# My 100-400 is Not focusing consistently specialy when the light is not optimal



## rpt (Jun 12, 2012)

My 100-400 is not focusing consistently specialy when the light is not optimal. I have done the MA three times now and I am not happy with the results. There does not seem to be a consistent behaviour if the light is not optimal. If I shoot a subject in sunlight, it is sharp and focuses correctly. When I shoot say a hawk in a tree with the sun at 11 o'clock and the sky seen through the branches, although the bird is clear and I shot the bird with centre point focus (and I am quite still - shot over 3000 shots of black kites with my rebel and the same lens) and I can swear I did aim right  the camera somehow does not focus on the bird...

When I shoot with my 24-105, the camera focuses correctly. So the camera does not seem to be at fault. It just occurred to me that I should probably clean the contacts. However, if that does not fix the problem, I am thinking of taking the lens to the Canon repair centre and have them look at it. The lens is almost 5 years old and has never been serviced.

Does anybody have any other suggestions? Has anybody experienced anything similar?

Look forward to your advice. 

Thanks in advance.


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## Mt Spokane Photography (Jun 12, 2012)

A rebel can be difficult to use for focusing on tough subjects, in your case, it might also be camera related.

You can check the lens by mounting it on a tripod and repeatedly focusing on a target, resetting the focus to mfd or infinity before each shot. All lenses will have some variance, and occasionally, totally miss focus, but it should focus accurately most of the time.

lenses can have internal issues that cause erratic focusing. If its new, exchange it, otherwise, have it checked by Canon.


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## rpt (Jun 12, 2012)

Mt Spokane Photography said:


> A rebel can be difficult to use for focusing on tough subjects, in your case, it might also be camera related.
> 
> You can check the lens by mounting it on a tripod and repeatedly focusing on a target, resetting the focus to mfd or infinity before each shot. All lenses will have some variance, and occasionally, totally miss focus, but it should focus accurately most of the time.
> 
> lenses can have internal issues that cause erratic focusing. If its new, exchange it, otherwise, have it checked by Canon.



My rebel shots with the 100-400 were good but that was 2 years back. Have not shot much with the 100-400 for the last few years. Sorry, did not mention this problem is with the 100-400 on my 5D3. AFMA was done with each setting that I tested, I de-focused and took 3 shots with the 2 sec timer (and naturally, the camera was on the stand). The 5D3 and 24-105 focuses correctly so I believe it is the 100-400 and not the 5D3...


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## lol (Jun 12, 2012)

Is the AF of the 5D3 picking something other than what you think? Even if you're only using the centre point, it's effective area can be bigger than you think. This is particularly troublesome if the subject is relatively small or low in contrast compared to something in the background.


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## rpt (Jun 12, 2012)

lol said:


> Is the AF of the 5D3 picking something other than what you think? Even if you're only using the centre point, it's effective area can be bigger than you think. This is particularly troublesome if the subject is relatively small or low in contrast compared to something in the background.



Is it even bigger than the outer square? The black outer square seemed smaller than the bird...

Thanks for replying.


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## Kernuak (Jun 12, 2012)

Have you tried playing around with different focusing and tracking settings? From experience with teh 7D, which has a less complex system, when the subject is small in the frame, spot focus often gives better results. If you add in the different tracking scenarios, then you may need to experiment to get the best out of the focus system on the 5D MkIII. What works wiht the 24-105 may not work with the 100-400, because the scenario may be different (at the very least, the subject will be further away). Also bear in mind, that with a longer telephoto, you are compressing the atmosphere between camera and subject, so you will get greater problems with pollution affecting image quality. I spent quite some time trying to understand why some days, I just couldn't get a sharp shot with my 7D and 300 f/2.8+1.4x extender, when other days the combination was sharp. It turned out it was due to the compression of heat haze and moisture, as on each occasion, the subject was low to the ground and there had been mist earlier in the day.


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## Marsu42 (Jun 12, 2012)

lol said:


> Is the AF of the 5D3 picking something other than what you think? Even if you're only using the centre point, it's effective area can be bigger than you think. This is particularly troublesome if the subject is relatively small or low in contrast compared to something in the background.



I see you've got many camera bodies, so maybe you can answer this, because I am experiencing exactly what you are saying on my 60d: 

If the spot I want to focus on is very tiny inside the af frame (like focusing on the eye of an animal with side eyes looking towards me) and large aperture, it's much better to shoot, refocus, shoot, refocus, ... than to rely on the af getting it right.

Is this "too large af rectangle" problem any better on the 5d3 (or 5d2 if we're at it) in comparison to an aps-c like my 60d?


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## neuroanatomist (Jun 12, 2012)

rpt said:


> Is it even bigger than the outer square?



Yes, it is. Here's an approximation of the standard and spot AF compared to the little black box in the viewfinder for the 7D (relative size is likely equivalent on the 5DIII):


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## rpt (Jun 13, 2012)

Kernuak said:


> Have you tried playing around with different focusing and tracking settings? From experience with teh 7D, which has a less complex system, when the subject is small in the frame, spot focus often gives better results. If you add in the different tracking scenarios, then you may need to experiment to get the best out of the focus system on the 5D MkIII. What works wiht the 24-105 may not work with the 100-400, because the scenario may be different (at the very least, the subject will be further away). Also bear in mind, that with a longer telephoto, you are compressing the atmosphere between camera and subject, so you will get greater problems with pollution affecting image quality. I spent quite some time trying to understand why some days, I just couldn't get a sharp shot with my 7D and 300 f/2.8+1.4x extender, when other days the combination was sharp. It turned out it was due to the compression of heat haze and moisture, as on each occasion, the subject was low to the ground and there had been mist earlier in the day.



Since the bird was sitting still, I shot it in 1 shot mode and not the servo settings. Hence I did not experiment with any of the other focusing settings. I did my usual acquire focus, AF and recompose. It worked for objects getting good light.

Also the bird was about 25 mtr from me in a tree and I could not see any visible pollution or thermals. Also it was probably about 7 mtr up...

Thanks for the response. If anything else strikes you do share.


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## rpt (Jun 13, 2012)

Marsu42 said:


> lol said:
> 
> 
> > Is the AF of the 5D3 picking something other than what you think? Even if you're only using the centre point, it's effective area can be bigger than you think. This is particularly troublesome if the subject is relatively small or low in contrast compared to something in the background.
> ...



I was focusing on the back of the bird. Not the eye - so that should not have been it. As neuro points out below, the spot is more a blotch! What lens do you use with the 60D where you are experiencing this?

Wen you say "shoot, refocus, shoot, refocus,..." do you mean manual refocus?


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## rpt (Jun 13, 2012)

neuroanatomist said:


> rpt said:
> 
> 
> > Is it even bigger than the outer square?
> ...



Thanks. So I guess I will do some testing with my 300D this Saturday.


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## keithfullermusic (Jun 13, 2012)

I have this lens and a 50D. I had to MA the you know what out of it. Still, when fully extended and objects are far away I have to shoot at f/7.1 or smaller. If I do, the images are sharp as can be. If I don't, they are usually blurry. When using this lens I usually start at f/7.1 and ISO 400 then go from there. Hope that helps.


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## LSV (Jun 13, 2012)

I also have this lens and I'm a newbie, so please forgive if my suggestion is simple. Have you switched the setting on the lens to 1.8m-infinity or 6.5m-infinity as appropriate for the situation?


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## rpt (Jun 13, 2012)

keithfullermusic said:


> I have this lens and a 50D. I had to MA the you know what out of it. Still, when fully extended and objects are far away I have to shoot at f/7.1 or smaller. If I do, the images are sharp as can be. If I don't, they are usually blurry. When using this lens I usually start at f/7.1 and ISO 400 then go from there. Hope that helps.



Thanks. I will shoot at f8 or f11 and check.


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## rpt (Jun 13, 2012)

LSV said:


> I also have this lens and I'm a newbie, so please forgive if my suggestion is simple. Have you switched the setting on the lens to 1.8m-infinity or 6.5m-infinity as appropriate for the situation?



Yes, it is set at 6.5m-infinity ans the bird was far away - 25m or so. Thanks. Hope you are enjoying your lens


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## rpt (Jun 13, 2012)

All, Thanks for your inputs. It seems the last round of AFMA has improved things. Also I realize shooting a bird behind leaves and branches of a tree when the bird is in poor light AND there is a breeze confuses the AF system. A hornbill came visiting today so I snapped it. Here is a 100% crop of the head. Would appreciate comments. May be I need to tweak the AFMA a bit? The shot settings were:
1/400, 5.6, Auto ISO which went to 500. I guess I would have set the f-stop to 8 if I were really taking the shot and not testing the lens


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## canon816 (Jun 13, 2012)

Its soft. If you are really struggling with the AFMA adjustment and want to take the guesswork out of it you might consider FoCal by Reiken. His program will calibrate your MA point and I have found it to be extremely useful and consistent. I used to fool around with my MA as much as aperture it seems, but after running FoCal I have left it alone and consistently get tack sharp images. A much higher percentage of my shots are in focus now.

I have calibrated all my lenses to both my bodies now. 

(I am in no way affiliated with FoCal, I am just an extremely happy customer.)

Also, you may consider shooting at a faster shutter speed and smaller aperture to see what you end up with. The 5D3 will give you very clean images up to 2000 ISO and keepers up to 6400 ISO. There is really no need to shoot at 500ISO especially when you are in lower light. Get your shutter speed up to 1/800 or 1/1000 and shoot at a smaller aperture. F5.6 can be fairly soft on this lens but if you shoot at f/8 through f/11 you will get much sharper images. (At a cost of shutter speed of course, but with the 5D3 just bump up the ISO and fire away)

Some people love this lens and some people hate it, but you can stack the deck in your favor if you pay attention to the camera settings. IMHO it is a great lens.


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## rpt (Jun 13, 2012)

canon816 said:


> Its soft.


I agree. I have been struggling and this is the best so far. Looking for AFMA tools...



> If you are really struggling with the AFMA adjustment and want to take the guesswork out of it you might consider FoCal by Reiken. His program will calibrate your MA point and I have found it to be extremely useful and consistent. I used to fool around with my MA as much as aperture it seems, but after running FoCal I have left it alone and consistently get tack sharp images. A much higher percentage of my shots are in focus now.
> 
> I have calibrated all my lenses to both my bodies now.


I am looking at FoCal too. Did you get the standard or plus? The problem is they say they need 3GB of ram and I have 2  so cant buy it till the upgrade (and it is an old laptop  )




> (I am in no way affiliated with FoCal, I am just an extremely happy customer.)


Lol! I believe you.





> Also, you may consider shooting at a faster shutter speed and smaller aperture to see what you end up with. The 5D3 will give you very clean images up to 2000 ISO and keepers up to 6400 ISO. There is really no need to shoot at 500ISO especially when you are in lower light. Get your shutter speed up to 1/800 or 1/1000 and shoot at a smaller aperture. F5.6 can be fairly soft on this lens but if you shoot at f/8 through f/11 you will get much sharper images. (At a cost of shutter speed of course, but with the 5D3 just bump up the ISO and fire away)


Yes, that is what I wrote - since it was a test, I left the F-stop at 5.6. Otherwise I would have done a F8 or even 11.




> Some people love this lens and some people hate it, but you can stack the deck in your favor if you pay attention to the camera settings. IMHO it is a great lens.


I love this lens. I have shot great pics of black kites nesting. I have no doubt once I nail the AFMA I will be good. The 5D3 is great!


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## canon816 (Jun 13, 2012)

I recommend the pro version. At $120 it is still a bargain but will give you access to the analysis and reports and will give you more tools and parameters for testing should you be interested in some of those features.

You get a nice graph with the anaysis showing you what the IQ is across the MA range and will alert you to any severe abnormalities within the body or lens. (I.E your shutter is bunk or the lens is really off and further servicing is required by Canon to correct for the issues)

Email FoCal to see if the RAM will be an issue. Reiken emails me back personally when I email them.

The service is great. You may be good to go as is.

Good luck.


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## rpt (Jun 13, 2012)

canon816 said:


> I recommend the pro version. At $120 it is still a bargain but will give you access to the analysis and reports and will give you more tools and parameters for testing should you be interested in some of those features.
> 
> You get a nice graph with the anaysis showing you what the IQ is across the MA range and will alert you to any severe abnormalities within the body or lens. (I.E your shutter is bunk or the lens is really off and further servicing is required by Canon to correct for the issues)
> 
> ...



Ok, I'll keep that in mind. I already left them a message. Thanks!


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## canon816 (Jun 13, 2012)

Good luck.

There is a similar discussion on another thread about FoCal right now.

http://www.canonrumors.com/forum/index.php?topic=7287.0


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## keithfullermusic (Jun 14, 2012)

i saw that you shot that wide open. i know that it is a must sometimes because of light, but seriously try f/7.1 or f/8 if possible when you're at 400mm. i wasn't happy with this lens when i first got it, but after i started shooting at f/7.1 i fell in love with it.

one thing to remember, while its by no means a cheap lens, it is like 1/10th of the cost as those other super telephotos, so shooting at smaller apertures is usually the only way to get shots that are as clear as its much more expensive big brothers.


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## rpt (Jun 14, 2012)

canon816 said:


> Good luck.
> 
> There is a similar discussion on another thread about FoCal right now.
> 
> http://www.canonrumors.com/forum/index.php?topic=7287.0


Yes, I saw it yesterday. I will read through it. Thanks. I intend to get FoCal soon and get the guesswork out of all this.




keithfullermusic said:


> i saw that you shot that wide open. i know that it is a must sometimes because of light, but seriously try f/7.1 or f/8 if possible when you're at 400mm. i wasn't happy with this lens when i first got it, but after i started shooting at f/7.1 i fell in love with it.
> 
> one thing to remember, while its by no means a cheap lens, it is like 1/10th of the cost as those other super telephotos, so shooting at smaller apertures is usually the only way to get shots that are as clear as its much more expensive big brothers.


That is my task this weekend. Need to keep my day job for this expensive hobby 

No cheap lenses for me. I waited 2 years to put money together to get this lens rather than the 70-300...


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## Mt Spokane Photography (Jun 14, 2012)

rpt said:


> No cheap lenses for me. I waited 2 years to put money together to get this lens rather than the 70-300...


 
Did you buy the lens used? you mentioned it was 5 years old. If its erratic when you test it with FoCal, thats a hint that it needs some service.


I really only use mine at or near 400mm, but being able to telescope to a short length is handy. I do not have any low light images with my 100-400mm L..


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## keithfullermusic (Jun 14, 2012)

I have quite a few blog posts where I used the 100-400, but here is one that I think really shows off this lens's capabilities. 

http://www.k2focus.com/blog/pelicans-2/


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## serendipidy (Jun 14, 2012)

Keith...amazing photos! I really liked the last few closeups. I love my new 100-400L. Thanks for posting those shots.


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## rpt (Jun 14, 2012)

Mt Spokane Photography said:


> rpt said:
> 
> 
> > No cheap lenses for me. I waited 2 years to put money together to get this lens rather than the 70-300...
> ...


No, the lens was brand new. I just bought FoCal Pro today and so will know the verdict in a few days...

The snap is lovely!


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## rpt (Jun 14, 2012)

keithfullermusic said:


> I have quite a few blog posts where I used the 100-400, but here is one that I think really shows off this lens's capabilities.
> 
> http://www.k2focus.com/blog/pelicans-2/


The pics are fab! I love the W wing when it dives! I wonder if there are any prototype fighters/projectiles using this wing configuration...


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## rpt (Jun 14, 2012)

serendipidy said:


> Keith...amazing photos! I really liked the last few closeups. I love my new 100-400L. Thanks for posting those shots.


Yes, weren't those fabulous? I am sure you will have lots of fun with the 7D and the 100-400.


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