Yes, it appears that the VC shot is slightly more blurred, though neither image is great when viewed highly magnified.

But is that due to the VC? It also could be due to missed focus. closer portions of the tree in the VC image appear sharper. It also could be atmospheric effects. And the lens might have performed better stopped down a little from wide open. You could have bumped your ISO up a stop from 200 to 400, to be able to use f9 instead of f6.3.

The biggest problem I see here is simply that you need to get closer. You're using the D7200's 1.3X "digital zoom" cropping mode, in addition to an extremely long focal length on a DX camera. Effectively you are reducing your 24MP camera to about 13MP when you use 1.3X crop mode... and using that setting is no different from later cropping your image in post-processing, possibly with more control than doing the crop in-camera.

When shooting at such extremes, it's about the odds. Any single shot may or may not be all that great. In fact you'll likely have more "bad" shots than you would in less extreme circumstances. You have to use more careful techniques to increase your odds of getting a "good" image, the very first of which is simply to get closer to the subject so you aren't pushing the gear to it's extreme. Next, take lots of extra shots. Micro focus adjust your particular lens to your particular camera. Hope for an absolutely clear day because you're shooting through lots of atmosphere. Avoid putting any extra layers of glass in front of your lens (i.e., filters).

Do everything possible to stabilize your rig: A good sturdy tripod and head, carbon fiber absorbs vibration better than metal. Add a weight underneath the tripod to further stabilize it. Lay a beanbag on top of the camera and lens. Use a remote release, so that you aren't touching the camera.

Pray for no wind gusts to buffet your rig.

Buy an $11,000 prime instead of an $1100 zoom. Is that a varifocal or parfocal zoom? (I.e., does it maintain focus when zoomed?)

Full view at + appears equivalent to a 50 inch or wider print on my monitor. Are you planning to make a print that large from this image? Are your expectations too high?

Sharpening? How much was done in-camera and what post-processing have you done?

When you're pushing the limits of your gear, it's all about the odds. It can help to take burst of shots or lots of extra individual clicks, to increase the odds that you will get one that's ideally focused and perfectly stabilized.

Making a judgment like this may or may not tell you anything useful. You're comparing a single VC image with a single non-VC image. But it's all about the odds when taking a shot like this, that's asking a lot out of your gear and your techniques. If you look at 100 shots made with VC and compare them to 100 without, you may see a different story. Maybe the non-VC are better on average... or maybe not. Maybe you'd get 25 out 100 usable shots with VC and only 10 out of 100 without it. Or maybe the opposite would be true.

It was a quick little test. I took two shots, one after the other. the one with the VC on is slightly worse. This was taken with $1100 so I don't expect crisp shots as if it were from a Nikon 500mm prime. I only wanted to show the difference between VC on and VC off. If you don't feel it's a valid test ... well, there's nothing I can do about that. My conclusion is that VC does affect the sharpness if left on while mounted on a tripod.
Re: Highly magnified - that's how I wrote it should be looked at ... the better to see the difference.

Hi Howard,

Yes, I understand all your points.

I'm just sayin' that you and some other responses here are painting with a pretty broad brush coming to the conclusion that stabilization will always effect sharpness and should always turned off when a lens on a tripod.

IMO, that's just not always the case. All stabilized lenses aren't the same, as suggested or implied by some above. And there are techniques even with a tripod - such as panning or "loose gimbal" - where stabilization is likely to work just fine and can be helpful. Plus there are other possible causes of problems in images, that stabilization might be getting the blamed for, as well as various techniques that can address those causes when working with extremely long telephotos.

Also there's a tendency on this and pretty much all forums to exaggerate "problems" by looking at images far larger than they're likely to ever be printed or used. For example, I think either of your images would look pretty darned good printed as 8x10s... maybe even a little larger. But when viewed 4X or 5X more magnified, they don't hold up.

I make a point of stating that my experience is with Canon IS lenses... I don't have hands-on knowledge of your particular lens' VC and it's limitations. So I'm not commenting in much detail about it specifically.

However some of the responses you've gotten make assumptions about all lenses with stabilization, be they Tamrons with VC, Nikkors with VR, Canon IS or Sigma OS. But, after many years using them, I've found a lot of those assumptions and conclusions to be incorrect when it comes to Canon IS lenses in particular.
Hope this helps!

"How about we leave it to the manufacturer as the final arbiter? Tamron says Turn off the VC when using a tripod. My little test was to see if it mattered; I concluded that it did. The manufacturer was right. I know my "Test" wasn't professionally done - it worked for me though and I posted what I thought was a simple straight forward message to others with this lens. Nothing more. As for the optics ... I could post a side by side comparison to my Nikon 500mm f4. That of course would not be a fair comparison - I mean a zoom against a prime. :-)"Howard

Looking again at this image (wading egret), in addition to some loss of fine detail due to diffraction caused by using a very small aperture, there are two other things...

First, 1/100 shutter speed. TThat's really pushing your luck! Even with image stabilization. On a Canon APS-C crop sensor camera a 600mm "acts like" almost 1000mm would on full frame, which the old rule of thumb suggests would require a minimum 1/1000 shutter speed to hope to get sharp shots. Stabilization helps and might manage a pretty good percentage of sharp shots one or two stops slower (1/500, 1/250)... but I'd expect fewer sharp ones three or more stops slower (1/125 or slower).

Also, if the subject was moving at all, 1/100 may not have been fast enough to prevent subject-motion blur either.

Second, the image might be front-focused or back-focused. It's kind of hard to tell in this case, because the waves or reflections in the water are all we have to go by and aren't all that clear.

It might be a focus error occured only in this one instance for some reason. Or it could be that the lens or camera is producing the same error consistently because they aren't perfectly adjusted. I don't know about this particular lens, but some even are erratic: dead-on accurate sometimes, but missing focus other times (for example, the Canon EF 50/1.8 II is known to do this and is nearly impossible to calibrate, as a result).

You'd have to do a series of very careful test shots to determine what's happening with your particular lens and camera combo. If you do find a consistent focus error is occurring, where most shots show a similar focus error, the camera or lens can be calibrated. Unfortunately it so happens that the Canon 60D you're using doesn't have the Micro Focus Adjustment feature that some other Canon models do, so you can't calibrate focus yourself. (It's always baffled me why Canon left MFA off the 60D... they put it on the 50D that preceded it, as well as the 70D that superseded it.)