Help with the Canon 100-400mm EF f4.5-5.6L IS USM Lens

[Clive]

Hello

I am new to photography and I purchased the above lens, I am using a Canon 550D Camera and finding it difficult to get a clear image in AF mode see image 1. I have also taken the same photo using a Canon AF75-300mm with a Vivitar 2x converter which is image 2. Both are taken using a tripod. It may be something simple and just me
All help would be much appreciated.

[mstrozewski]

What is the shutter speed on both of the images? Also - even though a long lens is on a tripod, if the TP is not steady or there is some wind, you will get some movement. That particular L lens is nice and works quite well if done correctly.

[Snarkbyte]

Looks like camera shake to me, and since you were shooting from a tripod, I suspect you had IS turned on. I would try the shot again, using a tripod as before, but with IS turned off.

[SteveK]

Hi Clive,

I'm no expert and I don't have that lens.
But did you have the Image Stabilization "IS" turned OFF???
Most IS lenses require it to be off when using a tripod

Steve

[jeeperman]

Also, give the tripod a little help and weight it down. I hang my bag and gear from the center, it can make a lot of difference with a big lens.

[rpcrowe]

It does look like camera shake or perhaps IS feedback. Any or all of the following parameters need to be addressed:

* What kind of tripod were you shooting with? Was it stable enough for this lens?
* Did you have the camera body attached to the tripod head or were you using the tripod ring?
* What was your shutter speed?
* If the shutter speed was very slow, did you use mirror lock-up / remote or timed release?
* Did you have IS turned off? Older IS systems must be turned off when tripod mounted.

I am curious that the ball in image #2 (75-300mm + 2x TC) is smaller than the ball in image #1 (100-400mm) what were the focal lengths that you used.

Finally, do you know of anyone who owns a Canon DSLR camera? It might help to try the lens on another body!

[Steve S]

If your trying to use a converter with that lens, autofocus won't work. Is autofocus even turned on???


A couple simple things it could be.

[Splatsworth]

Hi Clive
As others have said, is IS switched on?
Was it windy, did you use a cable release?
Did you use the 2x convertor with the lens as AF doesn't work with a 2x convertor

Trev

[Clive]

Hi
speed is 1/800 sec. Autofocus was switched on and IS was switched on, I was using a SLIK F630 tripod which was attached to the lens as opposed to the camera body, no converter was used. Will try same shot with IS off and see if that helps.

Thanks

[Jim B.]

Also,when you do use the IS,you need to give it a second or so to engage and stabilize.
You want to 1/2 press the shutter button, pause then full press to take the shot.

[Geoff F]

There isn't a lot of contrast in that scene so it is possible that the autofocus simply failed to 'lock on' successfully.

Try again with a better scene, following all the previous advice and see what happens.

It is always possible that you do have a faulty lens so some careful tests are certainly worth doing.

The shot with the 75-300 plus x2 converter is surprising good for such a combination, so your camera body must be OK. Did you manually focus for this shot?

[Clive]

I have tried other scenes and not much better, I have now tried the same shot with the IS switched off but to no avail. I again use the alternative lens and am getting good results I am now wondering if the lens is faulty.

[Jim B.]

Did you buy the lens new or used? Sounds like a definite problem.Are you getting focus confirmation on the camera?

[Clive]

I bought the lens new and the camera is registering the image as being in focus.

[Colin Southern]

Any filters on the lens? Rear element clean?

[Clive]

Camera and lens are all clean, lens does have a CPL filter
Thanks

[Jim B.]

Okay,one more thing to try.Put on a tripod,aim at something with good contrast,switch the lens to manual focus.1/2 press the shutter button and use the fine focus ring.When you hit focus you should get a confirmation beep and the focus point should flash briefly.Take a shot.

[Colin Southern]

lens does have a CPL filter

It's VITAL that you remove this for testing.

[Clive]

Ok will try that, have just tested it on a friends Canon 5D body. Again it confirmed that the image was in focus, however it was blurred, so it is definitely not the camera.

[inkista]

Take IS and auto-focus out of the equation. Turn of the IS, use a tripod, and use liveview with 10x magnification and focus manually. If there's still an issue, then it could be a decentered element; if manually focusing is fine, then AF calibration may be warranted. Either way, it's looking like a trip to a service center.