Trying to decide

Selling my bigmos and now Im looking at 3 possibles to replace it. Basically I shot wildlife, zoos, birds in flight if they are close enough, air shows nature. Stuff like that.

I've been looking at 300mm f4L, 100-400 L, 70-300 L, and the 400L.
I saw some tests with the 300mm with 1.4 tx and it showed softness. which is fine I dont have a tele

i've had the 100-400 and 300 f4, didn't like the 100-400 at all and if i were getting another 300 i'd look at the 400. my 300 was very good, but it seemed like i always wanted more reach.

torkk wrote in post #15363632
Selling my bigmos and now Im looking at 3 possibles to replace it. Basically I shot wildlife, zoos, birds in flight if they are close enough, air shows nature. Stuff like that.

I've been looking at 300mm f4L, 100-400 L, 70-300 L, and the 400L.
I saw some tests with the 300mm with 1.4 tx and it showed softness. which is fine I dont have a tele

I like the 100-400 for air shows, wildlife, BIF and other things, it's very versatile and sharp. If it was for primarily shooting birds the 400mm 5.6 would be my preference

I've not owned any of those lenses, but it would seem for what you are planning to do that the 400 would be the best fit. A lot of people also like the 100-400, but it seems to me that there is great variance in sharpness with the 100-400.

I forget the site but it has reviews and a comparison. set up those lens and the 300 seemed super sharp

torkk wrote in post #15364190
I forget the site but it has reviews and a comparison. set up those lens and the 300 seemed super sharp

I think this is the comparison tool you were talking about... just pick the two lenses, the focal length, and it will give you side by side sharpness comparison - http://www.the-digital-picture.com …O-12233-Sample-Crops.aspx

I own the Canon 300 F4 L IS and used to own a Canon 100-400 and have tried a few Canon 400 F 5.6 lenses.
I was happy with my 100-400 for over 5 years but traded it after trying the prime 300 and 400 lenses. I opted for the 300 F4 L IS as it had better AF and IQ than the 100-400. The difference in AF was marginal but I thought the 300 edged the 100-400 JUST! The difference in the IQ actually allowed me to crop to 400mm equivalent and still get a better image, still leaving 1.4 and 2 x extenders in reserve.
As to the 400 F5.6. A friend of mine and myself tried a couple out on our 1DMK3 and 1DMK4 cameras and neither of us were happy with the auto focus (he tried one for a week and still couldn't get it to work consistently), I have also tried a few belonging to other photographers and have not been entirely happy with the AF (that's 4/5 examples in all). This runs contrary to what you will read elsewhere, it could be my camera but I have 8 Canon lenses (from 17 to 600mm) and all AF properly without any adjustments. The 400 F 5.6 certainly gets rave reviews and is the only, current, lens in it's class - but try before you buy.
I find the 300 F4 IS a great walk-around lens (especially for larger insects), good for airshows (but would benefit from more reach) also the IS and faster aperture are very handy for me.