Canon TS-E 17 - Borders are out of focus on Sony A7r III

Jerome-140 wrote:

Hi everybody,

I've got some image quality issues with my Canon TS-E 17. I'm using it on a Sony A7r III with a Metabones V adapter. What's happened is that the borders of the images are very soft (approx 20-25% of the frame on each side). I say soft, but I realized that they are out of focus!

I get these results when I'm focusing on the center of the frame. The image is sharp from the foreground to the background but blurry on the sides. If I focus on the side of the plan, borders get tack sharp, but the center becomes blurry!

Here are some examples: (photo taken tethered on a tripod, F8, ISO100, sharpening at default in lightroom)

1: Center focus (on the tree in the middle of the frame)

100% crop center:

100% crop left border

2: Focus on the trees on the left (what you see on the cropped image)

100% crop center

100% crop left border

Focus position on 1st image (center focus)

Focus position on 2nd image (focus on the left border)

As you can see I've to focus to longer than infinity to get sharp corners....

Lastly, my lens just came back from canon after sales and they conclude that it is ok!

I already read a lot of articles from people saying that the TS-E 17 is softer when adapted on a Sony body. I was not thinking so much! I've bought this lens for high-end architecture and interior photography, where sharpness is needed all across the frame.

I've also run some tests with a Sigma MC-11, but the results are similar.

So here is my question: is it a Sony problem, or an adapted problem? I'm looking right now to move from Sony to a Canon EOS R5. But it will still require an adapter - this time originally made by Canon.

I will be very happy to read your thoughts on this, and especially from people who already had the chance to use this lens on an EOR R5 body.

Many thanks for your help!

Cheers,

Jerome

I would normally say this is typical of the Metabones adapter being too short but seeing as you have tested it on the MC-11 as well which is built to much higher specs ( I.e the correct thickness) it may be the lens needs recalibrating. My 17 was pretty peculiar before I had the front element replaced and the lens recalibrated. It would show this exact behaviour (curved focus field) which would actually get worse as you stopped down. My work around was to find a sweetspot on the focus scale  where the sharpness was averaged across the frame and mark it and use this to set the lens for distant shots rather than any focusing via live view. It was never very satisfactory and avoided using it as much as my 24. For interiors it was fine BTW as often walls were closer at the edges than the center of the frame. Since repair and recalibration it's not showing these issues. I would say however that neither the 17 nor the 24 have perfectly flat focus fields and there is a slight amount of near focusing at the edges and I find F11 is the best aperture to ensure optimal even ness across the frame even if you sacrifice a bit of center sharpness. On my A7rIV F8-F11 is also the threshold of moiré which is another benefit . Doubt it's anything to do with it being on a Sony camera as these lenses are very much retrofocus designs ( see how far the rear element is recessed) and the light rays hitting the sensor are very parallel so any cover glass thickness variations will have little effect. Lastly I'd still not rule out an adapter thickness error unless you have the facility to accurately measure it. How does infinity line up on your other lenses?

you can't say there is a problem with sony or tse 17mm, rather there intrinsic electronic characteristics the may not be 100% compatible, so you can't blame either one. just like 3rd party lenses that have problem achieving 100% AF on canon cameras.

i own canon tse 17/24mm lenses and they are impeccable when it comes to focus and sharpness on my dslrs. it was the 1st time i used on this day so i wasn't very familiar with TSE 17 when i took this shot--the ship was very close to me so it shows how wide this lens is, i don't see soft corners or soft wdges:

1Dx4me wrote:

you can't say there is a problem with sony or tse 17mm, rather there intrinsic electronic characteristics the may not be 100% compatible, so you can't blame either one. just like 3rd party lenses that have problem achieving 100% AF on canon cameras.

i own canon tse 17/24mm lenses and they are impeccable when it comes to focus and sharpness on my dslrs. it was the 1st time i used on this day so i wasn't very familiar with TSE 17 when i took this shot--the ship was very close to me so it shows how wide this lens is, i don't see soft corners or soft wdges:

How would 'intrinsic electronic characteristics' effect focusing on a MF lens or the shape of the focus plane? Also I wouldn't expect to see soft corners or edges when used on a 16mp crop sensor camera either - how is this relevant?

your experience demonstrate that there are differences somewhere, just like some of the 3rd party lenses have AF focus issues with canon cameras! it is not canon lens, such as TSE 17, or sony cameras that have any issue by themselves, so it has to be incompatibility somewhere between the 2. however, if you are convinced that it must be canon TSE 17 lens, then sorry, i can't convince you there.

here is another sample taken with canon FF 1Dx camera:

1Dx4me wrote:

your experience demonstrate that there are differences somewhere, just like some of the 3rd party lenses have AF focus issues with canon cameras! it is not canon lens, such as TSE 17, or sony cameras that have any issue by themselves, so it has to be incompatibility somewhere between the 2. however, if you are convinced that it must be canon TSE 17 lens, then sorry, i can't convince you there.

here is another sample taken with canon FF 1Dx camera:

Why does it have to be incompatibility and not simply a lens issue on it’s own? Can you explain where this incompatibility would exist and how it would cause the issue?

Jerome-140 wrote:

Hi,

I get a friend how owns a Canon 5DM IV. Here is the shot, center focus as the other.

Now I can say that the problem doesn't come from the lens.

But one question stay? How will it perform on an EOS R5 WITH Canon adapter ???

If you go to any of Ken Rockwell's Sony alpha reviews, say

https://www.kenrockwell.com/sony/a7r-iii.htm#compat,

you'll find an interesting standard paragraph about Sony's full frame sensors effectively being curved.  It's in the paragraph about third party lens adapters, just above the one about Metabones.  I think that's your problem, especially as a 17mm lens has a tiny depth of focus.  (Huge depth of field, tiny depth of focus, the other way around from a big long lens with its tiny depth of field and huge depth of focus.)

In one of his early Sony reviews he put it down to Sony's arrangement of microlenses.  I've not found it to be a problem with my EOS R and 12-24mm zoom.

Jerome-140 wrote:

Hi Shirozina,

Thanks for your reply. It's a shame to have to make this kind of compromise with a prime lens of this level and this price!

As mentioned above, it is just coming back from Canon and they told me it is ok....

Don't know what to think...

Cheers,

Jerome

These lenses are quite old now and maybe were never designed to work with such high MP sensors. Canon may not have done a full test and if they did the design spec may not be for a perfectly flat focus field at infinity. Few lenses are flat at infinity anyway nor are their focus fields.

Jerome-140 wrote:

Hi,

I get a friend how owns a Canon 5DM IV. Here is the shot, center focus as the other.

Now I can say that the problem doesn't come from the lens.

But one question stay? How will it perform on an EOS R5 WITH Canon adapter ???

The 5d IV doesn’t have the same resolution as your Sony so how can you be so sure? Also you can’t rule out your adapters unless you have measured them.