Blurry images with 70-300 IS lens

[dcomiskey]

Hi. New here. I've had a 70D for a couple of years now, and I will freely admit this is too much camera for me. It requires too much thinking and remembering on my end. That said, I can typically do fine with it. However, I've run into an issue that I think is just lens-based. I got a 70-300 IS a while back and it just refuses to take clear images. I did some tests compared to my EF70-200 and 17-40 USM. Of course, the 300 has the greatest zoom, which is what I prefer to use when taking pics of wildlife. I'm not sure what to do, as the lens is way out of warranty, despite not having a ton of use since I got it. Is there a way for ME to fix this, or does this call for a repair? 

Taken with 70-300 IS

Taken with 70-200 USM

[dcomiskey]

As a follow-up, I also have an EF 75-300. In taking nearly the same pictures, they are quite crisp, so it's definitley an issue with the 70-300. 

[jrhoffman75]

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@dcomiskey wrote:

As a follow-up, I also have an EF 75-300. In taking nearly the same pictures, they are quite crisp, so it's definitley an issue with the 70-300. 

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The 75-300 is not one of canon's better lenses, so if it is showing sharper than the one in question I would agree that you have a defective lens.

[jrhoffman75]

Can you post images taken with the 70-300 and the 70-200 at the same focal length (say 150).

Pick an easier subject.

Set the camera to A+ mode for this test.

[rs-eos]

To elaborate a bit on what John mentioned, pick a stationary subject (e.g. depending upon shutter speed, any breeze will be moving those branches/leaves).  Also, when you do the side-by-side, ensure the camera itself isn't moving (i.e. best to use a tripod with IS off).   Though of course, if trying to then compare the IS capabilities, go hand-held.

[Waddizzle]

I think the images look fine.  Assuming that the photos are not cropped, then your DoF, Depth-of-Field, should be quite narrow.  Visit the web site DofMaster dot com.  Punch in your camera body, and the focal lengths of the lenses.  You will see what I mean.

[ebiggs1]

"I would agree that you have a defective lens."

I don't, at least not from the two sample photos.  The first one is OOF, simple.  You missed focus or you moved or your SS was too slow. Whatever that ones on you.  The second one is in focus on the very first bud or leaf whatever it is. That, as stated above, looks fine.

[ebiggs1]

"It requires too much thinking and remembering on my end."

All you need to remember is to put the camera in P mode and the lens switch to AF. Set your ISO to 400 and average WB.   Most of the time it will make all the decisions for you and get you nice shots. The shots you displayed could have been done that way.

[dcomiskey]

Oh, thank you! That helps a tremendous amount!!

I hope to take better comparison pictures either today or tomorrow.

[Waddizzle]

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@dcomiskey wrote:
Oh, thank you! That helps a tremendous amount!!

I hope to take better comparison pictures either today or tomorrow.

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I am going to suggest using Av mode, with aperture set to f/5.6, and ISO set to Auto.  Shooting in P mode is generally good advice.  However, I think it works best at "normal' focal lengths.  I am not sure how well P mode works with telephoto lenses, especially with focal lengths as long as 300mm.

I do not think that P takes focal length into account.  The exposure settings will be determined by the brightness of the scene, the EV value measured by the metering system, and the ISO setting.  All exposures will fall somewhere along the bold line.

I seem to recall that Av mode might compensate for focal length.  I am almost certain that Canon DSLRs take focal length into account in Av mode, by trying to maintain a minimum shutter speed that is related to the focal length in use.  This is why you may want to use ISO in Auto mode, which will give the camera a wider range of shutter speed options.