From: otter on 6 Aug 2010 09:28 On Aug 6, 7:27 am, ransley <Mark_Rans...(a)Yahoo.com> wrote: > On Aug 6, 7:21 am, Martin Brown <|||newspam...(a)nezumi.demon.co.uk> > wrote: > > > > > > > On 06/08/2010 13:02, ransley wrote: > > > > I use the T1i, dpreview gives a higher rating to Jpeg over Raw. I > > > believe its because Jpegs settings are optimised by Canon very well. > > > For my jpegs they come out very good. Is Raw recomended because jpeg > > > looses quality every time you open and close it? Is the difference > > > noticable by opening and closing it say for example 5 times printed at > > > 5x7 or 8x11? Does the loss on jpeg only occur if you completely close > > > the photo? > > > This is a FAQ and dealt with in the JPEG FAQ. See Q10 of > > >http://www.faqs.org/faqs/jpeg-faq/part1/ > > > Opening and closing a JPEG file doesn't alter it at all unless you Save > > the file again as a JPEG *and* overwrite the original file. If you treat > > your original JPEGs are readonly then there is no problem at all. > > > The level of degradation with successive saves is not huge provided that > > you work at a fixed quality level. But it is ever present. This means > > that in a workflow you want to keep work in progress saved in a lossless > > format (typically one native to the application you are using that will > > preserve layers and masks). > > > > What are other benefits of Raw to make it worth the extra > > > hassle of complete editing. I am happy shooting jpeg, I am working > > > with 5 shot Photomatrix hdr and have done both Raw and jpeg [I think > > > Photomatrix loaded the jpeg] I am fully happy with the results but > > > jpeg is so much easier. I think for special photos made and composed > > > Raw may be optimal , but its time very consuming. > > > Raw gives you more freedom afterwards to rescue dynamic range and adjust > > colour balance. This can be important if you know that the image will > > contain black velvet in shadow and a white bridal dress in sunlight. And > > there is little chance of retaning it if the exposure is even slightly > > off. It is hard for the in camera auto adjust and save as JPEG to get > > both exactly right simultaneously and a risk if you let it. > > > Most of the time in camera JPEG encoding is fine - ie good enough. > > (some makers high quality JPEG encoding is better than others) > > > Regards, > > Martin Brown > > I use Adobe and just save as it prompts me, is that the proper way? I > wonder since Canons jpeg is optimised if I am not going backwards with > Raw and missing what they have put major effort into perfecting. How > is dynamic range improved? Color balance controls in editing are the > same, how is Raw better?- Hide quoted text - > > - Show quoted text - I wouldn't say that the Canon in-camera jpeg routines are better than what you can achieve in post-processing on a computer. Hasn't been my experience. The camera/lens correction profiles in ACR 6.1, for example, alone make it worth switching to shooting RAW, not to mention the increased ability to make color and exposure corrections without degrading the image. I have many jpegs from a few years ago that I was happy with at the time, but now wish I had shot RAW.
From: Martin Brown on 6 Aug 2010 09:52 On 06/08/2010 13:27, ransley wrote: > On Aug 6, 7:21 am, Martin Brown<|||newspam...(a)nezumi.demon.co.uk> > wrote: >> On 06/08/2010 13:02, ransley wrote: >> >>> What are other benefits of Raw to make it worth the extra >>> hassle of complete editing. I am happy shooting jpeg, I am working >>> with 5 shot Photomatrix hdr and have done both Raw and jpeg [I think >>> Photomatrix loaded the jpeg] I am fully happy with the results but >>> jpeg is so much easier. I think for special photos made and composed >>> Raw may be optimal , but its time very consuming. >> >> Raw gives you more freedom afterwards to rescue dynamic range and adjust >> colour balance. This can be important if you know that the image will >> contain black velvet in shadow and a white bridal dress in sunlight. And >> there is little chance of retaning it if the exposure is even slightly >> off. It is hard for the in camera auto adjust and save as JPEG to get >> both exactly right simultaneously and a risk if you let it. >> >> Most of the time in camera JPEG encoding is fine - ie good enough. >> (some makers high quality JPEG encoding is better than others) >> > I use Adobe and just save as it prompts me, is that the proper way? I So long as you don't overwrite original files then yes. In Photoshop you probably want to use its native format .PSD for intermediate files or whatever they call it now. > wonder since Canons jpeg is optimised if I am not going backwards with > Raw and missing what they have put major effort into perfecting. How Raw gives you something closer to what the sensor measured which is between 10 and 12bits of linear intensity data. JPEG gives you 8 bits of gamma corrected data which depending on the in camera JPEG settings might result in lost shadow detail or blown highlights. If the shot is hard to take again then RAW has a major advantage that you can adjust to get the maximum dynamic range and best colour balance afterwards. There are a handful of cases where classic JPEG decoder defects mean that a JPEG is visibly inferior for a few near pathological target images. Fine black detail on a saturated red flower is one such example. In this specific case the RAW image is better. > is dynamic range improved? Color balance controls in editing are the > same, how is Raw better? The controls in the programs are identical. You are starting from an earlier point in the processing chain when you use raw. This can be useful, but for most casual work it is overkill. You would do better to concentrate on composition and lighting than worry about RAW vs JPEG. The generational losses are much less than most people would have you believe. But they are there. Take an image and using constant quality settings save a copy image1, close and reload it, then save as image2, close and reload it then save as image 3. Use the arithemetic functions to difference them and you will see how much difference there is. Don't take peoples word for it you can do the experiment yourself. Regards, Martin Brown
From: ray on 6 Aug 2010 11:40 On Fri, 06 Aug 2010 05:02:50 -0700, ransley wrote: > I use the T1i, dpreview gives a higher rating to Jpeg over Raw. I > believe its because Jpegs settings are optimised by Canon very well. For > my jpegs they come out very good. Is Raw recomended because jpeg looses > quality every time you open and close it? That's not quite true - quality is lost every time it is saved. > Is the difference noticable by > opening and closing it say for example 5 times printed at 5x7 or 8x11? Only if you save it each time - then it will be, eventually. > Does the loss on jpeg only occur if you completely close the photo? What > are other benefits of Raw to make it worth the extra hassle of complete > editing. I am happy shooting jpeg, I am working with 5 shot Photomatrix > hdr and have done both Raw and jpeg [I think Photomatrix loaded the > jpeg] I am fully happy with the results but jpeg is so much easier. I > think for special photos made and composed Raw may be optimal , but its > time very consuming. raw gives you greater editing latitude. There is more dynamic range and every pixel is represented, as opposed to jpeg. With my Kodak P850, I routinely shoot in raw. In many cases the enclosed jpeg view is adequate so I don't even process the raw image - simply extract the jpeg. When I do want to 'tweak' things, it is simple to change, for example, the white balance - or the exposure setting. If a jpeg is under or overexposed there is little you can do to correct it - raw has much greater possibilities.
From: Barry on 6 Aug 2010 12:38 On Fri, 06 Aug 2010 13:21:30 +0100, Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote: >On 06/08/2010 13:02, ransley wrote: >> I use the T1i, dpreview gives a higher rating to Jpeg over Raw. I >> believe its because Jpegs settings are optimised by Canon very well. >> For my jpegs they come out very good. Is Raw recomended because jpeg >> looses quality every time you open and close it? Is the difference >> noticable by opening and closing it say for example 5 times printed at >> 5x7 or 8x11? Does the loss on jpeg only occur if you completely close >> the photo? > >This is a FAQ and dealt with in the JPEG FAQ. See Q10 of > >http://www.faqs.org/faqs/jpeg-faq/part1/ > >Opening and closing a JPEG file doesn't alter it at all unless you Save >the file again as a JPEG *and* overwrite the original file. If you treat >your original JPEGs are readonly then there is no problem at all. > >The level of degradation with successive saves is not huge provided that >you work at a fixed quality level. But it is ever present. Agreed, for the most part, but not always. PhotoLine editor, for example, does completely lossless JPG editing. The only pixels that change in any subsequent saves are the ones you specifically change. No other changes are made to the rest of the image during successive saves. For example you are working on cloning out a fence-line in a meadow. You do 1/3rd of that fence, save it as a JPG file, go to lunch. Come back and reopen the image you previously saved, clone out another 1/3rd of the fence. Get an important call, so you save your edits to the same JPG file. Come back later, open it again, finish the project. Save it again. The ONLY pixels that will have changed during the course of all these editing sessions will be the fence pixels you changed. Only those pixels that you change are put through the JPG compression algorithm again during saves. No others throughout the whole image, nor those in previous edits, will change no matter how many times you open, edit, save to same file, and open it again. (See PhotoLine's helpfile on what you can do to override this when needed, when you intentionally want to lose data with subsequent JPG resaves.) >This means >that in a workflow you want to keep work in progress saved in a lossless >format (typically one native to the application you are using that will >preserve layers and masks). > >> What are other benefits of Raw to make it worth the extra >> hassle of complete editing. I am happy shooting jpeg, I am working >> with 5 shot Photomatrix hdr and have done both Raw and jpeg [I think >> Photomatrix loaded the jpeg] I am fully happy with the results but >> jpeg is so much easier. I think for special photos made and composed >> Raw may be optimal , but its time very consuming. > >Raw gives you more freedom afterwards to rescue dynamic range and adjust >colour balance. This can be important if you know that the image will >contain black velvet in shadow and a white bridal dress in sunlight. And >there is little chance of retaning it if the exposure is even slightly >off. It is hard for the in camera auto adjust and save as JPEG to get >both exactly right simultaneously and a risk if you let it. It can often get both right, and often does. If you know how to set up your camera properly to begin with. If you will always be editing your best shots for prints or before sharing, then shoot with the lowest contrast setting on your camera that is available. This will ensure retaining the fullest dynamic range of the RAW sensor data in the resulting JPG file. So much so that it's difficult to get any extra dynamic range from the RAW data. Save your more contrasty "impact" edits for later. Unless you never edit any photos, then let the camera add the "impact" in your images. Then you're not the kind of photographer that cares all that much about dynamic range anyway, the content of any images is more important to you than any fancy editing. Neither way is right or wrong. Good content will always trump image quality or dynamic range. Once you've set your JPG to lowest in-camera contrast then get your exposure right. Those who always work with optical viewfinders are not aware of how accurately one can predict the final image if they were using a camera with an EVF (or even LCD). Under/over-exposures are so 20th-century with today's digital cameras that have a decent EVF, if you know how to use them properly. With an EVF, the exposure and color-balance that you see in the viewfinder is truly what you get. One other important tip for those using JPG most of the time. Avoid using your camera's auto white-balance in most situations. If you know you are shooting in sunny conditions, use daylight white-balance. If in cloudy conditions or deep north-light shade, use cloudy white-balance. If under tungsten lighting, use tungsten white-balance. Etc. Save auto white-balance for those times when you really don't care how good the image is going to look and you are willing to put up with odd color-shifts in your images at times. A good example of this problem was recently posted by a resident snapshooter. An older fawn in the forest under a deep canopy of green leaves filtering sunlight. Auto white-balance completely destroyed this image, turning the fawn into a maroon mess and making all the surrounding foliage blue and cyan. The camera doesn't know how to properly compensate for a green light-source such as that coming from all the leaves above and reflected greens off of the foliage beneath, stripping that color from everything and throwing them all off. The same would be just as true if you were shooting a party of people under a bright orange outdoor canopy in sunlight. Auto white-balance will try to strip out all yellows and reds (orange) in your image throwing off all skin-tones. Use the daylight white-balance in these situation because that's your original light source. Later, in editing, tone down the overall green light or orange light to something more pleasing, but don't remove it all or you've destroyed the realism in your image. Whites, blacks, and grays in the real world are rarely pure white, black, or gray. Snapshooters that depend on auto-everything, like auto white-balance, don't care if that's true or not. (Nor do tech-head geeks that live in their basements posting their "advice" online, never having seen nor experienced the real colors out in the real world. They insist that whites must be white, grays gray, and blacks pure black. BTW: This is a good way to spot basement-living pretend-photographer trolls online.) A classic example problem for an auto white-balance mistake are those that shoot spectacular sunsets. The camera's auto white-balance will try to strip out all the intense golds, reds, and blues of a sunset; muting them into muddy drab colors; trying to create whites, grays, and blacks amongst them all. The sun is lighting that sunset so leave your camera on daylight (sunlight) white-balance and your JPG file will present an image that looked just like that original rich sunset. > >Most of the time in camera JPEG encoding is fine - ie good enough. >(some makers high quality JPEG encoding is better than others) > >Regards, >Martin Brown
From: Ofnuts on 6 Aug 2010 12:45 On 06/08/2010 14:27, ransley wrote: > I use Adobe and just save as it prompts me, is that the proper way? I > wonder since Canons jpeg is optimised if I am not going backwards with > Raw and missing what they have put major effort into perfecting. How > is dynamic range improved? Color balance controls in editing are the > same, how is Raw better? When you open your original JPEG for editing, do at once a Save As and pick the Photoshop standard file type (PSD). Thus all mods will apply to this PSD and will be lossless. Once you are happy with the changes export to JPEG (under a different name) -- Bertrand
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