Sigma 150-600 C with teleconverter?

I have 150-600mm sport and the Sigma 1.4 teleconvertor.

With this combination, the D7100 indicates max aperture is f/9, but it will autofocus.   (The camera manual says it only autofocuses with max aperture f/8 or larger.)

So....

1. use the teleconvertor or
2. do not use the teleconvertor and just crop in post processing? 

I only used teleconvertor a few times and I could not determine which was better.  Mainly because what I was using it for there was so much atmospheric distortions I could not tell.  (Car racing on hot asphalt, and a ship sinking 1/2 mile away on the ocean.)

I have not tried it on something closer and stationary.

150-600C with Kenko Pro300 1.4x DGX on Canon 7D.

distance: 29 meters

Just received my Sigma 150-600mm with 1x4 teleconverter,well to be honest at the moment I’m quite disappointed,first time I’ve used a teleconvertor,also used to the Canon 70-300L lens,I’m a wildlife photographer I use a canon 80d ,the hand held shots I’ve took on the canon lens are superb ,anyway on to the sigma,as I said I’ve just received it and took a lot shots but I’m really disappointed as most are not very sharp,so unless it’s a bad combination ,I don’t no I’ll have to play with it a bit see were it gets me.the lens itself us supposed to be sharp as I read reviews so,I’ll percivier,after all its 600mm anyway should be enough without the teleconverter.

briantilley wrote:

Stevie57 wrote:

Just received my Sigma 150-600mm with 1x4 teleconverter,well to be honest at the moment I’m quite disappointed,first time I’ve used a teleconvertor,also used to the Canon 70-300L lens,I’m a wildlife photographer I use a canon 80d ,the hand held shots I’ve took on the canon lens are superb ,anyway on to the sigma,as I said I’ve just received it and took a lot shots but I’m really disappointed as most are not very sharp,so unless it’s a bad combination ,I don’t no I’ll have to play with it a bit see were it gets me.the lens itself us supposed to be sharp as I read reviews so,I’ll percivier,after all its 600mm anyway should be enough without the teleconverter.

I wouldn't blame the lens (or the TC) just yet!

Going from 300mm focal length to 840mm (with the TC) is quite a jump. Many people find that they need to tighten up their technique in order to get acceptable results.

By the way, this thread is more than two years old

Doesn't matter; 2 years on isn't going to change the fact that putting a TC on a long consumer-grade zoom is not going to result in very good IQ.

I’ve since changed the Focus Distance Range to 10 and the images seem better although on a tripod and without the teleconverter but need to try same settings with teleconverter

at f6.3 f7.1 f8.0  with teleconverter it starts at f9 does that make a difference.

Thanks for the info,I’ve been out today changed settings on camera used the 600mm lens and got some perfect shots,so I thought I’d add the teleconverter,loads of shots of the chafinch got back not one any good so you might be right,so it seems like the lens alone is the answer,but 600mm is still good length,never had a teleconverter before so won’t miss it now.but I might keep trying .

So I read a review written by a wildlife photographer and he likes the images he is getting with his long sigma and 1.4 TC.  I had another lens from Canon that had a reputation for being soft reported by many users.  And I was one of those users.

What I learned about me was that I wasn't using a fast enough shutter speed.  Shutter speed with long lens, especially with a TC added is critical for reasonable sharpness.  So on a hunch I look at the "Nesting Osprey" photo and it had a very low shutter speed guaranteed to produce soft images.

On a full frame camera with 1.4 TC, the minimum shutter speed should be 1/860 (or closest faster shutter speed).  If you are shooting with a Canon cropped camera plus 1.4 TC then your minimum speed shout be  1/1376 (or closest faster shutter speed).

When using this combo on my Canon full frame, I'd want a shutter speed around 1/1500 or faster and let my ISO float.