Focused properly and microadjusted lens give blurry image on Canon 80D and quite fine detail on 350D

Question

I'm an unhappy owner of brand new Canon 80D. I still have 350D which served me for nearly a decade. I use the same 24-105 1:4 L IS lens with both of them.

It turned out that lens is blurry. I've tested with other lenses and body is fine.

After the purchase of 80D I went for a trip and made many pictures. They looked fine on LCD screen, but on a PC, even when viewed as fit to screen (not 1to1), those pictures all look blurry.

So I've done micro-adjustments for 80D and 24-105 lens with Focal 2 software, a tripod and long enough exposure time. It computed adjustment of -3 which doesn't seem much. As far as I understand Focal changes the adjustment and analyzes picture of printed focusing board to calculate its sharpness. From the charts it looks that it really found the sharpest setting.

I have to note that I've made "Auto-focus consistency" tests for both phase auto-focus and contrast based with Live View. Both give more or less the same result in sharpness and sharpness of consecutive takes are the same.

I've also checked whether I could manually focus better, but each move on the focusing collar results in less focused view in the viewfinder.

For me it seems that auto-focus does work properly so why pictures downloaded look so bad?

I've also tried different Picture styles, sharpening settings etc. in Digital Photo Professional after taking a RAW.

I've visually checked the sensor for dirt also and lost all hopes to figure out what's happening.

Here's a comparison of photos taken with the exact same lens, on exactly the same setup. The same crop is cut out and megapixels matched.

Pictures and reports from Focal can be found under my gdrive

What else can I check? Should I send it to Canon service under guarantee? How to convince them not to send it back with information "it works for us"?

Answer 1

• Check for firmware updates for both your camera bodies and lenses.

• Check the diopter on your viewfinder in case it is contributing to your difficulties. You may also need to clean the viewfinder.

• Take focus-bracketed test images. This can help you determine whether the viewfinder is reliable.

• Compare test images with image stabilization turned on and off.

• Lenses are usually sharpest stopped down a bit and softest wide open. Try taking pictures at F5.6 and F8 for comparison. It's also not clear whether you used the same apertures when taking the comparison images.

• Consider calibrating AFMA manually with a yardstick and target set at an angle. This setup will also allow you to see how soft or sharp the lens really is.

• The EOS 350D has an 8mp sensor. As xenoid comments, the lower resolution may appear sharper because blurriness takes up fewer pixels than it does on the 24mp sensor of the EOS 80D. Also, any rotation, if you used any to create your comparison images, would contribute to blurriness. Try upsizing images from your EOS 350D to match the EOS 80D. Use a no-halo Lanczos/sinc algorithm. Try downsizing images from your EOS 80D with the nearest-neighbor algorithm. Other resizing algorithms are more likely to preserve blurriness.

• You don't specify exact settings used on each of the cameras. Also, you mention using raw files on the 80D, but not on the 350D. Exactly what settings are you using? Settings for the two halves of the comparison image do not appear to be matched. For instance, contrast in the left image is higher than on the right. Increased contrast increases apparent sharpness. Exposure may be different by a fraction of a stop, and there appears to be some glare on the right that is not present on the left.

• It's not clear what you mean by "same" lens. Do you mean the same physical lens that you are moving between bodies? Or are you using two copies of the same model lens? If you are using two different copies, do they have filters on them?

Answer 2

I have to note that I've made "Auto-focus consistency" tests for both phase auto-focus and contrast based with Live View. Both give more or less the same result in sharpness and sharpness of consecutive takes are the same.

Then your issue has nothing to do with AFMA, which only affects PDAF focus, but not Live View CDAF which does not use the PDAF sensor.

I've also checked whether I could manually focus better, but each move on the focusing collar results in less focused view in the viewfinder.

I've also tried different Picture styles, sharpening settings etc. in Digital Photo Professional after taking a RAW.

I've visually checked the sensor for dirt also and lost all hopes to figure out what's happening.

You've pretty much eliminated everything else except a problem with either the sensor alignment or an issue with the filter stack in front of the sensor.

What else can I check?

Have you tried another lens? Just to be sure it isn't some sort of weird alignment incongruity between that particular body and that particular lens?

Should I send it to Canon service under guarantee?

Absolutely. There's something wrong with the 80D if the example on the right is the best it can do and the same lens can get the result on the left with another camera using the same focal length, shooting distance, aperture, shutter time, ISO, lighting, processing, etc.

How to convince them not to send it back with information "it works for us"?

Print the example image you posted in the question, clearly marking that the one on the left was taken by your Rebel XT/350D and the one one the right was taken by the 80D after careful focusing. Include the print and the full information you included in the question above when you send the camera in for repair.

My own experience with Canon Factory Service in the U.S., via Canon Professional Services, is that the more you document the issue when you send them a repair, the better chance you have of the problem being fixed.