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-   -   Please help, blurry pics with SD750 (https://forums.steves-digicams.com/canon-21/please-help-blurry-pics-sd750-124574/)

nboerner Jun 27, 2007 6:48 PM

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I have owned my Canon Sd750 for 7 weeks now and I am thinking it is defective. I cannot seem to get a clear shot indoors. All my pics come out blurry and faded looking. I am not using the tele and have tried different modes, manual, auto and indoors. I have forced the flash. I tried an experiment and took the same pictures at the same time in the same spot with my husbands cheapy kodak and my S2 IS and the pics came out nice. When I look at the exif info it seem all cameras chose the same settings and used the same metering mode. I called Best Buy and they tried to say it was because the 750 does not have image stabalization. I think that is bull because I was not zooming and the other camera didn't have IS either. I have attached a picture, can anyone help. At this point I cannot return the camera and Best Buy said they would ship it out. What a pain. Thanks for any help.

JimC Jun 27, 2007 10:03 PM

What did you use to downsize that photo for posting here?

The EXIF is stripped out (the information about the camera settings used to take it). That may tell us a bit more about your issue.

That photo is also a bit small to tell what issues you may have. A bit larger image (I'd make it 640 or 720 pixels wide when downsizing) would probably help. From what I can tell from that one, it may need a it of sharpening and redeye reduction, and the flash was a tad hot from an exposure perspective. But, I can't see anything seriously wrong. Camera settings may give us a clue as to what you may be experiencing on some shots.

Can you downsize it with a tool that isn't stripping out the EXIF? If you're using Photoshop, don't use save for web (use File>Save As instead).

A good free tool to use for downsizing is http://www.irfanview.com

You'll find a way to do that under Image>Resize/Resample. Just check the box to keep the aspect ratio (so that when you change the width, the height changes the same proportions), and make it around 640 or 720 pixels wide. It won't make a lot of difference what algorithm you choose. But, I typically use Lanczos. Then, when you use the File>Save As menu choice from the main menu, leave the box checked to retain the EXIF (it will be by default).



nboerner Jun 27, 2007 10:48 PM

Thank you for the reply. I made the file smaller by using Picassa. I do not know how to downsize a picture so I email it to myself then save it. I will try the program that you recommended. Sould I not do any cropping like I did in the other image. I guess that is why it is so small.

JimC Jun 27, 2007 11:30 PM

If you're cropping a lot, and the subject occupied a smaller portion of the frame, you're not going to have as many pixels representing your subject. So, you wouldn't have as much detail left over and that could be part of your issue.

It's hard to tell from a smaller image. But, for purposes of getting camera settings info, almost any size would work OK. I probably wouldn't use an edited version (the editing can degrade image quality). I'd downsize from the original.


nboerner Jun 27, 2007 11:43 PM

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Ok, I tried resizing the picture in photoshop. I did not crop it and I am also including a comparative pic using my S2 taken at the same time from the same place. It seems so much sharper and the color looks better. It just seems that all my indoor photos from the 750 are washed out and not very clear. Thanks again for helping.

nboerner Jun 27, 2007 11:44 PM

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Here is the one form the S2 IS

nboerner Jun 27, 2007 11:50 PM

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Here is another from the sd750, it seems blurry to me.

JimC Jun 28, 2007 9:06 AM

The main difference I see between those cameras is that the SD750 is exposing brighter. That's why they look a tad washed out (they're overexposed in some areas).

But, they're really not too far off (considering the entire frames). Keep in mind that if you use a flash burst that is long enough to get a brighter background, closer subjects can be overexposed.

The opposite is also true (if the camera uses a flash burst that is the correct length for a closer subject, the background may be underexposed). That's why an external flash that is being bounced for more diffused light is preferred for flash photos (so that you have more even illumination).

With a built in flash, letting the camera know what part of the image is of the most interest to you is very important.

I noticed that you're using Multi-Segment metering with the SD750 shot, and center weighted metering with the S2 IS shot. That probably accounts for most of the difference in metering.

When you use Mult-Segment metering, most newer cameras will heavily weight your focus point.

So, if you're not focused on your subject, that will throw off the exposure (it may be trying to use a long enough flash burst to illuminate something further away or something that is darker than your subject).

Are you half pressing the shutter button before taking a shot, making sure that it's focusing on your subject?

AiAF is reportedly a bit unreliable. So, you may want to try turning it off. But, you'd still want to half press the shutter button and make sure your focus is locked on your subject. Otherwise, it's going to throw off both your focus and metering.

You may also want to try changing your metering to Center Weighted. That's the way you've got your S2 IS set now. Center weighted places more emphasis on properly exposing what's in the center of the frame, while still taking the rest of the frame into consideration.

If that doesn't solve it for you, your camera's metering may lean towards a slightly brighter exposure compared to your S2 IS. In that case, using a -EV setting with Exposure Compensation would probably solve it. Chances are, this will also impact your flash exposures. Take some test shots with it set a few different ways (-0.3, -0.7, etc.) until you've got it dialed in to where it's consistently the way you prefer it.

But, chances are, it's just the way you've got the focus and metering set (combined with what you're locking focus on). You may also want to try dialing back the ISO speed. I'm also seeing ISO 250 (my assumption is that the Auto ISO is setting it that way). You may want to turn off Auto ISO and let it stay set a bit lower, and see if it improves the dynamic range (range of bright to dark that the camera is capable of capturing).




nboerner Jun 28, 2007 10:49 AM

Wow, thank you so much for all the tips. I will give them all a try. I do always half press the shutter and make sure I am focusing on the person. Other than the color issue it seems that when I zoom in on the people they are always fuzzy. I will try truning off the AiAf and try the different metering modes. Thanks so much for taking the time to checkout the pics.

nboerner Jun 28, 2007 11:17 AM

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Well I tried changing several settings. It did help the exposure but to me they still seem blurry. I half pressed the shutter button with the box right on my sons face. Please let me know if you find them blurry too, maybe it is just my monitor but it surely does not seem as crisp as when I zoom in on pics from my other cameras.

nboerner Jun 28, 2007 11:24 AM

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Here is another but they all look about the same

JimC Jun 28, 2007 2:02 PM

nboerner wrote:
Quote:

Well I tried changing several settings. It did help the exposure but to me they still seem blurry. I half pressed the shutter button with the box right on my sons face. Please let me know if you find them blurry too, maybe it is just my monitor but it surely does not seem as crisp as when I zoom in on pics from my other cameras.
That first photo is very good.

I see you used a -0.3 setting with Exposure Compensation using Center Weighted Metering that time. That worked out nicely, especially considering that the harsh lighting from the window was the only light source.

A flash was not used with that image. For a non-stationary subject, shutter speeds were on the slow side (1/60 second at ISO 200 and f/2.8 ).

The default exposure algorithms don't know that you're shooting a non-stationary subject, and they are only concerned with trying to keep shutter speeds above 1/focal length "rule of thumb" (which is based on about what you'd need to prevent blur from camera shake).

For example, if shooting at a 35mm equivalent of 50mm, try to keep the shutter speeds at 1/50 second or faster (1/focal length in mm if you're using a focal length that is equivalent to 50mm on a 35mm camera). That's great for most people to prevent blur from camera shake, but not necessarily fast enough to prevent blur from subject movement.

So, it didn't use a flash.

That's tough lighting for any camera, since you've got a lot of ambient light coming in through the window.

You could force flash on and it would probably increase the shutter speed or stop down the aperture (smaller aperture/higher fstop number), to block out some of the ambient light to help out.

When flash is the dominant light source, the flash itself has the ability to freeze action, provided you don't have enough ambient light to expose the subject.

That's because a flash burst is very fast (usually from around 1/1000 second to around 1/20,000 second). So, your subject is only exposed properly during the short flash burst (freezing the action, regardless of shutter speed, provided flash is the dominant light source). The problem comes in when ambient light is contributing too much to an exposure. Then, you have to worry about blur from subject movement, and 1/60 second isn't fast enough.

A flash wasn't used at all in that first image. It was still a good shot, especially considering that all ambient light from the window was the light source.

The 1/3 stop -EV setting for Exposure Compensation (-0.3 EV) helped out, and the only hot spots I see are on the top of the shoulders. These areas are shown as black on white in this image.

That's about as good as you can expect to get unless you want to tweak the photo later, since the overall exposure looked like it worked out just about right.

This is zoomed in to 200%, and the black spots are the only areas overexposed (I've got this editor set to show me black on white for overexposed areas). That's pretty good for that lighting, and it's surpringly sharp considering the conditions with no flash used with a shutter speed that slow (ambient light only exposure at 1/60 second of a non-stationary subject).

http://www.pbase.com/jcockfield/imag...8/original.jpg

As for the difference in sharpness, that's only because Canon is using a relatively conservative approach to sharpening in some of their newer models.

I like that approach, since it helps to give you more latitude for sharpening later. Sharpening is mostly an optical illusion (most algorithms work by increasing contrast at edge transitions), and the more "real" detail a manufacturer leaves by default, the better from my perspective. There are too many cameras now that have sharpening, contrast, and saturation bumped up too much, limiting your ability to squeeze the best out of a photo later.

Here's an example of using USM (Unsharp Mask) to make the image look sharper. I'm zoomed in just a touch (133%) for this one and have this editor set so that you can see the before (left) and after (right) . Many image editors can do this kind of thing for you (sharpen).

http://www.pbase.com/jcockfield/imag...2/original.jpg


This is a more sophisticated algorithm.

In both the above USM and this Refocus type algorithm, I'm keeping the values very conservative (I don't like anything to look any sharper than this, since it can start to look artificial, as the photos from many cameras do now).

http://www.pbase.com/jcockfield/imag...0/original.jpg

Here is one of your originals:

http://forums.steves-digicams.com/fo....php?id=104295

Here is the same photo lightly sharpened using the algorithms in my last screen shot above:

http://www.pbase.com/jcockfield/imag...0/original.jpg


Try playing with the camera settings for sharpness if you want them to be sharpened more straight from the camera.

I personally prefer a more conservative approach (as your SD750 uses). You retain more "real" detail without too much sharpening being performed by the camera, and that really shows up in prints (you can't see that kind of thing using monitors set to 96dpi resolution, versus a print with a *much* higher number of pixels per inch).

As for the second image, you missed the focus.

Look at the area of the couch closer to the camera and the area of the couch further from the camera.

Despite the distance and perspective differences, the number of pixels occupied by the closest cushion and the cushion that's closest to your son are not *that* different. Yet, the closer cushion is much sharper.

You focused on something closer than your son.

Flash was used for the second image. The highlights in the windows are a bit blown (as you'd expect with sun shining in). Considering the conditions, that's not too bad at all. A faster shutter speed was being used for that one. So, motion blur was probably not part of the equation. So, the only major issue I see with your last photo was focus point (the camera appeared to be using a focus point closer to the camera compared to your son, for the photo of him on the far end of the couch).


nboerner Jun 28, 2007 5:29 PM

Thanks for such in depth help. I will keep playing with it and see if I can do better with the focus. I truly appreciate the time you took to help me out. I am having a baby soon and I need to make sure ther camera my husband uses at the birth is up to the job, a once in a lifetime photo opportunity.

harmonica Jun 29, 2007 8:31 AM

Wow, nice results in sharpening. Are you just cranking up the sharpening or doing other settings as well? I have photoshop, but I don't really know what to use other than the Sharpen tool. If overused it get's noisy.

JimC Jun 29, 2007 9:29 AM

All I did was a light sharpening using the "refocus" algorithm in digiKam (an open source photo management application for Linux). digiKam is included in a number of Linux distros. I'm running it under Sidux 2007-2 (a free Linux distribution based on Debian Sid). You can read more about Sidux here:

http://www.sidux.com/

You can see more of digiKam's features here:

http://www.digikam.org/?q=about/features09x

This particular sharpening algorithm does have some parameters to keep noise under control duing the sharpening process. But, that's not really necessary in many cases, depending on the ISO settings you used and your exposure. It's got similar features to this plugin for the Gimp, and there is a section discussing how it differs from other algorithms on this page:

http://refocus.sourceforge.net/doc.html

I personally prefer a relatively light touch to sharpening. You could make them look much sharper if desired with a bit of tweaking. I just used some default settings for demonstration.

Depending on the version of Photoshop you have, you will find multiple types of sharpening at your disposal, including USM (Unsharp Mask) and "Smart Sharpen" (just don't overdo it as the defaults can make a photo look way too sharp).

The USM option you'll find in many editors (including Photoshop) works fine for most images. See the sharpening screen print I made using USM. I didn't bother trying to tweak any of the parameters (that's just the defaults I use for web images). Note that an amount setting of 1.1 in my example, is equivalent to 110% in many other editors.

You'll find lots of tutorials on the web for how to use USM and what the parameters can do. Just use google to search for Unsharp Mask:

http://www.google.com/search?hl=en&q...=Google+Search

But, almost any type of sharpening could improve the photos. Even using the ordinary sharpen option (versus unsharp mask) can improve them significantly. You can also use more than one type of sharpening on the same image.

Here is a search for sharpening photoshop how to

http://www.google.com/search?hl=en&q...=Google+Search




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