Canon 400 f/5.6 or 300 f/4 IS w/ 1.4x teleconverter?

[Marv800]

I'm struggling here, so maybe someone with experience with both lenses can help.

I;m in the market for a lens with a longer reach, and I have arrived at either the 400 5.6 or the 300 f/4 IS with a 1.4x converter.

They are almost identical in price, but the 300 f/4 with the 1.4x converter results in an effective range of 420mm, and its image stabilized. The thought of a 400 w/ a 1.4x (resulting in 560mm) sounds appealing, but then i'd be at f/8 with no autofocus capabilities and no image stabilization.

My questions are this:

Does IS work well with a lens that has a 1.4x converter? Also, what would my likely image quality be like with the 300 x1.4 compared to a prime 400?

Which would you rather shoot with?

[Donb10]

Wow! What a dilemma. Over the past 18 months I have run across good deals on both of the lens, so now I have both of them.

The 400mm f/5.6 is a very sharp lens. For its size, it is very well balanced. With a 5.6 aperture you need some good light for a fast shutter speed if you hand hold or you will need a tripod or monopd. I have a Tamron pro series 1.4ex that I have placed tape on three of the pins that allows the 400 to autofocus. It slows it down but I have never really had the chance to use this combination alot. You might check on the buy and sell forum, Jim Victory has a 400f/5.6 for sale at a good price.

The 300mm f/4 is also a well balanced lens. Its a tad lighter than the 400 but is razor sharp. The IS on this lens is the old style and only gives a 2 f-stop advantage but it does help and old guy like me. I used a Canon 1.4x on this lens and it works very well. There again, your now at f/5.6 so youu will need good light to achieve a fast enough shutter speed.

If you buy either of these lens and don't like them, you won't have much problem selling them. Check the photos listed under the lens section. Sorry I could not be of more help. I like both of them.

[toverman]

The question I have for you is what do you like to shoot, how close can you get to your subjects and how much light are you working with? In some situations, the 400 might be too long, but the 300 is perfect (making that the better choice with a converter when needed), for example.

[zeroendless]

Does IS work well with a lens that has a 1.4x converter? Also, what would my likely image quality be like with the 300 x1.4 compared to a prime 400?

IS works with or without TC, any brand, however, less effectively due to extended focus distance, that's physic it can't beat.

Which would you rather shoot with?

One with IS.

[lhdvies]

I use both of these lenses a lot. If the light is OK and stabilazation is not a problem the IQ of the 400 is a little better than the IQ of the 300 w/ 1.4TC (but not a lot). If I had to choose just one I would get the 300 f.4 LIS. If you are shooting handheld (not difficult with either of these lenses) it is always nice to have IS. If you can shoot at 1/600 or faster it is less of a factor.
However another reason is the 300 is a very versatile lens (even good for some Macro work{I don't do that, but have seen some really good macro shots with it}). If the distance is right it can even be a nice "headshot" portrait tool. For the money, it is just an all around great lens!
As was said earlier, it would be hard to go wrong with either one. Good luck

[johnastovall]

A fixed focal length lens always beat a lens with a TX on it. Just go look at the MTF curves in "Eyes of EOS." You can download the chapters from Canon Europe. Get the section "OPTICAL TERMINOLOGY & MTF CHARACTERISTICS" Then you can look at the data not opinion....