A Viewfinder

I really really really underestimated the value of getting one of these before I got one. I won't shoot without it now.

Basically focusing on the little 3" screens on these cameras is very difficult. You think you've got a shot just right and then later once its on the computer you realise the whole thing is out of focus and completely unusable. There are two solutions to this problem. One is to get some kind of field monitor, the other is to get a viewfinder. 

I've shot several times using a 7" marshal monitor and it works great, especially for low or high angle shots. It is however bulky, especially when you want to go handheld. I therefore consider it a great tool but not one you want or need on every shoot.

A viewfinder however is small, doesn't need batteries and clips on and off your camera instantly. What the viewfinder or 'loupe' is, is a magnifying glass for your cameras LCD screen. It will magnify the screen 2-3times in size depending on the model, meaning you end up with a huge screen right in front of you eye. It also blocks out sunlight meaning you can view your image perfectly even when in bright sunshine. Another nice bonus is that it adds a very firm point of contact with your body meaning handheld shooting becomes far less wobbly. 

Currently there are two different models really worth considering. The first is the Zacuto Z-finder. Commonly regarded as the best out there, they feature a diopter for those with poor eyesight and anti-fog coating to stop the glass steaming up with extended use. They are however VERY expensive. 

A much cheaper option, especially for us based in the UK, is the LCDVF. They feature a x2 magnification which is slightly less than the Z-finder but works well enough for me. They are also prone to fogging so its worth buying some anti fog wipes. However they only cost around £100, and there is now even a 3:2 which will fit the 550d's different shaped screen which goes for around £80. I bought mine from a UK based company called Glidetrack who delivered it very fast.

UPDATE: Have just found a UK reseller who stock the Newest version of the Z-Finder. For anyone considering buying a Z-Finder this should get rid of all the nasty international shipping fees and import tax. Click here for the link.