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Thread: Sharp pix?

  1. #41
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    Default Re: Sharp pix?

    Quote Originally Posted by qingtian View Post
    And I will need to take note that f/11 and above will result in diffraction on a crop sensor as per Jed advised.
    Correct, with diffraction being greater the further you go from f11. That is to say, it doesn't "happen" at f11 onwards and f11 is not the same as f22 for example. So sometimes if you need the DoF then you stop down some more - it's a trade off and if you're familiar with the effects of both (not enough DoF and some diffraction) then you can make a better, informed decision as to what aperture you end up using.

    Next time you're out shooting a scene like this where DoF doesn't matter as much, take a shot at f8, take shots at f11, f16 and f22. And compare the differences. Then you'll have a clear idea about the damage diffraction does to your shots on a pixel level, and how bad it is at various f-stops. It does affect your quality at pixel level, and beyond, but I just don't think it's bad enough to impact getting a good 1000 pixel image.

    Quote Originally Posted by qingtian View Post
    Per your statement I guess "effectively is bumping your local edge contrast" am I right to say that is part of PP? Could I also check with you should I shoot at a lower megapixels as per what 7D offer would I encoutered such kind of softness issues as I dun really need a large resolution images.
    Yes, increasing edge contrast can be done in PP. I have done that to your image above (previous page now).

    I would still shoot at the higher resolution as it gives you more options particularly when it comes to PP; resizing the image on the computer and being able to work with that should, if anything, give you better results. As far as I'm aware the 7D doesn't do pixel binning when you shoot at lower resolutions, but shoots full resolution and then downsamples it. Exactly what you would be doing on the computer, in other words.

  2. #42
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    Default Re: Sharp pix?

    Quote Originally Posted by Numnumball View Post
    furthermore subjects are too far away to utlise hyperfocusing..
    You should be able to use hyperfocal focusing regardless of how far away your subjects are, it's just that in this case it's simply not needed with all the subjects clustered at close to infinity.

  3. #43
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    Default Re: Sharp pix?

    Quote Originally Posted by theveed View Post
    Many folks think that stopping down to f/16 or smaller is required for DOF concerns, but discounting any calculations in terms of actual DOF requirement and computation for hyperfocal distances based on the focal length used and the distance of the camera to the subject(s) as well.
    Because many folks shoot needing to try to get sharpness from say 2m to infinity, rather than just 10m to infinity.

    Quote Originally Posted by theveed View Post
    With a scene like yours, there isn't anything near your camera's position anyway to need that small of an aperture.
    Completely agree.

  4. #44
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    Default Re: Sharp pix?

    Quote Originally Posted by Jed View Post
    Next time you're out shooting a scene like this where DoF doesn't matter as much, take a shot at f8, take shots at f11, f16 and f22. And compare the differences. Then you'll have a clear idea about the damage diffraction does to your shots on a pixel level, and how bad it is at various f-stops. It does affect your quality at pixel level, and beyond, but I just don't think it's bad enough to impact getting a good 1000 pixel image.
    Yup, good suggestion, this

    After all, this is digital photography so it doesn't cost a cent to take a couple of extra shots. Besides, it'll help you learn the effects of stopping-up

  5. #45
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    Default Re: Sharp pix?

    Do view the comparison I did on the previous page, I'm slightly annoyed that it's only gone and disappeared to an older page and might get missed :P

  6. #46
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    Default Re: Sharp pix?

    Quote Originally Posted by Jed View Post
    Do view the comparison I did on the previous page, I'm slightly annoyed that it's only gone and disappeared to an older page and might get missed :P
    Haha... no lah, your well-illustrated sharpened image was very clearly visible on the previous page.
    In fact, to repeat what I stated in my earlier post, you have raised a very valid point about our over-eagerness in jumping onto the Diffraction bandwagon.
    Allow me to take this one step further: yes, certainly an increase in contrast plus an unsharp mask would drastically improve the sharpness. In this case, the only variable that I could find was the aperture that was a little too small. And that was what led me to deduce diffraction as the cause.

    Even more so, the original (slightly under-exposed) scene which the TS took was something so commonly shot by many an amateur photographer in terms of under-exposure & low-contrast, that we see it all over the forum. But then why was it that TS's photo was so soft compared to so many others? I asked myself this.
    I have gladly registered both yours and Kit's opinion on ambient light issue as a cause, and I will endeavour to explore and practise further.

    Thank you!

  7. #47

    Default Re: Sharp pix?

    agree with jed, looks plenty sharp with a bit of sharpening applied....

  8. #48
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    Default Re: Sharp pix?

    Not quite... Understand that post-processing sharpening sharpens edges only, especially hard edges. Soft originals will show really soft and blurry details inside those hard edges and the "fakeness" of over post-sharpening is clearly evident when the edges are so much more defined than the interior details.

  9. #49

    Default Re: Sharp pix?

    Quote Originally Posted by Rashkae View Post
    Bingo.

    So don't go above f/11 on a high-density sensor, and consider running a sharpening filter *after* you resize to a smaller size.

    If you are using photoshop, you can try to resize with bicubic (sharper) and you'll notice a big difference.
    I guess to a certain extend I still need to depend on PP to get the sharpness since my skill is still not there.

    Quote Originally Posted by Numnumball View Post


    Exactly.

    If you want to keep your images sharp, don't stop down that much with an APS-C DSLR. The effects of diffraction are clearly visible at f22 and above and it significantly degrade the image. Actually optimal sharpness depends on the lens you are using. For a lens with significant aberrations may give optimum results. For a lens with less aberrations optimum performance is maybe around f11, though both f8 and f16 are very similar. For a really good lens like the AFS 17-35mm f2.8 (which is the one i am using now) with well corrected aberrations, performance may peak at f5.6 and f8 and great at f11. f16 is acceptable, but f22 and smaller apertures should be avoided like i what i normally do. (Understand ur lens and its optimal aperture.)

    But imho, the smoothness of the photos be corrected easily in post processing if it is caused by diffraction. This is a small issue but if you want to get the maximum sharpness into your photos, diffraction is something to consider.

    Just my 2 cents worth
    Noted... btw just wat to check is there a specific guideline in choosing which f-numbers to use?

    I understand for low light shooting and to create bokeh you will need to use a lower f-numbers. Now for landscape I need to use between f/8 to f/16 but should try to avoid f/11 and above... Eh right now most of the term used in this thread are pretty technical... As I am a beginner... appreciate some helpful bro can advised me more on a layman term... or is there anything that is available online there is really easy for me to understand more on this pls.

    Quote Originally Posted by theveed View Post
    Many folks think that stopping down to f/16 or smaller is required for DOF concerns, but discounting any calculations in terms of actual DOF requirement and computation for hyperfocal distances based on the focal length used and the distance of the camera to the subject(s) as well.

    For example, using this http://www.dofmaster.com/dofjs.html calculator with a subject 30ft away.

    With a 50mm lens at f/11 on a crop, you'll keep things in focus from 17ft to 137ft.
    With an 18mm lens at f/4 on a crop, you'll keep things in focus from 9.5ft all the way to infinity. Switching to f/11 will only improve near-focus coverage...

    With a scene like yours, there isn't anything near your camera's position anyway to need that small of an aperture.
    Ic... so I should used a small aperture should my subject is not that near...
    Now I understand one of the bro pointed out that f/22 is more for Macro photography.

    Quote Originally Posted by Jed View Post
    Not quite the "amount" of ambient light but the type and quality of it. So a sunny day for example always results in more contrasty images that could give the perception of greater sharpness. If you should a portrait in a studio for example then a very softly lit shot of a subject would appear "less sharp" than a harshly lit subject.

    Personally I feel the second photo looks not dissimilar to the first, but the overexposure makes looking at it accurately quite difficult.

    I've done a little bit of editing to hopefully illustrate what I meant originally.



    I've sharpened the original image through two stages, a single low level general contrast enhancement, as well as the normal USM as you would do for publication. To me the second looks fine and a lot better already.

    I still stand by the fact that while diffraction does impact your quality, it shouldn't stop you from being able to get a good image at 1/26th the size of the original. It's obviously however very easy to jump on the diffraction bandwagon.
    Thanks for sharing more on this. I guess I will check up more info in how to use Photoshop for shapering.

  10. #50

    Default Re: Sharp pix?

    Quote Originally Posted by Jed View Post
    Correct, with diffraction being greater the further you go from f11. That is to say, it doesn't "happen" at f11 onwards and f11 is not the same as f22 for example. So sometimes if you need the DoF then you stop down some more - it's a trade off and if you're familiar with the effects of both (not enough DoF and some diffraction) then you can make a better, informed decision as to what aperture you end up using.

    Next time you're out shooting a scene like this where DoF doesn't matter as much, take a shot at f8, take shots at f11, f16 and f22. And compare the differences. Then you'll have a clear idea about the damage diffraction does to your shots on a pixel level, and how bad it is at various f-stops. It does affect your quality at pixel level, and beyond, but I just don't think it's bad enough to impact getting a good 1000 pixel image.



    Yes, increasing edge contrast can be done in PP. I have done that to your image above (previous page now).

    I would still shoot at the higher resolution as it gives you more options particularly when it comes to PP; resizing the image on the computer and being able to work with that should, if anything, give you better results. As far as I'm aware the 7D doesn't do pixel binning when you shoot at lower resolutions, but shoots full resolution and then downsamples it. Exactly what you would be doing on the computer, in other words.
    I will definitely do that so that I could do a comparison...
    I guess I will increase back to full resolution as what you suggested.

  11. #51
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    Default Re: Sharp pix?

    To the TS, just wonder did you use a cable release? The way you press the shutter release will contrbute to the overall sharpness of the pic.

  12. #52

    Default Re: Sharp pix?

    Quote Originally Posted by PhotoDog View Post
    To the TS, just wonder did you use a cable release? The way you press the shutter release will contrbute to the overall sharpness of the pic.
    Yes I did. I am using a cable release.

  13. #53
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    Default Re: Sharp pix?

    Quote Originally Posted by theveed View Post
    Not quite... Understand that post-processing sharpening sharpens edges only, especially hard edges. Soft originals will show really soft and blurry details inside those hard edges and the "fakeness" of over post-sharpening is clearly evident when the edges are so much more defined than the interior details.
    Okay this is a little misleading. I think I understand what you're trying to say, but your first line, that "post-processing sharpening sharpens edges only, especially hard edges", is wrong on its own. Actually, thinking more about it, it's wrong.

    Sharpening will sharpen any "detail". It doesn't have to be a hard edge.

    What you could say however is that hard edges sharpen more. Or alternatively, if your technique is flawed and your image is soft for whatever reason, then the soft details are the first things you lose, and obviously if they're not there, you can't sharpen them.

    But it's otherwise incorrect to say that sharpening doesn't sharpen the "interior details".

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