100-400 L with a 1.4 TC

[Kayaker72]

Is anyone using this combination? Do you like it? In addition to the autofocus issues (needs to have f/8 to autofocus), I am finding the shots straight out of the 5DIII to be close to or better than those taken with the 1.4 TC. I am wondering if the 1.4 TC doesn't degrade the IQ much of better glass (70-200 IS II, big whites, etc), but does in the 100-400 L.

A few examples of approximately 100% crops (yes, I am pixel peeping). All shots taken from tripod, remote release, manual focused using live view. Took multiple shots and below represents the "best":
A printout of the ISO 12233 chart you can download form cornell university..both images tweaked in LR to increase sharpness, etc taken ~35 ft (10 m):
5DIII only:

5dIII LR4 600x400-0073 by kayaker72, on Flickr

5DIII with 1.4 TC:

5dIII 14x LR4 600x400-0069 by kayaker72, on Flickr

Closer tree (~100 ft or 30 m):
5DIII only:

5DIII 600 400-0092 by kayaker72, on Flickr

5DIII with 1.4 TC:

5DIII 14tc 600 400-0094 by kayaker72, on Flickr

Tree Further away (~150 ft or 45 m):

5DIII 600 400-0097 by kayaker72, on Flickr


5DIII 14tc 600 400-0096 by kayaker72, on Flickr

Thanks,
Brant

[neuroanatomist]

I've used the combo, performance is acceptable but I haven't done any detailed testing as you've done, Brant. Might need to do some of that with an ISO 12233 chart. OTOH, I often need to crop a bit (with 560mm...and as you know, sometimes even with 1200mm). Below is a 'real world' shot with the 100-400L + 1.4xIII. The 'final' image ended up being 6 MP after cropping (~3000x2000 pixels), and without the 1.4x on there, the same image would have ended up as a 3 MP image. Below are processed image and a 100% crop of it. It was shot at 1/320 s, f/8 and ISO 5000 on the 1D X.

[HDNitehawk]

Is anyone using this combination? Do you like it? In addition to the autofocus issues (needs to have f/8 to autofocus), I am finding the shots straight out of the 5DIII to be close to or better than those taken with the 1.4 TC. I am wondering if the 1.4 TC doesn't degrade the IQ much of better glass (70-200 IS II, big whites, etc), but does in the 100-400 L.

It degrades them all, but the big whites just start out so much better than the 100-400L that you wouldn't notice it as much.
http://www.the-digital-picture.com/R...mp=7&APIComp=0

I was not happy with the 100-400mm plus convertors. Smaller prints it would probably be ok.

[Kayaker72]

It degrades them all, but the big whites just start out so much better than the 100-400L that you wouldn't notice it as much.
http://www.the-digital-picture.com/R...mp=7&APIComp=0

I was not happy with the 100-400mm plus convertors. Smaller prints it would probably be ok.

This is essentially what I am wondering. My likely flawed but hopefully holding some merit analogy is based on the transmittance on the MTF charts. I don't know what optically causes lower transmittance, but some optical inperfection(s) in each lens. Comparing f/8 the big whites/70-200 f/2.8 IS II have ~0-2% optical flaws (lack of transmittance) at f/8. If the 1.4 TC doubles that to 1-4% "flaws", it still isn't a big deal as the MTF score/transmittance is still >96% (with the "Excellent" standard being 90%). But if the 100-400L has ~6% optical flaws at f/8 and the 1.4 TC doubles that, well, 88% transmittance is starting to be a big deal, as it drops you below the "excellent" standard of 90% or 0.9.

I'll play around with my post-processing a little more. I think JRW is right in that there is an exposure issue and combining what John and JRW said, if there is more data in a cropped image with the TC, it may post-process better.

[HDNitehawk]

So if I catch the logic here is that on the big white lenses the teleconvertor degrades the image by a certain amount, say double from 2% to 4%. Since the 100-400mm starts much worse say 4% degradation it ends up doubling to 8%. Those numbers do not relate to anything and are just an example.

I used teleconvertors on the 100-400mm and 5D II when I had the lens. I never got a product that I would do a large (over 8x10) print with.
It sounds to me like you are going to be thinking about one of those big white lenses shortly.

[M_Six]

I've been toying with the idea of a 400mm f5.6 just to get the sharpness along with the additional reach. I usually end up with some cropping and I find I need to start with as sharp as image as I can possibly get in order to end up with a cropped image I'm happy to keep. Either that or I need to get friendlier with the birds.

[Kayaker72]

Thanks....I'll give it a try....

[Kayaker72]

As for my tests, 1 of 3 images with the 1.4 TC did sharpen up to be clearly better than the shot with the 5DIII alone with additional post processing in LR4. I didn't try JRWs suggestion, as I've never done anything like that so it will take me some time. I'd call the other two shots after additional sharpening/contrast/etc about even or an edge to the 5DIII alone. Overall, this has me thinking that I need to conduct more tests with AF, which I can't do until Canon releases the firmware update for the 5DIII, which they've "promised" in April.

It sounds to me like you are going to be thinking about one of those big white lenses shortly.

Scary thought but this is almost exactly the path that led to selling the 100-400 and getting the 300 f2.8 after close to a year with a used 300 f4, also sold, while I tested the theory out before spending the big bucks. No regrets image wise, just a little heavier to carry around.

I could be considering that path...... But it isn't in the cards for at least a year or two. So, it also depends on what comes out between now and then. For example, a 100-400 II or a 400 f/5.6 IS that worked well with the 1.4 TC could be enough. But for now, my core kit of 5DIII, 7D, 24-105 L, 50 f/1.4, 100 f/2.8 L, and 100-400 L should be good.