I often hear, "You should only pick your wedding photographer if they use a particular brand of camera/lens and use full format." - Usually Canon or Nikon. Let's dispel one myth straight away, there is no such thing as full format! There's full frame, medium format, crop format and micro four thirds format.
Full frame is equivalent to the 35mm film format, medium format historically refers to the 120 size film format that was used in the Hasselblad V System cameras. In digital photography, medium format refers either to cameras adapted from medium format film models or to cameras making use of sensors larger than that of a 35mm film format.
Crop format usually refers to a smaller sensor than full frame and usually has a crop factor of x1.5 in the case of Sony, Nikon and Fuji crop sensor cameras and 1.3x or 1.6x crop in the case of Canon crop sensor cameras. So the lenses used are 1.3, 1.5 and 1.6 times the focal length in use. For example a 70-200mm lens on a Canon 1.3 crop body would equate to 91-260mm.
In March 2014, I was introduced to the Micro four thirds mirrorless system which was developed jointly by Olympus and Panasonic and are the only two companies that make the system. The advantage is all their lenses are compatible across the two brands.
Micro four thirds is x2 crop factor, effectively doubling the focal length of micro four third lenses - see below for more explanation. Panasonic cameras and lenses are branded as Lumix.
In the case of some lenses, they're branded as Lumix Leica, as the two companies are in partnership with certain lenses.
Leica lenses are synonymous with superb quality and very sharp images. Having said that, all the lenses I use are capable of producing high quality images, which at the end of the day is what you're paying for.
This system is smaller and lighter than the Canon kit I was using at the time but with equally good image quality especially when using professional lenses from the likes of Panasonic, Olympus and Sigma.
I dipped my toe into the micro four thirds system but kept my Canon kit at the same time. However, in November 2016, I finally took the plunge and now exclusively use that system and for my professional work, I use the following kit:
Three Lumix G9 cameras and three Prime lenses. Primes are sharper than their zoom counterparts but I can still "zoom" just with my feet! One with a Sigma 16mm prime lens and one with a 56mm prime lens, both Have a fast aperture which will make the main stand out from the background which will be out of focus with the main subject pin sharp. The two Sigmas have a 35mm equivalent of 32mmm perfect for full length portaits and 112mm respectively, great for those head and shoulder portraits.
The third G9 will be strapped to my belt with a Leica 42.5mm lens with a fast aperture for lovely background bokeh. (Bokeh is a Japanese word meaning out of focus). This has a 35mm equivalent of 85mm, the perfect portrait lens.
Other lenses in my bag will be a Leica 8-18mm, Leica 12-60, Leica 50-200mm and a Leica 100-400mm lens - 35mm equivalent of 112mm, 16-36mm, 24-60mm, 100-400mm and 200-800mm respectively.
I could literally stand across the road in the car park and still get a shot of you signing the register with the 100-400mm or 50-200mm attached to any one of my cameras.
The 8-18mm is perfect for wide, sweeping shots of the venue and larger group shots. The 12-60mm lens is a great as a backup lens to the three primes. I'll also be able to get close up shots of the cake, rings etc., with the 12-60mm lens.
The 50-200mm and 100-400mm lenses, although not strictly wedding lenses will come into their own if I was stuck at the back of the venue as I often have been due to instructions from the celebrant.
So if I had to use a zoom lens during the ceremony/reception, then all eventualities are covered with my extensive zoom range from 12mm -400mm or 24-800 in 35mm terms.
As a backup and if all else failed, I have a Lumix G80 with a Sigma 30mm lens, which is usually resereved for street photography but also a great portrait lens, with a fast aperture, perfect in low light. This lens has a 35mm equivalent of 60mm.
The three G9's and the G80 are dust, splash and freeze proof down to -10 degrees as are all my lenses with the exception of the 30mm lens.
So if you're having a winter wedding, you can be safe in the knowledge that my cameras/lenses will keep going when your friend or friend of a friend with the entry level/cheap camera/lens will be running for cover.
My G9 cameras have dual memory card slots and I always save to both cards and I also have numerous high capacity memory cards, batteries and three flashguns, although I tend to prefer natural light as flash can spoil the ambient light and the ambience.
However, I will use the flashguns during the evening reception and usually off camera using a remote trigger to give more pleasing light than on camera flash. If you count the built in flashgun on the G70, then I have four flashguns. I have numerous spare batteries and high capacity memory cards as well.
As you can see, every eventuality is covered with my extensive camera kit and this is something to consider when hiring an amateur photographer to shoot the most important day of your life. Will they have this amount of backup? You only get one chance to photograph a wedding so why leave it to chance by hiring an amateur who will probably only have one camera and lens!
If my images have a "blurry background" this is done entirely for artistic reasons such as the image of the bride and flower shot and the groom in the mirror. This is one of the benefits of having a lens with a fast aperture.
The same goes if I cut heads off, this is done on purpose to emphasise a particular detail such as the bouquet shot below.
I offer the services of a second photographer as an extra backup and to cover your wedding from different perspectives, something your friend or friend of a friend wouldn't even consider.