I'm On a Mission and Need Lens Suggestion(s)

Returning once again to Costa Rica.  Have photographed much wildlife there over the years.

This next trip (in May) I will be on a specific mission to find and photograph a Margay.  Unlike Ocelots of which both are similar, Margays are Arboreal and mostly live in trees in dense rain forest.  That means Low Light.

I'll have my Canon R6 with me.  Last year I bought the new Canon RF 100-500mm which I love.  I still also have my 100-400mm Ver. II.

I worry a bit about whether the RF 100-500mm will perform the best for me in these low light conditions, especially if I'm zoomed to 500mm.

Is there a better alternative that I might consider renting that would enhance the prospects for a better photograph given what I've described?

Thank You.

The Canon 200-400mm f/4 would get you an additional stop of light but at the expense of a lot of weight (and rental fees).  I think the 100-500mm will be hard to beat.

Q

I would buy one of the several used EF 500mm L primes.  If you choose not to keep it, sell it for not much loss.  There are no other zooms worth considering.  The two lightweight RF primes are horribly slow, with not great resolution.  The 400/2.8 and 600/4 are extremely heavy and big.

John Crowe wrote:

I would buy one of the several used EF 500mm L primes. If you choose not to keep it, sell it for not much loss. There are no other zooms worth considering. The two lightweight RF primes are horribly slow, with not great resolution. The 400/2.8 and 600/4 are extremely heavy and big.

LensRentals charges $400 to rent one of those for a week... so buying a used and reselling is probably less expensive.

How high an ISO can you comfortably use with the R6?  And will you have opportunities to shoot stationary cats using low shutter speeds?  The camera's and lens's stabilization will be your allies there.  I recommend evaluating the lenses you're considering by shooting objects in shade trees near where you live.  Good luck and have a great trip.