JohnD3 Loc: Raleigh, NC

I want to take a moment to praise this rather small but powerful speedlight. Last Fall while at the State Fair taking photos of my grandson I noticed that I needed more ability to fill in lighting due to non-controllable factors such as movement and back lighting; however, due to facing a full day of lugging around weight and very crowded conditions (constant jostling by others and very limited personal space) I needed a flash that was very compact. I wrote a post onto here about my decision process between the SB-300 (current model in production) and the SB-400 (old model out of production); I received several good observations and a few decidedly less helpful ones (I made it clear from the start that I had plenty of large powerful units and was not looking for another of that type). In the end Ken Rockwell's review (https://kenrockwell.com/nikon/sb400.htm) and the positive comments resulted in my using eBay to find a used SB-400 (the unit I found included the carrying case and the snap on diffuser) at around $130.
I could not be more pleased with the performance of this little flash. It has done everything I hoped it would, it is now an essential part of my kit and is nearly always available in my bag or pocket. When one considers how near useless the on camera flash is I find it amazing that the companies continue to include it on their products (perhaps Nikon has it right with the D500); actually the on camera may be worse than useless when you consider it extreme weakness and the inability to bounce its output.
This is not an attempt to claim that the SB-400 can replace larger, more powerful speedlights, for most flash requirements it cannot; however, I have found that the SB-400 performs admirably for close in fill work as it is nearly twice as powerful as the built-in flash and is capable of bounce. I have also noted that due to its compact size and profile it is extremely useful in crowded situations where personal space is at a premium.
In summation, for the situations I have outlined the SB-400 has proven to be a very valuable resource.

CO

I've had an SB-400 for years. It's a jewel of a flash. It's surprising how much power it has for its diminutive size. The only thing I wish is that the head could swivel from side to side. I purchased an SB-700 after that because a needed flash with a head that swivels in both directions and one that has more features. I still have the SB-400 though.

OddJobber Loc: Portland, OR

The cute little form-fitting padded case that comes with it is worth the price of admission.

cameraf4 Loc: Delaware

Since both of my Nikon DSLRs have no pop-up flash (D850 - Df), I wouldn't be caught dead without my SB-400.

The Villages Loc: The Villages, Florida

Had one. The on/off switch broke. Bought another one. Then decided to have Nikon repair the broken switch (for a very reasonable price). Now I have 2 :) Great flash, and looks great/sleek on the camera.

Deanie1113

For those of you who don't want to purchase anything out-of-production, I just purchased the little compact and light SB 500 -- it's probably very similar to the 400. I am very happy with the SB500!

camerapapi Loc: Miami, Fl.

Like everything else in photography, properly used the little SB-400 is a very useful accessory.
By the way, the head can be flipped for bouncing the light.

JohnD3 Loc: Raleigh, NC

While my intent here was a discussion of the merits of the SB-400, not other flash units as I do not feel that there is currently anything available which is comprable I did consider the SB-500 when I arrived at my decision on purchasing the SB-400. Ken Rockwell covers it best when he gives a great review of the SB-500; however, as he states in his review, it is twice the size of the SB-400 (https://www.kenrockwell.com/nikon/sb500.htm).

I think that Nikon's error when they decided to replace the SB-400 was the failure to recognize that they had a great design and that had they simply added the ability for the head to swivel it would have been near perfect for a compact/rugged flash.

wapiti Loc: round rock, texas

The SB-400 is a jewel.

sxrich

I agree with the above praise. I paid $129 for mine years ago and they still go for that used. I also eventually needed a flash that swiveled so I picked up the sb700. BUT, the light that the sb400 put out, its ability to bounce and still throw light forward made it a gem of a flash and it's still in use. Very small, lightweight.

CatMarley Loc: North Carolina

Yes, the 400 was the best flash I ever had for the Nikon. When it died, I could not find another, so I replaced it with a Nissin i40. Almost as good!

CatMarley Loc: North Carolina

Twice the size of the 400!

kb6kgx Loc: Simi Valley, CA

Something like the SB400 would be great as a “travel” flash and for that purpose I might consider one or something similar.

However, for most of what I need a flash for, my trust Sunpak 555 does the job.

I have never used the pop-up flash (on my D7100) for anything. I wish it wasn’t there at all.

sxrich

The pop-up flash can act as a trigger for OCF on the d7100. Nice feature of Nikon's CLS system.

kb6kgx Loc: Simi Valley, CA

Of course, if one has a need for that. For me, personally, I just need to be able to light something up ahead of me and that’s all. The higher the GN the better.