm range.

BrentC · Aug 13, 2018

I don't think another lens is going to help with that. That is the behaviour of AF not the lens.

Donde · Sep 7, 2018

Thank you I was suspecting that. I wonder if there are cameras in the Canon line with superior AF ability that would over come that but should ask in the Canon Camera forum.

zombiesniper · Sep 7, 2018

In dense brush most AF systems will have an issue.

Every camera listed in my sig plus Jr's 80D will all have similar issues. The problem is that if the branches are in the field of view of the AF point and are the closest object, the AF will focus on them. This isn't Canon specific it is just how many AF systems work.
In situations like this I go to manual focus and try my best. It doesn't always work but sometimes it's good. Another thing to try is putting the AF point on the branch the bird is standing on and shooting. Your DOF should be deep enough to still have the bird in focus.

Overread · Sep 7, 2018

Thing is that the AF issue you've got is AF and that is linked more to the camera than the lens in most cases. A higher end lens like the various 400mm f2.8 versions (esp the newer MII and the super new MIII) will have faster AF so if the AF gets it wrong it can jump back faster, but otherwise the only other bonus is the f2.8 aperture giving more light to the AF system and thus working better in lower light conditions.

Otherwise the AF area is going to be more dictated by the camera body behind the lens - and with newer mid and upper range bodies you can change its AF to tune it to certain conditions. Eg you can tell it to be slower at changing focus on a moving target (or if it detects movement) so tigs blowing in front might not cause a sudden AF jump.

The other option is method; the 400mm has USM focusing so you can adjust the focus manually without changing any settings on the AF. So you can focus on the bird manually and then let AF take over or just focus manually when you need to. If you use back-button AF control instead of a half press of the shutter then you can turn the AF on and off at a whim without having to fiddle for the switch on the lens.