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08-12-2016, 03:37 PM   #1
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Sigma 8-16 brightness issues

Hello. I recently purchased a Sigma 8-16 from their official site soon after I purchased my first Pentax camera. I like the unique distortion and focal length, but it seems to me that the brightness is sort of an issue. Other than changing the aperture, is there a way to get brighter and contrasty result for both day and night?

08-12-2016, 04:09 PM   #2
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Is it specifically vignetting that's causing the issue? This can be corrected in post. I'd recommend doing that as lifting shadows isn't normally an issue. You could also overexpose by a third to half a stop, but this could potentially backfire.

Could you post some examples of the problematic shots?

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08-12-2016, 04:17 PM - 1 Like   #3
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I find I need to set exposure compensation at +1.0 when using the 8-16.
08-12-2016, 04:25 PM   #4
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QuoteOriginally posted by Adam Quote
Is it specifically vignetting that's causing the issue? This can be corrected in post. I'd recommend doing that as lifting shadows isn't normally an issue. You could also overexpose by a third to half a stop, but this could potentially backfire.

Could you post some examples of the problematic shots?
Thank you Adam. As you can see from pictures below vignetting is definitely a huge part of the dark outcomes. These pictures from sigma 8-16 are taken at Buford Dam GA today on a very sunny day right after a little bit of raining. I had all my arms burn but the picture don't look as bright as it was out there.

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08-12-2016, 04:49 PM   #5
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These kinds of scenes are tough on the camera's metering system, since the majority (the sky) is very bright and thus skews the exposure down a bit. You'll definitely have to use exposure compensation now and then (especially in the latter two, though the first is close and the second is just about perfect as is).

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08-12-2016, 05:05 PM   #6
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On the second I'd have brought up the shadows some and it would have been great in my opinion.
08-12-2016, 05:47 PM   #7
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QuoteOriginally posted by VoiceOfReason Quote
On the second I'd have brought up the shadows some and it would have been great in my opinion.
Thanks all for the tips! So...when setting the exposure compensation to +1, we use the +/- button right above the top LCD? and VoiceofReason do you mean tweaking metering modes?
08-12-2016, 06:10 PM - 1 Like   #8
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There are some situations where a camera exposure reading is tough, but other methods are easier. It pays to try some of them and check the results/fine tune them.
1. Learn the sunny f/16 rule (f/16 at 1/iso sec) and correct from there.
2. Learn the adjustments to sunny f/16 rule (combine following):
-- for bright or hazy sun and distinct shadows +0 ev (sunny f/16 rule)
-- weak hazy sun, soft shadows +1 ev
-- cloudy bright, no shadows + 2 ev
-- cloudy dull no shadows or open shade + 3 ev
-- within 2 hours of sunrise or sunset + 1 ev
-- snow scene or beach - 1/2 ev
3. Spot meter blue sky, far from the sun--it is a midtone.
4. Spot meter brightest area (e.g., white puffy clouds, or nearby bright snow) and set exposure at +3 ev
5. Get an incident light meter

08-12-2016, 07:12 PM   #9
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QuoteOriginally posted by VoiceOfReason Quote
On the second I'd have brought up the shadows some and it would have been great in my opinion.
I'm a bit confused. Could you tell me more about the things you would have done with the 2nd picture shadows?

Last edited by talkskiwon; 08-12-2016 at 07:18 PM.
08-12-2016, 07:38 PM - 1 Like   #10
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Like This; edited in LightRoom (there are other programs that do the same)

Exposure is +.6, contrast +19, Hightlights -69, shadows +40, whites +22, blacks -43.
I also dropped blue luminance by -22, and put a brush mask in the sky and used the color balance control to make the sky a bit bluer without making the ground bluer. Total editing time <5 minutes

Do learn some kind of editing program, it can help fix whatever may be not quite right in a photo.




---------- Post added 08-12-16 at 08:47 PM ----------

And just for fun, I did the other three, pretty much just using Auto Adjustment from LightRoom. On the first one, I did bump the exposure slightly brighter than the Auto result. The other two are just clicking the Auto button and voila:









---------- Post added 08-12-16 at 08:51 PM ----------

QuoteOriginally posted by talkskiwon Quote
Thanks all for the tips! So...when setting the exposure compensation to +1, we use the +/- button right above the top LCD? and VoiceofReason do you mean tweaking metering modes?
Correct. What I do in challenging light: Just take a picture. Press the blue button so you can see your shot. Press Info to bring up the menu, and click right to get the histogram overlay. Make sure this is more or less in the center. If it's too far to the left, use +/- and add +0.5 or +1 depending on how dark the photo is. If the histogram is too far to the right, set +/- to a small negative number. After choosing exposure compensation, take a second photo. Here is an article on the histogram. There are many others.

An even better idea is to get the book "Understanding Exposure" by Bryan Petersen.

Last edited by Kozlok; 08-12-2016 at 07:57 PM.
08-12-2016, 07:57 PM   #11
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QuoteOriginally posted by Kozlok Quote
Like This; edited in LightRoom (there are other programs that do the same)

Exposure is +.6, contrast +19, Hightlights -69, shadows +40, whites +22, blacks -43.
I also dropped blue luminance by -22, and put a brush mask in the sky and used the color balance control to make the sky a bit bluer without making the ground bluer. Total editing time <5 minutes

Do learn some kind of editing program, it can help fix whatever may be not quite right in a photo.




---------- Post added 08-12-16 at 08:47 PM ----------

And just for fun, I did the other three, pretty much just using Auto Adjustment from LightRoom. On the first one, I did bump the exposure slightly brighter than the Auto result. The other two are just clicking the Auto button and voila:









---------- Post added 08-12-16 at 08:51 PM ----------



Correct. What I do in challenging light: Just take a picture. Press the blue button so you can see your shot. Press Info to bring up the menu, and click right to get the histogram overlay. Make sure this is more or less in the center. If it's too far to the left, use +/- and add +0.5 or +1 depending on how dark the photo is. If the histogram is too far to the right, set +/- to a small negative number. After choosing exposure compensation, take a second photo. Here is an article on the histogram. There are many others.

An even better idea is to get the book "Understanding Exposure" by Bryan Petersen.
Wow. Before starting this thread, I was in contact with Sigma for return process, but I might want to take a hold on that thought. Thanks for taking time to do this. Will definitely learn some editing software sooner or later!

---------- Post added 08-12-16 at 08:14 PM ----------

QuoteOriginally posted by Kozlok Quote
Like This; edited in LightRoom (there are other programs that do the same)

Exposure is +.6, contrast +19, Hightlights -69, shadows +40, whites +22, blacks -43.
I also dropped blue luminance by -22, and put a brush mask in the sky and used the color balance control to make the sky a bit bluer without making the ground bluer. Total editing time <5 minutes

Do learn some kind of editing program, it can help fix whatever may be not quite right in a photo.




---------- Post added 08-12-16 at 08:47 PM ----------

And just for fun, I did the other three, pretty much just using Auto Adjustment from LightRoom. On the first one, I did bump the exposure slightly brighter than the Auto result. The other two are just clicking the Auto button and voila:









---------- Post added 08-12-16 at 08:51 PM ----------



Correct. What I do in challenging light: Just take a picture. Press the blue button so you can see your shot. Press Info to bring up the menu, and click right to get the histogram overlay. Make sure this is more or less in the center. If it's too far to the left, use +/- and add +0.5 or +1 depending on how dark the photo is. If the histogram is too far to the right, set +/- to a small negative number. After choosing exposure compensation, take a second photo. Here is an article on the histogram. There are many others.

An even better idea is to get the book "Understanding Exposure" by Bryan Petersen.
Thanks again for additional inspirations and the learning tips. Much appreciated!
08-13-2016, 03:57 AM   #12
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I owned this lens for a while and had exactly the same problem. Long story short, it's not actually a problem!

When you take in such a huge view of the world, it's inevitable you are going to be seeing bright patches (like the sun), and dark patches (E.g shadows). On the k-3 (where I used this lens most), the images would usually appear dark 99 times out of a hundred, and initially I tried to compensate by increasing the exposure. That just led to huge blown highlights around the sun. In the end, as I recall, I actually ended up using it at -0.3ev most of the time, and then compensating the shadows in post.

The sigma 8-16 is a great little lens, sharp, stupid wide, and with great colours; however it is not a lens for jpeg shooters. I can say that the 12-24 Pentax lens didn't have the same metering problems (possibly because the coatings were better able to cope with direct sunlight?), however the image quality was distinctly sub-par when compared to the sigma - the Pentax was always a little mushy. At 15mm, the DA15 limited came out on top mostly, but then you'd expect a prime to do just that! All in all, the sigma 8-16 was a fun lens, the only downside to it is that it's not as small as the DA15.

So yeah, tl;dr, metering is an issue with the sigma, but it delivers at that ultra wide end. At the narrower end, the DA15 comes out on top, but not my much.

---------- Post added 08-13-16 at 12:01 PM ----------

Oh yeah, forgot to mention. Pentax cameras seem to expose for highlights rather than shadows. Having one super bright spot in the frame will make the camera adjust the exposure to prevent clipping in the highlights. The rest of the frame will then appear dark, but you can adjust the curves later on, and get some great results.
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