There’s another long lens in the Chimp in Focus lineup, and a new round of field testing is underway. Our Sony FE 600mm f/6.3 GM OSS arrived on October 15, 2026. We’ve started making photographs, but it’s too early for results or conclusions. Here’s what we plan to explore.
The combinations
Our first outings have included the Sony a7R VI with the 600mm f/6.3 GM and the Sony a1 with the FE 300mm f/2.8 GM, both on its own and with the Sony 2× teleconverter. The converter takes the 300mm to 600mm f/5.6; the native 300mm gives us a useful reference for handling, autofocus, and image quality before adding it.
As opportunities allow, we’ll bring in the Sony a1 II with the 600mm f/4 GM and the Nikon Z9 with the 600mm f/6.3 PF as additional benchmarks. These are comparisons of complete camera-and-lens combinations. Differences in bodies, settings, and conditions will matter when we interpret what we see.
What we’ll be watching
Getting the bird in focus comes first. We’ll look at initial autofocus acquisition, tracking birds in flight, and reacquiring a subject after losing it against a busy background. Perched birds will give us opportunities to examine sharpness, fine feather detail, and contrast.
We’ll also look at higher-ISO files as the light drops and at how much cropping each combination can tolerate for a useful finished photograph. With the 300mm and 2× converter, we’ll pay particular attention to changes in autofocus behavior, detail, and contrast, alongside the flexibility of removing the converter when a bird comes closer.
Then there’s the part a specification sheet can’t settle: carrying the gear, getting it ready, following a moving bird, and staying comfortable through an outing. Portability and support requirements are part of the evaluation.
Out in the field
We’ll test across a range of wildlife locations and conditions, including parks, shorelines, wetlands, and wherever the subjects take us. Centerport’s park, bridge, and pump station will be part of that mix. We want to learn which setup suits each situation, how readily we can carry and deploy it, and how quickly we can respond when the action changes. Different backgrounds, working distances, and light will help us assess each combination in everyday field use.
Where possible, we’ll compare similar subjects, distances, light, and shutter speeds, and review files at comparable output sizes. We’ll note settings, support, cropping, and processing so the photographs have useful context. Field encounters won’t always line up neatly, so we’ll distinguish repeatable comparisons from observations made on different outings.
More to come
For now, this is the testing plan. We haven’t reached a verdict on any combination. We’ll share photographs and observations as the fieldwork continues, then draw conclusions when we have enough evidence to support them. There’s more monkeying around with the cameras ahead.