EOS 5D Mark IV Fuzzy artifacts with 2x teleconverter & 70-200 lens

[focs]

Hey everyone,

I noticed my 2x teleconverter started acting weird, especially at appertures below f/11. Photos come out fuzzy and it's driving me crazy. I used it on a 100-400 ii that I borrowed and it glitched a couple of times. The camera wouldn't autofocus.

The fuzz is evident on the long line on the swimmer's cap and other action photos I've take.

Lens: Canon 70-200 2.8

Camera: Eos 5D Mk IV DS126601

Is it dead 😣?

[Waddizzle]

What camera are you using?  Exactly which teleconverter are you using?  Please state the full model number, no abbreviations or nicknames.  Thanks, ahead of time.

Everything that you described sounds normal, to me.  If you are shooting through the OVF, then I do not believe any Canon DSLR will auto focus with an 2x teleconverter and that lens.  This reasons for why this happens are not exactly cut and dried.  Simply put, the laws of physics will always prevail.

[johnrmoyer]

Which camera?

Which 2x teleconverter?

Which 70-200 lens?

In general, a longer focal length might require faster shutter to avoid blur.

Smaller aperture might result in diffraction blur depending upon size of photo sites on the sensor chip as well as F number.

At a long distance uneven density in the air or movement of air will cause some blur.

A large F number together with long focal length will result in shallow depth of field with blur of background and foreground.

If the lens, camera, and teleconverter were all made by Canon and you have the camera set to save a raw file, then the free to download Canon DPP software "digital lens optimizer" will remove some of the diffraction blur.

Some DSLR cameras cannot focus at a large F number. Some require bright light to focus if the F number is large.

[focs]

Thanks, I updated the original post.

The reason I'm posting this is because a year or two back the converter worked much better!

Look at this much better photo at 400mm, full-on AF.

[johnrmoyer]

The bird looks okay to me. It seems to me that there is more unsharp mask than is my preference.

I see from the exif data that Picassa software was used. Did the behavior change after switching to that software or upgrading that software? Have you tried processing the raw file with Canon DPP software?

The more recent Extender EF 2x III works better than the two earlier versions.

EDIT:

[EXIF:Image]    Lens Model                      : EF70-200mm f/2.8L USM +2x

[Waddizzle]

I see you updated your original post, but still did not clearly and specifically answer the questions with the actual FULL model numbers.  The exact combination of gear makes a big difference.

So, I am suggesting that you download a copy of the full User Guide for the camera.  Do a search for the phrase “Lens Group”.  You should find a detailed description of how the AF systems works, where the different types of AF points are located, and what “lens groups” are all about.

Just a reminder, I think the gear is performing as designed.

[focs]

Thanks for all the hypothesis on this! I'm familiar with sharpness & diffraction at slow aperture and these are 100% crops.

The blur/mush/artifact is evident by simply zooming in 100% on the camera's preview screen.

Something distinctly happened after three years of use. I suspect that rattling it on motorcycle offroad trips may have affected it, the way motion stabilization hardware on phones can also be affected when mounted on bikes/motorcycles for a long time. Or perhaps some other physical damage.

The lens combo is in group F. Although there are exceptions there regarding the teleconverter, they never manifested previously.

I'll update here if I get more information.

Thank you!

[ebiggs1]

I don't think there is anything wrong. It is the combination of the limits of the gear and the shooter. Some shots are better because things were right and some are not so good because they weren't. It happens all the time to everyone. The 2x tel-con comes with a IQ penalty along with a two stop penalty. A 100% crop is at the very limit of great IQ, besides. Be happy it works as well as it does.

[normadel]

You should also download the manuals for your LENSES (yes, they exist) from Canon. The lens manuals tell whether or not the lens works with Canon's teleconverters. Some don't at all. Some say that they will not autofocus below a specific lens aperture size. Remember that a larger f/number is a smaller aperture. If your aperture is too small, whether manually-set or automatically-set, focus will fail.

Aftermarket teleconverters....who knows?