What the heck's going on here?

[CapeCodDan]

Hi all, I'm perplexed by a couple of recent images I've taken with my 6DMII; hoping you'll take a look and offer any thoughts as to what's going on and whether the issues are related. I've reached out to CPS and they've not been able to offer any constructive advice.  Both images downsized for upload.  (1) The group shot was taken with my 17-40 f/4L at 29mm, UV filter, ISO 200, f7.1, 1/125, on a monopod. Peripheral Illumination, Chromatic Aberration, and Diffraction corrections ON. Note the people on the left and right sides are soft, and I may be seeing some CA, esp on the right.  (2) The shoreline pic (using my 70-200 f/2.8L USM at 165mm, CPL filter, ISO 500, f8, 1/640). One-shot AF, Zone AF. Peripheral Illumination, Chromatic Aberration, and Diffraction corrections ON.  While the foreground bushes are supposed to be out of focus, and the man (on which I focused) is fine, everything degrades horribly - even the right side of the house is fine but the left is terrible.  (a) could this one be the fault of the polarizing filter?  (b) are these issues camera-related or lens-related?  I see no such issues with any lens on my crop-sensor 80D and 70D.  I would expect some issues on a full frame sensor in the corners, but these problems are not in the corners. Help!

[RobertTheFat]

---

@ebiggs1 wrote:

Another problem when using a UWA lens is you must keep it perpendicular and square and centered to the subject.  You did neither if you look at the risers you can see you were off a bit. You will always have geometry distortion. A tripod with level is a possible solution. 

---

I've found the full-time level on the 5D4 to be a great help in this respect. I wish my 5D3 and 7D's had it.

[TTMartin]

---

@RobertTheFat wrote:

---

@ebiggs1 wrote:

Another problem when using a UWA lens is you must keep it perpendicular and square and centered to the subject.  You did neither if you look at the risers you can see you were off a bit. You will always have geometry distortion. A tripod with level is a possible solution. 

---

I've found the full-time level on the 5D4 to be a great help in this respect. I wish my 5D3 and 7D's had it.

---

The 7D Mk II has it.

[RobertTheFat]

---

@TTMartin wrote:

---

@RobertTheFat wrote:

---

@ebiggs1 wrote:

Another problem when using a UWA lens is you must keep it perpendicular and square and centered to the subject.  You did neither if you look at the risers you can see you were off a bit. You will always have geometry distortion. A tripod with level is a possible solution. 

---

I've found the full-time level on the 5D4 to be a great help in this respect. I wish my 5D3 and 7D's had it.

---

The 7D Mk II has it.

---

The 7D2 does have an electronic level, but it displays only on the LCD screen, not in the viewfinder as the 5D4's level does. The 5D4's level is much more useful, IMO.

IIRC, the 5D3 does have a way to use the AF point display as a level, but it's much clumsier and less accurate than the 5D4's level. There may be a way to get the 7D2 to behave similarly. (The controls on the 5D3 and on the 7D2 are nearly identical.) But I spent a half hour with my wife's 7D2 this afternoon and wasn't able to find it.

[Waddizzle]

---

@ebiggs1 wrote:

Another problem when using a UWA lens is you must keep it perpendicular and square and centered to the subject.  You did neither if you look at the risers you can see you were off a bit. You will always have geometry distortion. A tripod with level is a possible solution. 

---

What he is saying about keeping the camera level with a UWA lens is true.  The 6D2 has a built-in level in the viewfinder, and a tripod for shots that must be absolutely tack sharp is a good idea, too.  

I am not seeing the same softness at the edges.  I see two ladies on the right standing next to one another.  One is soft, while the other is sharp.  That is a result of slow shutter.  

I grabbed a couple of images from my Facebook page.  These two images were taken with a 6D2 and the EF 16-35mm f/2.8L II USM at 16mm and f/8..  I chose these because of the detail at the edges.

The tree along the right side seems sharp, top to bottom, as is the rock wall on the lower left.

The tree on the left side of this image seems sharp, too.  The grass seems sharp, as well as the leaves overhead.

Maybe I got lucky and got a good copy.  Or, maybe I do not see the softness at the edges, which is entirely possible.

[Waddizzle]

Here are two crops of those same images.  This is what I am seeing in the corners on my laptop.

I think the images from my EF 16-35mm f/2.8L II USM are fine.  Am I wrong?

[Waddizzle]

The 7D2 has level display in the viewfinder. It is found in the [SET UP2 : Viewfinder Display] menu. This is the yellow wrench menus.

[RobertTheFat]

---

@Waddizzle wrote:
The 7D2 has level display in the viewfinder. It is found in the [SET UP2 : Viewfinder Display] menu. This is the yellow wrench menus.

---

Yes! Thanks, Waddizzle! I had managed to discover how to turn the level on and off on the 5D4, but didn't think to look back at the 7D2 to see if it worked the same way. Even though Tom had alerted me that the level is there, I still had it in my head that the 7D2 is merely a diminutive 5D3. Live a lot, learn a little, I guess.

[ebiggs1]

"I had managed to discover how to turn the level on and off on the 5D4,..."

The 1DX has this feature, too.  When I was younger I never had need of a level. I never had out of square or out of level shots.  But as I age it seems like the level is a nice feature.

[Waddizzle]

---

@RobertTheFat wrote:

---

@Waddizzle wrote:
The 7D2 has level display in the viewfinder. It is found in the [SET UP2 : Viewfinder Display] menu. This is the yellow wrench menus.

---

Yes! Thanks, Waddizzle! I had managed to discover how to turn the level on and off on the 5D4, but didn't think to look back at the 7D2 to see if it worked the same way. Even though Tom had alerted me that the level is there, I still had it in my head that the 7D2 is merely a diminutive 5D3. Live a lot, learn a little, I guess.

---

Here is neat shortcut to navigate the Canon menus.  Press the [Menu} button to open up menus.  Now press [Q] a few times.

[CapeCodDan]

Great input from everyone.  Just to follow up on my original post, I've now learned all about Canon MTF charts and the one for my 17-40 f/4L is truly awful!!   See https://www.usa.canon.com/internet/portal/us/home/products/details/lenses/ef/ultra-wide-zoom/ef-17-4...

I'm attaching a better view of my original posted image, comparing left side to center to right side.  You can see the problems are not a result of camera or people movement.

The good news is I did another similarly shaped group yesterday; this time used my 24-70 f/2.8L @ 34mm, f/9, 1/250, with terrific results - everyone sharp left to right.