Good yet affordable telephoto lens?

[K-amps]

I wouldn't mind the weight of the lens, but how do you think does the 70-300 compare image wise against the 100-400?

Sample shot both at 400mm to help you decide. I had to aggressively crop them due to file size limit.

Both were handheld. The Hydrant was 18 meters away and the weed about 2 meters or less away. Both f/5.6 shutter was 1/320 and 1/400. It was a bit windy. High ISO's were used due to available lighting... (cloudy day)

 

[K-amps]

This one was taken from 2 meters, shows bokeh and focus at 400mm.

 

[triggermike]

I believe the original question mentioned "affordable" - the 400mm f5.6 is an incredible value. Though without IS, it is a very lightweight and maneuverable. Very popular for birds-in-flight, and just razor sharp for any telephoto need. Remember, you will almost always be using a 400mm lens on a tripod - so you can work around the IS and f5.6 issues while you save for something more expensive.
Of note is the fact this lens focuses very quickly. Also of note, I find when I set out with a super-telephoto (I once owned the Sigma 50-500), I am almost exclusively at the long end. This convinced me a prime 400 or 500 mm is totally justified and often used. It also steered me away from the 100-400 option (more expensive than a 400mm f5.6). When going less than super-telephoto, you can get by with a 70-200.

 

[recon photography]

the 300mm f4l is is a good option as its actually faster than the 100-400mm unlike the 400mm f5.6

 

[Loswr]

the 300mm f4l is is a good option as its actually faster than the 100-400mm unlike the 400mm f5.6

True...but, it's only 300mm. I had the 300mm f/4L IS initially, but wanted more reach. I picked the 100-400mm over the 400mm f/5.6 mostly because the 100-400mm has IS, but also for the flexibility of the zoom and the more compact (retracted) length (fits perfectly in a Lowepro Toploader Pro 75 AW, whereas the 400/5.6 is too long).

 

[pwp]

Another vote for the f/4 300is. This is one of Canon's great sleeper lenses. I used one a lot until I got my f/2.8 300. In hindsight I'd have done well to keep the f/4 300 as well.

Reasons? It's about the same size as a f/2.8 70-200 but weighs much much less, it's scarey sharp wide open and because of it's light weight I tended to leave it in the bag as a regular take-along lens.

As new Canons deliver such awesome high iso performance, an f/4 lens doesn't cripple you in the same way it did when quality files topped out at less than 400 iso .

Hell, I might just go out on Monday and get another one!

Paul Wright

 

[Forceflow]

So many options, still not sure which one to get. But well, still have a while to decide. Probably wont buy the lens for another half a year anyways. (Still paying off my current equipment...)

Thanks so much to everybody for the help! Certainly got some great ideas here

 

[Forceflow]

Sorry to necromance this thread but since the decision on which to buy has been made I thought I'd check back in here again and thank everybody for their input.
I did decide to go with the 100-400 L from Canon and am very pleased with it. I just had it with me on a three day convention and was able to take some really great shots with it. IQ really is impressive and the 100-400 range is great to work with. It is damn heavy though and the push-pull does take quite some getting used to. (Still not fully comfortable with it) But I would say in this range this is the bes deal I could have gotten.
What really blew me away though was a moon shot that I took a couple of nights ago using the 100-400 with a 2x Sigma converter which I picked up used:

Would not have thought that this combination would end up with that much detail. Image has been cropped to 2778x1852 and then resized to 1920x1280.

 

[K-amps]

Grear choice for the money. Nice moon shot.