Trouble with Sigma 18-300C

Nitrogliserin · 10-27-2017, 03:43 AM

I got this weird white vignette or bleach with photos I take with Pentax k3 and sigma 18-300C.

What seems to be causing that cataract effect?

Adam · 10-27-2017, 04:20 AM

Just this once? Kind of looks like flare, assuming the sun was just to the right of the right edge.

Nitrogliserin · 10-27-2017, 02:02 PM

Originally posted by Adam

Just this once? Kind of looks like flare, assuming the sun was just to the right of the right edge.

It appears in different cases but yes, the position of the sun makes that issue. I mostly use a lens hood but I'm not sure if it's a fault by design,

The result can be harsh compared to other lenses I used so far.

Few more example

**tduell** · 10-27-2017, 02:42 PM

Originally posted by Nitrogliserin

It appears in different cases but yes, the position of the sun makes that issue. I mostly use a lens hood but I'm not sure if it's a fault by design

I use the 18-300C on a K-3 II, always with the lenshood, and never seen this effect, if that's any help.

Cheers,
Terry

**c.perkins** · 10-27-2017, 04:24 PM

The first three pictures look fine to me.
The last one is into the sun but not a bad photo either.
I use the 18~300 with a Hoya Pro 1 filter.
I really like this multi purpose lens.

Your mileage may vary.
Clarence

**BigMackCam** · 10-27-2017, 04:29 PM

Originally posted by c.perkins

The first three pictures look fine to me.

Bottom left corner of the images shows flare, no?

**c.perkins** · 10-27-2017, 04:37 PM

Originally posted by BigMackCam

Bottom left corner of the images shows flare, no?

Yes, I see something there.
Is that from the sun being to the right ?

Clarence

---------- Post added 10-27-17 at 06:55 PM ----------

Just went through all my pic's using that lens and do not see the same issue.
Do not know what else to say other than try the same photo with lens hood on and off.
The portion of the photo at the bottom left looks too man made than an exposure/image capture problem.
But then again I am far from an expert.

Clarence

Nitrogliserin · 10-28-2017, 06:44 AM

Originally posted by c.perkins

Yes, I see something there.
Is that from the sun being to the right ?

Clarence

---------- Post added 10-27-17 at 06:55 PM ----------

Just went through all my pic's using that lens and do not see the same issue.
Do not know what else to say other than try the same photo with lens hood on and off.
The portion of the photo at the bottom left looks too man made than an exposure/image capture problem.
But then again I am far from an expert.

Clarence

Correct.

Checking older photos and I see it's there.

https://image.ibb.co/grjBvm/Photo_70.jpg

a harsh way to tolerate sun light. In case you are not experiencing the same with your Sigma I guess I have a bad copy or something.

forensicscientist · 10-28-2017, 07:57 AM

Do you have a filter on the lens?

photoptimist · 10-28-2017, 08:51 AM - **1 Like**

First, the cataract effect is almost certainly due to sun or extremely bright sky light getting into the lens. The hood is a first line of defense but it has a severe limitations in that it only provides protection at 18 mm. If you zoom even a little (say to 28), it's easy to frame a picture with the sun falling outside the image but still falling inside the hood and striking the lens. And the more you zoom, the easier it is to accidentally let a lot of stray light strike the front element and fog the picture.

Second, these superzooms inhale a lot of air (and dust) when zooming. I've got an old Tamron 18-250 that's accumulated a layer of dust on the inside of the front element assembly from zooming. That makes these problems of flare even worse.

Some solutions are: 1) try to keep the sun out of the lens by keeping the sun behind you (which may not always be possible); 2) if the sun is in front of you, then use your hand or a bit of card-stock to shield the front of the lens; 3) keep the front element of the lens as clean as possible.

Nitrogliserin · 10-29-2017, 01:47 AM

Originally posted by forensicscientist

Do you have a filter on the lens?

No, I don't have any filters

---------- Post added 10-29-17 at 11:49 AM ----------

Originally posted by photoptimist

First, the cataract effect is almost certainly due to sun or extremely bright sky light getting into the lens. The hood is a first line of defense but it has a severe limitations in that it only provides protection at 18 mm. If you zoom even a little (say to 28), it's easy to frame a picture with the sun falling outside the image but still falling inside the hood and striking the lens. And the more you zoom, the easier it is to accidentally let a lot of stray light strike the front element and fog the picture.

Second, these superzooms inhale a lot of air (and dust) when zooming. I've got an old Tamron 18-250 that's accumulated a layer of dust on the inside of the front element assembly from zooming. That makes these problems of flare even worse.

Some solutions are: 1) try to keep the sun out of the lens by keeping the sun behind you (which may not always be possible); 2) if the sun is in front of you, then use your hand or a bit of card-stock to shield the front of the lens; 3) keep the front element of the lens as clean as possible.

Thanks a lot for the explanation!

I'll try to clean the lens if there's any dust inside and will def try to block the sun with hand

10-27-2017, 03:43 AM	#1
Nitrogliserin Senior Member Join Date: Apr 2013 Location: Turkey Posts: 246	Trouble with Sigma 18-300C I got this weird white vignette or bleach with photos I take with Pentax k3 and sigma 18-300C. What seems to be causing that cataract effect?

10-27-2017, 04:20 AM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,608	Just this once? Kind of looks like flare, assuming the sun was just to the right of the right edge. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Sigma 18-250 vs Tamron 18-200 vs Sigma 18-200	5150ds	Pentax SLR Lens Discussion	19	04-11-2011 05:00 PM
K-R trouble focusing in low light with Live View using Pentax 18-55 kit lens	sportv	Pentax K-r	8	01-02-2011 06:42 PM

10-27-2017, 02:02 PM	#3
Nitrogliserin Senior Member Join Date: Apr 2013 Location: Turkey Posts: 246 Original Poster	Originally posted by Adam Just this once? Kind of looks like flare, assuming the sun was just to the right of the right edge. It appears in different cases but yes, the position of the sun makes that issue. I mostly use a lens hood but I'm not sure if it's a fault by design, The result can be harsh compared to other lenses I used so far. Few more example

10-27-2017, 02:42 PM	#4
tduell Loyal Site Supporter Join Date: May 2015 Location: Melbourne Posts: 1,517	Originally posted by Nitrogliserin It appears in different cases but yes, the position of the sun makes that issue. I mostly use a lens hood but I'm not sure if it's a fault by design I use the 18-300C on a K-3 II, always with the lenshood, and never seen this effect, if that's any help. Cheers, Terry

10-27-2017, 04:24 PM	#5
c.perkins Loyal Site Supporter Join Date: Jun 2017 Location: New Lisbon, WI. Photos: Gallery \| Albums Posts: 515	The first three pictures look fine to me. The last one is into the sun but not a bad photo either. I use the 18~300 with a Hoya Pro 1 filter. I really like this multi purpose lens. Your mileage may vary. Clarence

10-27-2017, 04:29 PM	#6
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,704	Originally posted by c.perkins The first three pictures look fine to me. Bottom left corner of the images shows flare, no?

10-27-2017, 04:37 PM	#7
c.perkins Loyal Site Supporter Join Date: Jun 2017 Location: New Lisbon, WI. Photos: Gallery \| Albums Posts: 515	Originally posted by BigMackCam Bottom left corner of the images shows flare, no? Yes, I see something there. Is that from the sun being to the right ? Clarence ---------- Post added 10-27-17 at 06:55 PM ---------- Just went through all my pic's using that lens and do not see the same issue. Do not know what else to say other than try the same photo with lens hood on and off. The portion of the photo at the bottom left looks too man made than an exposure/image capture problem. But then again I am far from an expert. Clarence

10-28-2017, 06:44 AM	#8
Nitrogliserin Senior Member Join Date: Apr 2013 Location: Turkey Posts: 246 Original Poster	Originally posted by c.perkins Yes, I see something there. Is that from the sun being to the right ? Clarence ---------- Post added 10-27-17 at 06:55 PM ---------- Just went through all my pic's using that lens and do not see the same issue. Do not know what else to say other than try the same photo with lens hood on and off. The portion of the photo at the bottom left looks too man made than an exposure/image capture problem. But then again I am far from an expert. Clarence Correct. Checking older photos and I see it's there. https://image.ibb.co/grjBvm/Photo_70.jpg a harsh way to tolerate sun light. In case you are not experiencing the same with your Sigma I guess I have a bad copy or something.

10-28-2017, 07:57 AM	#9
forensicscientist Pentaxian Join Date: Jun 2008 Location: DFW Texas and Michigan - I commute :) Posts: 1,012	Do you have a filter on the lens?

10-28-2017, 08:51 AM - 1 Like	#10
photoptimist Pentaxian Join Date: Jul 2016 Photos: Albums Posts: 5,129	First, the cataract effect is almost certainly due to sun or extremely bright sky light getting into the lens. The hood is a first line of defense but it has a severe limitations in that it only provides protection at 18 mm. If you zoom even a little (say to 28), it's easy to frame a picture with the sun falling outside the image but still falling inside the hood and striking the lens. And the more you zoom, the easier it is to accidentally let a lot of stray light strike the front element and fog the picture. Second, these superzooms inhale a lot of air (and dust) when zooming. I've got an old Tamron 18-250 that's accumulated a layer of dust on the inside of the front element assembly from zooming. That makes these problems of flare even worse. Some solutions are: 1) try to keep the sun out of the lens by keeping the sun behind you (which may not always be possible); 2) if the sun is in front of you, then use your hand or a bit of card-stock to shield the front of the lens; 3) keep the front element of the lens as clean as possible.

10-29-2017, 01:47 AM	#11
Nitrogliserin Senior Member Join Date: Apr 2013 Location: Turkey Posts: 246 Original Poster	Originally posted by forensicscientist Do you have a filter on the lens? No, I don't have any filters ---------- Post added 10-29-17 at 11:49 AM ---------- Originally posted by photoptimist First, the cataract effect is almost certainly due to sun or extremely bright sky light getting into the lens. The hood is a first line of defense but it has a severe limitations in that it only provides protection at 18 mm. If you zoom even a little (say to 28), it's easy to frame a picture with the sun falling outside the image but still falling inside the hood and striking the lens. And the more you zoom, the easier it is to accidentally let a lot of stray light strike the front element and fog the picture. Second, these superzooms inhale a lot of air (and dust) when zooming. I've got an old Tamron 18-250 that's accumulated a layer of dust on the inside of the front element assembly from zooming. That makes these problems of flare even worse. Some solutions are: 1) try to keep the sun out of the lens by keeping the sun behind you (which may not always be possible); 2) if the sun is in front of you, then use your hand or a bit of card-stock to shield the front of the lens; 3) keep the front element of the lens as clean as possible. Thanks a lot for the explanation! I'll try to clean the lens if there's any dust inside and will def try to block the sun with hand