I don't feel there is a problem with amateurs taking shots - provided they have discussed it ahead of time with the bride and groom and the pro photographer, and are discrete.

When I was at my sister's wedding 20 years ago, I used an RB67 discretely - as much as one can with an MF camera. I did not use flash, and I stood back from where the pro was shooting and off to the side. (The shots were outside shots in a park setting near the church.) <b><i>I did not use the camera in the church during the ceremony.</i></b> My approach was to try and catch "the shot after the shot". By this I mean I would be off angle by about 30 to 45 degrees and far enough back to frame both photographer and the couple. I would wait between 1/2 and 1 second after the pro took his shot, and what I would get is the image of the pro taking his shot, and the relaxation of the Bride and Groom immediately following the shot - and that often was a moment of relaxation and genuine emotion after the formal shot. My shots then complemented the formal shots by providing the context and a more relaxed feel.

I think I took less than 24 images for the entire day, but there were some really, really nice ones. And, nobody got upset because I kept back and did my shots discretely.

The key is consideration for the event and the principal players. Do that and nobody will be remembering you as the "arse with the attitude." And if you get some great shots - which you will - they will help to frame people's memory of the event by providing another perspective.

As a result these big lenses may be able to take advantage of higher pixel densities than 36mp, BUT noise characteristics at a higher ISO may be needed for a 1/1000 to 1/2000 shutter speed to freeze the subject. And that may lead to favouring a lower mp camera with better noise characteristics at higher ISO.

As in so many things, there is no free lunch; just a choice of which compromises best work for the photographer and his area of interest.

We all get hung-up on semantics.

Pixel Density determines the resolving power of the sensor. Higher density = higher detail; (like fine grain film.) But, as in so many things, "There Ain't No Such Thing as a Free Lunch!" Higher pixel density with small sensor sites = more noise and less potential dynamic range. (That said: The D8xx cameras have some pretty amazing noise characteristics and dynamic range at base ISO.) The other limiting factor concerning pixel density is diffraction. It leads to diminishing returns with respect to resolution. If diffraction limits kick in at f8, as they do with the D8xx cameras, then the pixels buy less and less as you approach and exceed f8. This means that for all practical purposes, 36MP on a full frame and 16MP on an APS-C sensor is a practical limit. Yes, you can still squeeze some more resolution with the very, very best optics in a sweet spot that is between f2.8 and f8, but the physics will still ultimately limit, as will the pocket book.) The Zeiss Otus is a phenomenal $4K lens with tremendous resolving power, but even that lens does not out resolve the 36MP sensor - though it sure gets close to it. see -- http://www.dxomark.com/Lenses/Carl-Zeiss/Zeiss-Carl-Zeiss-Distagon-T-STAR-Otus-55mm-F14-ZF2-Nikon-mounted-on-Nikon-D800E__814

Some of the big bird lens could take advantage of a 24mp APS-C or 54mp full frame sensor, because their sweet spots tend to be stopped down 1 to 2 f-stops from full open. Keep in mind that at that pixel density diffraction limitation kicks in at f6.3; so your uber-expensive 600mm f4 lens will give its highest resolution at f5.6 or a wee bit more.

It is easy to get into thinking that a crop sensor increases the "effective" focal length of a lens. What it does is it crops the image, and that is all. The pixel density determines resolving potential in much the way of fine grain film. This is a better way of thinking about it.

I don't know, 8 x 10 sheet film may slow you down even further.

What do you shoot?

If you shoot street, the Sony is a no-brainer. If weight is important, (as in backpacking, the Sony also has a lot to commend it due to the weight.)

If you shoot event, or sports, or wildlife, then Nikon has something for you.

Base your decision upon what the camera offers for the style of photography you shoot.

Note: I took my D800 backpacking, and a smaller, lighter camera would have been deeply appreciated.

A D8xx camera is an excellent choice - (it has the same pixel density as a D7000 which at 16MP would have been the go to camera on a very tight budget in the Nikon crop sensor realm.)

Why high pixel density is important? Because a bird typically occupies a small part of the frame, (and this is particularly true of a bird in flight.) Hence, you want to have enough pixel density to allow cropping and enlargement. Using a 600 mm on a D4S will buy frames per second and high ISO performance, but at the cost of having less pixel density, and when cropping you start losing that resolution. (This is why the birding community that is vested in Nikon - usually by that honking and crazy expensive piece of glass - have been clambering for a D400 to replace the D300s.) That camera is what you want, but what can you do?

On the cheap and cheery side I would consider a second hand D7000. It is in many ways a better camera for a birder than the D300s you have today, and you should be able to pick one up for very little. A D7100 is also a possibility and is a definite step from the D7000 in pixel density while retaining the weather sealing, good low light performance and dynamic range of the D7000.

Below is the DxO comparison of these 3 cameras:
http://www.dxomark.com/Cameras/Compare/Side-by-side/Nikon-D7100-versus-Nikon-D7000-versus-Nikon-D300s___865_680_614

If bird in flight is your primary use then you could do a lot worse than staying with a crop sensor camera, (since most times you will be cropping well within the APS-C frame anyway.) Or you could hang on to your D300s and wait forever for Nikon to come up with a D400. For my money I would get the D7000 or D7100.
A D8xx will give you a lot of other things which make it a good choice if you also want to use it for things other than birding. (I do a lot of landscape photography and for that those 36mp with a tilt-shift wide angle lens is untouchable.)

As with so many things there is no perfect solution, but there are some very good choices. (Note: 24MP in an APS-C sensor is about the limit due to diffraction issues. Most times the camera out resolves the lens by this point, and any further increase in density has almost no benefit.) In other words, a D7100 may be the last word in a birding camera from Nikon, since they seem so adamant to not make a D400.

As previously stated, but hopefully a little simpler:

1) Shoot the background in aperture priority with the f-stop you will want to use for the person - typically 2 f-stops down from wide open depending on how much depth of field you want to separate the person from the background. (Use base ISO if possible, and adjust upwards if shutter speed is less than 1/100 or wind is an issue and requires a faster shutter speed. Do not allow the shutter speed to exceed the flash synch speed - typically 1/160 to 1/250 depending upon your camera. Note: I set my flash synch on the camera to the highest setting once when I purchased the camera and almost never touch it again.)

2) Proceed to manual mode and enter the f-stop and shutter speed that was used for the aperture priority shot and adjust shutter speed up or down if the test exposure was over or under exposed. (Do not exceed the flash synch speed ... very important.)

3) Place the person or people in the shot and shoot with your flash in manual mode. Start with a middle setting such as 1/8th of full power. Adjust flash power up or down based on how much fill you want. I tend to dial the flash up until it is too harsh and then back it down. The idea here is that you need to know the exposure that is too much, and then ease off usually about 1 or 2 f-stops worth of light. (e.g. if 1/4 was too harsh, backing down to between 1/8 and 1/16 is generally where I like it.)

4) Start shooting and be aware of changes to background lighting as well as changes in distance between the flash and the subject. If these remain constant you can shoot as long as you want, but just be aware that these things are seldom completely constant. (Clouds passing over the sun change the background as does the location of the sun.)

5) If background lighting changes adjust ISO or shutter speed, not aperture. (Aperture will reduce the light from the flash as well as the background whereas shutter speed will not because the flash duration is very short.)

Practice the above until it is a no-brainer, and be aware of metal, glass or other light reflecting objects on the subject or in the foreground to avoid flash blowout.

Advanced technique for reflective objects:

1) Place the flash off-camera and angled so that reflected light does not bounce back as a hot-spot, or simply remove the reflecting object(s). (e.g. remove glasses, or have the subject turn and/or tilt their head so that the reflected light does not bounce back.)

Like any other method this should be practiced until it is second nature. And remember each situation and your intent change things.

Choose the time of day, location and weather to suit your intent. Moody or brooding portraits require more brooding backgrounds and lighting. Cheery portraits, more bright and cheery backgrounds. Match the two or your image will feel wrong. (Note: There are exceptions, always. A depressed portrait with a bright and cheery background can show the profound disconnection that is depression.)

Always go with your gut for aesthetics, but use the knowledge you have to realize what your gut is telling you, (and really that is the way to approach any subject as a general rule.)

Almost always shoot RAW not JPEG. It enables you to recover from small oops more readily, and to colour balance in post-processing. With JPEG there is significantly less latitude to correct and refine in post-processing.

Other advanced considerations - after you master the basics - include being aware of the different colour temperatures of light between the flash, the sun and the sky. On anything other than a cloud free day the clouds introduce both diffusion of light and a higher / bluer colour temperature overall. Cloud free days mean two distinct colour temperatures, the sun's and the blue sky. Flash can be adjusted by using filters, and the more advanced speedlights come with a set of gels that can be easily used.

You are the artist, so use the tools at your disposal and your choice of setting, time of day, weather, et cetera to realise your vision. Adjust what you have control over, and typically that is a lot. When facing a constraint, be experimental. Nothing so increases creativity as thinking about ways of overcoming or working around or even with a constraint.

Fill Flash is the correct method.

How to do it?

Take a shot without the person in the scene for correct natural light exposure. Note the f-stop and shutter speed. Adjust ratio between f-stop and shutter speed for depth of field. (Most of the time I like a shallow depth of field to isolate the person.) Now put the camera in manual mode, with the f-stop and shutter speed set for proper exposure. Place your subject where you want him or her to be, and dial up the flash to 1/4 of full power and take a test shot. If the subject is too bright, dial back the flash to an 1/8 or 1/16. If too dull dial up to 1/2 or full. Once set, if the lighting for the background is relatively static you can have your subject change poses and keep shooting until you get what you want. If you have a powerful flash you can use an umbrella or diffuser to soften the light. Most of the time for fill flash this is not too much of an issue if you don't over expose. (I find slight under-exposure preferable to too much fill flash.) If you have a Nikon with the CLS system you can mount your flash off camera and use the camera flash in commander mode to trigger it. I dial the on-camera flash back to the lowest setting to trigger the off camera flash and have the off camera flash close to the subject, (but outside the frame), with a diffuser. That is generally the best way, and all you need is a small light standard to hold your off camera flash.

Play around for a bit and you will get the hang of it. Besides playing around is the best way to learn. You can even use yourself as a test subject and fire with the timer or a remote trigger.

The D800 is higher resolution and has better weather sealing. For landscape photography it is a no-brainer.

For studio portrait, and product work, either will work well, but the D800 is preferred due to IQ at low ISO settings.

There is gas, and there is GAS!!!

see http://www.geek.com/news/canons-5200mm-prime-lens-is-super-rare-and-quite-massive-1534367/

I agree about Downtown Camera. It is a small enough shop to develop a relationship with the sales staff and owners and obtain excellent personal service. They price more competitively than Henrys, and they have great selection and knowledge.

Henrys will compete, but you have to come in with a competitor's price in hand. Otherwise they will grab the low hanging fruit, (i.e. customers who will pay the higher price as listed.)

If you are shipping across borders, it is probably preferable to buy from within your country. It is just less hassle if there is a service-warrantee issue. You will know if the product is grey market or not, and whether you can obtain local service.

Still some will opt for the international purchase if the price is right. I would do a little more research first to see if you can get what you want locally at a price that you are happy about paying.

A few questions to consider now that we know the budget.

1) What type of photography do you spend most of your time with:
a) Studio;
b) Street;
c) Landscape;
d) Wildlife;
e) Sports;
f) Event;
g) Macro;
h) Architectural;
i) Other.

2) How important is it that the camera has strong weather sealing?
3) Is weight or size an issue?
4) How large do you print, and/or do you crop a lot.
5) How important is the number of frames per second?
6) How important is high ISO performance?

Answer these questions, and some of the candidate cameras will disappear and others will become obvious as the better choice for you.

I shoot a lot of landscapes, and some architectural and street. I use a D800 for the resolution and excellent weather sealing. It's weight can be a pain when backpacking, and it is a little large for street. If I were doing it now, I might consider a Sony A7R for size and weight, but then the battery life is not so high.

Nothing comes for free, and no camera is perfect. Make the decision based on what combination of features and compromises best suits you.

As an aside, I would love a Pentax 645Z with a wide angle tilt-shift lens, but schlepping that puppy on a mountain hike would be pure nastiest. I am pretty happy with the D800. Tried and true, and likely available on the second hand market for around 2K. It would be insane to use it for street, as any chance of a candid shot would disappear, with perhaps the exception of laying in wait types of shots where the set is there and I am sitting quietly in wait for a person to come and do the neat thing that will make the shot, (like puddle jumping or some such thing.) The D800 is intimidating enough for street photography, which is why that Sony A7 or A7R would be a sweet camera. Yes if I was doing it over I would go with the Sony for size and weight.

So Dexter could apply. Nice to know.

I think that was in large part comic rather than real. If those really are the filters for many women, they are saying things about women that would make me consider celibacy as an option.

I have a love-hate relationship with the 14-24.

It is a fast, highly resolving lens, and as wide as I will ever need. It is also a flare-pig of the first order, and forget about filters unless you want to spend big bucks for the Lee system. (There is probably another system by now, but the Lee was the go-to filter system for this lens.)

Thanks to everyone for their responses.

The camera is what I have so that is what I will take. Taking the 50 makes sense as has been pointed out. In the wide angle department it is the 14-24 or the 24mm tilt-shift. As I would like to do some near-far landscape shots, it probably makes the most sense to use. (Also the 14-24 does not support my filters - which is a bit of a PITA, but there you have it.) Next is, what about moderate telephoto? That leaves the 105 or the 135 DC. Could go either way on that.

The tripod was a bit of a no-brainer for me. Two photographers - one tripod makes sense for a multi-day backcountry hike, and he just went and purchased a lovely light Gitzo with a RRS head. It was share or carry in my aluminum Manfrotto which is a little heavy and hence was never really something I was willing to consider.

The 300mm is heavy, and while wildlife will no doubt appear, it is not at the top of my subject list - me being more landscape oriented. With the D800, I can also crop a fair if the wildlife appears - if I don't want to print big. That leave me with the 105 or 135 as my choice for a moderate telephoto, (or if I want to go light I take just the 24 and the 50.)

Thanks again to everyone for contributing. You each bring your own experience and perspective, and I appreciate that.