# Photo sharpness, am I imagining things?



## japvdk (Aug 21, 2016)

Hi all!
After a lot of online research, I recently bought a new lens, the sigma 18-250mm f3,5-6.3DC Macro OS HSM. However, since having bought this lens, I haven't been pleased with the overal sharpness of the images. It is not that the pictures are horribly out of focus, but they all seem a little soft. Of course, the easiest explaination would be blaiming my new lens, but I am reluctant to do so. Some online research gives me a vast array of possible explainations, one of which is too high expectations. I have attached some pictures I recently took, and I hope you can tell me if they are not as sharp as they should be. I have not zoomed in.

IMG_0896 — Postimage.org (f10 1/100 iso 100)
IMG_0394 — Postimage.org (f11 1/100 iso 100)
IMG_1378 — Postimage.org (f10 1/100 iso 100)
IMG_9753 — Postimage.org (f14 1/60 iso 100)
IMG_9025 — Postimage.org (f22 1/15 iso 100 tripod)
IMG_1573 — Postimage.org (f10 1/8 iso 100 tripod)

For the last two, I might have overestimated my tripod (very old), but for the other two the shutterspeeds seem fast enough for a hand held wide angle shot.
Thanks for your help, I hope the links work


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## Parker219 (Aug 21, 2016)

Did you shoot these is jpeg or RAW?


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## japvdk (Aug 21, 2016)

Parker219 said:


> Did you shoot these is jpeg or RAW?


jpeg


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## Braineack (Aug 21, 2016)

looks like a very bad copy of the lens.


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## table1349 (Aug 21, 2016)

Here is the conclusion from DP review on that lens.

_The Sigma 18-250mm F3.6-6.3 DC Macro OS HSM is one of the best of the current bunch of SLR superzooms, with decent optics, fast autofocus and effective image stabilization. It's a reliable performer, and its close-up capability is handy too.

*Good for:* Photographers looking for a compact, lightweight, all-in-one general purpose and travel lens.

*Not so good for:* Anyone unwilling to sacrifice image quality for convenience_

IQ is the compromise you accept with a super zoom.


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## japvdk (Aug 21, 2016)

@Braineack, what do you mean? That there is something wrong with the lens? Would you recommend going back to the store?
@gryphonslair99 I am aware of the setbacks of super zooms, it was a difficult decission, but do you really think that the image quality would this bad? When I was researching the lens I got the impression the differences in image quality between lenses where differences that could only be seen by trained eyes, and mostly at the extremes of camera settings, certainly not at apertures of f10. But I might be wrong of course.


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## astroNikon (Aug 21, 2016)

most people can't handhold 1/1o0 much less 1/60 for sharpness.


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## fmw (Aug 21, 2016)

The longer the zoom range, the more the compromise in image quality.  You can't expect this lens to perform with one that has a 2X or 3X range.


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## Light Guru (Aug 21, 2016)

The quality of the image posted is about what I would expect from a lens that is trying to be a all in one lens. 

When something or someone tries to do everything the quality is never as good as when you specialize in something.


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## HughGuessWho (Aug 21, 2016)

You must concider that the vast majority of reviews found on the Internet are written by those that are clueless


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## japvdk (Aug 21, 2016)

My aunt has a similar lens, and I always think her photos are really sharp. I'd rather hear that I need to use shorter shutterspeeds, a different aperture, and so on.. But the general conclusion seems to be that I can't hope to get sharp pictures with my new lens. What a sad conclusion...


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## Light Guru (Aug 21, 2016)

japvdk said:


> My aunt has a similar lens, and I always think her photos are really sharp. I'd rather hear that I need to use shorter shutterspeeds, a different aperture, and so on.. But the general conclusion seems to be that I can't hope to get sharp pictures with my new lens. What a sad conclusion...



Well you can certainly try those things.

The things people have said here are the reasons why a pro photographer would not use the lens. That does not mean others can use it with fine results.


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## SquarePeg (Aug 21, 2016)

Try a faster shutter speed with a wider aperture.


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## The_Traveler (Aug 21, 2016)

I looked at three of these, they were shot at 18 mm and a very small aperture and under lighting conditions that would tax any situation.
The images hadn't be sharpened in post-processing

The very end of any zoom lens' travel is generally not the best spot for sharp images.
The smallest aperture induces aberrations.
Most images need sharpening.
The best images are made when the light is diffuse but directional, not overhead and not in total shadow.
My guess is that, as you learn more about shooting, you will get better results from this lens.


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## japvdk (Aug 21, 2016)

@The_Traveler Wow great so there are things I can do about it, great! I wouldnt have thought that f10 is too small of an aperture. I read somewhere that f8 is mostly the best for sharp images and so I thought I'll stay in that ballpark but use a little smaller aperture fore landscapes, to get a larger depth of field. But if I understand it correctly the lessened sharpness of a smaller aperture negates the effects of a larger depth of field?

Post processing is something I am just starting to play around with (using gimp2) and I havent found the sharpening tool yet haha. 

I dont really understand why lighting conditions would effect the sharpness. I understand that it can make the exposure more difficult for a pretty picture, but how does it effect sharpness? 

Thanks so much for everyones help, it is good to learn where I made mistakes!


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## The_Traveler (Aug 21, 2016)

Look at DOFmaster.com and you can actually calculate the aperture you need for a specific DOF.
And lookup hyperfocal distance.
Since sharpness is really discerning edges and the difference in tones then light has a lot to do with sharpness.
My guess is that KMH will come along with a bunch of great links for you to read.

I have to go cook supper but help is on the way.


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## dennybeall (Aug 21, 2016)

You are certainly correct in that those are not sharp. With the shutter speeds listed I would want a very good tripod and a remote shutter release. Trying to handhold those speeds is not reasonable. I'd try some test shots with faster speeds to see if it's the lens.


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## japvdk (Aug 22, 2016)

I was reading online and on this forum and found that my standard camera settings have in camera sharpness at 3/7. Do you guys think it would be a good idea to increase that number? 

@dennybeall Im a bit confused, I thought 1/mm so 1/50 for 50mm etc was a good rule of thumb for handheld shots. So is 1/100 really not handholdable for mm<30 ?


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## Braineack (Aug 22, 2016)

japvdk said:


> @Braineack, what do you mean? That there is something wrong with the lens? Would you recommend going back to the store?



Looking at the pictures again... Do you have a filter on the lens? 

I refuse to believe that your shots are result of hand holding a long lens, the IQ is just horrendous.  It appears you shot through plastic.


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## table1349 (Aug 22, 2016)

japvdk said:


> @Braineack, what do you mean? That there is something wrong with the lens? Would you recommend going back to the store?
> @gryphonslair99 I am aware of the setbacks of super zooms, it was a difficult decission, but do you really think that the image quality would this bad? When I was researching the lens I got the impression the differences in image quality between lenses where differences that could only be seen by trained eyes, and mostly at the extremes of camera settings, certainly not at apertures of f10. But I might be wrong of course.


Actually yes.  People look at photographs made by competent photographers with top of the line glass ($$$$) and then go out and buy consumer grade super zooms for convenience and wonder why their results aren't the same.   And yes some of the comments made by others here in regards to shutter speed, hand holding etc. are quite relevant to the situation.  The fact remains that the compromise in super zooms is generally noticeable due to the huge range covered and the quality of the materials and construction.


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## japvdk (Aug 22, 2016)

@Braineack Yes I have a skylight filter on my lens, mostly for protection.


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## astroNikon (Aug 22, 2016)

japvdk said:


> @Braineack Yes I have a skylight filter on my lens, mostly for protection.


take it off
you may find you have a sudden improvement in IQ

I was going to mention before that you photos seem to have a lot of haze to them.  This degrades in the overall quality.

many professionals will stake out time, weather, lighting and everything else possible (after a rainfall which clears the sky etc) to get a nice clear photo of a scene.  Not just a quick snapshot. they may visit a place dozens of times just waiting for the best photo.


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## Braineack (Aug 22, 2016)

japvdk said:


> @Braineack Yes I have a skylight filter on my lens, mostly for protection.



You misspelled: blurry filter


You will find when you remove the cheap piece of plastic form in front of your lens, it will stop looking like youre shooting through a cheap piece of plastic.


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## japvdk (Aug 22, 2016)

@Braineack Wow that should be a relatively easy thing to fix haha, I have a Kenko skylight 1a on my lens, which I found in my dad's old photogear. Would you recommend buying a newer an better filter or leaving it off all together?

@astroNikon I realize that proffesional photographers invest way more time and energy in their photos than I do. It is of course tempting to compare my photos to those photos, but its something I try not to do. This was my first vacation with which I took almost no autoset pictures, and tried to go to places when the lighting conditions were optimal. I think that made the dissapointment in seeing somewhat unsharp images appear on my laptop afterwords a little bigger. But I'm really happy with all you guys responses, which gave a lot of different possible causes. Now I can try and avoid this dissapointment in the future !


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## Braineack (Aug 22, 2016)

#nofilters


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## astroNikon (Aug 22, 2016)

leave the filter off altogether, unless you really want that in front of your lens, then invest in a really good filter that won't cause any IQ loss .. of which you may choke on the price of good ones and decide not to anyways.


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## weepete (Aug 22, 2016)

Yup, first off get the UV filter off and bin it (or use it as a coaster if you really can't bear to throw it out). But even for a superzoom those are off. To me it certianly looks like there's some camera shake in there, but I'd have still expected these to be sharper.

So time for a test. First off get outside when there is good light, get a tripod or a stable platform, enable mirror lockup (or live view) and put your camera on timer. Set the camera to f11 and focus 1/3rd of the way into the image using a single point AF and focusing on  a contrasty area. Then take a shot, and you should have a sharp image. If the image still isn't sharp there's an issue probably with the lens, if it is sharp it's your technique.


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## Dave442 (Aug 22, 2016)

I also agree, take that old Skylight 1A filter off and put it back with the old photo equipment. I think the Traveler mentioned the Hyperfocal distance and I think you need to consider that for these types of landscape shots.


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## thereyougo! (Aug 22, 2016)

Your sensor could also do with a clean I suspect.  Two good chucks of dust there...

Edited to add:
Or else they might be on the inside of the filter...


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## japvdk (Aug 27, 2016)

Thanks guys! I tried it without the filter, and I think that did the trick. There are still some images that aren't very sharp, but I think I can explain why they would be my own fault.
Just to check:





This image was shot at (I guess) something like 50-60mm with an aperture of 7.1 and a shutterspeed of 1/250. If I use DOFmaster, I find that this will only give sharpness from 20-50 meters away from me, which is why the cliffs are unsharp. I should have used a smaller aperture, like f12. Correct?How low of an aperture can I go before diffraction makes my images noticably unsharper?

But most of the images are sharp like this one, which is probably what I should expect right?:


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## The_Traveler (Aug 27, 2016)

a bit of leveling and you're set.


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## Peeb (Aug 27, 2016)

Glad you're getting better images.

Many of which have already been noted, here are some things that can detract from image quality:

1) motion blur
a) camera shake- too slow shutter speeds (a suspect in your first set of pics)
     b) moving subject with too slow shutter​2) extreme aperture settings (max and min setting each introduce issues)
3) High ISO (not an issue in your images)
4) poor lens, or damaged equipment (a suspect)
5) zoom lenses at the extremes (typically at their worst at max and min focal lengths)
6) filter problems (a suspect for you)
7) focus problems- unlikely in 'landscape' images, but possible
8) Over-reliance on VR - ironically vibration reduction can actually introduce blur if you have a stationary subject and a camera on a tripod and/or adequate shutter speed.  While VR can be a godsend, it can also be a culprit.  Depends on the scenario.


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## japvdk (Sep 3, 2016)

weepete said:


> Yup, first off get the UV filter off and bin it (or use it as a coaster if you really can't bear to throw it out). But even for a superzoom those are off. To me it certianly looks like there's some camera shake in there, but I'd have still expected these to be sharper.
> 
> So time for a test. First off get outside when there is good light, get a tripod or a stable platform, enable mirror lockup (or live view) and put your camera on timer. Set the camera to f11 and focus 1/3rd of the way into the image using a single point AF and focusing on  a contrasty area. Then take a shot, and you should have a sharp image. If the image still isn't sharp there's an issue probably with the lens, if it is sharp it's your technique.



I think finding the new photos I took better might have been wishful thinking..
So I gave this a try as well . Here is the result. 31mm, f11, 1/160, iso 100. The light might not be optimal yet, if so, i'll try again later. 




In my opinion, it is still quite, well, blurry might be a good word.  
Hope to get you guys's opinions.


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## dennybeall (Sep 3, 2016)

Let's add a bit too much Hi-Pass sharpening: Now what do you think?


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## japvdk (Sep 3, 2016)

Well, to be honest, I'm still not sure. I mean if this is supposed to be the best sharpness I'm going to be able to get. At screensize, it's really not sharp. In any case, it's not a big improvement over the pictures I posted in the very beginning, still with the filter screwed on, and those weren't made on a tripod nor were the lighting conditions ideal. But maybe I'm imagining things, my thread is called that for a reason


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## weepete (Sep 5, 2016)

Yeah, that one of the trees looks very soft. What did the camera focus on and was there

Here's a website with some sample images of your lens and I'd expect the performance to be similar.

https://m.dpreview.com/reviews/sigma-18-250mm-3p5-6p3-os-hsm-macro/5

FYI diffraction normally starts showing at around f16 and gets worse with smaller apertures. F8-f16 is the sweet spot for landscape photographers.


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## japvdk (Sep 6, 2016)

weepete said:


> Yeah, that one of the trees looks very soft. What did the camera focus on and was there
> 
> Here's a website with some sample images of your lens and I'd expect the performance to be similar.
> 
> https://m.dpreview.com/reviews/sigma-18-250mm-3p5-6p3-os-hsm-macro/5



I focussed on the tree, so I would expect at least that to be sharp. The fotos on dpreview are what I expected when I bought the lens, not the very best image quality, but they are at least sharp. I'm thinking of going back to the store with my problem, do you guys think that will help?


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## weepete (Sep 6, 2016)

Yeah, I'd return it.


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## mcap1972 (Sep 12, 2016)

I'm sure it's a combination of few things like bad lens, misalignment, camera shake(mirror slap), post processing. Try doing some comparison tests with a different lens at the same focal lengths.


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## dannylightning (Sep 14, 2016)

I haven't read everything here. you may need a faster shutter speed,   the lens may need tuned to get a better focus,  some cameras have a focus fine tune,  some sigma lenses can be hooked up to the sigma dock so you can really fine tune the focus,     I own 3 sigma lenses that can be tuned with the dock,   the first one I got was tuned perfect from the factory.   the second one i got was a giant mess and i had to fine tune it and now its taking amazing photos,   the 3rd one I got was a little off on focus and I tuned it.    

so the lens may not have been tuned properly or you are doing something wrong,  sometimes you can contact the factory and send the lens to them and they will tune it for you,   I have heard of a few people doing this with different band lenses and when the lens came back it was perfect.     

it does have a huge zoom range and generally that is not going to give you the greatest image quality.  my nikon 18-200mm does pretty well, at times the photos that come out of it are perfect  but there have been some bad image too.   the photos on dp preview some of them look nice, some of them look soft.  

im gonna guess its just the lens its self   your better off getting two separate lenses if you care about image quality.   sure its nice to only need one lens for most shooting but that usually comes with a price.


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