When I am in the field, I normally carry the minimum amount of equipment possible. I hate bulky crap. Obviously, it is important to think through what to bring when on a photo trip. Luckily, it is possible to hand-hold the Bigma lens when the weather is good. 

Short nature trip:

On shorter nature trips, I take the 1D Mark II camera plus the Bigma lens, as well as an extra battery. This is typically sufficient when going on a short trip in the neighbourhood of the town where I live. I normally put the camera in the passenger-seat of the car and roll down both side windows, when driving around. In this way, I can get to shoot real quickly. Unfortunately, since the windscreen is curved, it is impossible to shoot through it. A beanbag for resting the camera on, when shooting out of the side window, would be a good investment. If the purpose is to take flower photos, I will bring the flash and a small (50 cm) c ollapsable reflector screen.

Longer nature trip:

On longer nature trips, like when going to the eagle reserve, I always bring the 1D Mark II with the Bigma lens attached. On top of that, I use a small Canon shoulder-bag, with the 24-70 f/2.8 and a 21 mm macro extender, and sometimes a flash. The bag also holds a spare battery and some lens cleaner. I often bring the Canon 210SX camera, if I have a spare pocket.

Longer family trips:

On longer trips, where the main purpose is to take photos of the family, I reverse the equipment. I will then handcarry the 1D Mark II with the 24-70 f/2.8 lens. Lately, I have also had the flash attached, for outdoor lighting. The flash is great as fill-light, to avoid dark faces when shooting outdoors. Anyways, when taking family photos outdoors, I will keep the Bigma lens in the shoulder-bag, together with a battery and the lens cleaner. I almost always carry the CPL filter in my pocket, to get that great deep-blue sky.

Tourist Photos:

This is a tough one, as it is often good to travel light. I most often use the 350D with an EF-S 18-55mm lens and the EF 75-300mm in a pocket. The EOS 350D has a built-in flash, which often comes in handy. This setup covers most situations in a city like London or Paris. Alternatively, I bring the 210SX compact camera.

Aircraft Museums:

The problem with aircraft museums is the extremely poor lighting in those places. I have tried using the 350D’s built in flash, but it is seldom enough. I will bring a big-ass flash in the future, possibly with the RF remote trigger, to avoid light being reflected directly back into the lens.

Airshows:There is only one camera for airshow user – the 1D Mark II plus the Bigma. It is fast enough for in-the-air pictures, as well as for static photos. A flash is a good thing, as is a CPL filter to remove reflections in the cockpit glass.

Walk-Around:

I carry the 210SX camera with me everywhere. It is a great camera; the auto-focus works, it contains a flash, an IS lens and 12 times zoom, and the picture quality is pretty good. In other words, it is perfect for taking pictures of unexpected situations.