Ultimate Supertelephoto for Travel

[Kayaker72]

Ok...a quick follow up....

On Bokeh, there still may be a slight difference, but I can't conclude anything for sure as the background light was shifting.

A quick example:

Top image being with the 400 DO II @400 mm, 1/1000, f/8, ISO 640. Bottom image 150-600S, @401 mm, 1/1000, f/8, ISO 1000. So, this is a better example of what I think may be going on. While the OoF rendering seems smoother with the bokeh balls less intense with the Sigma. Also, the transition in the railings is smoother. But, the light in the background was changing. The shadow cast by the lens is more intense, color temp warmer (granted I was AWB). After looking at about a dozen examples, I still might prefer the 150-600S (at same apertures), but I think it is mostly changes in background lighting. A good reason for truly controlled conditions when testing.

But, on the railings, a quick example: 400 DO II @ 400 mm, 1/1000, f/4, ISO 200

While the 150-600S doesn't do f/4, at equivalent apertures this effect is diminished, but I want to say that the 150-600S is smoother at same apertures.

But, as for T-Stops of these lenses, I went to DXOmark, and they didn't rate the 150-600S, so I can't do a comparison. But, I did swap these lenses out twice (so two sets of data). In both, the 150-600S was ~2/3 of a stop higher ISO compared to the 400 DO II at the same aperture. I think the lighting shift would be more random and it wouldn't be consistent as by the same margin and in both tests. If so, this, of course, compounds the f/stop problem. For example, at 560 mm, I shoot f/7.1-f/8 to get sharp images. The 400 DO II + 1.4TC is sharp at f/5.6. So, there is 2/3-1 stop difference in f/stop. If there is another 2/3 stop difference in T-stop (as I measured that at same f-stop), then the real difference is 1 1/3 to 1 2/3 stops in terms of light hitting the sensor.

I'll run more controlled tests (indoor, constant light) with the 500 f/4 II over the weekend as maybe the background light was brighter for the 400 DO by 2/3 a stop for both sets of data.