frode

<p>The vertical scale in the histogram is scaled automatically to occupy the full height of the available space for the histogram.</p> <p>In statistics a histogram is usually called "frequency distribution". The vertical scale shows the frequency of each binned range of values. The sum of the height of all the vertical lines will always be the number of pixels in the image (or 1 if you prefer to view it as a relative frequency distribution).<br> Hope this was of some help. If not, print it out, curl it up and throw it in the dustbin.</p> <p>Regards,</p>

<p>I don't think they are trying to give or refer to an authoritative general definition of the term "nature photography" (which I doubt even exist)<br /> The "General guidelines" (for that forum) that you have partly cited do state explicitly that the term "nature photography" is used "<em>In the strictest sense</em>". At least that mean that the term "nature photography" is not used in that text in a very broad sense. Therefore, an attempt to criticize the text while applying a broad sense of the term will most probably be more confusing than clarifying.<br /> Also, stating that it is to be understood "In the strictest sense" implies that the author(s) of that text admits that there also exist (at least might exist) a broader understandings of the term.<br /> ;-)<br /> Cheers,<br /> (and excuse my English. It's not my native language)</p>

<blockquote> <p>I found if I have to I can just set by experience and then chimp and it's still faster.</p> </blockquote> <p>Agree. When I use manual flash, it is for macro where things tend to be more straightfarward.<br> My post was ment for explaining what the guide number is (and maybe what it isn't).</p>

<p>Hi</p> <p>There is a very simple relationship between guid number (GN), object distance (D) and f-number (N):<br> GN = D x N at ISO 100<br> Remember that D is in meters if GN is in meters, D is in feet if GN is in feet.<br> Have a look at this article in Wikipedia:<br> http://en.wikipedia.org/wiki/Guide_number</p> <p>Regarding zoom flashes and guide numbers, have a look at this discussion over in dpreview (GN varies with zoom):<br> http://www.dpreview.com/forums/thread/3386098#forum-post-55965701</p> <p>Cheers,</p>

<p>I would say the figure is correct in the context it is used. You are correct in that the f-number is different in the two cases, but the text where you found the figure (assuming it is coming from here: http://www.photographycompendium.com/) does not say that the f-number is equal in the two cases. As I understand it, what the author wants to show is what will happen to the DOF when you only changes one single physical property of the lens, namely the focal length. The physical size of the aperture (the aperture diameter) is held constant.<br /> The f-number is not really a physical property of a lens. It is a relation between two physical properties, namely the ratio between the focal length and the aperture diameter (and from what you write, I understand that you already know it). If you keep the aperture diameter constant and changes the focal length, the f-number will of course change.<br /> I think the article explains the basics of DOF very well. I do however think that it would have gained in clarity if a more explicit term had been used instead of only "aperture", for example "aperture size" which is used one place in the text, or even more clearly "aperture diameter". Then there would have been no room for ambiguity.</p> <p>If this was of no help, please print it out, curl it up and throw it in the trash.</p> <p>Cheers,</p> <p>(And excuse my English. It is not my native language)</p> <p> </p>

<p>You could also try light. Many types of bugs will move towards lighter areas, so maybe you can mount a lamp a couple of feet from the camera and leave the camera in dark shadow. Just a thought...<br> I often use this trick when getting small water bugs (small as sand grains) out of my drinking cup when I am backpacking (in my Country you can drink most water in woodland and mountains without cleaning). You may just drink them, but I think the water is more delicate without them. I cover the cup with my hand leaving a small part open for light to slip in, maybe third of a sqquare inch. The bugs will gather there, and by pouring out a little water from that same part the bugs are gone.</p> <p>Cheers,</p>

<blockquote> <p>I know uncompressed TIFF is universally supported (except for web). How about LZW compressed TIFF?</p> </blockquote> <p>LZW has been her for years (older than zip as far as I know), so if some software can handle TIFF I would expect it to handle LZW compression as well, at least uncompressing. LZW is also a very simple algorithm to implement. Conclusion must be that the question is not about compression, but if your clients have software that handles TIFF or not.<br> I do not have much experience with TIFF, but I have seen the advice not to use LZW on 16 bit TIFFs, only on 8 bit TIFFs as LZW may more often than not result in larger files when compressed with LZW. ZIP is better for 16 bits.</p>

<p>Hi,<br> Most modern browsers will as far as I know handle PNG, so you can use PNG on the Internet. As I see it, the main advantage of JPG is the small file size due to lossy compression and the main advantages of PNG is that it is lossless and it handles something JPG does not have at all: transparency (partial transparency or <em>alpha transparency</em>). The latter may be important for graphical designs which may very well include photographs.<br> There is something called TinyPNG that is, as I understand it, a lossy compression method that will reduce the file size of PNGs. It do so by reducing the colors in the original and using the indexed color mode.<br> Is PNG better than JPG for photographs? There is no yes or no to this question since it depends on your requirements/usage. There might be one very important factor other than file size and lossless compression to consider for photographs though, and that is whether sites like photo.net do allow for other formats than JPG.<br /><br /></p> <blockquote> <p>people seems to be saying that PNG is best for graphic arts files rather than photos</p> </blockquote> <p>I believe this is because they presupposes that file size is the main factor. For use on the Internet that may very well be a correct assumption since graphics tend to have very few colors compared to a photo. Few colors together with indexed mode will give small files for PNGs.<br> But on the other hand, as you say: File size may not be that important. And lossy compression may not be desirable in some situations.<br> Personally I use 99.999% JPG for the Internet (and the other 0.001% might very well not exist), just because it has become a habit and because it is very easy in Photoshop to just Ctrl-Alt-Shft-S an image when I want to save it for Internet usage (it takes care of everything without me needing to do thinking stuff).</p> <p>Cheers,<br> Frode Langset</p> <p>(And excuse my English. It is not my native language)</p>

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<p>You can use it for landscape type photos (not same lens, but a Pentax M* 300 f/4):<br> http://www.photo.net/photo/17832741<br> http://www.photo.net/photo/17828556<br> http://www.photo.net/photo/17828557<br> http://www.photo.net/photo/17837779<br> http://www.photo.net/photo/17830739</p>

<p>Hi,<br> I haven't read what the others have responded and neither do i know your camera, but if image #1 is JPG i would have considered reducing contrast drastically and then increasing exposure by maybe 1 stop. If your camera have highlight and shadow recovery settings you could probably have used these instead of or in addition to reducing contrast.<br> I don't know, but I suspect your camera was on the edge of blowing out the details on the white walls in the background (there are some evidence that suggests that small parts are already blown out). If so, I deem the exposure to have been correct (if keeping all other settings unchanged). I would not say that blowing out the details in the white wall would suit this image. If that was the only option (i.e. only increasing exposure without taking down the highlights and lifting the shadows) I would have recomposed the image in order to exclude these white walls.<br> Another option is to edit the image now and make the above corrections there.</p> <p>For Image #3 I would increase contrast and exposure a little.</p> <p>I don't shoot JPG, but I do believe that if you want to have JPGs straight out of the camera without any post editing, you should at least adjust contrast in addition to setting correct exposure.</p> <p>Hope this was of any help. If not, print it out, curl it up and throw it in the trash.<br> Cheers,<br> Frode Langset</p>

<p>Hi,<br /><br />There is no "best practice" since there is no standard result to measure the outcome against. You should challenge these scenes and find your own ways to do them. You will soon find out that there are multiple ways to catch the scene, and each one emphasizes different aspects of the scene.<br /><br />Back-lit scenes are by no means bad practice. I would say that you should rather seek them and challenge them instead of avoiding them. They might be challenging in that you will have to make decisions before you take the picture, decisions that cannot be changed afterwards in the post processing. But they also have opportunities that is difficult to find in other scenes. There are of course different techniques that will help you, like flash, reflectors, HDR etc. that you have already been advised on. You can even use lens "faults" creatively by letting lens flare, stray light and reflections be part of your creative image. But the important part is first to decide how you want the scene rendered.</p> <p>Hope this was of any help. If not, print it out, curl it up and throw it in the trash.<br> <br> Cheers,<br /><br> Frode Langset<br /><br> <br> (And excuse my English. It is not my native language)<br /></p>

<p>Image magnification describes how big an object in focus is being imaged on the sensor in relation to the real size of the object itself, and thus also how big (or "near") it will be in the final image.</p> <p>Image magnification is not only influenced by the focal length. The distance between the object in focus and the lens' front nodal plane, and the distance between the lens' back nodal plane and the camera's sensor (or film) also influences the magnification. You can use a variety of focal lengths to obtain a given image magnification. Field of view will however be different for same magnification with different focal lengths, so the image will not look the same.</p> <p>You manipulate the distance between the front nodal plane and the object by moving back and forth. This alters the magnification (nearer for higher magnification).</p> <p>Extension tubes and bellows both change magnification by manipulating the distance between the sensor and the back nodal plane, as well as does the simplest way of lens focusing mechanism by moving the complete lens away from the sensor for more magnification. Extension tubes insert "distance rings" between the lens and the camera. Bellows achieve the same with a retractable bellows with the camera mounted on one end of the bellows and the lens on the other end.</p> <p>You can also alter the lens focal length by placing optical elements in front of the lens, usually a simple close-up lens, but stacking two ordinary lenses will also work, the front one usually inverted. Or you can place optical elements between the lens and the camera (a tele converter).</p> <p>Two or all three of these methods can also be combined. Experimenting is encouraged (and is very fun).</p> <p>A good book (but somewhat old and from the film era) explaining this and lots of other things in macro photography in an uncomplicated way is John Shaw's "Closeups in Nature". I am sure there are lots of other good (and even better) books explaining this in a comprehensible way, but I have not read them and thus cannot point at any of them as better than others.</p> <p>Hope this was of some help. If not, print it out, crumple it up and throw it in the bin.</p> <p>HNY & regars,<br /> Frode Langset</p> <p>(and excuse my English, its not my native language)</p>