p.1 #1 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
I have chased this problem down for about 3 months now. My bird photos are slightly soft taken with R5 mark ii and EF 400 F2.8 is iii. I have also tried an R7 and EF 400 F2.8 is iii and they are also slightly soft. The photos are soft with and without the EF 1.4 iii extender. Ive used this lens handheld for 2 years without issue.
My better half uses an r5 mii with an RF 200-800 and her photos are blowing mine out of the water even if we are at the same zoom. I get that my focal plane is always going to be thinner (even if I up the aperture) and I like that about my photos. This started about half way through a trip to Costa Rica in 12/25. We just spent 3 weeks in India doing bird photography and I thought I had the problem licked. Its a very clean piece of glass, no blemishes or distortions with a flashlight down the barrel. I switched to a gimbal and monopod before India and took tons of test shots. I could not replicate the problem. As I sort my photos from India... Grrr... Same slightly soft photos. It was really hard to tell how sharp they were in the field, it was smokey the whole time in India and no access to a 4k monitor. There are no tack sharp photos but many can salvaged in lightroom. I know I am being picky but I am used to this lens being tack sharp. To me it looks like the image stabilization isn't working but it does the same thing on a tripod. Slightly soft subject with wavy non smooth background bokah.
Not sure how to proceed... ship camera, adapter, extender and lens to canon? Replace the RF to EF adapter? Take them to the shop for a pro level cleaning? Sell it and get a 200-800 (arguably better for bird photography if you can't get close enough anyway)?
p.1 #2 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
Would it be possible to post a link to full resolution examples of a representative soft and sharp image?
Regarding the gear in question, one way to determine where a potential fault lies would be to try the lens on another camera, the camera with another known good lens, etc. I realize you already did this somewhat with the R7 and 400 combo, but what about trying the 400 with your wife's R5II? Or letting her use it instead of her 200-800. Who knows, it might be something introduced by the operator!
Or rent another 400 to compare.
Very curious to see some images, if you're willing to share.
p.1 #3 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
Post some examples. Could be the lens (misaligned glass, defective IS unit). Is your drop-in filter inside? Is it clean? Could be the adapter or maybe the camera. Try as many combinations as possible.
p.1 #4 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
I would set the camera and lens combo on a solid ball head and tripod to test sharpest. If pictures are sharp using this approach, then you'll know your technic is the problem. If pictures are still soft, then you'll know its a gear problem.
p.1 #6 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
Sage11 wrote:
I would set the camera and lens combo on a solid ball head and tripod to test sharpest. If pictures are sharp using this approach, then you'll know your technic is the problem. If pictures are still soft, then you'll know its a gear problem.
Yes, and ES mode, IS off and trying manual focus too.
p.1 #8 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
luvfatbirds wrote:
Slightly soft subject with wavy non smooth background bokah.
I missed this when I posted my first response.
Wavy, non-smooth bokeh is a telltale sign of atmospheric thermal distortion that will degrade image sharpness.
It will be more apparent with a faster, higher quality, sharper lens.
It's something I deal with very frequently photographing motorsports and field sports, especially on artificial turf. On warm days, sunny or not, the artificial turf absorbs heat and then radiates it, causing atmospheric thermal distortion that can range from mild to extremely destructive of image quality.
Here's an example of the same player, two separate plays. Maybe even separate games. Both games at the same location on artificial turf. One shows minimal atmospheric related image degradation while the other shows more. You can see that the bokeh in the more degraded image is correspondingly more warped.
The previous poster's comment about testing without the hood is also related to atmospheric distortion. It's a known issue with equipment that has been stored in a warm environment and is initially used in a much colder setting. The warmth of the lens hood heats up the air around it, especially the air trapped inside it, which spills out and mixes turbulently with the surrounding cold air, resulting in image sharpness degradation. Eventually the hood's temperature stabilizes with the surrounding environment and the problem stops.
As always, I tend towards operator error and try to learn from my mistakes. I included a couple of shots of our wall of fame as we call it. We do get good shots occasionally!
Unfortunately, this is one of those touchy feely sort of problems where i feel the sharpness has degraded over time. That and my wifes pictures are generally much sharper side by side than mine. She uses the r52 with 200-800 exclusively and i use the r52 with 400 f2.8 with the occasional ef 1.4 extender. It was pretty chilly in India so I doubt there was too much atmospheric distortion. Always possible, but I am in texas and I am pretty careful to not run the AC in the car and chill the cameras down when we go birding when its hot.
I tried without the hood and didn't notice a difference. I cleaned the drop in protect filter and the photo in the above folder of the brown pelican was taken with the drop in polarizing filter just to see if that helped at all. Still looked soft to me. The protect filter was a little dirty, but not terrible.
From a user standpoint I find myself pushing shutter speed more than I ever have trying for more sharpness. It's not helping.
"Yes, and ES mode, IS off and trying manual focus too.
EBH"
With the R52 i shoot exclusively in ES. With the R7 it was mechanical. I take a lot of hummer pictures and the rolling shutter on the R7 was awful. I half ass tested it this morning with the IS on and off and included the test shots in the above link. The tripod is missing... grrr... those 2 shots were on a gimbal and monopod. Is it my imagination or does the test pattern look sharper with the IS turned off?
Again, thanks everyone for your help and suggestions!
p.1 #10 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
The link worked. I agree it's going to be a 'touchy feely' kind of situation with regard to figuring out whether or not there is a problem. Each of us will have subjective reasoning for why an image is acceptable or not.
WRT to the test chart photos, the plane of focus is different in each one, but at the plane of focus, they appear extremely similar in sharpness. Low ISO would possibly help clean up the image and better reveal small differences, assuming there are any. Even at high shutter speeds I feel IS can potentially degrade image sharpness slightly from shot to shot because the optics in the IS module are in motion. It's probably a tradeoff between a stable viewfinder experience and potentially more stable for the AF system vs. extracting potentially maximum image quality if other factors align to minimize or offset loss of sharpness related to camera movement. Do you use IS all the time, which IS mode and do you change IS mode for stationary vs. moving subjects?
The 'real world' bird photos are difficult to assess without comparison against 'gold standard' images that reflect ideal results. Most of the photos with the 400 are with the subject at some distance and are situations where various factors likely affected optimum results. In the photo of the parrots (I assume they're parrots - I'm not a bird person), there is good sharpness detail in the plane of focus in the leaves to the lower left but lacking in feather detail. It's unclear if the shot was slightly front focused or if feather detail was lost due to the high ISO.
The 200-800 photo in comparison is more of an ideal situation to maximize feather detail because the bird fills the frame and was at 277mm and comparatively low ISO. How does the 200-800 compare at 400mm or 600mm with much looser framing?
While I doubt it would make a difference, what firmware version is your R5II (May 2024 production) compared to your wife's camera (Dec. 2023 production)? This page explains how to determine production date from Canon's serial numbers. There was past discussion on this board about performance issues introduced with certain fw updates, but don't recall the details offhand.
I still think you need to try a second 400 as a point of comparison/reference. If you're a CPS member, you may be able to request an evaluation loaner, or otherwise rent one from Lens Rentals, etc.
p.1 #11 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
I downloaded your RAW images and viewed them in Canon DPP.
My foremost conclusion was that, based on the images you chose to share, you are doing apples to oranges comparisons to your better half's images. I think you are going to have to perform a much more rigorous comparison before you can conclude that you can't achieve at least equivalent sharpness with your EF 400 III to her RF 200-800.
The RF 200-800 example was:
-- shot under optimal lighting conditions with shadow to emphasize feather detail
-- shot close enough that the lens was zoomed out to 277 mm for in-camera composition
-- f7.1 [@ 277mm] rather than narrower apertures at longer focal lengths
By comparison, your 400r52 india extender:
-- yes, shot under good lighting conditions for shadow enhanced feather detail, but
-- not shot close but at 560mm and not as tight framing [leading to less detail]
-- f4.0 [@ 560mm] gave noticeably shallower DOF which had areas of IMHO great sharpness but clearly highly variable sharpness and probably not where you really wanted it
-- higher ISO than the comparison picture
r52 400 india no extender:
-- sharp but not as detailed and comparison,
-- distance much longer combined with subject with much finer feather detail
-- even so, there are areas of sharp feather detail but
-- shot at f2.8 [@ 400mm)
-- ISO 10000 [versus ISO 2500 in comparison]
My point being, get past a "touchy feely" comparison to a more "objective" comparison to certify that you even have a problem. I'd suggest both of you going out and shooting side-by-side a same subject like your r52-200-800 subject and shooting conditions [doable in Houston] but;
-- use same focal length
-- use same aperture
-- use same shutter speed
-- use same AF/ eye detect/Case settings
-- use same Picture Style [I believe you are already doing this]
And then make your determination of whether or not you have a lens problem.
I can't speak to your impression that the situation degraded in mid-December. Once again, as presented, that is "touchy/feely". Try looking through your archives to see if you have matches from before December that correspond to one of your problem images as described above. That could provide a more evidence-based conclusion that you have a problem that started in mid-December. It might even reveal a change in your shooting configuration that may have occurred.
On a personal note, and based on the observation that you are a recent registrant to FM and therefore possibly a fairly recent viewer of the quality of images presented here, I found myself in somewhat the same boat. I had good equipment (EF 100-400L II IS] but ended up being very frustrated that I wasn't matching the sharpness and detail I see here. It wasn't until I upgraded to the RF 100-500 that I started to approximate what I see here on FM daily. It seems that exposure to FM caused me a problem by raising my expectations.
p.1 #12 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
rscheffler wrote:
The previous poster's comment about testing without the hood is also related to atmospheric distortion. It's a known issue with equipment that has been stored in a warm environment and is initially used in a much colder setting. The warmth of the lens hood heats up the air around it, especially the air trapped inside it, which spills out and mixes turbulently with the surrounding cold air, resulting in image sharpness degradation. Eventually the hood's temperature stabilizes with the surrounding environment and the problem stops.
You guys always nail some oddly specific issues. I definitely question this might have been an issue for me recently. I don't use hoods that often but needed to because of the angle of the sun. The photos were soft which is very unusual for my setup. This is definitely something to look out for in the future.
p.1 #13 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
StephenS_CP wrote:
I downloaded your RAW images and viewed them in Canon DPP.
My foremost conclusion was that, based on the images you chose to share, you are doing apples to oranges comparisons to your better half's images. I think you are going to have to perform a much more rigorous comparison before you can conclude that you can't achieve at least equivalent sharpness with your EF 400 III to her RF 200-800.
The RF 200-800 example was:
-- shot under optimal lighting conditions with shadow to emphasize feather detail
-- shot close enough that the lens was zoomed out to 277 mm for in-camera composition
-- f7.1 [@ 277mm] rather than narrower apertures at longer focal lengths
By comparison, your 400r52 india extender:
-- yes, shot under good lighting conditions for shadow enhanced feather detail, but
-- not shot close but at 560mm and not as tight framing [leading to less detail]
-- f4.0 [@ 560mm] gave noticeably shallower DOF which had areas of IMHO great sharpness but clearly highly variable sharpness and probably not where you really wanted it
-- higher ISO than the comparison picture
r52 400 india no extender:
-- sharp but not as detailed and comparison,
-- distance much longer combined with subject with much finer feather detail
-- even so, there are areas of sharp feather detail but
-- shot at f2.8 [@ 400mm)
-- ISO 10000 [versus ISO 2500 in comparison]
To throw another hat into the ring. I looked at these 3 images. Everything looks exactly in order and nothing seems out of place.
The 400mm no extender has a lot of noise but critical sharpness is perfect. It's in the shade at 10,000 iso, and it's very obvious that ISO is the limiting factor here. In this case if they were still I'd be trying to drop the 1/3200 shutter down to at least 1/800 as that's plenty fast enough to compensate but will give you back 2 full stops. The reality is that there is nothing you can do to make it look like the 200 - 800 shot because of how it's being lit.
The 400mm extender also looks like how I would expect it to. It's clearly focused around a point, just not the eye. That's a good F4 DoF and it what you get to work with on a lens of that caliber. There are some soft "patches" on the head which makes me think that either there was something between you and the subject or some type of noise reduction was kicking in and causing some blur. It doesn't look like a lens aberration to me though.
The 200 - 800, The image is sharp in the plane of focus, but it's actually a tad bit back focused. If this one was at F4 or F2.8 it would greatly decrease detail on the foreground.
The thing is you definitely could take your 400 and shoot it at F8 if you want to. It would help a bit with depth of field, but it's not going to make or break the images. Your lens is performing exactly as expected, and are taking great images.
Stephen already said it, but it's worth repeating. Distance and lightning are the two main differences here. There has to be at least 4 stops between the bare 400mm and the 200 - 800mm photo. But even more so the distance is at least quadrupled, if not more. One way you can take a guess at this is to simply measure the eye at 100% resolution. In the 200 - 800 mm photo if I look at that at 100% the eye is like 2" tall. The 400 + extender the eye is maybe an inch tall. The 400mm they are 1/2" at best. It may not seem as dramatic, but it's a huge deal for resolution.
Example:
If the 200 - 800mm was shot on 20MP, you'd need twice as many pixels in each direction, so 80MP to capture the same level of detail on the 400 + extender. You'd need to double the resolution again to hit the same detail on the 400mm image. That's 320MP to achieve that same detail you can squeeze out of a 20MP camera. There's no way to make up for the difference in distance, you need to get closer and get lucky.
Mar 09, 2026 at 11:42 AM
AmbientMike Offline • • • • • • [X]
p.1 #14 · Soft photos from R5 mark ii and EF 400 F2.8 is iii
As always, I tend towards operator error and try to learn from my mistakes. I included a couple of shots of our wall of fame as we call it. We do get good shots occasionally!
Unfortunately, this is one of those touchy feely sort of problems where i feel the sharpness has degraded over time. That and my wifes pictures are generally much sharper side by side than mine. She uses the r52 with 200-800 exclusively and i use the r52 with 400 f2.8 with the occasional ef 1.4 extender. It was pretty chilly in India so I doubt there was too much atmospheric distortion. Always possible, but I am in texas and I am pretty careful to not run the AC in the car and chill the cameras down when we go birding when its hot.
I tried without the hood and didn't notice a difference. I cleaned the drop in protect filter and the photo in the above folder of the brown pelican was taken with the drop in polarizing filter just to see if that helped at all. Still looked soft to me. The protect filter was a little dirty, but not terrible.
From a user standpoint I find myself pushing shutter speed more than I ever have trying for more sharpness. It's not helping.
"Yes, and ES mode, IS off and trying manual focus too.
EBH"
With the R52 i shoot exclusively in ES. With the R7 it was mechanical. I take a lot of hummer pictures and the rolling shutter on the R7 was awful. I half ass tested it this morning with the IS on and off and included the test shots in the above link. The tripod is missing... grrr... those 2 shots were on a gimbal and monopod. Is it my imagination or does the test pattern look sharper with the IS turned off?
Again, thanks everyone for your help and suggestions!...Show more →
I'm in TX, tends to be more atmospheric distortion in February than July, more likely on 50°'s F days or less
My alt 300/2.8 has to have the drop in filter in, and it matters which way you put it in, for best sharpness. So you might try flipping it around , to see if that helps
Pretty much always a good idea to mf zoomed in to test if you're having lens issues imo. Preferably on tripod if you have one
