Well I think I MIGHT have made my Nikon D5200 work with my new Ninja Blade in 24p mode.

Problem: Ninja Blade does not recognize 24p from Nikon D5200 though can easily record at 30p and 60i but NO INPUT when picking 23.98/24p.

Answer: (I think at 6:00am)
1. Set camera to 24p
2. HDMI output to Auto. (comes out interlaced but supposedly with flags)
3. Pull Live View lever to enter Live View mode.
4. Click the (Play) button on the back of the Nikon D5200 several times entering into to Review to Live View mode an average of 3 sets of times and then the Ninja Blade seems to recognize a pull down pattern.

I tried waving my hand in front of the lens for 30 seconds or longer with no success, however the above 6:00am I have repeated a dozen times without coffee. Final Cut Pro X shows footage as 1080p at 23.98p. The footage when viewed in quicktime or in clip viewer is clearly interlaced, however when dropped into 23.98 timeline the flags seems to be recognized and the combing disappears instantly with no rendering and looks pretty 24p to me. I will test this week and see if I return or keep the Atoms Ninja Blade or ditch the Nikon D5200 for a better Nikon or used Black Magic Pocket Camera.

Anyone else run across this problem on other Nikon Atomos 24p issues?

Great to hear! I own a D5200, and looking to buy a Samurai Blade soon. Be good if works with SDI/HDMI convertor.

I'll experiment some today and tomorrow. My first gut feeling is not to spend the money on this or any recorder for the Nikon D5200 if 24p is important to you. Everytime I jump out of Live View and back in, requires 4-10 cycles of the review button to reconnect. Now if you are shooting 30p, 60i it works flawlessly.

I will also try soon to hook it up to a friends Red Scarlet and see how real world it works with that unit. Of course it won't shoot Cinema Raw, but 220mbs and cheap off the shelf 2.5 HDD is a good thing.

I was wrong. Though I was able to get my Atomos Ninja Blade after clicking the Nikon's Play/review button 5-10 times and got the Atomos to indicate that it was recognizing the 23.98 flags, it does NOT record correctly. The footage looks something like a DVD that has been ripped but not decombed or deinterlaceds properly.

I went to the local (1 hour drive each way) brick and mortar store today to try the same test on the slightly newer Nikon D5300 and again failed the same ways. To repeat 60i and 30p work as advertised but 23.98/24p is non functional.

I did try a Canon Rebel 5xti (or something like that) and the Atomos recognized the 3:2 pull down immediately and recorded fine. I was not able to get a clean full image from the Canon on the Atomos, but I have never used a Canon DSLR before so it may well be possible or maybe on other Canon's in the Rebel line.

I'm waiting to hear back from B&H and Atomos if the Nikon D5500 works. If not maybe have time to return the Atomos and get a Black Magic Micro or pocket camera and call it good.

Recap Nikon D5200/5300 1080i 59.97i, 30p work, 23.98 does not, even when tricking the unit to think it's decoding correctly it isn't.

Well drove the 2 hours each way to the local camera store.. (nope not kidding) tried out the Atomos Ninja on the Nikon D5550, D7100 and D7200.. same issues in 24p. The D610 I think I got it to work, full screen with no Nikon overlays. It might have been a different Nikon honestly but after an hour I was tired of dealing with it and for $2,000 body to use the Atomos for 24p I'll just get the Black Magic Ursa mini with a $85 Nikon to Canon EF adapter.

The random Canon we grabbed off the wall worked pretty well, though I hesitate to say which model it was or if there wasn't any info showing on the HDMI feed.

Now if you like 30p most or all the Nikons worked.

Shipping Atomos back. Waiting for BlackMagic URSA mini to become readily available.