[candgpics]

Hi:

I recently purchased the Sigma 10-20 f/4-5.6.

I am a portrait photographer for the most part (enthusiast, not pro!!!), but wanted to have a wide angle lens for some landscape work and am traveling this coming summer to Europe and wanted to have the option of having a wide angle lens.

When I played around with the lens for a bit at home and in our backyard I was very disappointed. Even at f/8 the lens seemed a bit "smeary," both indoors and outdoors.

I was set to return the lens and decided to shoot with it in our home without a UV filter on it (an expensive one at that--it came from my DA* 300, which produces great images). I recently read a post from someone who found out that his lens (I forget which lens) performed poorly with a UV filter on it.

I know there is a whole debate out there about the need for such filters, but I always have shot with one on all of my lenses and up until now have always been happy with my images.

I just had the time to take a few quick pics in our house and without the UV filter the images were quite good. The lens back focused a fair amount, but so do all of my Sigma lenses. A quick +4 took care of that. On my original test images, even though the lens back focused, nothing was really sharp, anywhere. Not horribly out of focus, but soft everywhere.

I am going to test the lens outside over the next few days to see if the lens does well outside without the UV filter--and I would assume it would, if it did well indoors without the UV filter.

So my question is this, do wide angle lenses, perhaps this one in particular, perform poorly or less well with a UV filter?

The lens is relatively inexpensive and I would love to be able to keep it.

Thanks so much for any thoughts or suggestions.

[Kwong]

Hi:

I recently purchased the Sigma 10-20 f/4-5.6.

I am a portrait photographer for the most part (enthusiast, not pro!!!), but wanted to have a wide angle lens for some landscape work and am traveling this coming summer to Europe and wanted to have the option of having a wide angle lens.

When I played around with the lens for a bit at home and in our backyard I was very disappointed. Even at f/8 the lens seemed a bit "smeary," both indoors and outdoors.

I was set to return the lens and decided to shoot with it in our home without a UV filter on it (an expensive one at that--it came from my DA* 300, which produces great images). I recently read a post from someone who found out that his lens (I forget which lens) performed poorly with a UV filter on it.

I know there is a whole debate out there about the need for such filters, but I always have shot with one on all of my lenses and up until now have always been happy with my images.

I just had the time to take a few quick pics in our house and without the UV filter the images were quite good. The lens back focused a fair amount, but so do all of my Sigma lenses. A quick +4 took care of that. On my original test images, even though the lens back focused, nothing was really sharp, anywhere. Not horribly out of focus, but soft everywhere.

I am going to test the lens outside over the next few days to see if the lens does well outside without the UV filter--and I would assume it would, if it did well indoors without the UV filter.

So my question is this, do wide angle lenses, perhaps this one in particular, perform poorly or less well with a UV filter?

The lens is relatively inexpensive and I would love to be able to keep it.

Thanks so much for any thoughts or suggestions.

You have described the exact same problem i had with my DA* 300. Same issue. With protective filter or UV or Skylight same issue. Though my lens does not have any back focus problems. Now i just use it without filters and everything is perfect. Had the issue on both my K5 and K3. I also have an original Sigma 70-200 f2.8 with old skylight filter on it and no issues but is set to +6 for back focus. Images are the same with or without filter. Go figure. If someone out there can explain this they are a genius.

[crewl1]

In general I find uv filters only make IQ worse so I do not use them.

The DA *300 is such a fine lens that it takes a lot to make it look bad.
The same filter on your wide angle could be impacting a marginal lens more severely.

Since I don't use them at all I cannot tell you if they impact any particular focal length.

If you are concerned most about image quality you should not use UV filter at all no matter how expensive.

If you use them to protect the front element a lens hood is a better choice.

[Dave's clichés]

I have this lens and use a filter Hoya HMC and no real problems and I have checked, be careful however with the AF at 10-12mm as the DOF produces variable AF results, except for closer work I set the focusing to my predetermined infinity point, marked with a white spot by me using LV. There is also a large field of curvature at 10mm, DPreview compromised their focus setting when testing the lens(see their review). Also check to see if the lens is well centered, my lens was returned decentered to Sigma which they repaired successfully.

[candgpics]

Hi:

Thank you all for your great replies. I will play around with the lens over the next week or so and test things with and without the UV filter.

I have the Sigma 70-200 f2.8 and Sigma 24 f1.8. They are a bit quirky and back focus, but once I figured them out they really are very nice lenses and have good build quality.

The 10-20 f4-5.6 seems like a good lens build wise, especially at the price point, and at $399 I think it was a very good buy (save for any Black Friday/Holiday sales). I really would like to keep it if I can.

I will let you know what happens.

Thank you again!!!

[mgvh]

I have Sigma 10-20 f4-5.6 which I use on both a K-x and a K-30. This is my only lens for which I use a filter. It's a good Hoya UV filter, and I just feel a bit better to give a bit of protection to that glass sticking out on the front of the lens. I just tried a test with and without the filter, but I can't see any difference.
Mine is not the greatest at 10mm (very soft borders), and I need to use at least f8. As I go longer, I get better results opening up, so that at 20mm, f5.6 gives best results.

[schnitzer79]

the only lens I use a filter on is my 18-135, since I use it a lot when hiking, so would like some extra protection. ive tested the lens with and without the UV filter and have not noticed any difference whatsover in IQ. I use the Hoya Pro1 by the way. The only thing I can think of, is if the anything on the glass is fooling the AF and thats why your images appear soft. Try manual focusing to see if your images are sharper.if not, then the problem is with the lens

[rrstuff]

Hi:

I recently purchased the Sigma 10-20 f/4-5.6.

I am a portrait photographer for the most part (enthusiast, not pro!!!), but wanted to have a wide angle lens for some landscape work and am traveling this coming summer to Europe and wanted to have the option of having a wide angle lens.

When I played around with the lens for a bit at home and in our backyard I was very disappointed. Even at f/8 the lens seemed a bit "smeary," both indoors and outdoors.

I was set to return the lens and decided to shoot with it in our home without a UV filter on it (an expensive one at that--it came from my DA* 300, which produces great images). I recently read a post from someone who found out that his lens (I forget which lens) performed poorly with a UV filter on it.

I know there is a whole debate out there about the need for such filters, but I always have shot with one on all of my lenses and up until now have always been happy with my images.

I just had the time to take a few quick pics in our house and without the UV filter the images were quite good. The lens back focused a fair amount, but so do all of my Sigma lenses. A quick +4 took care of that. On my original test images, even though the lens back focused, nothing was really sharp, anywhere. Not horribly out of focus, but soft everywhere.

I am going to test the lens outside over the next few days to see if the lens does well outside without the UV filter--and I would assume it would, if it did well indoors without the UV filter.

So my question is this, do wide angle lenses, perhaps this one in particular, perform poorly or less well with a UV filter?

The lens is relatively inexpensive and I would love to be able to keep it.

Thanks so much for any thoughts or suggestions.

I too found that UV filters make the lenses worse. In an ultrawide angle this could be particularly bad, since the angle of incidence is close to parallel. That means a light ray will be shifted as it passes through extra piece of glass. Just thinking now, this could cause both loss of sharpness and some extra vignetting. I would go without the UV filter unless you are shooting in some really bad conditions, like a windy desert.

My 10-20 is ok. Nothing to rave about, but it is competent and does the job well enough, that it is not a problem for internet sharing. I haven't printed any shots from it.

[btnapa]

Hi:

I recently purchased the Sigma 10-20 f/4-5.6.

I am a portrait photographer for the most part (enthusiast, not pro!!!), but wanted to have a wide angle lens for some landscape work and am traveling this coming summer to Europe and wanted to have the option of having a wide angle lens.

When I played around with the lens for a bit at home and in our backyard I was very disappointed. Even at f/8 the lens seemed a bit "smeary," both indoors and outdoors.

I was set to return the lens and decided to shoot with it in our home without a UV filter on it (an expensive one at that--it came from my DA* 300, which produces great images). I recently read a post from someone who found out that his lens (I forget which lens) performed poorly with a UV filter on it.

I know there is a whole debate out there about the need for such filters, but I always have shot with one on all of my lenses and up until now have always been happy with my images.

I just had the time to take a few quick pics in our house and without the UV filter the images were quite good. The lens back focused a fair amount, but so do all of my Sigma lenses. A quick +4 took care of that. On my original test images, even though the lens back focused, nothing was really sharp, anywhere. Not horribly out of focus, but soft everywhere.

I am going to test the lens outside over the next few days to see if the lens does well outside without the UV filter--and I would assume it would, if it did well indoors without the UV filter.

So my question is this, do wide angle lenses, perhaps this one in particular, perform poorly or less well with a UV filter?

The lens is relatively inexpensive and I would love to be able to keep it.

Thanks so much for any thoughts or suggestions.

I bought the same lens about 6 months ago. It is relatively sharp. I have not used any UV filter with it. As a matter of habit I do not use any filters on any of my lenses, unless it is a polarizer or ND or other specialized filters. The Sigma 10-20 looks pretty good with my B&W polarizer. My landscape shots are mostly at f11 or f13 and they look sharp but not super sharp. I am not sure if my camera auto focus is the issue or just the lens is not as sharp as it should be.

I did some product shots and the assignment called for dramatic wide angles in close range. For those shots, the Sigma looks as sharp as my FA 43 which was my main lens for most of the assignment.