There is simply a switch on the side of the lens. AF/MF.
Works just like the one on the camera, so I don't see much point in it. Maybe it is more convenient for some??

I wish I had a better photo of the rain that my K10D suffered through, but a few seconds after this image was taken, rain fell in sheets of water. The camera could not even focus through all the water on the front of the lens.
With manual focus, all I could get was large water spots.

I had once placed my K10D under the shower to test water resistance... he, he... that was nothing compared to this rain. (That was with the 50-135mm)

Earlier that day we had several tornados and most of the city was without power. I was just out checking the damages when the skies went from almost partly sunny & blue to this and torrential rain soon after.

I had to scramble to a neighbor's yard and dump his newspaper out of a plastic protective bag so I could throw my cell phone into it. (felt bad, but it was one of those free newspapers no one wants anyway)

Got home 10 minutes later (walking of course... idiot) to find that there was in fact a tiny bit of evidence of water inside the door were the USB cable connects. A small droplet of water, I swear no more than 1/3mm.
Other than that, a day and a half later, the power is restored and the camera and lens are doing well and the photos turned out well -- for what they were.


K10D, DA* 16-50mm, t-shirt, sandals, wishing for a towel.

Not sure how to answer for someone else's needs, but isn't the field of view of 135mm so close to 200mm that it would hardly make sense to add a 200mm? Unless there were other special requirements, I would probably go for the 300mm just to stretch out the range a bit.

Oh yeah... and a second for no filter.

Sorry. Yeah that is pretty much what I meant.

Just by watching cars go by with my own eyes I can see the effect. At the right speed I'll see flickering and sometimes even a back and forth motion. I'm not sure why, (although perhaps persistence is a factor), but perhaps simply due to slight changes in angle as the car moves that cause reflections to change and shift slightly. Either way, the effect is perceptible.

I have little doubt that SR enhances or creates the effect where it may otherwise not be visible, but because everything else in the photo appears pretty smoothly blurred, and because the spacing between repeated patterns looks quite large, I would have to says it is simply a reflective strobe effect off the wheel hub.

I think beakynet was closest but SR probably has little to do with it.
I would have to say it is very simply the overlapping of highlights as the wheels turn, move and bounce. If the wheel hub was solid you'd probably get a smooth blur, but the wheel is spoked (in a way) and you will get cyclical highlights that overlap or give a strobe effect and expose greater than where they intersect only with empty space.
You'll notice that at the edges where the wheel is smooth, the image is more consistently blurred, other than a few wavy patterns from the wheel bouncing on the road.

Anyone finding themselves stuck while out in Northern Virginia/Washington DC area, feel free to give me a ping.

I suppose they know more that I, but logically it don't make a lot of sense to me.

I would assume that in addition to aperture, the subject distance would need to be known to correctly adjust for aberrations. There would be a few points on a graph that it would "know" about. Anything in between would be essentially guesswork (complex math, but still guesswork).

As I understand things, the sensor judges contrast sharpness for focusing.
If it were to throw that out the window and make pre-calculated adjustments,
I'm just not convinced that would give the best results.
It sounds like you'd end up taking what was otherwise critically sharp at one point, and adjusting for the rest by backing off to give an average across a larger area. The result would be a overall sharpness but with loss of some sharpness at the focus point.

I suppose thats why some don't like the idea. Not sure I do either, but I guess I would need to see before and after shots to see if it adds a benefit and to what degree it might detract from otherwise "perfect" focus.

Still, quite interesting.

And of course I cannot get it to re-focus, now that I try to make it happen.

Of course, no matter your selected aperture, the lens should always be wide open until you actually take the photo. So focus should not differ with your AV mode set at f/2.8 or f/11, etc... (unless you're moving an aperture ring on an older lens).

I have also heard that for most good zoom lenses that focusing should not change when zooming throughout the range. e.g. focus at 16mm, zoom the lens to 50mm and the subject should still be in focus. That used to not be the case, but at the moment focus is spot on throughout the zoom range without focus adjustment.

Could back/forward focus adjustment affect those?
Unfortunately, Ive had the internals of my camera replaced since I actually paid attention to the behavior. Plus I recently played with the focus adjustment hack. So who knows what I did.

Perhaps the behavior is a flaw that has been fixed on my camera in one way or another. : : :

I don't know as far as what percentage of the time, but it happens enough that when I know I have a static subject, I will AF, then switch to MF so that it won't refocus every time I take another shot.

I have not played with seeing how aperture affects that. I will see if I can get some time to experiment and let ya know.

Yep, much easier for tilted images than using the cumbersome and slow Lens Correction filter.

But I have yet to see anything as easy to use as PaintShopPro's ability to draw a box over an object that "should be square" and have the entire image adjusted to be "square" (square as in having four 90 degree angled corners) Its like the transform tool on steroids.