[Kerrowdown]

Here's a thought for you to maybe consider, with the advent of the FF being "hopefully" only a few months away now, even the humble SMC Pentax-A 20mm F2.8 will give a much wider view than the current 15mm on on the K3 and it's your required speed too.

Whilst I appreciate this does not help you right now with your K3, it's just something that might work for your requirements for the future.

[MikePerham]

That's a good question.
I shoot a lot of trail runners in the early morning. So, there's not a lot of light, they're moving (obviously), and I want to capture them with an ISO that isn't crazy high. Also want to get as much of the mountain landscape in the background as possible. Examples: https://www.flickr.com/photos/28805392@N02/
Most of those shots I took with my Sigma 10 20. A great lens. I'm basically just wishing it was a bit faster, or for a prime like the 15 DA in a slightly faster offering.

---------- Post added 04-11-15 at 09:46 AM ----------


The Samyang would be a good option except for the fact that it doesn't have AF. In the early morning light, I need AF to capture moving runners.

So why not the 14 f/2.8?

[bassek]

The DA14/2.8 is better than the reviews give gredit for, I'm quite happy with my copy at least.
I have to admit I would have preferred the DA15/4 due to size, but I got the fourteen so cheap that I could not resist.
It's the best value lens that I have bought new.

Seb

[atiratha]

The 12 24 is too slow for my needs. I have the Sigma 10 20, and it's a great lens. I'm wanting something faster to compliment it though. The DA 14 gets pretty subpar reviews at SMC Pentax-DA 14mm F2.8 ED [IF] Reviews - DA Prime Lenses - Pentax Lens Reviews & Lens Database

I went through the reviews and it seems, most people are rather taken with the lens. The biggest gripe being that it is larger and heavier. Also, the moustache distortion can be a bit of concern to some. Otherwise, from my use, I must say a very good lens.

[Nicolas06]

The Samyang would be a good option except for the fact that it doesn't have AF. In the early morning light, I need AF to capture moving runners.

No you do not if you want the background to be sharp too and apparently that's what you want.

14mm f/2.8 set at hyperfocal distance (3.7meters) give you everything from 1.8meter to infinite in focus... Things are quite simple:

- you can focus to more distant objects, you'll still have the same background in focus, but less focus in front... Bad compromize.
- You can put the focus at nearer distance than 3.7m and you'll not get the background in focus. If your subject is nearer than that, you screwed and need to use a more closed down apperture to get more deph of field and so bump the isos accordingly.


You can check the focal length, apperture and hyperfocal things on this link: http://www.dofmaster.com/dofjs.html to check what the max apperture you case can afford and if there even any interrest in an f/2 lense or if the deph of field is too shallow. Depending of your findings you may want Samyang 14mm f/2.8 or Samyang 16mm f/2 or maybe f/4 is the max acceptable setting for you.

Check in particular the distance you are from the subjects and if you the type of rendering you are after (all in focus) is possible with the apperture you want to match.

Last but not least, There are the gear, the technique... You can spend lot of $ for it. The day you may spend $1400 for a 24mm f/1.4 and $2000 for the associated FF is the day you may discover that there no longer enough deph of field in yours shoots.

Also you don't need to take everything that happen in your life in photos. If you can take the picture at iso 3200 f/4... There chances 5 minutes earlier/later when there more light you could be at iso 800 f/4. So when you go shooting know when it is worth to start shooting and when you should stop.

Last but not least, learn how to get the most of your isos. Shooting raw, using good noise removal settings (like DxO prime) do wonders... a carefully post processed 3200 shoot can really look good, as good as out of camera JPEG at 1200-1600 isos. That give you the same gain than a better lense, but the software is less expensive than the lense... And the day you buy the lense you can cumulate.