Edges appear jagged in picture when zoomed in

Discussion in 'Canon EOS' started by jack_traven, Jan 2, 2010.

  1. Hi all,

    I previously posted a question regarding enlarging my photos for oversized wall prints. I noticed my pictures have incredibly jagged lines. Is this normal? My camera body is a Canon 1Ds MKIII with the 24-70 2.8L II Lens.
    Attached is a cropped example.
    Thoughts?
     
  2. example
    00VOol-205993584.jpg
     
  3. Are you zoomed in past 100%?
     
  4. Sorry, yes. Try this attachment, it is at 100% original size.
    00VOpL-206001584.jpg
     
  5. What quality are you shooting? Do you shoot RAW, L, M, or S? I would guess it was shot in S (small) quality and is a low res photo. The photo above is the full photo, not a crop correct.
     
  6. Spearhead

    Spearhead Moderator

    How could it be the full photo, it doesn't have the right aspect ratio. It has to be a crop.
     
  7. The appearance of angled lines in digital photos depends on many processing parameters, most obviously sharpening.
    If you're shooing raw you have complete control; if you're using the in-camera processing (ex. to create a JPEG) then you need to experiment with those settings to get results you like.
    I often resort to localized sharpening in "problem" areas to get the look I want.
     
  8. Hi all, Sorry, I meant to say it is cropped but not zoomed past 100% if that makes any sense. I was shooting in RAW (which shows the jaggies even more pronounced) but I did a post-process conversion from RAW to JPEG (so the pic you see above is post-process JPEG).
    Here's some other data:
    File name
    352G0284.CR2
    Camera Model Name
    Canon EOS-1Ds Mark III
    Firmware
    Firmware Version 1.1.4
    Shooting Date/Time
    12/29/2009 20:37:06
    Tv(Shutter Speed)
    1/10Sec.
    Av(Aperture Value)
    F14
    Metering Modes
    Evaluative metering
    Exposure Compensation
    0
    ISO Speed
    400
    Lens
    EF24-70mm f/2.8L USM
    Focal Length
    70.0 mm
    Image size
    5616 x 3744
    Image Quality
    RAW
    Flash
    Off
    White Balance
    Auto
    AF mode
    AI Servo AF
    Picture Style
    Standard
    Parameters
    Tone Curve : Standard
    Sharpness level : -
    Pattern Sharpness : -
    Contrast : 0
    Sharpness : 3
    Color saturation : 0
    Color tone : 0
    Long exposure noise reduction : Enable
    High ISO speed noise reduction : Disable
    Highlight tone priority : Disable
    Color matrix
    -
    Color Space
    sRGB
    File Size
    22352 KB
    Dust Delete Data
    No
    Drive Mode
    Shooting with self-timer
     
  9. I thought the same thing Jeff.
     
  10. were you using a tripod?
     
  11. I just noticed "Sharpness : 3" in the camera EXIF data. Maybe I should turn this to Zero?
     
  12. how much of a crop is this? Do you have the full photo?
     
  13. yes, using a Gitzo GT2531 with an Arca Swiss Monoball Z.
     
  14. also, you should never use Al servo focus on non moving objects. This makes the focus continuously focus and refocus and is designed for sports and action where there is a lot of movement. The very slight movements in the focus while using al servo can make an out of focus photo on a non moving object. I'd use one shot AF.
     
  15. I just thought 1/10 second is a slow shutter, but its fine for a tripod. And if you're using a tripod, I'd set ISO to 100 to get the best quality since shutter speed won't matter.
     
  16. Hi Nathan,
    Regarding AI Servo Focus, yes I completely agree and was not paying attention to that setting when I normally do.
     
  17. I don't know how big the original file was, but this looks to me like its an extreme zoom. Full frame cameras allow for nice crops, but I would guess this pushes the limits. Can you look at the properties of the crop and tell us the pixel dimensions?
     
  18. Yeah, I do it too. I hate it when a careless mistake messes up a great photo, but sometimes there's so many settings that you forget about something small like that.
     
  19. Here's another one on a completely different day with lower ISO:
    Tv(Shutter Speed)
    8Sec.
    Av(Aperture Value)
    F11
    Metering Modes
    Evaluative metering
    Exposure Compensation
    0
    ISO Speed
    200
    Lens
    EF24-70mm f/2.8L USM
    Focal Length
    70.0 mm
    Image size
    5616 x 3744
    Image Quality
    RAW
    00VOqh-206015584.jpg
     
  20. The first photo, the crop where you circle the jagged edges, is only 457x900 pixels. I know that is a crop to show the flaw, but that's less than a 1/2 megapixel image. Even the larger image you showed us can't be any more than 3 or 4 megapixels. I think its just cropped too much.
     
  21. that one is even less, its only about a 0.13 MP image. If you look at the whole photo it should look fine, but this is like a pinpoint on the original image.
     
  22. Hi Nathan,
    First Crop Pixel Information:
    Width: 339 pix
    Height: 370 pix
    Original Pixel Information of the original file:
    Width: 5616
    Height: 3744
    Second Crop Pixel Information:
    Width: 721 pix
    Height: 577 pix
    Original Pixel Information of the original file:
    Width: 5616
    Height: 3744
     
  23. "If you look at the whole photo it should look fine, but this is like a pinpoint on the original image." -- Ok, I must be doing this post processing crop all wrong but if I open the original JPEG file in Photoshop (converted from RAW) and then go straight to Image->Canvas Size without manipulating the photo, the Canvas Size is Width 78inches, Height 52 inches. Am I missing something here?
     
  24. The original file was 21MP, the crop is 0.42MP. That's 1/50 of the original. I don't know if you plan on printing an image that cropped or if you're just hitting the magnifying glass in photoshop a hundred times to see what it looks like, but that's too much of a crop to use for a practical situation. All cameras no matter how many megapixels they are will show those jagged edges if zoomed in enough. Pixels are square and when you get close enogh to see individual pixels this is what it looks like. If you want to crop your images that much and use them, I suggest buying a telephoto lens so you don't have to crop or so the crop isn't as extreme.
     
  25. change the inches to pixels on the drop down menu, it should then read 5616 x 3744
     
  26. you're probably changing the inches to 8x10 (or something similar) and without realizing it, lowering the resolution of the photo
     
  27. also, you should be changing image size, not canvas size, when you change the canvas size it cuts out the rest of the photo. Changing image size will retain the entire photo while reducing the file size. I would only reduce the size though for posting to the internet. If I was going to make a print, I would want the full size image.
     
  28. "If I was going to make a print, I would want the full size image." -- Ok, I think we share the same thought here. My objective is to take my original RAW file and make a print in its native resolution/size. Thus, if I am understanding the unchanged image data in Photoshop correctly, the print should be: Width: 5616 pixels x Height: 3744 pixels or the equivalent of Width: 78 inches x Height: 52 inches.
    If I understood that correctly, then all I am doing with my "cropping" examples is taking a crop slice of Width: X inches by Height: X inches out of the overall 78in x 52 inches -- kinda like printing the whole thing out at 78in x 52in and then taking an exacto knife and slicing out little sections to show the forum members the jaggies. Not sure if that makes any sense?
     
  29. you are exactly right, that is why you resize image NOT canvas. This will just compress the file, not take an exacto knife to it.
    Also, although the native print size is 78''x52'' that doesn't mean you have to print at that size or reduce the size for an 8x10, just take the full size image in for whatever size you want to get the best quality
     
  30. also, just a few things I noticed about the photo data:
    If you have enough time to set up the tripod, I'd shoot in Manual, not Tv. This just gives you more control over the image and things like f/stop and depth of field.
    Also, like I said ealier, use ISO 100 for best quality.
    Mirror lock up is also a good function to use. This raises and locks the mirror prior to opening the shutter to prevent vibration from the mirror slapping the inside of the camera. This can be found in the custom functions menu.
    Probably all stuff you already know, but thought I'd give some tips just in case.
     
  31. alright I think we finally got on the right track here. I think the main problem was changing the canvas size when we should have been changing image size. I hope this solves the problem. It's 1:45am and I finally feel like I accomplished something today. Good luck Jack, if you have any more questions you know where to come.
     
  32. Jack at 78" with 5616 pixels you are reproducing at 72 pixels an inch, that is way way to few for the print you want, ok for images that won't be viewed close but not for the one in your dads dinning room. That is why you are seeing jaggies too.
    Do what Nathan said and you will end up with the boxes looking like this.
    Hope this helps, Scott.
    00VP0Y-206143684.jpg
     
  33. I meant change the document size to pixels not the pixel dimensions. Anyways changing the boxes wasn't the problem, it was that he was changing "canvas size" not "image size"
     
  34. It looks like a combination of over-sharpening and compression.
     
  35. Looks like compression artifacts. Make sure that you use the highest available quality setting when using JPEG.
     
  36. I agree with Geoff and Scott about oversharpening (whatever the source) being evident in a number of places. For example, in the second image, not the lighter colored fringe on the tree branches.
    Also, look at what appears to be a silhouette of the wall "tower" in the second image. The oversharpening has created a sort of ringing (in terms of spatial frequency) into the shadowed portion, resulting in every other pixel band being lighter than it should be.
    The JPEG compression artifacts only make matters worse, resulting in color distortion in these high-contrast areas, further exacerbating the problem for enlargements. Given the obvious challenge of your print size, I would consider the following:
    • Don't use JPEG at all, opting instead for a lossless compression format such as TIFF. Consider outputting PDF format, selecting "High Quality Print" profile. If you have to use JPEG, go for the highest possible quality.
    • Given your humongous print size, do not resample your image at all in post-processing. Let the print driver take care of that.
    • Disable sharpening in the camera, opting instead to control it yourself in post-processing. There is a lot of good information on this site regarding judicious use of sharpening. Is your print driver also contributing to the sharpening? If so, this should also be considered.
    • Finally, experiment by making smaller prints of these crucial high-contrast areas. That way you won't spend a fortune remaking prints. Stock up on yellow and magenta and black ink <grin>.
     
  37. I am some what new to photography, but I do get the point that the photo is coming out with compression issues. Now, I have heard this and I'm not sure about it as a fact.... so at the risk of all you knowledgeable photographers out there that know a thing or two about a thing or two I'll repeat it and you can tell me if I am way off base on this.
    Could it be that it has to do with having IS turned on while the camera is mounted on a tripod? I have heard that when your using a tripod that IS should be turned off. True or false? And would it result in a compression issue such as this or simply an out of focus issue?
     
  38. On second thought perhaps that lens does not come with IS, so my point was mute. But if any of you do know the IS with tripod question I'd love to know.
     
  39. Vicki, I simulated the zoomed in image by resizing to 700%, disabling resampling (looks exactly like the original zoomed in with PS). I have marked what I believe are some problem areas from my previous comment. Wouldn't IS result in a blurring, not oversharpening of the high contrast areas? Please see http://bergdev.com/Zoom.png. I am a Photoshop enthusiast who has stared at a lot of images. Opinions from more experienced photographers would be welcome.
     
  40. Nathan I realised that, I just happened to have the file open so thought it might help, that was all.
    Scott, Mathias, Lee and Vicki, this has nothing to do with compression, artifacting or IS. It is over-enlaging an unresized image file, that is all.
    Vicki, as far as IS and tripods go it is a little confusing, some lenses should be switched off and some shouldn't. The difference is that some lenses have a sensor in them that will switch off the IS automatically when there is no movement, if the IS is on and the camera does not move at all then the IS can hunt, or search for movement. This is easy to show, put your camera on a sturdy table and look through the viewfinder, half press the shutter, if your lens turns IS off automatically then you will hear the IS wind down, if it does not then as you look through the viewfinder every now and again the image will jump, that is the IS hunting. If you had the second type on and it was on a tripod it could result in a slightly blurred image, not compression issues though.
    Hope this helps, Scott.
     
  41. Just Crop the thing; don't use resize for 100% crops. PS shortcut 'C'. Set the pixel dimensions if you like, maybe to 300x300 px. Or mark a 300x300 px rectangle (shortcut key 'M'), copy it, and paste it into a new image. Save it to a JPG with File | Save for Web...
     
  42. Michael,
    That a fast way of getting a 300x300 pixel crop but that is not what Jack was trying to do, he wanted a 5x7 or so crop of a large print to check quality, for that you have to resize either before or after cropping.
     
  43. Scott, if that's the case, and I don't believe I read any other mention of printing, set the image resolution to a reasonable value without resampling. My lab prefers 320 px/inch. Then mark a rectanglular marquee, fixed size of 7 in wide by 5 inch high. Copy it, and paste it into a new image.
    Otherwise, for clipping a 100% crop to post here, mark a fixed size marquee for 300 px by 300 px (or whatever size); copy it to the clipboard; create a new image, and paste; File | Save for Web....
    [​IMG] [​IMG]
     
  44. Michael,
    It all stems from an earlier thread of Jack's but that is what he wanted to do. In Photoshop, like almost all programs now, there are many ways to achieve the same goal. I got the impression he wanted to print the corners of large prints for sizing and comparison purposes. My way is no slower to get his four corners reproduced at different ultimate print sizes.
     
  45. Vicki, I spoke to a Canon rep some time ago regarding the IS and tripod issue. He said that the IS circuitry is always working when it's turned on and you're ready to shoot. With the camera tripod-mounted, the IS stuff will sense any minuscule movement and then try to correct for it, so tripod work = I/S Off.
     
  46. Could it be that it has to do with having IS turned on while the camera is mounted on a tripod? I have heard that when your using a tripod that IS should be turned off. True or false? And would it result in a compression issue such as this or simply an out of focus issue?
    Vicki, I spoke to a Canon rep some time ago regarding the IS and tripod issue. He said that the IS circuitry is always working when it's turned on and you're ready to shoot. With the camera tripod-mounted, the IS stuff will sense any minuscule movement and then try to correct for it, so tripod work = I/S Off.​
    IS will not cause this issue. Some Canon lenses with a tripod collar (new versions) will sense a tripod but most (including all without a tripod collar) will not. Even if your lens has a tripod sensor don't trust it and manually turn off IS. If IS is left on or the tripod sensor fails to detect a tripod, the lenses may move even if there is no motion for IS to detect. This will turn a point light source into a line in the final image and will cause edges to appear out of focus. My 24-105mm L F4, 70-200 L F4IS, and 100-400mm L F4-5.6 (all less than 5 years old and only one with a tripod collar) Do not detect my Bogen tripod. The EXIF data for both photos indicates the 24-70mm L F2.8 lens was used. There is currently no IS version of this lens. IS does not in any way affect image compression.
    I agree with Geoff and Scott about over sharpening (whatever the source) being evident in a number of places.​
    Sharpening works by darkening one side of a line and lightening the other side of a line. In extreme over sharpening a edge will have a black band on one side and a white band on the other. It will not create square blocks as are evident in the photos that were attached.

    As Nathan Gardner pointed out and Jack Traven confirmed the images were incorrectly resized from the original RAW files before they were saved as JPEGs. So JPEG compression is not a issue even though it could cause a similar problem.
     
  47. Check that in whatever program you use to convert RAW to jpg, that the image resolution is set to something like 240 pixel per inch (I believe this is the default in LR). It looks to me you use a significantly higher resolution for this conversion. In this case, multiple pixels in your converted filw represent a single original image pixel. When viewed at 100% you then see the image as pixilated.
    It certainly has nothing to do with compression, sharpening, image size etc.
     

Share This Page