Problem with Canon 24-70 2.8 L

[Baadsport]

I've had a Canon 24-70 2.8L for about a year. It's a wonderful lens with its low light and tack sharp capabilities. BUT.....one problem I have witht he lens is every 30-40 shots or so I get a strange shadowing that ruins the picture. At first I thought it was the built-in flash on my 40D casting a shadow over the big lens, so I take another shot and the picture is fine. This has also occurred outside in bright sunlight, so the pop-up flash theory is out.

I have read in another forum somewhere of someone having the same issue with that lens. But for the life of me, I can't remember where I saw it. The lens was way too expensive to have an issue with it.

Has anyone heard of a problem like this before???

It does not happen with any other lens in my collection...70-200 2.8L, 100 2.8L IS, 100-400L IS and 85 1.8,

Thanks in advance for your input.

[3n-Out]

It could be the lens hood, when using flash It can cast a shadow if shooting in portrait mode. I have seen this with mine. solution? Maybe remove the hood when shooting with flash. Hopefully it's as simple as that for you.

[prncfarquad]

I have had mine for a year or so now and never had this problem.

[Daniel W.]

Post a picture of the problem, it is a fine lens but it couyld be vignetting, or as mentioned - shadow cast by the gargantuan hood.

It wouldn't occur with your other lenses as they are pretty long in range as opposed to the wide angle of the 24-70.

[Baadsport]

Thanks for the replies so far. I don't use the hood on that particular lens. Here's the only foto i've saved with the cast shadow. The shadow starts half way down...when I'm inside or outside it doesnt matter.

[Brains]

That sure looks like shadow from the on-camera flash.

Solution: Get an external flash

[Daniel W.]

Well, this one has me a bit off, but it really does seem like an issue with the built in flash, IIRC the body of the 24-70 does extend a fair bit with the zoom and that, in conjunction with the built in flash would cast a shadow, no matter what the situation. That's just the downside of using the built in flash.

If you want to, charge the battery, find a large neutral wall and play with the flash, see if you can get a repeatable issue. Vary the zoom of the lens and how close your're standing and whatnot ,I'm betting that you'll find what combo of situations causes it. For me, it's a large diameter lens, at a wide angle, with a built in flash that gets progressively worse as I get closer to the subject. Try it out.

Your best bet, as mentioned, would be to get an external flash. The 420EX is a few models behind the times but is cheap (usually under $150 in good condition) and would do the trick. It doesn't have all the bells and whistles, but it is a reasonable step up from the built in flash. It will also let you bounce the light in landscape and portrait position, which means much better quality of light in the right situations.

If you want something simpler/compact, there's the 220EX and 270EX but they're very simple and straightforward - just an on/off switch for control (maybe a high speed sync switch, but that's a different episode). Both are priced along the lines of a 420EX though.

The 430EX II and 580EXII are also nice, but they're $$$$. Avoid third-party flashes (promaster, quantaray, RPS, etc) - they all have issues with compatibility and even the most compatible, the Sigma 500 series, has been plagued by issues of compatibility.

by the way, nice cake. Dangit. Now I want cake...

[Baadsport]

Thanks for that answer Daniel. I have a 580EX II but when I get lazy I leave it in my bag and try to use natural light with the lens 2.8 opening. I guess for my mom's 74th birthday I should have used the 580EX.
As far as re-creating the effect, i'll keep plugging away with it until I find the right combination to avoid. The only puzzling thing about all this is that it's happened outside with full sun and no flash needed.

Thanks again for everyone's reply.

D

[David Whatley]

Could it be your SS was a little to high to synch with the built in flash, but you had enough avaliable light to get most of the exposure?

[brewercm]

What's most interesting about this is the part about this happening without the flash outside also. Have you looked at the data on all the pictures it's happened with? If not I'd save some of them and compare the data from each and see if there is a common item with each that it's happening (etc. all at 30mm, f3, etc.). Maybe this can narrow down that it's not at a specific setting on the lens that it's happening.

[kronos2818]

If it is happening when you are not using any kind of flash, then it would not be a lens shadow issue at at all. And because the shadow goes across the bottom of the whole image, it can not be in 1 or all of the apature leafs in the lens. That means it may not be the lens. So the only other thing it can be is the shutter in the camera, it can be sticking and slowing down when it reaches to that area of the frame. Giving you that shadow, because part of the shutter is being caputred in the images. Now it may be working fine for 20 or 30 shots but very once and a while the shutter sticks giving you that shadow effect.

But looking at the sample you put, the shadow has a left to right downward sloop and a little upward dome starting from the wine bottle to where her hip is. So that can be the two things at work. The left to right shadow slope is the sticky shutter and the dome is a reguler lens shaddow.

That is my best guess.

[Baadsport]

Well Kronos, I never thought about a sticky shutter. That sounds logical to me, though I've never seen the results of a shutter sticking. Maybe I should just take the body in for a cleaning or a "tune up"...or this gives me a good reason to get that 7D I've been thinking about.

[kronos2818]

Dave keep me posted on the results, I want to know if my theory is right on the sticky shutter.

Thanks
Sam