frode

<p>Hi<br> If you have one of those UV filters or "lens protection" filters mounted on your lens, try removing it. They often make things much worse.</p> <p>Cheers,</p>

<blockquote> <p>or on the final resulting image</p> </blockquote> <p>Beware that this will also not be correct, but much better than just adding the layers. The correct result will be achieved by adjusting each image 3 stops up <em>before</em> you blend them together (usually in the RAW converter). This will be indistinguishable from the single 8 seconds exposure.</p>

<p>Hi<br /> You could have added pixel values (after aligning images) if you could do it on the RAW files themselves (before gamma encoding). The gamma encoding (which is reversed by your screen hardware before you see the image on your screen) makes the relationship between the RAW pixel value and the final image pixel value (JPG, TIFF or whatever) nonlinear. A very simple example to show what I mean: If you have two values, say 2 and 5, and add them together you get 7. But if you take 2^2 = 4 (2 squared) and add to 5^2=25, you don't get 7^2=49. Instead you get 4+25=29. So adding after squaring makes a much smaller value (29) than adding before squaring (49). Gamma encoding works just like the squaring, but it makes it the opposite way since it uses power of 1/2.2=0.45 instead of power of 2. You will get a very overexposed image as you have experienced (but not only overexposed, the colors and tones will be completely messed up)</p> <p><br /> Emulating multi exposure:<br />To emulate an 8 picture multiple exposure with layers in photoshop you might use the opacity control on each layer. If we count layers from the bottom, i.e. the bottom layer is layer 1, the one above is layer 2 etc, then:<br /> <br />Layer 1 has 100% opacity<br />Layer 2 has 100% / 2 = 50% opacity<br />Layer 3 has 100% / 3 = 33.333% opacity (rounded to 33%)<br />Layer 4 has 100% / 4 = 25% opacity<br />Layer 5 has 100% / 5 = 20% opacity<br />Layer 6 has 100% / 6 = 16.667% opacity (=17%)<br />Layer 7 has 100% / 7 = 14.2857% opacity (=14%)<br />Layer 8 has 100% / 8 = 12.5% opacity (= 13%)<br /> <br />All layer blend modes are set to "Normal".<br /> Now, this is if each image was correctly exposed, i.e. each image exposed for 8 seconds in your example. What you get is an average of each image, i.e. the result will contain equally much from each image (about 12.5%).<br /> Since you had each image exposed for only 1 second, you will have to adjust the exposure 3 stops up, either on each image or on the final resulting image. Each image will then have the same quality as a 3 stop underexposed image (since that is exactly what they are), but when averaged you will get the same quality as a correctly exposed image (8 seconds in your example).</p> <p><br />The value of multiple exposures is grossly underestimated. It has a multitude of uses. :-)<br /> <br />Cheers,<br /> <br />Hope this was of any help. If not, print it out, curl it up and throw it in the dust bin.</p>

<p>...or maybe that chain is actually standing like that, without falling. It looks like the chain's links are rather big.</p> <p>Cheers,</p>

<blockquote> <p>By which I mean is it more critical to hold a 24 mp camera steady than a 12 mp camera. If so why is that?</p> </blockquote> <p>If the sensors have the same size and the focal lengths are equal, the only difference for the same amount of camera shake will be that the 24 mp camera might show more details. Under the mentioned circumstances the 24 mp camera will never show less detail than the 12 mp camera. If there is enough camera shake they might end up showing the same amount of details.<br> The only reason that the 24 mp camera might look soft at pixel level while the 12 mp camera does not (same circumstances as before mentioned) is that the 24 mp might show you details of camera shake that the 12 mp camera is not able to show you. In this the (potential) sharpness of the 24 mp is at least as good as that of the 12 mp camera. You might even reduce the 24 mp image to 12 mp to remove the extra blur that is in the 24 mp vs. the 12 mp.</p> <p>Cheers,</p>

<p>Hi<br> Maybe the book "Understanding exposure" by Bryan Peterson? I have not read this book myself, but I have seen it recommended numerous times.<br> http://www.amazon.com/Understanding-Exposure-Fourth-Photographs-Camera/dp/1607748509/ref=sr_1_2?ie=UTF8&qid=1449561568&sr=8-2&keywords=understanding+exposure<br> (Btw: Fourth edition is new, so if you want to see customer reviews for this book you must look at the third edition:<br> http://www.amazon.com/Understanding-Exposure-3rd-Photographs-Camera/dp/0817439390/ref=sr_1_1?ie=UTF8&qid=1449561568&sr=8-1&keywords=understanding+exposure )</p> <p>Cheers,</p> <p>Hope this will be of any help. If not, print it out, curl it up and throw it in the dust bin.</p>

<p>Hi<br> It is difficult to understand your question.<br> The contrast in a scene is in general only dependent on how much light the various parts of the scene reflects relative to other parts of the scene. For example, if you have only one light in a room you cannot change the contrast in the scene just by changing the brightness of that light. If you take one picture, then turns the light down to say 1/8th of what it was you will have to increase the exposure by a factor 8 (three stops). When you now take a new picture with this new light and exposure you will end up with exactly the same contrast in the two images.</p> <p>Cheers,</p>

<p>I usually look at an image from various distances. Any of them might be more optimal than the others depending on what I am looking for.<br /> There is no "optimal distance in relation to its size" per see. Optimization always need at least one varying input value (here "viewing distance in relation to its size"), at least one output value (here unspecified) and an optimization criteria (a rule/function that says when the output is most optimal, here unspecified).</p> <blockquote> <p>I guess there is no upper limit..</p> </blockquote> <p>Oh yes, there might be. Most people would for example not even be able to spot a 4 in. x6 in. image at a viewing distance of 1 mile. :-)</p> <p>Cheers,</p>

<p>I bought Photoshop because I thought I needed it, but after a learning ACR I do most editing (99%, maybe more) in ACR. From what you said I would therefore recommend LR, since ACR is more like LR that PS.<br /> Btw: Any changes done in Photoshop's camera raw converter, i.e. Adobe Camera Raw (ACR) are just as non destructive as in LR (I believe they are more or less the same tool when it comes to image adjustments): contrast, colors, sharpness, cropping, spot removals, local adjustments of most settings by using a brush, noise removal, vignetting, lens corrections, perspective corrections etc. etc, most of the editing you can do in LR i believe (I have however not used LR, so I might overlook something). You can also have multiple conversions saved with one raw file in ACR (as "snapshots"), and you can make your own presets, have camera profiles, lens profiles, etc, etc. You can also edit JPGs in ACR if you want to do that. All this goes at least for PS CS6 (the last version before CC). However, if you as me only are going to use ACR, you throw a lot of money out the window. The only thing I use Photoshop for is printing ans saving, and I think printing is at least as easy in LR as in PS.</p> <p>Cheers,</p>

<p>Hi<br> The short answer is no. There is however at least one camera that can make multiple exposures into one single raw file, both for simple multiple exposures and for in camera HDR. As with ocus stacking, HDR is much more complex than simple pixel value adding or averaging as is done with ordinary multiple exposure. Therefore HDR is fully automatic - as would focus stacking have to be - and you loose any control of the merging itself (except for a simple "strength" setting). Most of the complex work in HDR and focus stacking is done on each single layer (including their layer masks) before they are merged.<br> I haven't heard of any raw file format that supports multiple layers. You would therefore have to merge the files before you could save them to a raw format. But to merge them you will have to convert them to an image format supporting layers first, and then put each image to a separate layer and merge these layers into a single layer. However, then there would be no need to go back to raw format since now you now already have a single layer and can edit the way you wanted on this layer.</p> <p>And then there is that Lightroom and Photoshop do not edit raw files. They keep the raw files unchanged and change a layer (or probably a set of layers) between the raw file and the image displayed on the screen (i.e. they change the transform itself via transformation layers). To you this is transparent, except that you in fact can have several conversions from one singe raw file at the same time. If you were to save back to a raw format you would have to do a "reverse raw conversion", i.e. reverse bayer interpolate. reverse gamma correct etc. And you would have to do this for every change you made to the image. At best you would not gain anything by doing this, at worst you would ruin your image after repeated conversion and reverse conversions. And you would have to make a copy of the raw file if you wanted to keep the original raw file and also for each version you would like to make from the same image, for example color, b&w, different styles, different crops, high resolution print, low resolution web image etc. etc.</p> <p>Hope this was understandable and of any value. If not, print it out, curl it up and throw it in the waste.</p> <p><br />Cheers,</p>

<p>And here is how the images looked with ACR default settings (and how they would look at the camera's LCD screen). Somebody will call the ISO100 image underexposed. I suggest that the ISO 1600 is overexposed, even though it looks correct on the camera LCD screen and even if most light meeters will tend to suggest an exposure in the same ballpark.<br /> BTW: This strategy is nothing that I have developed myself. It is often refereed to as "expose for the highlights" and keeping ISO low gives more headroom (dynamic range) for doing exactly that.</p><div></div>

<blockquote> <p>Would it be better to shot at the native ISO and underexpose, correcting in PP or shot at a higher ISO and have not to brighten the image in PP?</p> </blockquote> <p>This is camera (sensor) dependent. With my Pentax K3 I very often use 1-3 stops lower ISO than the camera recommends and correct in post processing as necessary (most often on ISO 100). If I take two images of the same scene, one with correct ISO, say 1600 and one with 4 stops lower, here 100 (exposure kept the same, that is unchanged aperture and time), I can hardly see any increase in noise at all. I can however easily see decrease in dynamic range (4 EV in this case) for high contrast images. Look at the lamps on the attached image. Especially when photographing back lit scenes, maybe including the sun or sunlit clouds on the sky I keep the ISO well below what the camera says, some times even 5 stops (5 stops is the limit of adjusting exposure in Adobe Camera Raw).<br> There are of course situations where you should avoid this strategy. Raising the exposure in very dark areas might give you some problems, especially with banding/pixelisation type noise. Other camera sensors will have more of so called "read noise" which in (very) short is noise that will increase signal to noise ratio with higher ISO, especially for the lowest ISO values. Typically these cameras will show no or low increase in dynamic range towards the lowest ISOs. For these cameras you should almost never use the above strategy as I use for the K3. Experience will show you how much your camera will take before things start to happen.</p><div></div>

<p>Hi,<br /> The best approach to reduce noise is always to use as large an exposure value as you can for the scene you are photographing. And the lesser light that is available in the scene, the larger exposure value you will need.<br /> <br /> Exposure value is a value describing how much of the available light will hit the sensor when the picture is taken. Technically, the exposure value is decided by two camera settings, the f-number (=aperture) and the exposure time. The smaller the f-number you use (=the larger aperture opening you use), the more light hits the sensor. And the longer exposure time you use, the more light hits the sensor. And more light means larger exposure value. At the same time, when more light hits the sensor you can crank down the ISO (which in turn makes very many people thinks it is high ISO that generates noise when it technically is (mostly) due to too little light hitting the sensor during the exposure).<br /> <br /> So if you want to optimize for lowest possible noise, you should use as small f-number as you can and as long exposure time as you can. How small f-number and how long exposure time to use in a given scene will be a decision to be made by you based on the actual scene and how you want the image to be. Things like movement in the scene, whether you want these movements frozen or visible, how trained you are with keeping a camera still during exposure, whether you have a tripod available, wanted depth of field etc. will be the deciding factors. Available light in the scene will also be a factor since to much light reaching the sensor will burn out the brightest parts of the scene. So don't crank up the exposure value too much then. ;-)<br /> <br /> This may look complicated to you, but is pretty simple as you focus on it when taking pictures and gain experience.<br /> There is a description of exposure value on Wikipedia with a table of exposure values (EV) for different combinations of f-stops and exposure times, but don't go to technical about this: https://en.wikipedia.org/wiki/Exposure_value</p>

<p>Hi,<br> I suggest that you try this question on the Norwegian photo forum <a href="http://www.foto.no">foto.no</a>. There might be some people knowing the answer. Generally this is regulated by "<a href="https://lovdata.no/dokument/NL/lov/1961-05-12-2">Lov om opphavsrett til åndsverk</a>" . You might also find some information on Gisle Hannemyr's site, for example here: <a href="http://hannemyr.com/faq/legal_dm07.shtml">http://hannemyr.com/faq/legal_dm07.shtml</a><br> Cheers,<br> Hope this is of any help. If not, print it out on paper, curl it up and throw it in the dust bin.</p>

<blockquote> <p>Frode, there was only one grammatical mistake in your comment.</p> </blockquote> <p>;-) You should hear me talk. Or maybe not...</p>

<p>Hi<br> I think selfies most of all is a natural and necessary extension of everyday communication via social media and text messaging. It replaces body language that is a natural and important part of communication where people are present and can see each other.<br> <br> Cheers,<br /><br> Frode<br /><br> <br> (and excuse my English, it is not my native language)<br /></p>