As one commenter suggested, the P900 indeed has a second battery. While some cameras have a replaceable button battery, most have them hardwired onto the camera's motherboard -- the P900 falls in the latter camp. Page 15 of the P900 reference manual discusses this battery; it is charged off your main (rechargeable) EN-EL23 battery and is fully charged after 10 hours; it can then maintain date and time for several days. The manual states that once this battery is exhausted, you must re-enter the date and time when the camera is turned on. You should also be aware that if you use the "U" shooting mode to create a custom set of settings, they will also be lost along with the date and time (see p.35).

I have never experienced this with my P900. If you are just swapping batteries and have experienced no issues with your main battery (ie, you are getting a few hundred shots per battery and when you are not shooting it should last days or weeks without requiring a charge), then your back-up battery is faulty and you will need to have it repaired or replaced by Adorama. If you have just one battery and you let it run out of juice, your clock battery will simply expire a few days later.

If the latter is the case, you might consider getting a dedicated battery charger (e.g. the Nikon MH-67P or third party equivalent) and a spare battery.

Hope that helps -- good luck!

Per CO's earlier comment, your ViewFinder (VF) uses Phase Detection AF (PDAF) while LV uses Contrast Detection AF (CDAF). PDAF is extremely fast and quite accurate, CDAF is slower but is generally capable of even sharper focus than PDAF. The PDAF system is used when the mirror is down for the VF, and some of the light is diverted to the PDAF array located in the camera body separate from the sensor. It is the PDAF system that has the 51 focus points.

In LV, the mirror flips up and the light from the lens is directed to the sensor. The PDAF system is then offline and the CDAF system takes over with hundreds of focus points located across the entire sensor surface. Yes - the area modes consist of Normal and Wide, the latter being a larger "box". If you unlock your Focus Selector, you can move the box anywhere on the screen -- you are not limited to the more centrally located PDAF focus points.

For a brief explanation on how the two systems work, here is a youtube video -- somewhat geeky but a pretty good explanation of the two systems from about 1:00 to 2:25: https://www.slrlounge.com/primer-phase-detection-autofocus-vs-contrast-detection/

Personally, I don't use LV very often but I do find it useful in special circumstances and for stationary shots where I need razor sharp focus and have the time to attain it (portraits, landscapes). I will normally use a tripod, set the camera at AF-S/Normal, move the focus box to my focus target and then use my BBAF to attain focus. I will often check the focus box by zooming in, and if necessary may switch to manual focus to fine tune it (although that is rarely required). I then use a cable release to minimize vibration. I don't use LV for moving subjects (I consider AF-F to be primarily for shooting videos) -- the PDAF system is much better at tracking action.

Hope that helps!

I would add that the settings you list pertain to the PDAF system; the CDAF system is entirely independent and has its own settings. When you switch to LV, you can see your CDAF focus settings at the top center of the LV screen. If you have not changed them, it will likely be in "AF-S, Norm" - if you are shooting moving subjects in AF-S, that would account for your blur. You can change these settings the same way you change your PDAF settings, except you do it in LV mode (ie, press your focus button on the AF/M switch while rotating the Command and Subcommand dials; for the D3300 owner, I believe you press the "i" button while in LV). For moving subjects, you will need to be in AF-F (although your VF's PDAF system is far better for moving subjects). The CDAF system is somewhat limited in its ability to track moving targets. If you are shooting stationary scenes, then the problem is something else. As CO suggests, you may need to allow the CDAF more time to acquire focus; it will often overshoot the focus point and then come back. Nikon CDAF systems operate in focus priority for both AF-S and AF-F in LV to prevent this, but your BBAF set-up effectively overrides it. Camera shake is also possible, especially if you are using a longer lens (eg 150mm+) and have unsteady hands.

I have that lens as well and you are right, it's almost impossible to screw on a filter when its in M mode without changing the focus. You might try switching it to AF while you screw it on since that seems to lock it in place, then reset it to M when you have the filter installed. Haven't tried it, but it might just do the trick. Good luck!

First, eye safety: ND filters will not provide the necessary protection for your eyes so DO NOT use your viewfinder -- Live View only!

Camera safety: You say "eight stop ND filter" -- ND filters are typically rated on a logarithmic scale, i.e. 10^N, so a ND 5.0 is 100,000X reduction of visible light (16.6 stops). An 8.0 is huge (26.6 stops), more than what you need, while an "8-stop" ND would be an ND "2.4" -- not nearly enough. Since I don't know what your ND actually achieves, I can't answer your question. But if you have an ND 4.0 or 5.0 (13.3 stops and 16.6 stops respectively), that's what you need (I would use the 5.0). Here is the exposure information for both 4.0 and 5.0: http://www.mreclipse.com/SEphoto/SEphoto.html

And again -- don't use your viewfinder!

And to the OP's comment -- based on what I have seen here and elsewhere, there are going to be a lot of people with fried cameras and sadly, damaged eyes.

There's a lot of confusion in this area. The only definitive advice that I've seen is from NASA and the AAS and that pertains to eye safety not cameras. NASA originally advised only #14 glass was adequate to observe the sun; they have now relaxed that standard to #12 glass, (for comparison, high amp plasma arc welding, >400A, requires #11). But that's to protect your eyes, and your camera is not as sensitive to UV which is a critical factor for the eyes.

Unfortunately, I am not aware of anybody who has actually done a spectral analysis of welding glass to determine what is safe for cameras. I have read countless warnings that ND filters lack the necessary IR and UV protection for the eyes, but are routinely used to photograph the eclipse (just don't use your analog viewer -- digital viewers or Live View only). The ND filters used to photograph the sun are typically 4.0 and 5.0, about 13.3 stops and 16.6 stops of visible light reduction respectively (NDs are rated on a logarithmic scale, e.g. 5.0 = 100,000X reduction).

My best guess is that #10 glass would probably be enough to protect your camera, but #12 for sure.

These recent posts have moved off-topic -- the OP's issue is specific to D500 firmware which apparently requires a logic chip in the battery. The OP has an older battery that lacks that chip. I responded that the new Watson EN-EL15 has it and works fine with the D500 -- I suspect most reputable third-party battery companies now have the necessary chip.

Here's a more relevant older thread on the topic: http://www.uglyhedgehog.com/t-389012-1.html

Not much time left, but you should be able to obtain eclipse glasses -- the simple cardboard glasses work quite well, but as many have warned, get them from a reputable vendor. The AAS has a site listing reputable vendors: https://eclipse.aas.org/resources/solar-filters

NASA and the AAS have also relaxed their advice on welder's glass for those who prefer that route: they now advise that #12 welder's glass or higher is sufficient (but don't expect to find any in the workplace; most welder's glass is #10 or lower, and almost all glass at #10 or above is on the welder's full face shield or helmut). You can find it on the web, but there is a lot of phony welder's glass being peddled there -- AAS warns of this but does not yet have a safe vendors list for welding glass, so it's buyer beware.

Here is the AAS site on viewing safety: https://eclipse.aas.org/eye-safety/iso-certification
Here is the NASA/AAS/NSF/etc site: https://eclipse2017.nasa.gov/safety
And a clever NASA site on how to turn a cereal box into a pinhole viewer: https://eclipse2017.nasa.gov/how-make-pinhole-projector-view-solar-eclipse

Good luck!

Sorry I'm late to this party, but I didn't see any definitive reply. I purchased my D500 from B&H and it came with a "free" spare Watson EN-EL15. It works fine.

You are absolutely correct, according to NASA #14 welder's glass is the exception and are safe for watching the eclipse. Those who plan on traveling to watch future eclipses and want a permanent pair of "eclipse glasses", this is an excellent choice (and if they are truly welder's glasses, they will be built to ANSI Z87.1 or EU equivalent impact standards -- a pretty robust standard). But make certain they are #14 glass -- most commercially available welder's glass is #10 or less.

For those just interested in safely watching the eclipse with a "throw-away" solar glasses, here is the AAS site on reputable vendors: https://eclipse.aas.org/resources/solar-filters

Quite a remarkable shot! I don't believe I've ever seen the sun shot with this kind of filter combination. Sorry I'm late to the party -- I didn't see this until I read your post today (Aug 8). When I looked carefully at this shot I realized it was shot on Aug 3, and then noticed that's the date you posted it. Did you catch the sunspot in your photo? It appears at about "10:00" on the sun's face, about 3/4 the way from the center point to the sun's edge (it appears as a small dark fleck on your photo). There's been very little sunspot activity, but this spot appeared on Aug 1 at the sun's horizon at about "10:30". This afternoon it appeared at about "6:00" about 1/3 the way down from the sun's center. I expect that it will continue to track diagonally and vanish off the lower right quadrant before the eclipse -- a pity, since I've found it to be a handy focusing aid! Here's what it looked like today around 3pm using a standard DayStar (SolarLite) white light (eclipse) filter:

(Download)

Safe for your camera, yes; safe for your eyes, maybe not. Whether you cite NASA, the American Astronomical Society or whoever -- they all rely on the international safety standard ISO12312-2 (2015). That standard specifies a range of 14.9 to 20.6 stops for safe viewing of the sun. However, the ISO standard emphasizes the need to protect the eyes from nonvisible radiation (UV and IR) as well as visible light. If you are using Neutral Density filters, be aware that they are designed to filter light in the visible range and are much less effective on UV and IR (eg, about 2 -4 stops). In short, your camera will be OK, but you will be OK only if you use Live View or digital viewfinder -- if you use an analog viewfinder typical in most DSLRs, you could do serious damage to your eyes. If you use white light filters, as those designed for viewing the sun, no problem.

Also, contrary to what many have read here and elsewhere, welder's glasses are not a good choice for the same reason. They are designed to filter radiation from an arc welding torch which generates a very different light spectrum than the sun -- much lower in UV and IR radiation. Welders glasses therefore are explicitly classified under ISO as "inappropriate for solar viewers".

I would start simple. Try Mac Photos as one person suggested and see how you like it. You should also download Nikon Capture-D and its browser, View NX-i -- both are free from Nikon. Capture-D is a RAW converter with basic photo editing capability, but it is surprisingly good for free software. It is basically a dumbed-down version of the old Nikon NX2 software that used to cost about $140.

Once you get some experience in the basics, you can then decide whether you need more, and if so will have a better idea on what you need and what you are willing to pay for.

A lot of good advice here, but one VERY IMPORTANT thing I did not see (perhaps I missed it) is Image Quality. Since it's your CEO in the shoot, I assume the shots will be used in some kind of publication (print or electronic, or both). One thing the corporate people will want is high resolution files. In your D3400 menu, in Shooting Menu (the camera icon), you should see an item called "Image Quality" (3 or 4 down). Select it and you will see a list of shooting options -- I recommend selecting "NEF(RAW) + JPEG fine". That will give you a high resolution JPEG that will probably be good enough, but if the corporate people want to make any post-production adjustments, they have the RAW file.

Quite the opposite -- with side-mounted eyes, he's watching something to his right or left and has you squarely in his blind spot. So, he either trusts you, or more likely, figures you are too far away (at 8000mm!!) to pose a threat. Isn't that P900 fun?