Disappointing Canon Quality Control with RF 15-35 F2.8???

Hi Everyone. I'm shooting on an R5 and evaluating the RF 15-35 f2.8. I've been doing the standard centering/tilt tests on objects in the distance/well past hyperfocal distance.

The lens corners are pretty solid 20mm-35mm. The corners are weaker wider than this. Particularly at 15/16mm. Below are corner crops of license plates @f2.8 and 15mm with lightroom white balance/color corrections only. **The crops are a high 400%**

At 15mm --- I'd argue that the bottom left corner is consistently worse and having lower contrast. However, I understand that getting the corners of a wide zoom perfectly even --- is very difficult.  Still this is a 2399 usd lens…

How would you grade my copy? I could still return it if I wanted to. Good/average/bad? I can tell that the bottom left is "weaker" through f5.6.

Main use cases for the lens will be landscape at small apertures (so should be fine) and then a lot of milky way astro wide open at 15-20mm (which is my concern).

I'm a perfectionist...but also accept a perfect lens is also a unicorn.

I was under the impression that the lens was designed with perspective correction as part of post processing, have you tried with corrections applied?  Regardless 400% seems a bit overboard.

I am not a lens test chart testing type of photographer. I test my new lenses in real world conditions with a lot of different settings. If I like the results I keep the lens. I bought my RF 15-35 last Spring. I have been very pleased with the images. Over President's Day I used the lens exclusively on my first day. My big regret is not using the lens more the next two days. The images with the lens are fantastic. The conditions were interesting with a lot of Snow, very blue skies, people and red rocks.

I have also used the lens several times for Astrophotography and I am very happy with the results.  The main reason I bought the lens over the 14-35 was speed for astro work. I have also found the speed helpful for many other situations.  I should mention I develop with DxO PL6.

I personally really like the lens on my R5. I  also know that now all lenses are the same and sometimes you have sample variations.

johnpul wrote:

Kokopelli_Rocks wrote:

I am not a lens test chart testing type of photographer. I test my new lenses in real world conditions with a lot of different settings. If I like the results I keep the lens. I bought my RF 15-35 last Spring. I have been very pleased with the images. Over President's Day I used the lens exclusively on my first day. My big regret is not using the lens more the next two days. The images with the lens are fantastic. The conditions were interesting with a lot of Snow, very blue skies, people and red rocks.

I have also used the lens several times for Astrophotography and I am very happy with the results. The main reason I bought the lens over the 14-35 was speed for astro work. I have also found the speed helpful for many other situations. I should mention I develop with DxO PL6.

I personally really like the lens on my R5. I also know that now all lenses are the same and sometimes you have sample variations.

Hi Kokopelli_Rocks - thanks for the reply! You method of testing is probably the more sane route, but the engineer in me can't help but scrutinize every optical detail.

I strongly agree that the sky "blue" coming off this lens is impressive and a bit unusual. The photos seem to have almost a polarized appearance.

Fully understand. My wife is an engineer.

I can't comment on your issue with the LR lens profile. I used LR since the first release until I bought my R5. I was not happy with the results developing my R5 RAWs with LR. I decided to test several other RAW development products. I decided on DxO. I am not using DxO PL6 and I am very happy with the results.

Slightly decentered lense(s) is the illness of zooms. The chance here is that you do 400% crops to see it. Mind has also an illness : it wants perfection and control over everything 😁

You lens seems usable as it is, you can get worth if you change, who knows..

johnpul wrote:

Two more examples.

So as one might expect on a budget zoom - I would expect a bit better on an expensive L

johnpul wrote:

I think I'm going to keep the lens and mail it into a Canon repair center for some tweaking. Can anyone tell me what is causing this "ghosting effect" in the image? An aspherical element issue? I hope to steer them toward the problem. Note in particular

the mountain states toyota lettering.

The distinct double image in the far corners points toward astigmatism (common in ultra-wide designs).  My far corners at UWA exhibit a little of this too (but it’s really only seen wide open at high mags).  During normal shooting stopping down helps this.  If astig was better corrected then another area would likely suffer (given the same lens cost).

Of course shooting wide-field astro you wouldn’t be stopping down, so you’ll either have to crop it out, or buy a dedicated prime for this.  You can get good recommendations over in the Astro Forum.  Best of luck!

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CameraCarl wrote:

johnpul wrote:

I think I'm going to keep the lens and mail it into a Canon repair center for some tweaking....

If you do, don't be surprised if Canon tells you the lens is within specifications.

By the way, have you taken it out and actually made some real world images of the kind you intend to use the lens to make? And do you see this "disappointing" image quality when viewed at a reasonable magnification such as 1:1? I think we might like to see some of these poor real world images.

Right-O!

R2

johnpul wrote:

Kokopelli_Rocks wrote:

I am not a lens test chart testing type of photographer. I test my new lenses in real world conditions with a lot of different settings. If I like the results I keep the lens. I bought my RF 15-35 last Spring. I have been very pleased with the images. Over President's Day I used the lens exclusively on my first day. My big regret is not using the lens more the next two days. The images with the lens are fantastic. The conditions were interesting with a lot of Snow, very blue skies, people and red rocks.

I have also used the lens several times for Astrophotography and I am very happy with the results. The main reason I bought the lens over the 14-35 was speed for astro work. I have also found the speed helpful for many other situations. I should mention I develop with DxO PL6.

I personally really like the lens on my R5. I also know that now all lenses are the same and sometimes you have sample variations.

Hi Kokopelli_Rocks - thanks for the reply! You method of testing is probably the more sane route, but the engineer in me can't help but scrutinize every optical detail.

I strongly agree that the sky "blue" coming off this lens is impressive and a bit unusual. The photos seem to have almost a polarized appearance.

Yes, the colors that come through this lens are superb. Most lenses are not capable of rendering skies so deeply blue. It can indeed be a bit startling to those who have not witnessed it.

Not posted for artistic merit  .  Click on "original size"

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