6d and EF 40 pancake?

Hi everyone. I'm a few months into enjoying the new 6d and in particular its low light performance (especially compared to the 7d). I find the 24-105 f/4 to be a great walk around lens for the camera. It's not too large or heavy, and the f/4 is often wide enough for low light shots given the great high ISO performance of the 6d. I also love the EF 85 f/1.8 with it. I feel like I can shoot in the dark with that combo.

My question is whether anyone has used the 6d and EF 40 pancake combo. The size and weight advantage is obvious. But other than that, do you think I would find the combo useful given the other two lenses? How's the IQ? I don't have a fast 50 or 35 prime. And if I get one, it would probably be the new sigma 35 f/1.4 that everyone raves about. But that's $900 and heavy vs. $150 for the pancake and not happening any time soon.

Thanks for your input!

Brian

I have both the 6D and the pancake. The IQ is really great for the price and as you said, the size and weight advantage is obvious. It can make the difference between taking your 6D with you or leaving it at home in certain circumstances. I don't have many pictures worth posting as I didn't have many occasions to take pictures with this combo lately. If I get something in the near future, I'll post it here.
I can't be too specific because I don't have any 35 or 50 to compare the pancake to, but if you're not planning to buy the sigma soon and considering the price of the pancake, it would be a great way to wait for it. I think that even after buying the sigma, you could find a use for the 40mm with its unique advantages.

I don't have the 6D, but I have a 5D II, the pancake, and the Sigma 35mm f/1.4. The sigma really is a great lens, but for the price, you simply can't beat the 40mm pancake. In fact, I used the 40mm lens on a professional shoot not too long ago (paired with the 5D II) when shooting a personal training studio - and the images were great.

Pick up the 40mm lens - you simply cannot go wrong with it (IMO).

I've been thinking about getting the 40mm as well to pair with my 6D. I think a good option is to rent it for a week and play around with it to get an idea of how you like it. You can rent it for $17 a week from borrowlenses.com

Well that's all it took! Thanks for the push! I'm $150 poorer but looking forward to the new glass.