# Canon 100-400 L



## stinson222 (Feb 4, 2012)

Hi I'm a newbie here. I have been reading through some of your discussions, and I was hoping for some help.
I have a Canon 100-400 L lens that is less than a year old. I shoot with it using a Rebel Xsi.
Recently, I had to send the lens in to Canon under warranty because the AF was not working properly. It was front focusing rather badly.
When I got the lens back, they said they replaced the zoom mechanism and slides, and all internal mountings , readjusted the optics, cleaned and tested.
Now,, it appears that the IS system is not working. I never get TACK sharp pictures with this lens, at 100% crop shooting at 400mm f8,, but now,, I only get "pretty sharp" if I have the camera solidly mounted to a sturdy tripod and shoot with a remote shutter release.. Hand held at all is not possible. Even if the tripod is not stable,, I get some distortion.
I am wondering what the possibility is that now that the lens has been worked on ,, that the IS is not functioning.??
does that seem reasonable?.. 
Can you give me some advice on testing it?
I have been trying to test it on my own, but have had mixed results. I even shot at at yard stick ruler at 50 feet away from a tripod and remote release, and one of the two shots I took was sharp, and the other not so sharp., very confusing.


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## ferdi (Feb 4, 2012)

The 100-400L emits a whirring noise when IS is active.
Can you hear it when half-pressing the shutter button?


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## stinson222 (Feb 4, 2012)

No noise that I can tell,,, I am an old guy,, so I don't often hear very well, at least that is what my wife says,, lol.
I had her listen too, and I switched the AF button off and on,, nothing as far as any noise that we could hear


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## Kernuak (Feb 4, 2012)

You can normally also see a slight jerk when the IS first activates. However, I have never found the IS on the 100-400 to be overly useful, but then it is the first generation, with only two stops and it needs to be switched off when on a tripod, as it isn't able to detect tripod use, leading to the opposite effect to what you want.


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## stinson222 (Feb 5, 2012)

I guess the most interesting thing is that this lens worked GREAT last summer at several air show.
I think that the IS is not doing anything at this point however.
The weather here in Minnesota has been too crummy to get out to shoot very much, so testing is has been a issue.
I may just take it back to the dealer that sent it in for Focus repair, and ask them if they can test it.

This lens has been great to shoot aircraft in the air at various shows, and I do agree that the AF is a bit slow and hunts at times. But. I believe that the IS is not working at all. The AF does seem to act differently on AI SERVO, or AI Focus.
When it was set to AI Servo,, it was worse ,, on the focus,, than on AI Focus.


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## Mt Spokane Photography (Feb 5, 2012)

stinson222 said:


> Hi I'm a newbie here. I have been reading through some of your discussions, and I was hoping for some help.
> I have a Canon 100-400 L lens that is less than a year old. I shoot with it using a Rebel Xsi.
> Recently, I had to send the lens in to Canon under warranty because the AF was not working properly. It was front focusing rather badly.
> When I got the lens back, they said they replaced the zoom mechanism and slides, and all internal mountings , readjusted the optics, cleaned and tested.
> ...



I'd say it sounds like a problem you are turning off the IS when on a tripod? Don't leave it on, when the lens is motionless, the IS tends to drift and can cause blurring.

That said, I use mine hand held exclusively. I also use higher shutter speeds when I can. Using it at 1/100 sec handheld will not be tack sharp, the IS is not that good. Some images will be sharp and others not.

The rule of thumb for shutter speed I use is 1/ 2X focal length X 1.6 on a crop camera without IS or at 400mm and IS off, 1/1200 sec. With IS on, at 400mm, shots 2 stops slower at 1/320 should be sharp.

This one is handheld at 400mm 1/320 sec shutter with my 1D MK III. IS is on.


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## stinson222 (Feb 5, 2012)

Nice shot,, and Thanks,, I will give your suggestions a try.


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## cfargo (Feb 5, 2012)

With the Canon 100-400 L, you can get good ones or bad ones. Just yesterday I compared my 100-400 against my friends on the same camera in the same lighting with the same exposure and both set to approximately 300mm. I did this while doing some AF Micro Adjusting for a him. My lens is too soft to AF Micro Adjust as you can't find its sharpest point his on the other hand isn't bad at all . When I do AF Micro Adjusting, I convert the images to embossed which helps you see what is sharp and what isn't.


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## cfargo (Feb 18, 2012)

cfargo said:


> With the Canon 100-400 L, you can get good ones or bad ones. Just yesterday I compared my 100-400 against my friends on the same camera in the same lighting with the same exposure and both set to approximately 300mm. I did this while doing some AF Micro Adjusting for a him. My lens is too soft to AF Micro Adjust as you can't find its sharpest point his on the other hand isn't bad at all . When I do AF Micro Adjusting, I convert the images to embossed which helps you see what is sharp and what isn't.



I ended up sending my soft 100-400 in to Canon for repair and they fixed it. I'm not too happy with myself as I should have done this back in 1999 when I first bought it instead of living with the softness. I now have a very usable lens just in time for them to come out with a replacement.  

Thanks Canon for making my lens sharp (under warranty)!


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