Nobody Expects Backfocus

Bad printing on your test chart, in focus, that's what you want to see!

Bad printing on your test chart, in focus, that’s what you want to see!

Took up bird photography lately. Using the 200 – 500 mm f/5.6 supertelezoom on my Nikon D850, I was getting good results, I thought. But when I reached for more reach,
I got this:

Focussed on the wing casing ...

Focussed on the wing casing …

... but that's not sharp ...

… but that’s not sharp …

... the water behind the swan is!

… the water behind the swan is!

What had changed from the sharp feather detail in the “Lovely Plumage” post on my Ornithology ‘blog?

This had.

This had.

I had added a Nikon TC 14 III teleconverter between the lens and the camera for that little bit of extra reach. Unfortunately, this resulted in severe backfocus.

There's a procedure for that.

There’s a procedure for that.

With the help of Thom Hogan’s very thorough “Complete Guide to the Nikon D850”, I did a manual AF fine tune for this combination of lens and TC. The automatic AF fine tune procedure wouldn’t work, apparently, my tripod isn’t sturdy enough to keep the camera absolutely still. Well, it isn’t a mountain of a Gitzo!
Anyway, after much to and fro in the menus, I got to the result in the lead photo and declared it enough for bird work. That is, until I put it to the test in the field. Will add sharper birdie snaps later, I hope!

Tags: , , , , ,

One Response to “Nobody Expects Backfocus”

  1. chammann Says:

    Reblogged this on This is a late parrot and commented:

    Fine tune your camera’s AF!

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s


%d bloggers like this: