Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Is the pentax fish eye 10 -17 an autofocus lens and is it a rectangular fisheye
Document: We use the Pentax DA 10-17mm f/3.5-4.5 ED (IF) Fish-Eye lens for creating semi-pro 360 degree panoramic images on our K-5 DSLR. The photo quality is very close to the Nikon 10.5mm fisheye that we've used in a Nikon D7000. What amazes me is the value.
I have the Pentax 12-24 lens already, but found that I really wanted something that was going to offer another perspective. The DA 10-17mm f/3.5-4.5 ED(IF) by Pentax offers a fish-eye look at 10mm while having minimal distortion by 17mm. Colors are great (as is typical w/ Pentax lenses) and the sharpness of this lens is excellent. There are some scenes where a fisheye is just fun and adds interest to the picture.
I've gone sort of nuts buying Pentax lenses for my k5 and kx. I have the 10-17 Fisheye, 15mm Limited, 21mm Limited, 35 mm Macro Limited, 40 mm Limited, 70 mm Limited, 200mm DA*, 50mm Takumar m42 and just bought the 50mm f1.2 SMCA. I take a lot of events/street, flowers and nature shots. I find this to be my second or third most used lens which is saying a lot given that it is normally considered a niche lens.
Plus another customer commented that my review was not a product review but an opinion on my "mistake" to purchase a fisheye lens. YES, I wish I would have spent the money on a regular wide-angle lens, but over time I am often glad to have this incredible fish-eye lens in my bag. I use it with my K5 and could not be happier with the product after almost 2 years of regular use.
Sometimes you just need to go to the extreme - in this case it is really wide angle. In my old Canon film-camera days, I had the 15mm 2.8 fisheye which was an even bigger chunk of glass because of its speed.Now that I have gone to the Pentax K100D camera, I was pleasantly surprised to see this 10-17mm lens was available.
Hello. Did you ever notice you can spell He LOL with the letters form the word "Hello"?But that's beside the point. I'm here to talk about the Pentax DA SMC 10-17mm 3.5 fisheye lens. I just got this big-eyed puppy for X-Mas. It's a beauty. I use it on my Pentak K20D, which I also love, in a platonic way.
The DA 10-17 is a special lens. It is not the sort of lens that you would use every day or, even as a "walk around" lens. At the same time, it provides a field of view that you have a hard time achieving with a rectilinear lens.
I can always add fish-eye with software if needed. The wide view angle is what I was after not the fish-eye....I will keep as an experiment and I am sure to get good shots from this but regret the purchase. **** Update Many moons later...****I am going to increase the "stars" to 5 as this is a quality Pentax lens. I get amazing pictures from the lens, especially landscapes.
The Fish-eye is an interesting lens. It gives you that neat fishbowl look to your pictures, which can be fun and also allow you to capture some really wide angle shots. For a non "limited' lens from Pentax - the build quality is very good. Focus ring is nice and smooth, metal mount and it comes with a nice aluminum lens cap and a decent lens bag.A couple of things to note:*You can't use a filter on this lens - just the nature of the beast.
Talk about a fun lens. I am doing fun stuff again. Of course too many fish-eye shots are not well received in a wedding shoot but the option to shoot in tight  surroundings like stairs, or group up the groomsmen and bridesmaids  and add a little flair is  great! I've found nothing wrong with this lens and it's fun to see people's reactions to the shots. After some Photoshop lens correction the shots are can also be acceptably distortion free. Once again Pentax provides the value for the money.
Answer: Yes the Pentax 10-17 fish eye is an autofocus lens, if by rectangular you mean that it leaves no circlen inside a black background on the picture, then yes it's one, you can find an example of the picture here (no crop)http://www.flickr.com/photos/lere/5876189228/