100-400 paired with A9/1.4x TE or A7IV in crop mode?

Started 3 months ago | Discussions thread
dcstep Senior Member • Posts: 1,255
Re: 100-400 paired with A9/1.4x TE or A7IV in crop mode?

VisionLight wrote:

When taking all lighting conditions into consideration, it is most likely that the A9 will win the day for C-AF and tracking vs. the A7R IV. But when the light is good, those differences may well be outweighed by the sheer resolution benefits of the A7R IV. Keep in mind that in crop mode that the A7R IV puts 26mp on your subject, more than the A9 in full mode. Your 100-400mm would be 600mm and still have a good degree of cropping room.

I often use my Sigma 60-600mm Sport handheld on my A7R IV in crop mode for wildlife. The crop mode allows me to more precisely place the point of focus, have less extraneous outer area which helps exposure, and composition can be better tuned right in camera with less or no crop in post. In good light, C-AF, once initially pointed and acquired, and tracking are excellent. Here is an example of the above parameters in a 4 shot composite at 8 fps:

A composite of the dynamics of a bald eagle's flight at 8 fps. Using 600mm in APS-C mode (900mm equiv.) on the A7R IV, each individual 26mp frame in only slightly cropped to line up the direction of flight.

The same eagle turned around and flew back into the trees where the A7R IV was still able to track it while maintaining focus:

You will be using a "lighter" lens in the 100-400mm, but still I think you will be happy with the results of the A7R IV in crop mode.

Let me know if you have any further questions.

Shoot at ISO 800 and f/8. The under-wings are way too dark.

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