ER01 on 50D w/ Tamron 70-200mm f2.8

<p>I bought a Tamron (new, off the shelf at a local retail store) 70-200mm f2.8 Di to use on my 50D a couple of days ago. Today is the first day I used it hard and had a problem with the 50d every now and then coding out w/ ER01 lens communications error.<br>

Of course I had to cycle the camera to clear it (happened half a dozen or so times over 1213 exposures), it is very annoying, and I'm glad nobody but me noticed! The first time it happened I pulled the lens off, inspected (contacts were clean of course), wiped anyway, and replaced. <br><br>

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I'm wondering if anybody else has had this experience with this Tamron lens. I still have the option of returning the lens and going for the Sig glass (same price range). I'm leaning toward that now, but I guess I'm looking for some advice on whether or not it is going to be advantageous to do so.<br>

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Oh and of course my 50d has 1.0.3 ver firmware (the latest on canon's web site.) I tried this evening to replicate on my XTi and couldn't get a failure at all(!?!)<br></p>

<p>The XTi is an older camera than the 50D and thus the lens ROM is more likely to be compatible. If your other Canon lenses are fine on the 50D probably the Tammy needs a ROM update. I had the same problem with all the Sigmas I've owned: old cameras fine, new camera has errors when I tried to stop down. I had a Tokina 17mm do the same. Oddly even my oldest Canon optics from the late 80s work fine on my newest body (50D).</p>

<p>I suppose that's a possibility, but if I send it off for a ROM update, I'm going to be out of a lens for several weeks (at best). I'll probably just return it. As I review my pictures from yesterday, I'm also finding that at the long end, and wide open(f2.8) The focus is slightly off. For example the molding on the wall behind the couple is tack sharp, but the medals on his chest that the AF confirmed are a little blurred (that's probably one/two feet actual difference in distance).<br>

I'd like to point out that I never had that problem on a (rented) Canon 70-200 f2.8, or even my f4 IS.<br>

Does anybody have any specific experience with this lens (good or bad) to help me out?</p>