[Wingincamera]

When I purchased my K-5 II the widest lens I had was the DA 18-135mm. The lens I was eventually wanting was the DA 15mm F4. Meanwhile awhile back B&H has the sale on the Bower 14mm f/2.8 manual focus lens. I really liked the image results from this lens, but it was large and could not take any filters, so I still wanted the DA 15mm. Finally B&H had a sale on this lens and it becomes part of my kit.
I decided to do a comparison test between the lenses I have. For location I picked the inside of our church. I was not concerned with white balance. Focus point was the top of the white table leaned on its side at the back of the roll of chairs.

Photos were taken in RAW, converted to JPG with no sharpening or other processing, other than adding the text to identify which lens was used.
Here is a direct link to the photo album. You can download the original size if needed.
Zenfolio | Will Edwards | Wide Angle Lens Comparison

Wide angle lens comparison between four lens:

Pentax SMC DA 35mm F2.8 limited macro
Pentax SMC-DA 15mm F4 ED AL Limited
Pentax SMC DA 18-135mm 3.5-5.6 ED AL (IF) DC WR
Bower 14mm f/2.8 ED AS IF UMC manual focus,

If the image links below don't work, just use the link above to view them all.

[reeftool]

The 35mm isn't really a wide angle on our aps-c digital cameras so the comparison isn't really a wide comparison with the 35 in the mix. The distortion in the 18-135 and the Bower 14mm is quite apparent compared to the DA15. That is correctable in PP. One can easily make the case for owning the DA 35 Limited, DA15 Limited, and the DA 18-135 because they are quite different in the way you would use them. The Bower 14 I would pass on if I already owned the DA15. Yes, it has f/2.8 and that might make a difference to a few folks but almost all my wide shots are stopped down quite a bit. I own the DA 15 and DA 10-17. They are both wide and the lengths overlap but they are so different in the way I use them, there really isn't a conflict.

[Wingincamera]

I was aware the DA35 is not a wide angle, but just threw it in at the time. I got the Bower 14 before the DA15 because I couldn't afford the DA15 at the time. I mainly wanted to see the actual difference in view between the 14, 15 and 18mm and thought others might be interested too.
The Bower worked fine for me until I was able to purchase the 15. I want to try some night time sky/star photos and the Bower might come in handy for that, until then it will sit on the shelf at home.
I did a write up on the Bower after I had purchased it. https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/238153-bow...m-f-2-8-a.html

[sterretje]

It's surprising how the da15 is not that much wider than the 18-135

I also noticed that. It gives those that say that 1 mm makes a lot of difference in UWA something to think about

[nater]

I just picked up the Samyang 16mm f/2.0 (Rokinon branded) lens, which is APS-C and takes 77mm filters. I've been very impressed with it's quality so far, right from f/2.0. Unless you need the full frame capabilities of the Samyang 14mm, I'd recommend the 16mm over it.

[marmitse]

I just picked up the Samyang 16mm f/2.0 (Rokinon branded) lens, which is APS-C and takes 77mm filters. I've been very impressed with it's quality so far, right from f/2.0. Unless you need the full frame capabilities of the Samyang 14mm, I'd recommend the 16mm over it.

Thanks Wingincamera for comparison. Good to see the limited difference in 14, 15 and 18 mm. I am just about to go eBay-shopping for a Wide angle lens for my K-3. I already have the Pentax 18-135/3.5-5.6, but would like to have a prime lens at around 14-20 mm mainly for Landscape photography and secondly for close space indoor photo.

My choice is

1) Samyang 16mm/2.0 (I beleive it is the same lens also sold as Bower and Rokinon)
2) The New Pentax 15mm/4.0 or possibly
3) Pentax 14mm/2.8
4) A zoom alternative would be Sigma 10-20mm/3.5

For Landscapes I typicaly shoot at f/8 or smaller so the Samyang wide aperture is maybe not key. I do need filter threads (for CP filter) which I believe all of these have. The other use, indoors would benefit from fast lenses. Pricewise the Samyung is very competitive. The only main drawback I have found is the lack of AF. The new K-3 does have Peak focusing in LiveView to assist manual focusing, but it is not really distinctive.

Any support in my choice or things to add to the complexity are appreciated. Also real life experience on manual focus with Samyang/Bower/Rokinon is of interest.

[reeftool]

I also noticed that. It gives those that say that 1 mm makes a lot of difference in UWA something to think about

The difference is enough. I use my 15 at car shows where it is often crowded and cars are parked close together. 18 mm is not wide enough to get the shot. The 14 would probably be decent for car shows also. One of the reasons I prefer the 15 for cars is that most shows are midday in pretty strong sunlight and the lens is highly flare resistant. Stop it down and and those wonderful starbursts appear on the chrome and areas of the finish.

How we use a lens and what we photograph is just as important as sharpness. We have a lot of wide angle options availablle and fortunately for us, they are all pretty good. The decisions aren't easy. I think the DA 15 is worth owning even if we already have the focal length covered.

[nater]

The only main drawback I have found is the lack of AF. The new K-3 does have Peak focusing in LiveView to assist manual focusing, but it is not really distinctive.

You might consider a precision matte focus screen designed for manual focus. The only downside to a precision matte screen is that it will give you a darker viewfinder than the stock screen if you have lenses f/5.6 or slower. To my knowledge the K-5 and K-3 take the same replacement focus screen, so this would be what I'd recommend considering:

Focusing Screen

[marmitse]

The difference is enough. I use my 15 at car shows where it is often crowded and cars are parked close together. 18 mm is not wide enough to get the shot. The 14 would probably be decent for car shows also. One of the reasons I prefer the 15 for cars is that most shows are midday in pretty strong sunlight and the lens is highly flare resistant. Stop it down and and those wonderful starbursts appear on the chrome and areas of the finish.

How we use a lens and what we photograph is just as important as sharpness. We have a lot of wide angle options availablle and fortunately for us, they are all pretty good. The decisions aren't easy. I think the DA 15 is worth owning even if we already have the focal length covered.

I decided to go for the Pentax prime DA 15/4,0 HD ED AL Limited. Found a great price on eBay and I just received it by UPS from Germany. First I thought this was a faulty delivery of a micro 4/3 lens - it is so tiny! But it mounted OK on the K-3 and feels really solid.Took a few shots, the AF works like a charm and I have a feeling that this will be one of my favourite lenses.