Talk about having something at the tip of your tongue. A fun picture of a nuthatch eating seeds, it was not easy for it to get a seed. The nuthatch kept dropping the seeds and had to try again to pick one up. The picture is taken with a Canon 6D and Tamron 150-600mm.
Quantity or quality, what do you want?
I recently got the Canon 6D and there is a great difference in quality when you are using Tamron 150-600mm. You can for example go down to 6.3 when you are using 600mm without any problems. On 70D the ISO would shot up very high if you were at 600 mm and you would get a lot of pixels showing when you were looking at the picture in your computer.
With Canon 6D you get better picture quality, since it is a full format camera house you can easier crop the picture in post production to only focus on the parts you like to keep. If you would crop a picture taken with Canon 70D that would effect the picture quality and make some parts blurry.
Canon 6D is not made to take pictures of birds flying by, that is much better with 70D since the picture per second is 7 and only 4,5 with 6D.
This picture is taken with Canon 6D and Tamron 150-600mm. It was little dark but 6D managed to take a great picture anyway. This picture is only taken at 250mm so there is a great sharpness in the picture. The ISO is at 1000 but there is no pixels visible compared if I would take this picture with 70D.
The softness that you get in the background with 6D is always a plus. I am now considering always using my Canon 6D for wildlife, but it is good to have 70D if you are expecting to take picture of flying birds or bigger animals like a tiger or leopard on a wildlife safari trip. I recommend to have both camera houses in your camera bag if you have the possibility.
This picture is also taken with Canon 6D, this is taken at 600mm but there are still nice sharpness and the background is blurred out to make the picture even better. The aperture is at f7.1. If I would take a picture with Canon 70D I would use f9 to f11 in aperture to get a sharper image. The amount of pictures that turns out great are more with Canon 6D then 70D.
If you have any question feel free to ask in the comments field below.