If you are a regular reader of my blog, then you may well be aware of the problems I have experienced with my Fuji 55-200mm lens. Following some rather odd results, the lens was returned to Fuji back in November who couldn’t find any problems. Wex then returned it for a second time following a review of some test images as they agreed, there must be a fault.
The lens is still being inspected by Fuji but Wex have kindly allowed me to trade it in against another lens. This is a huge help as being without a good telephoto lens means I can’t use the Fuji kit properly and always end up taking a second camera with me. Thanks to the trade in I now have the Fuji 50-140 f/2.8 + 1.4x Teleconverter and this weekend was my first outing.
Unfortunately, the location we chose was very foggy and remained so for most of the day. The fog did lift to a certain level but generally it was too dense to use the new lens properly. I did however manage a few test shots of distant rocks which a group of climbers were scaling. I mounter the camera on my tripod and lined up the shot using both the lens and teleconverter. The conditions were still with no wind and I was using a cable release.
To my horror, when I zoomed in to check the image I could see a lot of camera shake and the image was blurred. I tried again and again but I couldn’t remove the shake. I then tried removing the teleconverter to see if it was the cause of the problem but it wasn’t. The results looked very much like those I experienced with the lens I had returned.
Below you can see one of the problem images. Notice how the shake isn’t consistent across the frame and some areas almost come into focus but don’t quite get there.
And a section at 100% magnification.
Then through trial and error I worked out the cause of the issue. Take a look at the image below which was shot immediately after the image above. This time the image is pin sharp across the frame.
And again, a section of the image at 100% magnification.
The cause of the issue was the Lee 0.3 ND grad filter I was using. With the filter on the lens, the images were out of focus and appeared shaky. With the filter removed the images were crisp and sharp. I could repeat the result time and again with all my Lee filters.
What appears to be happening is that the filter is causing a problem for the autofocus mechanism in the XT2 and it continues to refocus as the shot is being taken. Later I turned off the autofocus and could focus manual to capture a pin sharp image. If I set the camera back to autofocus the problem occurred again. What I haven’t been able to work out is why I have only seen the issue with the telephoto lenses. My other lenses (10-24, 16-55 and 18-55) all work fine with my filters.
This is one to watch out for if you are a landscaper and use filters. I was also wondering if anyone else has experienced a similar issue?
The Lightweight Photographer 
Useful to know Robin. Thanks. I’ll look out for that but rarely use GND’s with the 50-140. Superb lens too.
I also don’t tend to use NDG’s that often with long lenses but sometimes they are necessary (unless you want to blend images). Yes, I love the lens but its very heavy.
If I am set up to use external filters (I.e. Not screw-in filters) I am usually on a tripod and using manual focus to make sure that I am focussed on the desired area in the picture.
It’s often a tripod for me although I tend to prefer the autofocus. I find my hands shake and make focussing difficult with a long lens.
Very interesting discovery Robin & glad you got to the bottom of it. But still quite strange why only the zooms seem to be affected this way by the use of filters. Also do you think that the filters may have been a source of, or contributor to, some of the RAW conversion problems that you were having with Fuji X sensors?
Hi Jed. The filters are definately not the source of RAW conversion problems. I can produce great results now with Adobe although the best results still come from RAW Therapee in terms of outright image quality. I have been wondering if the filters are causing some form of reflection which is causing the autofocus to have issues. Both my Lee 100mm and Lee Seven 5 filters cause the issue. I must try it with some old HiTech filters when I have time.
Good detective work, I was thinking camera. Perhaps worth warning Fuji about your find?
Thanks. I have already raised this with Wex and want to give them a couple of days before I alert Fuji.
Regardless of the problems, it’s lovely to see some pictures of The Roaches. Grew up near there.
Thank you, it was a great day and I intend to return again in the future. Hopefully I can share some more shots. And regarding the problem, I’m delighted I worked out what it was. It’s cost me money trading in what is probably a perfectly good lens, but I now have an amazing lens and some very useful information to share. In my book, that’s a result.
Thanks for your Expierence.
I shot a couple of pictures with the 50-140 and Lee75 GND in AF and had no problems. But i used the X-T1.
I already got the X-T2, but haven’t made any Pictures with that setup.
Thanks, that’s very interesting. I had the problem on both my X-T1 and X-T2 but that was with the 55-200 and it wasn’t as obvious with the X-T1. I’m going to experiment a little more.
Hi Robin
a pro landscape photographer I know had similar issues with some (not all) his Lee filters and his Sony A7 (not sure which lens/es). He discussed it with Lee who asked him to check if his filters were perfectly flat. They were not – very slightly curved – and Lee replaced them for him. He considers it may have been due to them being stored incorrectly, under pressure from other items in his bag, which he leaves packed ready for action. He now ensures that doesn’t happen, as apparently it is a known problem.
The depth of focus, i.e. at the sensor level rather than depth of field at the subject, is much smaller with long focal length lenses versus wide angles. This may account for why you have only noticed the effect with the longer zoom lens.
Nigel
Thanks, I hadn’t heard of this problem with the filters. I checked mine and they are all perfectly flat. I also don’t have this problem when using them with the Olympus EM5 and 40-150mm lens or the Canon 70-300 on a Sony A7R. I still think its related to the auto focus. I have a friend who uses glass filters and next time I’m out with him I will give those a try. Thanks again for the info.
Hi Robin,
I am not sure if your problem is already fixed but the blurry photos presented are very similar to my case as well as some others. Look to :
https://www.dpreview.com/forums/post/59823913
or
https://www.fujix-forum.com/threads/blurry-images-with-brand-new-x-t2-and-18-55-ois.66252/
Blurry images with brand new X-T2 and 18-55 OIS
I personally returner for the second time my Fuji X-T2 + 18-55/2.8-4.0 + 50-140/2.8 to the warranty claim.
Should you are interested I can send you the description of the problem and my findings.
I am also using filters, particularly: B+W filtr UV XS-Pro Digital MRC nano 72mm and 58mm.
In my opinion, even if the blurry photos are caused by filters there is a technical problem with the camera.
In this case with Autofocus measuring. The camera MUST allow usage of the filters! and B+W is not a cheap piece of plastic.
Interesting that others seem to experiecne a problem – I never had a reply from Fuji.
I know now without any doubt that it’s filters that cause the problem ad it seems long lenses are prone to this. I have expereicend the same issue on a number of lenses and cameras when using filters. Remove the filter and the issue stops. Switch to manual focus and there’s no problem. I do think its the reflection fromt he filter that’s fooling the autofocus system. The reason I say this is that I have noticed how the autofocus seems to pick up rain on the from the lens and sometimes tries to focus on it. It seems very sensitive to anything on the lens.
Thank you for your comment.
I wonder how Fuji will resolve my warranty claim. In my case, I have many examples where there is nothing between lenses and far distant landscape (just pure air) and I still could produce blurry photos. In my last test, after Fuji returned me “repaired” camera with new firmware (ver 2.1), I found out, that the autofocus measures wrong distance (thus producing blurry photos) in some cyclicity. Especially with my 18-55/2.8-4.0 lens zoomed to 18mm. Following is the description:
… The pictures were taken with Focus Mode selector on „s“ + Drive Dial mode on „S“, i.e. single shot/single frame, mainly using middle size focusing area (3×3 points). Nevertheless the blurry photos are produced also for single focusing point. I list the testing photos on the below table. One row always represents photos with the same view and the same placement of the focusing point – related to the distance from the camera.
The main problem is, that the focusing points indicate (by changing of the color to green and by beeping) that the camera is focused while it is NOT, i.e. not focused to the area of the indicated focusing poins. When I was focusing to the sky with fog the focusing indicator properly informed me that it was not focused (by changing to red color and not beeping).
The most obvious is the issue just on the preview on the camera where the focused point is marked by small green cross. When the area around this cross is zoomed in then for blurry photos it is not focused there…
In any case, for me this kind of camera behavior is not acceptable.
Regarding filters: I expect the camera should allow filters, especialy the one in this price and quality level.
I have had a similar problem but although I use a filter, it is a B & W nano pro XS clear (007). The thread below explains:
https://www.dpreview.com/forums/post/61351128
Cliff
Thanks for sharing. It’s interesting what some of these filters will do to the Fuji focus system. I have now switched to using Kase glass filters and I haven’t had a problem since.
I have stopped using a filter just to protect a lens, unless I am shooting in an environment that really demands it, such as dusty, sandy, or with sea spray. I always use a lens hood and I have only ever tripped and dropped a lens – when that happened not even the lens hood and filter stopped it getting broken. The only filters I now use are polarisers and ND if the subject demands it. Otherwise I leave my lenses ‘naked’. I have found far fewer AF issues, especially with tele lenses, now I don’t use filters. And the filters I was using were very expensive multi-coated ones designed for digital.
Hi Marco, so you think the blurry photos were caused by the filter ?
Hi Marco, have you looked at the clear glass protectors? I switched to these when one of my infrared cameras was constantly blurred by using (any) UV filters. They may be worth looking into. A lens fell out of my bag a couple of weeks back when the zip split. The front filter saved a very expensive lens.
Hi – well I have tried the most expensive Hoya clear glass ‘made for digital’ multi-coated filters (Hoya HD range for example). Some people have said to me they are no good and only BW are good, but actually in reviews the expensive Hoya filters normally come out at least as good as the BW ones. I still found they affected one of my big 70-400 tele lenses I use on my Sony system. So I always keep that lens free from filters and (a) make sure I use the hood and (b) keep the lens cap on when necessary. I don’t shoot on beaches or in very dusty or wet environments typically BTW. Interestingly other folks had similar experiences using filters on that Sony lens, so it appears to be the case that some lens designs are more sensitive to having their performance impacted by filters than others. Were I a jobbing photog shooting every day then maybe I would stick a protective filter on all my lenses but I don’t shoot more than about once a week and try to really look after my gear. So I have dispensed with filters even on my $2000+ lenses. But every time you read a debate about filters there is never a consensus – there are folks like me saying don’t use them unless you have to, and folks who have an automatic knee-jerk reaction to just always ‘protect’ a lens front element with a filter, as if it is the obvious, natural thing to do. Of course I do sometimes need and therefore use pola and ND filters, but otherwise it’s naked front elements for me. As a scientists I usually take some convincing about things, but I have seen with my own eyes how filters have degraded sharpness and AF performance on my big tele lenses enough to persuade me to ‘go naked’.
That’s interesting. I have only experienced filter problems with specific cameras. With regard to UV filters, I stopped using the expensive ones a long time back. I used to use B&W but they seemed to pick up a reflection of the outer edge of the lens back onto the inside glass. This was most obvious when using lenses with white writing around the edge of the lens. I still use UV filters but they are very cheap ones that I think are good value. I buy them from Amazon, they are made by Polaroid and cost less than £10.
There are different discussions going on here and one shouldn’t confuse them. I’ve seen enough evidence to convince me that filters can sometimes cause AF problems and a lack of resolution and contrast. That’s one issue. But the other issues here are more broadly about AF problems and they can be notoriously difficult to pin down when trying to diagnose causes. As mentioned above, sometimes a poor firmware impacts AF in an unexpected way. Sometimes it is user error, as cameras come equipped with ever more AF options. Sometimes there is indeed equipment failure – it is possible to get a dud lens, with, say, mis-aligned elements, or just a bad AF motor. Sometimes a camera’s AF system is not always up to the job all the time – this will especially be the case when attempting to track a fast-moving subject (and even a child can be a fast-moving subject, it doesn’t have to be an F-16 !). A careful process of deducting one possible cause before testing for the next is needed. For example, go to a store and test another copy of the lens you are having problems with, or use the forums to arrange a meet-up with another user who has the same camera and lens. In this way you can see if the problem is your specific camera or lens and also share with other users what settings and technique you are using, just in case they are the issue.
You’re right. It’s very easy to confuse different problems and someone describing an image as blurred may only appear soft to another person. It is essential to be able to pinpoint the situation it occurs through testing. I can replicate the problem I experienced just by placing any of the Lee ND Grads on my long lenses and on different bodies and importantly, using other peoples copies of the same lenses. I can do this inside or out, with the camera tripod mounted and using a remote release (and no other filters). The results are 100% consistent across multiple shots in different conditions. Fortunately, my switch to Kase filters means I can use those without an issue. I don’t think I ever did get a reply from Fuji about the problem.
Are you really sure there are no other causes?
If this question is directed to me *as the author of the article), I’m 100% certain the cause of the issue was using the Lee filters on a long lens. I can replicate the problem on demand with either the Fuji 35-140 or 55-200 lens. As soon as I add the Lee filter I get the blurring but if I switch the camera to manual focus or remove the filter I don’t get the blurring. I have also replicated it on another X-T2 camera.
I have since switched to using Kase Wolverine glass filters and haven’t experienced the issue since.
Hi, I am asking, because I suffer the same (or very similar) problem with my X-T2 (see also my earlier comment on this conference). I am using the protective top BW UV filters. I tested OTHER X-T2 body as well, with the set lenses 18-55/2.8-4.0 without protective filter and to my surprise, the camera also produced some blurry pictures. I am getting higher percentage of poor pictures on the focus length of 18mm and aperture of 2.8. With the new firmwares the percentage of blurry photos decrease but there is still some. Surprisingly the best results I had with the “problematic” firmware 4.0 which was immediately replaced by 4.01. Both were perfect for AF! The 4.10 version is again on the same poor AF quality like 3.0… So I am anxiously expecting the indicated 4.2 camera body fimware now. There are some tricks, how to ged rid of this AF issue (by camera setting) but I would prefer the firmware fixing to be able to use my prefered operationh of the camera.
On my previous tests I had blurry photos even on my Fujinon 50-140/2.8 – the percentage is low, but there is some.
This may be related to the problem I reported but it sounds different. My issue only happens with two long lenses and the filters that cause it are the slot in type. Have you tried updating the firmware in the lens as well as the camera body? I would also go through a series of controlled tests with the camera on a tripod and using a remote release to minimise affecting the results. If you can pinpoint a repeatable set of conditions that cause the issue I would report your findings to Fuji as a defect.
To Jiri BESTA – Fuji is generally appreciated by owners for their ‘kaizen’ approach of using firmware to significantly improve performance and features long after a camera is released. However, sometimes these firmware are released a little too early, without sufficient testing, and problems only come to light after user feedback. With that in mind I tend to wait a few weeks after a firmware is released before updating, and read forum comments on the new firmware first. There is also an issue of expectation perhaps – no camera + lens will give you perfect AF 100% of the time, whatever the situation. We want a high % of keepers, sure, but there are too many variables in the mix to expect 100% perfect AF every time