[interested_observer]

I am looking for a few folks who have shot with both the Sigma 8-16 and the Pentax 12-24.

It appears that I may have an opportunity to shoot something that I may never have the opportunity to do again - one time shot. It will be sunrise and sunset (blue and golden hours), and the positions to shoot from will be very limited. I will be using a tripod, ballhead and possibly a panohead. So while I am waiting for a decision on my request, I have started looking at the geometry of the shoot and it looks like my DA 12-24 maxes out at a FoV of about 88 degrees. The Sigma 8-16 runs a FoV of 111 degrees. Worst case I will be dealing with will be around 117 degree FoV to get what I want. However, I have the latitude of moving (in one direction) and repositioning to make the Sigma work, but the Pentax is limited enough that I would need to stitch and in this particular case would bring up some post processing problems - want to shoot 5 frame brackets, and the software I really want to use does not handle stitching very well.

I have the funds, and would be willing to commit them to this endevour for the Sigma - however the last thing I need is another wide angle lens. I am really very satisfied with the Pentax. I have looked at the Sigma and was impressed with the IQ and sharpness for a UWA, even though the poster had to send it back due to focus issues. Which brings up another point. If I do order, I need to order early enough to be able to swap the lens out possibly 2 or 3 times, to get a good copy.

I have walked through the Sigma 8-16 lens club thread several times. The color rendering is excellent. I paid particular attention to the sunrise / sunset shots, along with the architecture shots.

• https://www.pentaxforums.com/forums/lens-clubs/107938-sigma-8-16mm-club.html

Some questions -

• Sigma's colors compared to Pentax's? The Sigma colors appear to be closer to my 10-17 more vivid and contrasty than the 12-24.
• Sigma shooting into the sun, with possible opportunity for CA. How does the 8-16 handle CA? I really did not see any CA in the lens club shots.
• What would you depend on, Sigma or Pentax? After walking through the lens club thread a few times - I am getting the feeling that the Sigma is the lens.
• How bad is the distortion, especially on straight lines? I will have lots of straight lines (of varying thicknesses) at a wide variety of angles, all over the frame. A lot of cathedral shots in the lens club that puts this to rest.
• Are there situations where you would switch from the Sigma to the Pentax given that the FoV works for both? Do I need to carry both or just the Sigma?
• How dependable is the Sigma? I really do not need AF, since I will be at infinity most of the time.

My plan is to use either the 12-24 or 8-16 as the principal lens.

[northcoastgreg]

Sigma shooting into the sun, with possible opportunity for CA. How does the 8-16 handle CA? I really did not see any CA in the lens club shots.

I've never used the Sigma, but I think it's safe to say that you'll run into CA issues shooting into the sun no matter what lens you use. If you throw harsh light at an ultra-wide zoom, you're probably going to get some CAs. Given how well raw converters such as Lightroom 4 clean up CA in post, I don't think this is a significant issue. Also note: CA happens to be one of the chief weaknesses of the DA 12-24. If anything, the Sigma is probably superior in this respect (the photozone tests tend to bear that out).

I think the more significant issue is flaring. I know that the DA 12-24 has some flare issues (it's not on par with DA 15 or the DA 10-17), but I have no idea how well the Sigma handles flare.

[mikeSF]

stitching UWA images is much more difficult due to the massive amount of distortion at the perimeter. If the scene does not have many lines, more doable if you overlap much more than you would with a standard wide lens. Both of these zooms will probably flare on you; i'd be more concerned about the flaring than the CA, which is more easily corrected. It really does not matter which of the two lenses is more contrasty when you are losing contrast to flaring. i do hope it works out for you!
I have the Sigma 10-20 and when the sun is going to be in my image, i switch to the DA15, period. A zoom is more unwieldy than a prime when shooting the sun.

[MegaPower]

I have a question for you.
Have you consider to buy a tele one to shot for sunset/sunrise?

Back to the topic, I tired the sigma 12-24 on FF canon. (so 8-16 APSC)
It is very useful indoor. For outdoor, stitching or step backward can still help.

[joe.penn]

Sigma's colors compared to Pentax's? The Sigma colors appear to be closer to my 10-17 more vivid and contrasty than the 12-24.

When shooting with the UWA lenses, most of the time when shooting daylight metering picks up on more brights because of the FOV and thus more accurate overall scene metering is achieved - check out some 8mm samyang shots (tamron shots also @ 10mm) and you will notice some of the same characteristics.

Sigma shooting into the sun, with possible opportunity for CA. How does the 8-16 handle CA? I really did not see any CA in the lens club shots.

The FLD elements of the sigma provide some of the best CA control from any manufacturer.

What would you depend on, Sigma or Pentax? After walking through the lens club thread a few times - I am getting the feeling that the Sigma is the lens.

The sigma is the lens, the nikon and canon forums will also confirm this for you.

How bad is the distortion, especially on straight lines? I will have lots of straight lines (of varying thicknesses) at a wide variety of angles, all over the frame. A lot of cathedral shots in the lens club that puts this to rest.

Noticeable but not overly bad, this is fixable in LR with profiling.

Are there situations where you would switch from the Sigma to the Pentax given that the FoV works for both? Do I need to carry both or just the Sigma?

Carry whichever one you feel most comfortable with.

How dependable is the Sigma? I really do not need AF, since I will be at infinity most of the time.

Great customer service, fantastic warranty period, lens adjustments are covered during the warranty period (for things like dropping your lens and de-centering, they got you covered) - I would say they are pretty dependable. I have no issues with any of my sigmas except a slight BF on my 70-200 which Sigma will fix (they will calibrate and re-chip lens) as soon as I send it to them.

[interested_observer]

I've never used the Sigma, but I think it's safe to say that you'll run into CA issues shooting into the sun no matter what lens you use. If you throw harsh light at an ultra-wide zoom, you're probably going to get some CAs. Given how well raw converters such as Lightroom 4 clean up CA in post, I don't think this is a significant issue. Also note: CA happens to be one of the chief weaknesses of the DA 12-24. If anything, the Sigma is probably superior in this respect (the photozone tests tend to bear that out).

I think the more significant issue is flaring. I know that the DA 12-24 has some flare issues (it's not on par with DA 15 or the DA 10-17), but I have no idea how well the Sigma handles flare.

I have had my 12-24 for going on 5 years now. In the beginning I expected some flare and CA however I have never really run into any to any extent. I don't think that its luck, certainly not skill - If it were skill, I should be able to explain what I am doing to mitigate the problem (flare and CA) and I really can't. The few times I have run across it (CA), post processing fixes it just fine. I do shoot sunsets and its directly into them, so I guess its been luck. What I do find from time to time is either water spots - rain drops, dirt etc. that is on the front element that does show up - so I have taken to cleaning them more often.

stitching UWA images is much more difficult due to the massive amount of distortion at the perimeter. If the scene does not have many lines, more doable if you overlap much more than you would with a standard wide lens. Both of these zooms will probably flare on you; i'd be more concerned about the flaring than the CA, which is more easily corrected. It really does not matter which of the two lenses is more contrasty when you are losing contrast to flaring. i do hope it works out for you!
I have the Sigma 10-20 and when the sun is going to be in my image, i switch to the DA15, period. A zoom is more unwieldy than a prime when shooting the sun.

I have actually had very good luck with distortion. I choose the DA 12-24 because it had less distortion than the 10-20 or 10-24, and it has worked out well in that regard. I do stitch probably more than most - with the 12-24 and even my 10-17. When I was looking at the posted images on the 8-16 lens club, I was looking for flare and CA. I was also looking at the straight lines, and was very satisfied with what I saw. Most folks probably post their best or most interesting images, so I believe its there, just not shown to any real extent. On the issue of flare, I was shooting up in Jerome and I saw that I was going to get some flare on certain shots with the 12-24, and just incorporated it into the shot as a feature.

I have a question for you.
Have you consider to buy a tele one to shot for sunset/sunrise?

Back to the topic, I tired the sigma 12-24 on FF canon. (so 8-16 APSC)
It is very useful indoor. For outdoor, stitching or step backward can still help.

The telephoto idea I have already incorporated in to my plan. On my recon try - I did not go to any other lens, but I know exactly what I want and how to get the shots. I also am going to take my 31 Ltd, A 50 and CZ 85. The K135 is not the best lens, but I will also throw it in along with the 55-300. I am also considering taking the K 28 shift lens. I don't want to spend all my time changing lenses, especially if there is a wind, but I am planning out the primary shot locations and have a very good idea as to what I will probably get. I am also using google earth, for measurements and shot angles, which I can measure and with a bit of geometry - ok trig, I have figured out that the 12-24 will not cut it and thus I need a larger Angle of View on the UWA.

That brings me to your stitching and framing with my feet. Stitching I am already planning to do some. However, on some of the major positions, I really want a bracketed 5 frame single shot, so that I can tone map easily with out going through some of the problems I believe I will encounter. At -2ev some of the frames will be pretty much black, and thus be very difficult to stitch several all black frames together. If I stack them first, then they contribute - but then I have the stitching problem knitting them together after tone mapping. In several positions I really can't move back or I will go into the water - not good. However, I can move to the side and thus increase the distance - however, I will be moving off the shot line that I am after. Its all going to be a compromise in real time.

[interested_observer]

When shooting with the UWA lenses, most of the time when shooting daylight metering picks up on more brights because of the FOV and thus more accurate overall scene metering is achieved - check out some 8mm samyang shots (tamron shots also @ 10mm) and you will notice some of the same characteristics.

The FLD elements of the sigma provide some of the best CA control from any manufacturer.

The sigma is the lens, the nikon and canon forums will also confirm this for you.

Noticeable but not overly bad, this is fixable in LR with profiling.

Carry whichever one you feel most comfortable with.

Great customer service, fantastic warranty period, lens adjustments are covered during the warranty period (for things like dropping your lens and de-centering, they got you covered) - I would say they are pretty dependable. I have no issues with any of my sigmas except a slight BF on my 70-200 which Sigma will fix (they will calibrate and re-chip lens) as soon as I send it to them.

Joe - all wonderful information. Thank You!! With reviewing the lens club posting and the views from you and the rest, I think that the Sigma is the lens. I had not really considered the Samyang, but that may be a good option to consider. Since the Sigma came out, it has been in the back of my mind, but I have really been satisfied with the Pentax.
______________________________

edit - The Samyang 8mm is a fish eye - I had forgotten that. I already have the 10-17 and the real need is for a rectilinear lens with a FoV in the 111 degree range (horizontal). Good suggestion though....

---

Last edited by interested_observer; 07-26-2012 at 02:18 AM.

[barondla]

I have both lenses. Bought the Pentax 12-24 t the end of last year and the Sigma 8-16 beginning of this year. Both lenses are great performers. Think my 12-24 slightly nudges out the Sigma in sharpness but the Sigma has a little more contrast. The Sigma has more vignetting which also makes it look contrastier. Both lenses are so good I can live with the IQ of either. Haven't noticed major flare or ca problems with either lens and don't feel my 10-17 is a lot better than either.

Bought the 12-24 to get back the ultra wide lost when going digital. My 35mm uw is a Pentax 15 3.5 ( not FE). The 12-24 got close. Then the sigma came out and I had to have it. Now I am wider than the 35mm uw. Love it.

Some things to consider.
Pentax has a huge diameter hood that is tight fit in the largest Domke bag insert. Must be 3" diameter or more. It will take thin 77mm filters w/o problem. Manual focusing is light and delightful. Lens is constant f4 aprture.

Sigma lens is a little longer in length, but hood is less in diameter, so it fits bag better. Sigma hood does not come off. It will not take any kind of filters. A provided collar fits over the hood allowing the normal lens cap to be used. Below about 10mm Pentax cameras won't show focal length in exif data. Pentax needs to fix this. In manual focus the ring is fairly tight feeling.

I love both lenses but probably love the Sigma a little bit more. I love extremes. Truthfully there is such a difference in their angle of view they really aren't competing with each other.
thanks and good luck
barondla

[pinholecam]

I have had my 12-24 for going on 5 years now. In the beginning I expected some flare and CA however I have never really run into any to any extent. I don't think that its luck, certainly not skill - If it were skill, I should be able to explain what I am doing to mitigate the problem (flare and CA) and I really can't. The few times I have run across it (CA), post processing fixes it just fine. I do shoot sunsets and its directly into them, so I guess its been luck. What I do find from time to time is either water spots - rain drops, dirt etc. that is on the front element that does show up - so I have taken to cleaning them more often.



I have actually had very good luck with distortion. I choose the DA 12-24 because it had less distortion than the 10-20 or 10-24, and it has worked out well in that regard. I do stitch probably more than most - with the 12-24 and even my 10-17. When I was looking at the posted images on the 8-16 lens club, I was looking for flare and CA. I was also looking at the straight lines, and was very satisfied with what I saw. Most folks probably post their best or most interesting images, so I believe its there, just not shown to any real extent. On the issue of flare, I was shooting up in Jerome and I saw that I was going to get some flare on certain shots with the 12-24, and just incorporated it into the shot as a feature.



The telephoto idea I have already incorporated in to my plan. On my recon try - I did not go to any other lens, but I know exactly what I want and how to get the shots. I also am going to take my 31 Ltd, A 50 and CZ 85. The K135 is not the best lens, but I will also throw it in along with the 55-300. I am also considering taking the K 28 shift lens. I don't want to spend all my time changing lenses, especially if there is a wind, but I am planning out the primary shot locations and have a very good idea as to what I will probably get. I am also using google earth, for measurements and shot angles, which I can measure and with a bit of geometry - ok trig, I have figured out that the 12-24 will not cut it and thus I need a larger Angle of View on the UWA.

That brings me to your stitching and framing with my feet. Stitching I am already planning to do some. However, on some of the major positions, I really want a bracketed 5 frame single shot, so that I can tone map easily with out going through some of the problems I believe I will encounter. At -2ev some of the frames will be pretty much black, and thus be very difficult to stitch several all black frames together. If I stack them first, then they contribute - but then I have the stitching problem knitting them together after tone mapping. In several positions I really can't move back or I will go into the water - not good. However, I can move to the side and thus increase the distance - however, I will be moving off the shot line that I am after. Its all going to be a compromise in real time.

Can't help you on the lens part, but for sitching, I use Hugin, and it can save the stitch parameters for use on the other exposure shots.

[interested_observer]

I have both lenses. Bought the Pentax 12-24 t the end of last year and the Sigma 8-16 beginning of this year. Both lenses are great performers. Think my 12-24 slightly nudges out the Sigma in sharpness but the Sigma has a little more contrast. The Sigma has more vignetting which also makes it look contrastier. Both lenses are so good I can live with the IQ of either. Haven't noticed major flare or ca problems with either lens and don't feel my 10-17 is a lot better than either.

Bought the 12-24 to get back the ultra wide lost when going digital. My 35mm uw is a Pentax 15 3.5 ( not FE). The 12-24 got close. Then the sigma came out and I had to have it. Now I am wider than the 35mm uw. Love it.

Some things to consider.
Pentax has a huge diameter hood that is tight fit in the largest Domke bag insert. Must be 3" diameter or more. It will take thin 77mm filters w/o problem. Manual focusing is light and delightful. Lens is constant f4 aprture.

Sigma lens is a little longer in length, but hood is less in diameter, so it fits bag better. Sigma hood does not come off. It will not take any kind of filters. A provided collar fits over the hood allowing the normal lens cap to be used. Below about 10mm Pentax cameras won't show focal length in exif data. Pentax needs to fix this. In manual focus the ring is fairly tight feeling.

I love both lenses but probably love the Sigma a little bit more. I love extremes. Truthfully there is such a difference in their angle of view they really aren't competing with each other.
thanks and good luck
barondla

Excellent information - just what I was afraid to hear. If my request is approved, I think that the order goes in. My backpack to carry the lenses, is becoming severely over committed. The last thing I want is to have to pick up another backpack to haul my equipment around in. I was just looking at the shots I took last week, which was essentially a recon trip. I want to retake those test shots (outside the security perimeter) - and they were at 24mm. So, if I go the 8-16 mm route, I am going to need to cover 24mm also - either with the Pentax 12-24 or the Zeiss 25 - which is still taking yet another lens. Maybe I should bring a pack mule too.

Can't help you on the lens part, but for sitching, I use Hugin, and it can save the stitch parameters for use on the other exposure shots.

The HDR / Tone mapping software package I use (which does not support stitching) suggests this approach. I have been lazy enough to not pursue this approach - yet. I am just going to have to break down and walk the process - to get the results that I want and know that are there - just waiting.