# What am I doing wrong? Is the lens back/front focusing?



## sanjosedave (Oct 1, 2019)

Canon 7DII with Canon 100-400mm II Tripod, ISO 640, 400mm, f5.6, 1/2000

Bird 1 pic shows the focus point

Bird 2 pic shows an out of focus bird based on the focus point in bird 1

What am I doing wrong?

Thanks


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## unfocused (Oct 1, 2019)

Doesn't look like a back/front focusing problem. Everything is quite far out of focus. Is this consistently happening or is it a one-off? Looks to me like the autofocus completely missed on this one. Maybe the dark bird against a dark background caused problems.


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## neuroanatomist (Oct 1, 2019)

Can you try a simple test? Pick a static subject with some depth and good contrast (red wine in a glass on a dining table comes to mind, probably because that’s in front of me), shoot it with both regular AF and in live view, and compare the results.


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## Mt Spokane Photography (Oct 2, 2019)

neuroanatomist said:


> Can you try a simple test? Pick a static subject with some depth and good contrast (red wine in a glass on a dining table comes to mind, probably because that’s in front of me), shoot it with both regular AF and in live view, and compare the results.


Yes, test autofocus where you control all the variables. High contrast subject, lots of light, stable tripod, high shutter speed, for a 400mm shot, turn off IS and use 1/800 or faster shutter.

As Neuro said, compare live view and phase detect. Then, turn on the IS and take shots with both live and phase detect again, the results might point you in the right direction for further tests.

Dust on the AF sensor can play havoc with AF, there are many possibilities, but first do the basic tests to verify the problem.


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## Deleted member 378664 (Oct 2, 2019)

sanjosedave said:


> Canon 7DII with Canon 100-400mm II Tripod, ISO 640, 400mm, f5.6, 1/2000
> 
> Bird 1 pic shows the focus point
> 
> ...


Did you turn off the IS on the lens?
This does not look like an AF issue to me. Rather an unsharpness caused by the IS.

Frank


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## Kit. (Oct 2, 2019)

Look at the image of the reflection in the bird's eye. It doesn't look unsharp; it looks motion-blurred.


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## unfocused (Oct 2, 2019)

Kit. said:


> Look at the image of the reflection in the bird's eye. It doesn't look unsharp; it looks motion-blurred.


I thought about that, but he said it was shot at 1/2000 of a second, said he was using a tripod and the bird is standing still.


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## Kit. (Oct 2, 2019)

unfocused said:


> I thought about that, but he said it was shot at 1/2000 of a second, said he was using a tripod and the bird is standing still.


It might be helpful to see the Exif of the original image. If we trust the provided data, it looks like an IS-related problem.


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## Mt Spokane Photography (Oct 2, 2019)

Kit. said:


> It might be helpful to see the Exif of the original image. If we trust the provided data, it looks like an IS-related problem.


Yes, 1/2000 with IS on can sometimes be a issue. A test with both IS off and on but similar settings might pin it down to the use of IS with a high shutter speed, or even a IS issue.


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## Graphic.Artifacts (Oct 2, 2019)

My 7D mark II would drop a clunker like that every once in a while if I was shooting servo AF at 10 FPS. I always figured it was due to the mirror not getting settled between frames and the AF module getting a false read on the subject.


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## dcm (Oct 2, 2019)

Another possibility. I noticed a couple of other things in the view, such as an object off to the left. You didn't describe the environment you are shooting in, but I've had the situation where another smaller object that was nearer passed through the AF point, causing AF to shift. By the time the shutter released it had moved, but the focus is set near which causes everything behind to be out of focus. I was fortunate to spot the in-focus fly off in the margin. With a really tight shot it may be out of frame. This depends on how you have your AF tuned.


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## Deleted member 378664 (Oct 3, 2019)

sanjosedave said:


> Canon 7DII with Canon 100-400mm II Tripod, ISO 640, 400mm, f5.6, 1/2000
> 
> Bird 1 pic shows the focus point
> 
> ...


could also be an effect of scintillation with different temperated layers of air between the object and your lens. E.G. when you are shooting from a warm interior into a colder ambient.


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## Focus Pocus (Oct 4, 2019)

I don't know if it's the same, but I have experienced something similar on my 70D and 5DIV. I think 5DIII worked correctly, but it's possible that I didn't put it into same conditions. Lenses: 85/1.8, then later 135/2L.

When lighting is a bit lower, for example in a shade an hour before sunset, and when trying to capture an animal with fur, for example a gray cat (target being its head), camera may front-focus by a lot. No seeking, quick lock, but completely off. There wouldn't be anything near used focus points that is in focus. This post sounds a lot like it. I found one post mentioning issues with furry animals, but that's it.

I just took this as a Canon AF limitation, initially thinking it is due to a lower level body and older lenses. Never had success reproducing this in a controlled environment. Maybe I should buy a cat, or at least a plushie...


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## SecureGSM (Oct 5, 2019)

sanjosedave said:


> Canon 7DII with Canon 100-400mm II Tripod, ISO 640, 400mm, f5.6, 1/2000
> 
> Bird 1 pic shows the focus point
> 
> ...


i suggest reading in its entirety including comments. I hope it explains.






Canon EOS-7D Mark II/100-400 II Warning « Arthur Morris/BIRDS AS ART







www.birdsasart-blog.com


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## Valvebounce (Oct 6, 2019)

Hi SecureGSM. 
I’m not sure what it was supposed to explain, but as a 7DII + 100-400 user I thought I would read it, the whole thread is built on the mistake that the picture was taken with a 7DII, it was not, it was taken with a 1Dx (for which Art Morris apologises!). 
Art then goes on to say that camera / lens shake is a factor of the square of the focal length, my interpretation of this (Art doesn’t clarify his statement) is that rather than a shutter speed of 1/focal length he believes that we should use 1/focal length ^2 (squared)! 
For the effective focal length of 896mm that he gives, this would require a shutter speed of 1/802,816th of a second! I suspect that Art is not an idiot, just that he does not understand the concept of squared, however it leaves me with little confidence in his post. 
It also leaves me with the suspicion that he may have been confusing the recent hypothesis that a value of 1/2x focal length is required to prevent camera shake on higher density sensors including the 7DII. 

Cheers, Graham. 



SecureGSM said:


> i suggest reading in its entirety including comments. I hope it explains.
> 
> 
> 
> ...


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## unfocused (Oct 6, 2019)

Given that the OP seems to have made his post and then moved on without responding or providing any additional information, I think we should all move on as well.


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## YuengLinger (Oct 11, 2019)

Valvebounce said:


> Hi SecureGSM.
> I’m not sure what it was supposed to explain, but as a 7DII + 100-400 user I thought I would read it, the whole thread is built on the mistake that the picture was taken with a 7DII, it was not, it was taken with a 1Dx (for which Art Morris apologises!).
> Art then goes on to say that camera / lens shake is a factor of the square of the focal length, my interpretation of this (Art doesn’t clarify his statement) is that rather than a shutter speed of 1/focal length he believes that we should use 1/focal length ^2 (squared)!
> For the effective focal length of 896mm that he gives, this would require a shutter speed of 1/802,816th of a second! I suspect that Art is not an idiot, just that he does not understand the concept of squared, however it leaves me with little confidence in his post.
> ...



Good catch. I think he simply meant double the focal length, just guessing. Not a defense, but from what I understand, he was often sleep deprived when writing blog entries at that time in 2015. Like two hours a night for days or weeks at a time. Also wonder why he never fixed the error.


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## AlanF (Oct 11, 2019)

YuengLinger said:


> Good catch. I think he simply meant double the focal length, just guessing. Not a defense, but from what I understand, he was often sleep deprived when writing blog entries at that time in 2015. Like two hours a night for days or weeks at a time. Also wonder why he never fixed the error.


The idea behind it is that the amount of shake goes up faster than the focal length, possibly as the focal length squared, for the very long focal lengths, but it doesn't start at zero. The way this translates into practice is that say the shutter speed necessary at 400mm is 1/400s, then at 800mm it is 1/(4x400)s not 1/(2x200)s. Frankly, 1/400s is not good enough for a 400mm lens with IS on a high density sensor when you start serious cropping.


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## YuengLinger (Oct 11, 2019)

AlanF said:


> The idea behind it is that the amount of shake goes up faster than the focal length, possibly as the focal length squared, for the very long focal lengths, but it doesn't start at zero. The way this translates into practice is that say the shutter speed necessary at 400mm is 1/400s, then at 800mm it is 1/(4x400)s not 1/(2x200)s. Frankly, 1/400s is not good enough for a 400mm lens with IS on a high density sensor when you start serious cropping.


That makes more sense!


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## stevelee (Oct 11, 2019)

With the 100-400L II, I recently shot the moon and Jupiter. With IS on at 400mm, handheld shots I took at 1/320 second looked good enough to post one of them, as I did in the moon section. I cropped it and posted a 100% pixel peep. I didn’t add any extra sharpening, and just did a bit of highlight recovery in ACR. My camera won‘t shoot at 1/160,000 second anyway.


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## SecureGSM (Oct 12, 2019)

stevelee said:


> My camera won‘t shoot at 1/160,000 second anyway.


How come? Have it checked by Canon


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## AlanF (Oct 12, 2019)

stevelee said:


> With the 100-400L II, I recently shot the moon and Jupiter. With IS on at 400mm, handheld shots I took at 1/320 second looked good enough to post one of them, as I did in the moon section. I cropped it and posted a 100% pixel peep. I didn’t add any extra sharpening, and just did a bit of highlight recovery in ACR. My camera won‘t shoot at 1/160,000 second anyway.


I sometimes take acceptable shots at 1/20s hand held, frequently at 1/100s, and use 1/250s in Tv in dark conditions at 400mm. But, shake leads to a softening, which you don't see as movement but as a slight blurring, and you do see when cropping high resolution sensors. This is nicely illustrated in shots of a $ bill in http://arihazeghiphotography.com/blog/focus-micro-adjustment-is-it-always-needed/
I like to be above 1/400s, and preferably above 1/1000s to get that real sharpness.


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## stevelee (Oct 12, 2019)

AlanF said:


> I sometimes take acceptable shots at 1/20s hand held, frequently at 1/100s, and use 1/250s in Tv in dark conditions at 400mm. But, shake leads to a softening, which you don't see as movement but as a slight blurring, and you do see when cropping high resolution sensors. This is nicely illustrated in shots of a $ bill in http://arihazeghiphotography.com/blog/focus-micro-adjustment-is-it-always-needed/
> I like to be above 1/400s, and preferably above 1/1000s to get that real sharpness.


Interesting. While it illustrates your point, I see less difference between the two than I would have expected.

Obviously one needs to balance concerns of shake, high ISO noise, DOF, etc. I was surprised that the best compromise I found for the moon shots were the ones taken at 1/320.


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## AlanF (Oct 12, 2019)

stevelee said:


> Interesting. While it illustrates your point, I see less difference between the two than I would have expected.
> 
> Obviously one needs to balance concerns of shake, high ISO noise, DOF, etc. I was surprised that the best compromise I found for the moon shots were the ones taken at 1/320.


True. High iso will lead to noise that leads to loss of sharpness. So, there is always a balance. I find a shutter speed of about 1/300 good for moon shots, but they are not cropped nearly as much as many bird shots and there is less lunar fine structure and sharp edges than in feathers. Fortunately, DOF is not too much of a problem in moon shots.


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## stevelee (Oct 13, 2019)

AlanF said:


> True. High iso will lead to noise that leads to loss of sharpness. So, there is always a balance. I find a shutter speed of about 1/300 good for moon shots, but they are not cropped nearly as much as many bird shots and there is less lunar fine structure and sharp edges than in feathers. Fortunately, DOF is not too much of a problem in moon shots.


Focusing is an issue for me. Autofocus might work, or it might fish around looking at a mostly black sky. I can’t focus visually while holding a long lens over my head. So I set it to what looks like infinity on the scale and try to remember what the line means. So I feel like I need to stop down a bit to give me margin of error and maybe hit a good spot for the lens.

The exposure issue was that I needed to get Jupiter to show up but not blow the sunny side of the moon out too bad. Fortunately, they weren’t flying by too fast, so I could do a lot of bracketing manually. While I can enjoy other people’s shots, I don’t have any interest in shooting BIF myself.


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