Basically, these are six suggestions for what to buy if you're serious about buying equipment to take great quality photos. When you're spending a lot of money you don't want to find out the equipment doesn't do what you want it to do after a bit of use - and it's then non-returnable. I've called the post camera equipment essentials, but each item is only essential if you can afford it; however, most of these items (bar the camera of course) are reasonably low cost.
Secondly, I'm not going to get all technical on you - I will try to explain things in layman's terms as much as possible. Also, I fully understand photographic equipment costs serious money. I should know - I did a photography degree course for three years. Being a student and funding my own photographic work was not easy (also because those were the pre-digital days and I had to buy a lot of film and a lot of photographic paper).
So these are my suggestions for what I consider the essential basics:
1. DSLR camera with a fast, standard lens.
If there's only one camera (with one lens) you're going to buy for blog photos - and you have (ballpark) £400 to spend - this is what I'd recommend. Make sure you buy only what you really need, and spend your money wisely.
DSLR stands for Digital Single Lens Reflex. This means the camera lens uses mirrors and prisms that bounce the light around that mean you see in the viewfinder exactly what will be photographed. They were invented in the days when amateur-use cameras allowed light into the camera onto the film through one hole (the lens), and light into the eye through another hole (the viewfinder). Therefore, there was a difference between the view seen and the image taken; called parallax, it was a really significant difference, and SLRs (i.e. film cameras, pre-digital) were a godsend for the amateur and professional photographer alike.
A fast lens (and yes I'm repeating what I wrote in my 12 Quick Ways to Improve Your Blog Photos post) means one where the shutter - the hole inside that opens to let the light in when you "click" - is able to open up to the maximum size any lens can go. Light is everything in photography, and more light = better quality photos. They cost a lot more, but if you can afford a very fast lens with a maximum aperture or f-stop (the shutter hole size) of f1.4, you will not regret it because the images produced will be sharper and brighter with richer colours. You can photograph in really low light levels, too.
A standard lens - also known as a normal lens - photographs closest to the view seen by the naked eye, i.e. it won't widen you in places you don't want to be widened, or shorten you in places you don't want to be shortened. I read this great article about why the standard lens is so great despite its recent drop in popularity - it's worth a read if you want to know why it's the lens of true photographers (in my humble opinion).
There are many tricks you can utilise to ensure the best from a point-and-shoot camera (I call them compact cameras), but if it's high quality [high resolution] photos with crisp subjects and soft blurry backgrounds that you're after, then you will almost certainly have to splash out on a DSLR camera with a standard, fast lens. Make it a fast, standard lens. Make it a fast, standard lens... I think I've made my point.
2. Spare battery.
This is easy: Make sure you buy a spare battery. Keep it in your camera case. Always charge it as soon as it runs flat and put it back in the camera case straight away. (But don't leave the camera case at home with the spare battery in it, whatever you do.)
3. UV filter (and lens cap).
A UV filter actually makes very little difference to a shot, but you should always buy a UV filter primarily as protection for your camera lens. Lenses cost a lot of money, but UV filters do not... never, ever run the risk of scratching a lens when you could scratch a £4 filter instead. The only drawback that you may notice is that you may get a bit of lens flare from a UV filter in bright sunshine; however, if you're shooting into the sun, the artistic effects of lens flare can be very attractive (and is quite popular in blogs at the moment). Buy the filter at the same time as buying your DSLR (or new lens) so it's protected straight away. On top of that, a lens cap is extra, extra protection and utterly essential. If you lose it (like I've done in the past), buy another straight away.
4. Lens hood.
This is like a lamp shade attachment that goes on your lens - it blocks the sun and prevents lens flare; they can be bought from as little as £5. Although I said in the point above that lens flare can be attractive, you don't want too much flare or you'll blast the photo with light. Also - it gives yet more protection to your lens... if you're clumsy (like me), you may swing the camera round and knock it on something. That knock to the lens could be absorbed by the lens hood if it has one.
If you ever take self portraits, or intend to, you will need a decent tripod. The heavier and sturdier it is, the less chance there is of it being knocked or blown over by strong wind. However, the sturdier it is, the more expensive it will be, so again - spend as much as you can afford if you're your own photographer. If you need it to be versatile, a great alternative (and perfect for outdoors) is a gorillapod. It has bendy, grippy legs that grip to most things like tree branches, garden gates, posts, etc.
6. Camera remote.
This will take the picture for you as soon as you press the button, same as changing the channel on the TV remote (some cameras have a short delay option). Pros: You don't have to rope in a best friend/husband/stranger off the street to help you with taking outfit pictures - you can photograph yourself whenever and wherever you like. Also, you can take pictures in quick succession without having to constantly jump up and set the self-timer. Cons: It can be difficult to get it to focus on the right part of the photo, i.e. you. You may end up with a blurry face and pin-sharp background if you weren't positioned where the camera was focusing.
As far as purchasing it all goes, I tend to buy camera equipment online as I know what I need and generally don't need a salesperson's help. However, an experienced camera shop salesperson will be invaluable for advice - as long as you are absolutely clear about what you want the camera for and the effects you're after. Don't let anyone talk you into what they think you need simply to get a sale.
It's the camera and lens that cost big bucks to start with. There is a very valid argument that point-and-shoot cameras (I've always called them 'compact' cameras) are more than adequate for your blog photos. (This makes interesting reading on IFB about the subject - read the comments left which, interestingly, mostly disagree with why DSLRs are the best.)
Personally - and remember this is just my opinion - I think you can't beat photos taken on a DSLR. I've used them since I was 17 when I borrowed my dad's manual one (we are talking the late 80s, people), and I actually find an all-singing, all-dancing compact camera confusing and bewildering... give me a DSLR any day. It just feels right when you're holding a bulkier camera body with a lens that sticks out. You hold it in both hands, you bring it up to your right eye and squeeze your left eye closed. Your whole stance changes and most importantly - you're right in the there with the picture. I'm convinced it helps you take better photos - a DSLR makes you feel like a photographer.
Put it this way: If you want to make like Leonardo da Vinci, you'd don the painter's smock, use a palette and long brush and daub away at a canvas on an easel. It would make you feel like you're making history with those long brush strokes and poised palette. But wearing your PJs and using a biro on a napkin won't make you feel like you're producing the Mona Lisa...!