Why are my pics coming out not very sharp?

Discussion in 'Canon EOS' started by tre_gibbs, Jan 21, 2009.

  1. I purchased a Canon 12.2 MP digital EOS SLR rebel xs1 camera. The landscape pictures I've taken so far aren't nearly as crisp or clear as the ones taken on my little Canon 7.1 MP powershot.
    I've tried manual settings, I've tried photographing in RAW, superfine, tried auto focus, manual focus, etc. The pictures are not crisp like my former ones with the smaller camera.
    What am I doing wrong?
     
  2. Are you paying attention to your depth of field?
    What lens do you have on it?
     
  3. Can you upload a sample images with EXIF data intact?
    Your point and shoot, being a consumer camera has more default sharpening applied to its jpg files. Due to the nature of their design digital point and shoots have lots and lots more depth of field than a DSLR and therefore can appear sharper. As your point and shoot was 7MP and your DSLR 12MP, if you're relying on 100% views to determine sharpness, your 12MP images may "appear" less sharp when they are not.
    There are many variables that can cause people to say "not very sharp." You need to be more specific and provide examples and/or sample images.
     
  4. If you shot RAW you have to apply some sharpening yourself. An easy fix might be to shoot jpeg and turn up the in camera sharpening. For landscape try to use a larger F stop (F/8 or higher), and make sure you are shooting at about 1/100th or faster to elliminate camera shake from making your photos unsharp. Like Rob said, the 100% crop might be the problem, have you had any prints made to compare the 2 cameras? What lens, f stop, and shutter speed are you using? Can you post a sample of each picture from the different cameras.
     
  5. If you have eliminated AF and other equipment problems, I would suggest you try shooting in JPG. If the sharpness improves, then there is your problem.
    RAW files are inherently not as sharp as JPG files. All JPG files from cameras are post processed by the compression engine to include some degree of sharpening. If you bump up the sharpness using DPP, I like 7 or 8, you should be able to achieve similar sharpness as you P&S.
    Simply, all RAW files need post processing to achieve their full potential.
    /bing
     
  6. Do you use a tripod, MLU, timer or romote ? what lens ? etc etc.
     
  7. Try F11. When I shoot in RAW with F11 and 1/125 I get fairly sharp images unless the target is in motion or I cause camera shake (i.e. wind is blowing). Just my 2 cents. I'm very new to the EOS Digital Rebel XSi as I've had it less than 2 weeks.
    Marburg
     
  8. Do NOT try f/11 on a cropped sensor body like the Rebel series. At f/11 the maximum sharpness begins to deteriorate due to diffraction blur. In general, f/8 is likely to be the aperture with the greatest sharpness potential, though there are factors that could make a larger aperture sharper in some cases. (On a full-frame DSLR or a 35mm SLR the f/11 advice would be good.)
    I'm hopeful that you will post an example of a shot or two with the "problem." There are many possible causes of reduced sharpness, and without some evidence we are all reduced to guessing wildly and making very long lists of all the possible causes.
    Dan
     
  9. Maybe you are using a poor quality lens or there is something wrong with the lens you have. Which lens do you have? Do you have more than one lens? Have you tried other lenses on your body? Have you tried your lens on another body?
     
  10. [[At f/11 the maximum sharpness begins to deteriorate due to diffraction blur.]]
    This statement is at odds with Bob Atkins' findings here:
    http://www.bobatkins.com/photography/technical/diffraction.html
     
  11. If you look at the last series done with an L lens, 11 is less sharp than 8. However with less sharp lenses, improvement may extend further but not get the sharpness available from the L lens at 8.
    My nikon lenses start softening at 11.
     
  12. [[At f/11 the maximum sharpness begins to deteriorate due to diffraction blur.]]
    This statement is at odds with Bob Atkins' findings here:
    http://www.bobatkins.com/photography/technical/diffraction.html
    I would disagree with the idea that f/11 will be the "sharpest aperture" when shooting on a 1.6x cropped sensor camera. (Having said that, I suspect that we might agree that seeing the difference between f/8 and f/11 in a 8 x 10 print would be difficult, going on nearly impossible.)
    Understanding the effect of diffraction can be a tricky thing. For example, if you make a photograph with a 50mm lens at f/11 on a full frame camera and then with the same lens/aperture on a full frame camera with the same pixel pitch and compare crops on screen...
    ... they will appear to be identical. In both cases the "blur" will be of the same "size" on the surface of the sensor.
    But if you make prints at the same size from the two images the diffraction blur will be "larger" on the photo from the camera with the smaller sensor? Go ahead, scratch your head for a moment. Wonder about my sanity. It's OK.
    Let's imagine that the diffraction is (to use a really, really gross example) .1 millimeter "wide" when measured at the sensor in both cases. Same amount of diffraction, right? Measured in an absolute manner, yes. Measured as a percentage of frame width - which is what actually matters in a photograph - no. .1mm is a larger percentage of the image width in the case of the smaller sensor, so at a given print size the sample from the smaller sensor will have "more diffraction blur" at a given aperture.
    The onset of diffraction blur is not a function of "how good" your lens is. It affects great and poor lenses equally. It is an optical effect that is directly affected by aperture and focal length, and secondarily affected - but it an extremely critical way - but the size of the sensor/film onto which the image is projected.
    Dan
     
  13. Point as shoots have a lot of default sharpening and contrast, which is initally eye catching but not necessarily that realistic. DSLRs at default settings produce softer more realistic images, and this allows them to be worked over later without losing too much quality.
    For a point and shoot look, turn up the in-camera sharpness and contrast settings in your picture styles setting if shooting JPEG. If shooting RAW you will need to learn about post processing. Other than that there are lots of variables that may make images soft including camera shake, aperture settings, depth of field, missed focus though these tend to affect pictures individually rather than all of them. If you are consistently producing pictures too soft for your liking it is probably the in-camera sharpness and contrast settings.
     
  14. [[But if you make prints at the same size from the two images the diffraction blur will be "larger" on the photo from the camera with the smaller sensor? Go ahead, scratch your head for a moment. Wonder about my sanity. It's OK.]]
    I don't have a problem understanding diffraction.
    I think it is terribly disingenuous to claim that f/11 should NOT be used with a camera employing a APS-C sensor. Blanket statements like that, with no context, have very little value.
    Doubly-so in a thread where the OP appears to be a novice.
    [[If you look at the last series done with an L lens, 11 is less sharp than 8]]
    Which means nothing. The difference in sharpness is almost immeasurable.
     
  15. OK, Rob, I'll agree that it is incorrect to make a blanket statement to not use f/11 on a crop sensor camera. There are, indeed, situations where I would use f/11 on crop, though they would be rare and they would be for photographs where some other aspect of the photograph was more important than the sharpness of the image. (I do the equivalent on occasion with my FF body by shooting at f/22, for example when doing long exposures of moving water in which sharpness isnt' the main thing but extending the exposure may be.)
    I'll also agree that the difference in sharpness is very small, especially (as I think I pointed out above in my parenthetical) in prints of, say, 8 x 10 size.
    However, it very definitely is the case that if sharpness is what you are concerned with (as our OP stated) that closing down past f/8 isn't going to get you more sharpness on a 1.6x cropped sensor camera. I should have been more clear in linking to that point.
    I will say that it is generally not a good idea to shoot at f/11 on crop unless you are willing to give up some increment of sharpness for other reasons, and I am also confident that going to f11 from f8 on crop will _not_ improve sharpness.
    Dan
     
  16. Tre, it is nearly impossible to diagnose these kinds of problems without some examples.
     
  17. The Digital Picture.com has a table of DLA's for various cameras. It can be viewed about halfway down the page at this link.
    http://www.the-digital-picture.com/Reviews/Canon-EOS-5D-Mark-II-DSLR-Digital-Camera-Review.aspx
    DLA is calculated for different sensors. For the XSI, onset of diffraction limiting is calculated to begin at f/8.4. For the 5DII DLA is f/10.3.
     
  18. That last link regarding diffraction is misleading in the context of actual photographs. For example, a reader of that link who doesn't think this thru might conclude that you should limit yourself to larger apertures on a crop sensor body with higher photosite density (say a 15MP body) than on a lower photosite density (let's say 8MP) body.
    This is definitely misleading and I would go so far as to say it is wrong.
    Make a photograph with a 15MP 1.6x cropped sensor body using a particular lens and aperture (let's say f/8) and then make the exact same photograph with the same lens and aperture but on a 8MP cropped sensor body. Go through typical skillful post-processing of both image. Make prints at the same size.
    The amount of diffraction blur in both prints will be identical.
    There is a situation in which the higher density sensor (say the 15MP 1.6x cropped sensor as compared to the 8MP 1.6x cropped sensor) could have an additional advantage. If you make a photograph with very careful technique and use a very high quality lens, there is some small potential for slightly greater sharpness at a somewhat larger aperture on the body with more photosites.
    Bottom line:
    If you switch to a higher photosite density sensor in the same format and shoot at the same apertures you shot at before, the amount of diffraction blur will be identical and you should make no changes to your aperture selection process.
    In a few limited cases you may be able to achieve slightly _improved_ (as compared to the lower photosite density sensor) sharpness by opening up a stop or so (roughly speaking) on the higher MP camera, but you would only see the difference in very, very large prints.
    Dan
     
  19. "What am I doing wrong?"
    I would bet $1,000 you don't print larger than 4x6 inches. Correct? The premise of your question is wrong.
     
  20. [[I will say that it is generally not a good idea to shoot at f/11 on crop unless you are willing to give up some increment of sharpness for other reasons, and I am also confident that going to f11 from f8 on crop will _not_ improve sharpness.]]
    [[I'll also agree that the difference in sharpness is very small, especially (as I think I pointed out above in my parenthetical) in prints of, say, 8 x 10 size.]]
    These two statements are at complete odds with each other. There is no reason most any photographer should shy away from using F/11 on a crop-sensor camera. You must realize that your statements are indexed in google and come back in search results. This is why the forums are filled with new photographers fretting over obscenely small differences in image quality when they can't even figure out how to keep their flash from popping up in low light. The error bars associated with their images are HUGE and will not be smaller than the differences between f/8 and f/11 for a long, long time, if ever.
    The level of pixel peeping required to discern differences between these two aperture values is something only the most obsessive measurabatory person would try and do, and I would be willing to bet, would not be successful at.
    Anyone making prints large enough that they even think they can see a difference between f/8 and f/11 (even assuming they know what they're doing to make prints that large in the first place) will either already be familiar with diffraction or will be able to ask intelligently about it.
    It's as if the OP went to a doctor with a common cold and the doctor started talking to him about the minutia of techniques used in less than 1% of all brain surgery operations done in the world today. Great for an academic but has no connection to the problem at hand.
    I think your information is great and please don't consider my response a personal insult. I just don't see any reason to start talking about these insanely small differences here or in any other thread where the person has not given enough information to discern anything beyond "they own two cameras and have a problem they can't properly describe." If you were in a camera store and a random person came in with the same question, I find it hard to believe that the very first thing you would say is "oh well don't shoot at f/11."
     
  21. If you switch to a higher photosite density sensor in the same format and shoot at the same apertures you shot at before, the amount of diffraction blur will be identical...
    For a technical description of diffraction, please see the following link. http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm
    There is a diffraction calculator. Using your example, 15 MP f/8, Diffraction limited - YES. 8MP f/8, Diffraction limited - NO.
    I made a PDF file that shows both calculations. If I can upload the file, I will.
    I don't see how to attach the PDF. Those who are interested will have to enter the data themselves. Be sure to check the "Set Circle of Confusion = Twice Pixel Size? " check box.
     
  22. Frank,

    Thanks for the link! This will definitely help me out when deciding how much DOF I want and still get my image as sharp as possible.
     
  23. When I got my first DSLR (a D80) not about a half year ago, I read a lot about diffraction and all this advice in forums etc. saying never to use an aperture smaller than f/8. I got scared to reduce the aperture beyond that. This ruined many shots for me.
    You need first to consider what you want to achieve with a particular picture. If you need a lot of DOF, that should determine your aperture. I have seen many professional landscape/nature photographer shooting at f/16. I have seen examples of fashions photographers that use nothing but f/11 when they shoot in studio settings.
    As I grew a little more confident I decided to try out my lenses in a couple of situations to see for myself. For the lenses I own, I could see a difference between say f/5.6 or f/8 and f/16, but I need to look at 100% side by side to determine which is which. I can not tell which aperture was used in an arbitrary file just by looking at it. However, something out of focus due to to shallow DOF can be seen even on low res files. Obviously, if I am shooting a subject with high contrast lines or if I don´t need the DOF, I choose the sharpest aperture.
    If anything, if I shoot something where I consider it important with corner sharpness, I really try to avoid opening up completely.
    Well, that my two cents.
    /Jonas
     
  24. Another thing not mentioned here is hyperfocal distance. There's probably a good reason for that, like say, your lens might not even have hyperfocal distances listed on the barrel.... which is becoming more and more common with AF lenses. Companies producing lenses consider hyperfocal distance to be a useless feature to most users and so it's not included.... but here's the rub... where you focus in a landscape will determine some of the sharpness of the overall image.
    If you focus on "infinity" at the horizon, you will have a soft foreground. If you focus on the foreground, you will have a soft background. If you focus on the middle ground, with your lens set to the sharpest aperture and the best DOF (a combination which may be f/11 or f/8 depending on the lens) then you should be able to get sharp background and foreground all the way through the image. Do some reading up on hyperfocal distance and you will find more about the specifics.
    As other have mentioned, use a sturdy tripod, with self timer or remote release. I'm not sure what Canon dSLR's offer cable release sockets, but those little do-dads are super cheap and really wonderful.
     
  25. Rob, it _seems_ that you are looking for an argument here or trying to impugn my motives.
    I will agree that I wrote (quickly, in a forum, without careful editing) something that could be misinterpreted by a casual reader. In fact, I acknowledged that in my response to you above.
    But, speaking of context, go back to the message to which I was responding. The claim was that a shooter with "sharpness" problems on a crop sensor body should stop down to f/11 to fix that issue. I maintain that this is poor advice. Good advice might have been stop down to f/8.
    As I wrote (more than once now) I agree that diffraction blur will not likely be visible in an 8 x 10 print. (I guess that makes it, what, three times now?)
    However, I stand by the fact when making a recommendation about the "best" aperture for sharpness - and sharpness alone, ignoring other factors for the moment - that recommending f/8 is the "best" recommendation for someone shooting at APS-C sensor body.
    Also, I don't know what references you found on Google, but please keep in mind that different posts of mine are written in different contexts - for beginners, for full frame shooters, for people delving deeply into the technical issue.
    As a matter of fact , I frequently write about why pixel peeping is not a very good thing. But there is a difference between pixel peeping and understanding how and why things work the way they do. In fact, understanding some of the minutae of this stuff is part of what convinces me to NOT pixel peep.
    Take care,
    Dan
     
  26. Another data point - not an argument, just an example for anyone to consider in whatever way they deem fit. (But also and example of what might seem like pixel peeping... but the objective of discouraging too much pixel peeping, it that makes any sense.)
    Sharpness and Aperture Selection of Full-frame DSLRs
    Dan
     
  27. I wrote but failed to edit the following: "... but the objective of discouraging too much pixel peeping, it that makes any sense.)"
    Gack.
    Should have read: " but WITH the objective of discouraging too much pixel peeping, IF that makes any sense.)"
     
  28. Rob, apparently writing about me, wrote: "The level of pixel peeping required to discern differences between these two aperture values is something only the most obsessive measurabatory person would try and do..."
    Yeah, thanks... Jeez.
     
  29. "There is a diffraction calculator. Using your example, 15 MP f/8, Diffraction limited - YES. 8MP f/8, Diffraction limited - NO.
    I made a PDF file that shows both calculations. If I can upload the file, I will."​
    Just in case anyone thinks that "diffraction limited" in this case suggests that s print of some size would be more negatively affected by diffraction at f/8 on a 15MP APS-C sensor than on at f/8 on a 8MP APS-C sensor...
    ... it would not . There would be exactly the same amount of diffraction blur in both prints .
    What the different points of "diffraction limiting" mean is that you could potentially (in very limited situations that I won't describe here) get a very slightly better image in terms of resolution from the 15MP sensor than from the 8MP sensor at some larger aperture where diffraction would not be a significant factor on either camera.
    In other words, in the context of diffraction and its effect on your print , the news is all good with the sensor with more densely packed photosites... though the "improvement" is, ahem, probably trivial in almost all cases.
    There is a lot more I could say, but somehow I don't think it would be appreciated in this thread. :)
    Dan
     

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