 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
| PhotoKB HomeDiscussion Groups Digital Photography Digital PhotoDSLR CamerasZLR CamerasPoint & Shoot CamerasFilm Photography 35 mmLarge FormatMedium formatDarkroomFilm and LabsOther EquipmentPhoto Technique Nature PhotographyPeople PhotographyTechnique GeneralGeneral Photo Topics General TopicsAustralian PhotographyUK PhotographyDirectoryPhoto Clubs |
Photo Forum / Digital Photography / DSLR Cameras / January 2005Digital Rebel LCD focus blurry
When I try to check for fine focus on the LCD screen, the 4x magnified image is a little blurry and I can't tell any difference from in and out of focus areas until I look on my computer monitor. Is there some adjustment to be made for screen focus? Thanks. Rich www.richardclinton.com > When I try to check for fine focus on the LCD screen, the 4x magnified > image is a little blurry and I can't tell any difference from in and out > of focus areas until I look on my computer monitor. Is there some > adjustment to be made for screen focus? Thanks. I've never been able to check focus with the LCD, even with zooming. It just doesn't work. >> When I try to check for fine focus on the LCD screen, the 4x magnified >> image is a little blurry and I can't tell any difference from in and out [quoted text clipped - 3 lines] > I've never been able to check focus with the LCD, even with zooming. It > just doesn't work. Hang on! Are you guys talking about the EVF focus, cause I have no way of focusing through the LCD when taking a shot. Or am I confused as usual? > >> When I try to check for fine focus on the LCD screen, the 4x magnified > >> image is a little blurry and I can't tell any difference from in and out [quoted text clipped - 6 lines] > Hang on! Are you guys talking about the EVF focus, cause I have no way of > focusing through the LCD when taking a shot. Or am I confused as usual? No, we are talking about post-shot viewing on the LCD. You can zoom the image with the button at top right of the camera up to 10x the original image size, and navigate round the image with the < and > buttons. Colin >> >> When I try to check for fine focus on the LCD screen, the 4x magnified >> >> image is a little blurry and I can't tell any difference from in and out [quoted text clipped - 12 lines] > > Colin Ha! I was reading this thread and trying to imagine how these newfangled DSLRs got an image to the LCD on a continuing basis. Pellix mirrors? Mirrors that cycle > 30 Hz continuously? Noiselessly!? Walk around looking at the LCD instead of the viewfinder, like the non SLR digitals? I was starting to get excited! What the hell have I missed! :O Will D. > > No, we are talking about post-shot viewing on the LCD. You can zoom the > > image with the button at top right of the camera up to 10x the original [quoted text clipped - 9 lines] > > What the hell have I missed! Well, youve missed some, but you're in good company, as many others have asked the same question. DSLR's do not have preview on the LCD. They have optical reflex finders as in film SLR's, and the LCD will show you the shot after you have taken it, together with histogram info etc. DSLR's have mechanical shutters, and the sensor is not exposed until the shot is taken. Additionally, the mirror would be in the way if the shutter wasn't there, or was open. Colin >> > No, we are talking about post-shot viewing on the LCD. You can zoom the >> > image with the button at top right of the camera up to 10x the original [quoted text clipped - 20 lines] > > Colin Aw shoot! You mean that DSLRs are nothing more than SLRs with a digital sensor instead of emulsion film? Here I was all set to get excited about some automagical whizbang I'd never heard of before! Dang! Finding out that you knew what was going on all along sure is boring... At least with DSLRs you get an instant return mirror. The non SLR digitals blank out the LCD during image storage, which means that if you are following the action, you'd better be using the optical viewfinder, for whatever good that would do. With shutter lag, you won't get what you want anyway. Wonder how many people that are used to the viewfinder digitals actually expect DSLRs to have a continuous LCD readout? Wonder how many of those know what an SLR camera is? RFL!! Will D. > Wonder how many people that are used to the viewfinder digitals actually > expect DSLRs to have a continuous LCD readout? Wonder how many of those > know what an SLR camera is? RFL!! > > Will D. Ok, what's an SLR camera....; >> Wonder how many people that are used to the viewfinder digitals actually >> expect DSLRs to have a continuous LCD readout? Wonder how many of those [quoted text clipped - 3 lines] > > Ok, what's an SLR camera....;> Simple Light Rugged camera? Well, they used to be, at least compared to a Speed Graphic. Now, how about Super Luxurious Robot? And then if you ask the elite snobs that only tote a Leica M, it's probably Stoopid Loser Rangefinder-wannabe. What's that you say? Three strikes and out? Oh okay... You're up to bat, Rudy. ;) Will D. > > When I try to check for fine focus on the LCD screen, the 4x magnified > > image is a little blurry and I can't tell any difference from in and out > > of focus areas until I look on my computer monitor. Is there some > > adjustment to be made for screen focus? Thanks. While I can't say for sure, this is what I *think* is causing it: Doing full-quality decompression of a full-size JPEG from the Digital Rebel not only takes a fair amount of processing cycles, it also takes a pretty good amount of memory in which to store the image. Because of those constraints, when displaying the image on the LCD screen, a full-quality decompression isn't done - the camera does a "quick & dirty" decompression to obtain an image of a resolution suitable to the LCD panel, or maybe a small bit above. When you zoom in on the image, it's just magnifying that low-res version, *not* going back and performing another decompression of the original. Zooming in on a photo shot in "raw" mode seems to be a bit sharper on the LCD than one shot in JPEG, but still nowhere near what the LCD *could* be displaying if fed the proper information. Because of that, I imagine that the camera simply takes a down-sized version of the RAW data to display, and simply magnifies that to let you "zoom". As always, I could be wrong. steve It just doesn't seem logical ( what else is new?) to have zoom in capacity that yields a blurry image. Would that it could show the area of focus point in greater detail. Has anyone with the hacked firmware version http://www.bahneman.com/liem/photos/tricks/digital-rebel-tricks.html#what had a different experence? Why would the 17-85 IS lens give sharper zoom in than the 18-55? Any thoughts? Rich www.richardclinton.com >> > When I try to check for fine focus on the LCD screen, the 4x magnified >> > image is a little blurry and I can't tell any difference from in and [quoted text clipped - 25 lines] > > steve "Mine is too, though when I got the 17-85mm IS lens, the magnified view on the LCD wasn't nearly as burry as with the kit lens, though it still is a little. Colin" > It just doesn't seem logical ( what else is new?) to have zoom in capacity > that yields a blurry image. Would that it could show the area of focus [quoted text clipped - 3 lines] > than the 18-55? Any thoughts? > Rich Well, the 17-85mm lens is a better lens than the kit lens - which is not to say the kit lens is not good, it just isn't as good. Also, autofocus, by its nature, has a tolerance built in to prevent constant hunting while focusing. A misfocus within the tolerance amount will not initiate a re-focus, so the shot can be slightly out of focus, and at 10x up on the LCD you can see this. BTW, this tolerance, or hysteresis, is common to all autofocus systems, and not limited to any particular make. Colin. > It just doesn't seem logical ( what else is new?) to have zoom in capacity > that yields a blurry image. I've been using this function on my OM E300 and it gets sharper and more detailed up to the 10X max, easy to see if it's a keeper or not so this -is- possible to do well. Just something canon decided to do this other way?  SignatureStacey > While I can't say for sure, this is what I *think* is causing it: > [quoted text clipped - 5 lines] > > As always, I could be wrong. I got digging through the exif data tonight with a Perl module (Image::ExifTool), and found that the camera does, indeed, use a low-res image for display on the LCD panel. The Exif data has both a thumbnail image (160x120, 8k), and a preview image (1536x1024, 221k). For fun, I extracted the preview image, and blew it up a little bit, and it is of noticeably lesser quality than the original JPG - given the file size of only 221k, you'd expect that. The LCD has 118,000 pixels, which makes it (I believe) 420x280. That means that you can only zoom in to about a 1:4 ratio before you run out of resolution in that preview image, and the camera will have to start upsampling to give you something to look at. At higher zooms on the viewfinder, because it has to upsample, it could either show you something blocky and pixellated, or anti-aliased and "blurry" - it looks like Canon chose the blurry. : ) Interestingly enough, there is also exif data embedded in both the preview and thumbnail images - exif data embedded in images which are embedded in the exif data embedded in an image! steve > The LCD has 118,000 pixels, which makes it (I believe) 420x280. It might be worse than that - it may 118,000 of red + green + blue pixels, i.e. only about 39,000 full-colour pixels..... David > When I try to check for fine focus on the LCD screen, the 4x magnified image > is a little blurry and I can't tell any difference from in and out of focus > areas until I look on my computer monitor. Is there some adjustment to be > made for screen focus? Thanks. > Rich > www.richardclinton.com Mine is too, though when I got the 17-85mm IS lens, the magnified view on the LCD wasn't nearly as burry as with the kit lens, though it still is a little. Colin |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2009 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.