Originally posted by sholtzma The range of the Bigma is helpful, but what do you really need? For animals at a distance, you need a long tele, for animals closer up (sunning snakes and lizards, sleeping crocs), you need a moderate tele. For close-ups you need a macro. For environmental shots you need some normal to moderately wide focal length(s).
You already have a 400 for the long tele.
One option is a 70-200, along with a 100mm macro, and maybe a fast 50 or 35. Or go with two zooms, say a 28-70 and a 70-200. Even a relatively weighty 70-200 will feel light compared to the Bigma and will be easier to handhold.
Do you mind changing lenses in the field? Do you mind the total weight in your pack, compared with the weight of the one lens you are handholding? What sorts of animal shots do you anticipate? How much will you be able to "zoom with your feet"? Will you have a tripod or monopod? Will you need some fast lens capability to shoot in low light (or thick brush)?
Thanks for your answer. I'm a wildlife biologist, and not a stranger of lugging various gear around, and also changing lenses in the field is not a problem, nor trying to get as close as possible. I was thinking about the Bigma simply because of it's versatility, as I can have it attached most of the time, either seeing a bird or something a bit closer. For shots of snakes and other herps and flowers in a more or less controlled setup I have the Sigma 105 Macro, and for landscape shots I have the Tamron 17-35. On other hand, Canons 70-200 2.8 on a 5d mkII isn't any more lightweight combo then K-5 with a Bigma
I could use own Pentax F100-300 lens, but I wanted to take advantage of renting a bit better lens for the trip. Another option I was thinking about was renting either Tamron/Sigma 70-200 or DA 60-250, a little less range for general use, but faster and could be combined with Tokina 400 in areas where birds would be the main target...
Maybe I'm just overcomplicating, but I'd like to make the best out of this trip from the photographic point of view also