There's a couple things about Nikon lenses that you need to know, particularly if you're thinking of buying one of the modern Nikon camera bodies.

The current version of the Nikon lens has a designation of AF-S, which refers to the focus mechanism of the lens.  There's a secondary designation, "G" which is the lens series.  G lenses do not have an aperture ring on the lens.  We'll leave that to another discussion though.  You don't need the aperature ring on a modern camera anyway.

The simple explanation is that an AF-S lens has the focus motor in the lens itself.  This motor is what moves the all the bits and pieces inside the lens to bring it to a sharp focus when you press the shutter button on the camera.

Any other lens designation, and there are a ton of them, use a focus motor that resides inside the camera.  

Here's the reason why it's important - many of the modern Nikon camera bodies do not have a focus motor in them and therefore REQUIRE the use of an AF-S lens to work at all.  

Nikon is not great about explaining that and I almost fell victim to it just recently when I was looking to buy a back up body on the cheap and was about to pull the trigger until I decided to take another closer look at the camera specs.  Whew.

Now the reason why it's good to have a camera with a built-in focus motor is that it allows you to use older lenses, auto focus and manual focus.  The best of the older lenses are the ones that have a "D" designation.  These are great lenses, typically smaller and lighter than their AF-S versions and normally at least as sharp and absolutely more durable.  The one downside is that D series lenses tend to focus slower than the AF-S lenses and can have a  bit more trouble in low light conditions.

There is a subset in the D line and those have a designation of "ED" which indicates optically superior glass.  D series lenses are largely out of production but are easy to find used and are almost always a tremendous bargain.

I shop KEH.com for used lenses and they are the only place I trust.  I've never been disappointed by a lens I got from KEH.

If you're doing landscape or general use photography and your camera can use the D series lenses, I strongly recommend looking closely at the D series lenses before shelling out huge cash for the modern AF-S and especially the newest AF-S VR or VRII lenses.  

One caveat to that is that if you have a camera that's above 16 megapixels, and particularly if you get to the 24 megapixel range and above, then the most modern lenses will perform better with those cameras.  High megapixel sensors are not forgiving of lesser lenses and it does show up.  It's not a night and day difference though - you'll have to look very carefully to see any difference between a top end AF-S VR lens and an equivilent D series lens.  

For example I have a 80-200 f2.8 D series lens that is great and I like it a lot.  I also have a 70-200 f2.8 VR II lens that is even better in that it's sharper and I can really see a difference in my 24 megapixel camera, but do not see much difference in my 16 megapixel camera.  But the newer lens is bigger and heavier and cost $1000 more.  Is it worth that extra $1000?  No, not really.  And sometimes I regret that expense.

Also keep in mind that Nikon, like most any company, produces two or more lines of lenses for different target audiences and just because a lens has the AF-S or AF-S VR designation doesn't necessarily mean it's a good lens.  Read reviews thoroughly, lots of people have been down this road before and so there's plenty of opportunity to learn from others' mistakes and good fortune.

Canon or Nikon?  By far it's the number one question I get asked.  I'm sure most any other photographer gets the same question.

It's an easy answer...it doesn't matter.

There used to be some points of consideration, such as Nikon had better flash technology for years, upper tier Nikon lenses may have less distortion than a comparable Canon lens, Canon camera body technology is better than Nikon's, Canon's have better ergonomics and so on.

But today I think the differences are so small and esoteric that it's meaningless.  Get the camera that feels better to you.  If you like the word Canon better than the word Nikon, then get the Canon, if the Nikon fits your budget better than the comparable Canon then get the Nikon.  

You get the idea.

So once you decide on Canon or Nikon, then you have choose which camera body to get.  This is a whole 'nother ballgame.  I can't help you here.

However there is this fella, Thom Hogan, that has a website and he reviews pretty much every camera out there, as long as it's a Nikon.  It's very a helpful site but not organized all that well.  You have to dig around a bit to figure it out.  Thom is a protege of Galen Rowell, which is a pretty darn good pedigree.

http://www.dslrbodies.com/newsviews/

There is another guy that does a more "common man's" reviews.  Some do not trust his views but I find them to be worth reading anyway.  This web site is easier to navigate as well.

http://www.kenrockwell.com

If I find a similar resources for Canon camera reviews, I'll pass that along as well.

One of the big photo houses in NYC is Adorama.  A really good and huge photo vendor.  They have a "house" brand which is Flashpoint.  Some of that brand gear is really good, and some not so much.  

One of the best lines they offer is a monolight series.   A monolight is a big strobe that has it's own power source (no external power pack).  They come in a number of different power capacities.  In a monolight, or really any flash, power is listed as Watt Seconds and abbreviated "w/s" or just "ws" most of the time.  The bigger the more powerful. A typical shoe mounted flash that fits on your camera is going to be around 80-100 w/s and could get up around 150 w/s.  A moonlight can be as low as 160 w/s and can get as high as 1600 w/s.  Beyond that an external power pack is often required.  In any case, they're really bright.

The Flashpoints are solidly built and a great value, with one huge exception.  The power switch fails on the higher powered models.  I have four 1820A lights, they're rated at 900 w/s and I use them all the time.  Every day.  Every one of them has failed within a year of use.  Adorama warranties them no problem, and that's great, but they always fail when you need them to work.  I mean, you don't set up and plug in these babies to use as mood lighting in your home, you set them up when you need to shoot and you need them to work right then.

Because they can and do fail at exactly the wrong time, they are hard to trust.

When the unit is new and working, the power switch has a nice crisp, distinct "click" feel to it when you turn the unit on or off.  At some point that switch's tactile feel becomes mushy, indistinct and the "click" goes away.  When that happens, the unit will probably fail the next time you turn it on.

I've searched the web for a DIY fix and found none, so I experimented on my most recently failed 1820A and am reporting success.

My feeling all along was that the failure point was just the power switch itself, which if you buy a thousand of them, will run 12 cents each.  That's a pretty unfortunate choice by the manufacturer.  I'm betting if they procured the 18 cent switch these failures would stop altogether. 

Anyway, I picked up a Double Pole, Single Throw switch (DPST) at my friendly Radio Shack, removed the power leads from the original switch and put them on the new switch, and it worked!  The unit powers up, fires, shuts down and is overall a real happy unit, which in turn makes me really happy.

Now you have to have just a tiny bit of ability to unscrew things and solder some wires in the same order you took them off, and maybe a smidgen of experience with a dremel tool and a tube of super glue, you're good to go.  You probably will need to solder a couple inches of wire to the existing wires to extend them far enough out to work on, but that isn't a big deal at all.  It's not going to hurt to have some heat shrink tubing available to keep things tidy after you're done soldering.

Oh yeah, don't touch the wires together - just in case. And don't poke around the capacitors either, they carry a lot of power and there's no good reason to mess with them.  I have no idea how much residual power is left in them, but I'm not taking any chances of discharging them.

So is this worth doing?  If the new switch provides a long term, reliable solution, then yes.  I'll put this unit back in to service and we'll see how it goes.  In a year I'll post another message with the update.  

On the other hand, getting a return authorization from Adorama only takes a few minutes.  It'll run you about 15 bucks to ship it back to them and then they'll send you a new one in another couple days.  

That's really good service, but it doesn't increase my trust in the reliability of the flash much at all.