Recently, while on a tight budget, I purchased the Vivitar 19-35mm AF lens for my Canon EOS 1D Mark II camera body.  Mainly I wanted a lens in the ultra wide category for tight scenics and this lens fit the bill. I bought the lens from auction on ebay for about $50.00 in like new condition. It came with the original box, a lens hood and lens cap.

Lens Build
The build of the lens is consistent with most of the affordable lenses in this category.  It made entirely from plastic but does have a metal mount.  Like most Vivitar products it was created by other manufacturers and marketed under the name Vivitar.  The plastic lens hood that comes with it is acceptable but you may wish to purchase something a little bit better to cut down on flare. It also sports a 77mm filter diameter which can be costly when compared to the price of the lens.

Autofocus
First, I need to say that the autofocus works quite quickly except for some minor connectivity issues causing the autofocus to not engage properly.  To overcome this I had to really snug the lens down one more time after it clicked into place.  The focus speed of the lens was as quick as any of my Canon lenses so I feel like it is a non-issue.  I have heard other complain about a noisy focus with this lens but I was satisfied with the noise from the motor. Perhaps they are comparing the noise to the "L" quality lenses which is really just silly.

In the Field
After purchasing the lens, I took it out for two days of shooting waterfalls in western NC.

My first test was to shoot Looking Glass Falls located in the Pisgah National Forest.  I have photographed this falls in the past so I thought it would make a good test subject.  After shooting the falls from several angles I returned back to the cabin for post process and a good look at the results. I found the color to be warm which is ideal for this type of shooting.  The edges look like they lose resolution slightly but it was an adequate performer.  Below is the most straight forward shot of the falls.

Looking Glass Falls - Canon EOS 1D Mark II,  Vivitar19-35mm AF (At 19mm), 4 seconds, ISO 50
Next, I took the camera to Pearson Falls in Saluda, NC.  The lens performed quite well, but it has its own unique style compared to Canon lenses.  It has good contrast and a nice warm color to it.  This may not work for you if you prefer a cooler temperature. Especially if you shoot film and do not have control over white balance.  Sharpness was better than adequate and was quite close to my 22-55mm Canon kit lens.  Below is the image taken near Pearson Falls...

Pearson Cascade - Canon EOS 1D Mark II, Vivitar 19-35mm AF (at 19mm),  F22, 8 seconds, ISO 50

Conclusion
If you are on a budget, which most of us are, this is a fairly good performer and will not disappoint the average weekender out there.  A professional might need a little more resolving power but then again, I assume if you make money from your photography you wouldn't be looking at an inexpensive lens.  By the way, I don't believe in looking at charts of lens tests to figure out which lenses to buy. The best way to decide if you like the lens is rent it or buy it and give it a try.  If it works for what you want it for then do not feel like you need to go higher in price on a lens. I doubt I will keep this lens forever but for now it fills a need in a poor economy.