Guided Bird Song Hike & 840mm

May 10, 2026 · 2 min read · 4 visits

Last week left me feeling that even a good camera kit doesn’t guarantee inspiration or good photos. I was looking forward to today’s trip to break the loop of dissatisfying pictures.

Today the NABU Südraum Leipzig held its annual guided bird song hike, a good chance to put the Sigma TC 1401 to work on the Canon 1D-X Mark II with the Sigma 150-600mm f/5-6.3. That puts the effective focal length at 840mm. Nadine brought her Canon 2000D and Canon EF-S 55-250 f/4-5.6.

My takeaway: the Sigma TC 1401 only makes sense in specific situations: plenty of light and stationary subjects. In the forest the Canon 1D-X Mark II pushed the ISO into the thousands to compensate for the narrower aperture. AF response drops from around 100ms to around 300ms. I shrugged the effect off at first, sunk cost fallacy at its best, but it is constant and seriously hurts focus at the full 840mm, locking onto subjects gets hard. The Canon’s subject tracking loses reliability too, which I did not expect.

The Sigma TC 1401 will have a place in my kit but not for bird photography under challenging circumstances. It works best with plenty of light and a stationary subject, and likely also in lower light as long as I drop the shutter speed to compensate. I cannot recommend it as a daily driver to push the lens beyond 600mm because there is no way to mitigate the slower AF and the reduced reliability of subject tracking. Skip the TC and either stick to 600mm or save up for a longer lens.

A Eurasian blue tit mid-flight above green oak leaves

A great spotted woodpecker clinging to a tree trunk among green leaves

A male common chaffinch on a branch with dried seed clusters

A Eurasian blue tit on a moss-covered tree stump

A slow worm coiled around a person's fingers, green background

Photos by Nadine#

A pink and white shield bug on a grass seed head

Topics: Daily Photo, Photography