topic Re: Focus issues in EF & RF Lenses

EOS R7 & RF100-500mm lose focus at 400-500mm

lschaerer — Tue, 24 Jun 2025 12:48:47 GMT

Hello. I'm not sure if this is a camera or lens issue, but I'm guessing lens. I've had my R7 and RF100-500 for 2 years. About a week ago, I started experiencing a focus issue with the lens. When zoomed to 400-500, it will be focused fine, then suddenly the whole scene blurs. It will not refocus on anything until I zoom back out to 100mm. The distance of the subject from the lens doesn't make a difference. I'll be taking multiple shots of the same thing, focused clearly, then suddenly, everything is a blur. It does work fine on MF, only happens in AF. I've tried all the suggestions I can find on internet, checked all the switches, changed cards and battery, turned camera off and on, lightly cleaned contacts, but I haven't found a solution yet. O

I've attached a photo from my LCD screen of the blur when it happens. I had taken several clear shots in a row of this flower, then it suddenly blurred out. I appreciate suggestions. I know many are quick to say "user error" but, again, I've been using this combination for 2 years, and this is something that's just started happening last week.

Re: Focus issues

Waddizzle — Mon, 23 Jun 2025 21:13:53 GMT

What is your shooting mode? What is your AF point selection?

Does this happen in Auto shooting mode?

Re: Focus issues

lschaerer — Tue, 24 Jun 2025 00:55:19 GMT

I only shoot in manual mode. I typically shoot with spot focus….almost always, in fact. I also tried in One Shot and Servo. Same happens in either one. Tried with Vehicle, People, animals, eye detection on and off. High contrast, low contrast, sunny and cloudy. No difference. The only difference is that it happens at over 400mm. I can’t get focus at all if I start out zoomed in at 400 and up. I have to find the object at 100-200mm, half press the shutter, keeping it pressed, then zoom in to the subject. I can typically get in a few shots that way, but it will shortly blur, and I have to zoom back out to refocus. I don’t notice the problem with manual focusing.

Re: Focus issues

p4pictures — Tue, 24 Jun 2025 12:46:47 GMT

Firstly I wonder how big these flowers, are and how close to the flower you are. The reason for this is that the lens has different minimum focus distance at different focal lengths. Your photo shows a red focus frame, this is the indication that the camera is not able to focus, and with a subject that is "too close" you will see this red coloured frame.

Minimum focus info from the RF 100-500mm lens instruction manual

100mm - 0.9m / 2.95 ft
300mm - 1m / 3.28 ft
500mm - 1.2m / 3.94 ft

Is it possible you are close enough that when the lens is set to 100mm or 200mm the flower is within minimum focus distance, but when you zoom in to beyond 400mm the flower is actually closer than the minimum focus distance at that zoom setting?

For flowers, you are best to set the subject to detect to none since a flower is not one of the subjects that the intelligent subject tracking is designed to identify. You might want to also try switching subject tracking off, so the AF point stays in the same place rather than follow the subject.

Re: EOS R7 & RF100-500mm lose focus at 400-500mm

ebiggs1 — Tue, 24 Jun 2025 14:02:37 GMT

Yes, I think Brian is on to the solution. I did notice a couple things in your post that needs to cleared up. One OOF issues are almost always user error, sorry, but that's a fact. And second cleaning the contacts rarely to never helps.

If you eliminate the possibility of being too close to subject all is well then we can assume the lens is working. So try the same shot only step back ten feet or so.

Re: Focus issues

lschaerer — Tue, 24 Jun 2025 21:33:50 GMT

I was actually about 25' from that flower. I wasn't trying to get a perfect photo, only trying to get the camera/lens to duplicate the blurry issue to post a photo here. ( I was probably about 20' from the flower, though). Over the past week, I have taken many photos at many distances from the subject with the same issue. If I were taking the flower photo, for instance, to print, or for a paying job, I would have changed the various settings, like subject detect and tracking, but, again, that's not what I was trying to achieve at the moment.
I just got back from my local camera shop. I have had much trouble with my R7, which he was familiar with. (motherboard/processor replaced by Canon under warranty). He put the 100-500 on their R7, and it worked perfectly. He then placed their 100-500 on my R7, and the focus immediately blurred and wouldn't focus on anything above 400mm, and even shots that appeared in focus below 400mm were very soft. I told him all the settings I had tried changing in an effort to resolve the issue. The one thing I had not tried, that he mentioned, was doing a factory reset. He suggested we try that before sending the camera off ( out of warranty, of course), and the lens immediately started working properly again. He said just like computers, sometimes things just get crazy in there, and when all else fails, do a factory reset. Seems to be working as it should now, with quick and sharp focusing in all ranges.

Re: EOS R7 & RF100-500mm lose focus at 400-500mm

lschaerer — Tue, 24 Jun 2025 21:40:44 GMT

Thanks for your reply, but Please know that I'm not an amateur. Been a photographer for 16 years, also with a Photography Certificate from 2 year program at my local university. I spend some time learning and practicing photography every single day. I display and sell my photographs in several local art galleries and markets. I'm not bragging, by any means, as there are much more advanced and wonderful photographers than I even just in my area, but just saying I'm not a novice. Please read the reply from above post that I copied/pasted here. Is this user error? I don't know, but I don't necessarily think so.

I was actually about 25' from that flower. I wasn't trying to get a perfect photo, only trying to get the camera/lens to duplicate the blurry issue to post a photo here. ( I was probably about 20' from the flower, though). Over the past week, I have taken many photos at many distances from the subject with the same issue. If I were taking the flower photo, for instance, to print, or for a paying job, I would have changed the various settings, like subject detect and tracking, but, again, that's not what I was trying to achieve at the moment.
I just got back from my local camera shop. I have had much trouble with my R7, which the repairman was familiar with. (motherboard/processor replaced by Canon under warranty). He put the 100-500 on their R7, and it worked perfectly. He then placed their 100-500 on my R7, and the focus immediately blurred and wouldn't focus on anything above 400mm, and even shots that appeared in focus below 400mm were very soft. I told him all the settings I had tried changing in an effort to resolve the issue. The one thing I had not tried, that he mentioned, was doing a factory reset. He suggested we try that before sending the camera off ( out of warranty, of course), and the lens immediately started working properly again. He said just like computers, sometimes things just get crazy in there, and when all else fails, do a factory reset. Seems to be working as it should now, with quick and sharp focusing in all ranges.

Re: EOS R7 & RF100-500mm lose focus at 400-500mm

deebatman316 — Tue, 24 Jun 2025 22:01:27 GMT

I still believe you’re hitting the minimum focusing distance just as my colleague pointed out. Minimum focusing distance doesn’t matter how close or far you are to something. As long as you’re in the minimum focusing distance. The camera will NEVER achieve focus regardless of AF or MF.

Re: EOS R7 & RF100-500mm lose focus at 400-500mm

lschaerer — Tue, 24 Jun 2025 22:47:16 GMT

Whatever you may think, the camera/lens are now working just as expected, just as they have for the past 2 years (when the camera itself was working properly). I’ve had so many mechanical problems with this camera that the repairman has said I may have just gotten a lemon. Said it’s possible that whatever caused it to “get out of whack” may happen again knowing the camera’s history, but at least I know how to correct the issue, even if it’s just temporary. Hoping the R7 M2 will be out soon, and much improved. Saving up.

Re: EOS R7 & RF100-500mm lose focus at 400-500mm

deebatman316 — Tue, 24 Jun 2025 23:03:03 GMT

Check the setting “Lens Drive when AF Impossible”. Make sure it’s set to “Continue Focus Search”. If it’s not set to that the camera will give up.

Re: EOS R7 & RF100-500mm lose focus at 400-500mm

lschaerer — Tue, 24 Jun 2025 23:46:51 GMT

The repairman at my local camera shop did a factory reset which fixed the problem (the only thing I didn’t think to try). However, now I have to go put all my settings in again. I’ll make sure to look at that. Thank you.

Re: EOS R7 & RF100-500mm lose focus at 400-500mm

lschaerer — Wed, 25 Jun 2025 13:21:46 GMT

Thanks. I'm having to reset all my custom functions now, so I will check that.

Re: EOS R7 & RF100-500mm lose focus at 400-500mm

ebiggs1 — Wed, 25 Jun 2025 14:52:35 GMT

"He said just like computers, sometimes things just get crazy in there, and when all else fails, do a factory reset."

I wholeheartedly urge folks do a camera reset when things go haywire but I will say it is 99.5% of the time because of a setting that the user did and not the camera going "crazy in there". It sounds like you have had a bit of a problem with your camera so if I were you I would send it to Canon and ask for a C&C just for piece of mind. If you are as you claim to be, it is imperative you have a working and dependable camera. The C&C will tell.