Interesting development with 70300IS

There is a thread going at DPR about the new 70300IS and IQ degradation when in portrait/vertical framing. I initially smiled it off, but then decided to give my copy a test run. Lo and behold, serious IQ degradation when in vertical position. Over and over, consistently worse than horizontal framing. Also, it doesn't matter if "IS" is on or off. I also gave my 100400IS a run and no problems. Others are reporting issues as well. I'm contacting Canon Irvine at this time to see if they know of something more on this problem. Here's an example of consistent results I'm getting:

HTTP response: NOT FOUND | MIME changed to 'image/gif'

Very strange. Keep us posted about what you find out.

Odd

The only thing I can come up with is that the autofocus somehow messes up when in the vertical orientation (which still doesn't make sense). The only other thing I can think of is that the elements in the IS group settle slightly out of alignment when turned vertical. Either way, it's very, very odd. Does the same thing happen when you manual focus?

I'm fairly sure it's a lens-specific issue; my 100400 and 70200 have no problems at all on the same body. I just went outside and shot over 20 different subjects and compositions, and EVERY SINGLE shot the horizontal is sharper and more contrasty than the vertical; it is really night and day. Somehow it seems to me one or more elements are shifting in a way that degrades IQ when in vertical position. My contact at Canon Irvine might be out today, so I may have to wait until tomorrow. But I am sure I'm sending it in. I like this lens in every way, except this.

Added some more test crops here http://www.pbase.com …o/image/5471916​8/original

I would say that it was probably harder to keep the camera horizontal whilst holding the camera sideways, due to the posture you have to adopt. I guess it would need to be done on a tripod to blow that theory out of the water.

Just my initial thoughts.

Graham

Is this specific to one camera model? It looked like everyone at DPR who reported a problem was using the 350XT (although maybe I missed something). But then you have a 20D, don't you Jojo?

Wouldn't you know it - I just ordered one of these yesterday.

Again, it isn't a body issue; it's a lens issue. And yes, FWIW, I use the 20D. I've gotten in touch with my Canon contact and since he will be in tomorrow I'm driving the lens down to him. We'll figure this thing out soon enough.

I did understand that, but I can see how my question looked stupid. I was just wondering if it was a vertical vs. horizontal AF issue with the Rebel, but it looks like you (and others) have ruled that out. I'll keep quiet and see how this pans out.

Thanks for keeping everyone updated.

Wow...with me being a big supporter of this lens, I would sure hate to have to eat my words in this case. I will await your findings about this lens. Thanks for doing the leg work JoJo...

My eyes were on this lens, but now I'm beginning to question.
I don't think I will be doing any vertical position shots at the telephoto end. However, I wouldn't want a lens knowing that it was incapable of doing such a thing.

Looks like the 70-200 f/4 L will increase in sales . Kinda stinks though as my next purchase will be a telephoto zoom and this lens was on the radar.

Well, I wouldn't quite write this lens off that quickly. I spoke with Canon Irvine today and my contact said it's "very strange" but it could be the inner barrel that is slightly loose (this isn't "L" build after all) and when put into vertical format it shifts everything enough to offset the IQ. Sounds reasonable but we'll see what they find out. I'll be taking it down tomorrow and I would think they will get it done by early next week.

In2Photos wrote:
Looks like the 70-200 f/4 L will increase in sales . Kinda stinks though as my next purchase will be a telephoto zoom and this lens was on the radar.

Or Sigma's 100-300 f/4, which is not that well known, but is a good solid lens.