4k and 4k+

When the camera supports 4k+ (2160x4096) makes it sense to upload files in this resolution or is it better to upload standart 4k?

What you call 4K+ is a standard called Digital Cinema Initiatives or DCI (4096 x 2160 pixel resolution). I do not know if Pond5 supports DCI video, but I recommend that you upload it if it is supported. In fact, if you can take the shot at both standard 4K (3840 x 2160) and DCI, take the shot both ways and upload both. For example, if you are shooting hot air balloons at a distance, shoot and upload both 4K and DCI versions. It's possible that some Pond5 client may prefer the DCI version.

When I have time and the shoot permits it, I shoot at both 29.97fps and 23.98fps, just so I have a version of the same thing that will work internationally. I think the same is true for 4K and DCI.

DCI can be recropped to 4k, so isn't it redundant?

If you upload to somewhere like Fotolia at DCI they downconvert it to a weird HD format, because they make 4096 into 1920, leaving the vertical at a weird number like 960 or something.. it's a mess :-P

I usually just shoot UHD (4k), since that's what most tv's are

"DCI can be recropped to 4k..."

Yes, but what if someone wants DCI resolution and aspect ratio?

Again, I don't know if Pond5 supports it. If Pond5 does support DCI, then you might as well upload material in that format. Who knows if someone will be looking for it.

The HD down convert is the point as most buyers by HD. That's also here. P5 down convert to 2048x1920. Means i have to upload normal HD version extra.

I shoot 4096 whenever I can. It can easily be used in standard 16x9 projects. And all agencies now downconvert to HD properly. Some cut off the edges making a standard 1920x1080, while other keep the aspect ratio and downconvert to 2048x1080. Both are acceptable.

ODesigns ....... that's good to read because i like this 4k+ resolution

Pond5 does support DCI and of course 4K UHD. I upload both always and sell both many times at random, one or the other.