Canon 100-400mm f/4.5-5.6 USM IS II

Started Jul 2, 2019 | Discussions
ohthatgirl Junior Member • Posts: 28
Canon 100-400mm f/4.5-5.6 USM IS II

I have had my lens now for roughly two years. At the beginning, the images I took using the lens were sharp, but over time I noticed they were losing their sharpness. I am using it along with my then new 7D Mark II. I fooled around with micro adjust calibration, AF settings and even considered sending it in to Canon to have a look. I also noticed almost from the start a small dust particle on the inside of my lens - which mainly irritated me but did not impact the image. Just recently I went on a road trip and cleaned my lens and Hoya filter before I left. I have always had my filter on my lens from the beginning. I used a magnifying glass and light to clean it and noticed the same dust particle and several more.  On my recent road trip my images looked fine (and continue to look fine) however, on a very bright sunny day the light was shining on my lens so that I could see a fine vertical crack had appeared. I have no idea how long my lens has been like this because in normal light, you cannot see it at all. It's there and not impacting my images, but has anyone ever heard of this? It has not been dropped or even low impact in anyway.

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OhThatGrl

Canon EOS 7D Mark II
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CameraCarl Veteran Member • Posts: 7,163
Re: Canon 100-400mm f/4.5-5.6 USM IS II

It is not unusual to have a bit of dust inside a lens. It is unusual to have a cracked element.  I would send it in to Canon for inspection and repair. When you get it back, try using it without a filter. There have been reports that filter use tends to result in unsharp images, but you day your images were sharp at first, so I don't know what to say.

1Dx4me Veteran Member • Posts: 9,437
Re: Canon 100-400mm f/4.5-5.6 USM IS II
1

ohthatgirl wrote:

I have had my lens now for roughly two years. At the beginning, the images I took using the lens were sharp, but over time I noticed they were losing their sharpness. I am using it along with my then new 7D Mark II. I fooled around with micro adjust calibration, AF settings and even considered sending it in to Canon to have a look. I also noticed almost from the start a small dust particle on the inside of my lens - which mainly irritated me but did not impact the image. Just recently I went on a road trip and cleaned my lens and Hoya filter before I left. I have always had my filter on my lens from the beginning. I used a magnifying glass and light to clean it and noticed the same dust particle and several more. On my recent road trip my images looked fine (and continue to look fine) however, on a very bright sunny day the light was shining on my lens so that I could see a fine vertical crack had appeared.

is it a chip on the glass or crack on the glass (is it the front lens)? do you see any indentation on the barrel where the crack has occurred? it had to be a blow to the barrel or a direct hit in order for the glass to crack! one more question, is the crack on the surface or deep inside the lens? i dropped mine on my driveway, mounted on my 1Dx, but i was so fortunate that everything turned out just fine

I have no idea how long my lens has been like this because in normal light, you cannot see it at all. It's there and not impacting my images, but has anyone ever heard of this? It has not been dropped or even low impact in anyway.

i would not recommend MFA on any lens unless one really must and knows what needs to be done! i have 13 "L" lenses, including big white primes and many telephotos, and not have seen any need or curious enough to perform MFA on my lenses. yours may have needed to perform MFA on it but it is really difficult to perform that on telephotos due to their wide range of focal length. i would have a professional to do that. sorry to hear about having a rough time with your 100400, a year after purchasing it, i hope you resolve all the issues with your lens in a successful and satisfactory way. good luck.

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Pocket Lint Senior Member • Posts: 1,115
Re: Canon 100-400mm f/4.5-5.6 USM IS II

I would be especially careful with a lens that has fluorite elements. Fluorite is not like glass, it is a mineral and thus its tensile strength is lower.

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1Dx4me Veteran Member • Posts: 9,437
Re: Canon 100-400mm f/4.5-5.6 USM IS II

Pocket Lint wrote:

I would be especially careful with a lens that has fluorite elements. Fluorite is not like glass, it is a mineral and thus its tensile strength is lower.

+1

indeed!

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You miss 100 percent of the shots you didn't take!!! "Wayne Gretzky"

Pocket Lint Senior Member • Posts: 1,115
Re: Canon 100-400mm f/4.5-5.6 USM IS II

1Dx4me wrote:

Pocket Lint wrote:

I would be especially careful with a lens that has fluorite elements. Fluorite is not like glass, it is a mineral and thus its tensile strength is lower.

+1

indeed!

Indeed. Canon makes some incredible lenses in the ultra telephoto range, and any lens with a fluorite element is pretty special. It is neither easy, or cheap to produce those magnificent optical wonders.

Cheers

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John Sheehy Forum Pro • Posts: 23,694
Re: Canon 100-400mm f/4.5-5.6 USM IS II
1

ohthatgirl wrote:

I have had my lens now for roughly two years. At the beginning, the images I took using the lens were sharp, but over time I noticed they were losing their sharpness. I am using it along with my then new 7D Mark II. I fooled around with micro adjust calibration, AF settings and even considered sending it in to Canon to have a look. I also noticed almost from the start a small dust particle on the inside of my lens - which mainly irritated me but did not impact the image. Just recently I went on a road trip and cleaned my lens and Hoya filter before I left. I have always had my filter on my lens from the beginning. I used a magnifying glass and light to clean it and noticed the same dust particle and several more. On my recent road trip my images looked fine (and continue to look fine) however, on a very bright sunny day the light was shining on my lens so that I could see a fine vertical crack had appeared. I have no idea how long my lens has been like this because in normal light, you cannot see it at all. It's there and not impacting my images, but has anyone ever heard of this? It has not been dropped or even low impact in anyway.

Any optical sharpness vs autofocus question is very easy to solve; just go outside, find a wall in bright sun, shoot it at about an 80 degree angle with a fast shutter speed, and look at the part of the wall most in focus and see how sharp it is.  Try with IS turned off and turned on.

If you can't find the sharpness that you used to have, then maybe something did happen to the lens.  If the wall is sharp somewhere in the frame, then AF calibration is your issue.

Marquee Regular Member • Posts: 332
Re: Canon 100-400mm f/4.5-5.6 USM IS II

A possible cause of your progressive softness of results could be a lens element de-centering issue - certainly both my 70-200 zooms have suffered from this and softness has appeared particularly on one side of the frame. They both had to go to Canon for optical alignment and were great after that. Dust on internal elements is a fact of life with the 100-400II due to the amount of air displaced with the zoom movements. Dust on internal elements will not typically affect image quality at all, and might look bad but we should resist the temptation to fret about it. A crack on an internal element suggests the lens maybe got a knock at some point and an internal element may be out of alignment. In the UK Canon charge a flat fee for different classes of lenses for a typical optical bench alignment. For a 100-400II I would imagine this is around £200

Mark

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Dave
Dave Veteran Member • Posts: 5,367
Re: Canon 100-400mm f/4.5-5.6 USM IS II

Might the "crack" possibly be a thread of spider's silk?

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OP ohthatgirl Junior Member • Posts: 28
Re: Canon 100-400mm f/4.5-5.6 USM IS II

I love DPReview and how helpful everyone is. Honestly didn't know what to do. I called Canon and discussed with them the issue. Not surprised to hear they need me to send it in and they can make the call. As I mentioned, the dust (or even the crack I saw) does not seem to impact my images and I more or less consider dust to be part and parcel of a long lens over time. It's the crack that I saw that concerns me more. I have been back for a few days from my road trip and looked under a flashlight and other lights and cannot see the crack. I know it's there. It was very clear. I'm pretty sure it was deep and not the surface - which I have protected with a filter. I'm also very sure it has never even had a low impact. It's pretty protected in my bag and I wear it - shamelessly never use a tripod. I could move on and figure it was an optical illusion on my part, but it does make me wonder why my shots are not as sharp as they were in the beginning. Anyhow, I appreciate all the feedback.

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OhThatGrl

John Sheehy Forum Pro • Posts: 23,694
Re: Canon 100-400mm f/4.5-5.6 USM IS II
1

ohthatgirl wrote:

I love DPReview and how helpful everyone is. Honestly didn't know what to do. I called Canon and discussed with them the issue. Not surprised to hear they need me to send it in and they can make the call. As I mentioned, the dust (or even the crack I saw) does not seem to impact my images and I more or less consider dust to be part and parcel of a long lens over time. It's the crack that I saw that concerns me more. I have been back for a few days from my road trip and looked under a flashlight and other lights and cannot see the crack. I know it's there. It was very clear. I'm pretty sure it was deep and not the surface - which I have protected with a filter. I'm also very sure it has never even had a low impact. It's pretty protected in my bag and I wear it - shamelessly never use a tripod. I could move on and figure it was an optical illusion on my part, but it does make me wonder why my shots are not as sharp as they were in the beginning. Anyhow, I appreciate all the feedback.

It would be a shame to send the lens in for nothing, if it's out of warranty. Make sure there's really something wrong with it, and you haven't accidentally changed settings on the camera or lens since you last got the sharp images.

For example, you can't recompose with AIServo and one-point AF, IS may be set wrong on the lens, an accidental micro-adjustment may have been made. Does AF work right in live view?

OP ohthatgirl Junior Member • Posts: 28
Re: Canon 100-400mm f/4.5-5.6 USM IS II

I'll do some testing and let you know. Thanks for the suggestions.

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OhThatGrl

photonius Veteran Member • Posts: 6,895
Re: Canon 100-400mm f/4.5-5.6 USM IS II

ohthatgirl wrote:

I love DPReview and how helpful everyone is. Honestly didn't know what to do. I called Canon and discussed with them the issue. Not surprised to hear they need me to send it in and they can make the call. As I mentioned, the dust (or even the crack I saw) does not seem to impact my images and I more or less consider dust to be part and parcel of a long lens over time. It's the crack that I saw that concerns me more. I have been back for a few days from my road trip and looked under a flashlight and other lights and cannot see the crack. I know it's there. It was very clear. I'm pretty sure it was deep and not the surface - which I have protected with a filter. I'm also very sure it has never even had a low impact. It's pretty protected in my bag and I wear it - shamelessly never use a tripod. I could move on and figure it was an optical illusion on my part, but it does make me wonder why my shots are not as sharp as they were in the beginning. Anyhow, I appreciate all the feedback.

Well, if you cannot see the crack with a flashlight, and don't have an impact on the images, then I suspect it's not a crack. A crack in glass should be pretty obvious with a flashlight. Sometimes a fine line/smear of grease (say if you clean your front element, or filter), can look like a crack, but it is not. Since it is on the inside, as others have said, maybe something else is in there, a tiny spider thread, some dust fiber, which as moved again so you don't see it anymore. Since you saw it in extreme brightness (sunlight), maybe it was just some reflection of a lens edge on a glass element? It's difficult to say what it is, but it does not seem to have the characteristics of a crack.

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