Ronniebootwest Posted October 12, 2004 Report Share Posted October 12, 2004 I know that resolution has been the topic of discussion in this forum many times and I am sorry to bring up the question yet again. However, I am a little confused. I realise that the suggested resolution is 72 for a windows monitor or 96 for a Mac and most people will simply reduce their photo's down to this resolution in a photo editor, e.g. photoshop. A modern digital camera is capable of producing very larg resolution files and these not only fill your compact flash card very quickly but also take up huge amounts of hard disc space on you computer. If you know that you are taking pictures that will only be used for a PTE slide show, then there seems little point in taking hi-res shots at the taking stage. Is my thinking wrong here? or do you folks have a different view?In order to save space all round, why not take low-res jpeg shots to begin with?Ron West Quote Link to comment Share on other sites More sharing options...
Ken Cox Posted October 12, 2004 Report Share Posted October 12, 2004 Ron i have been experimenting with digital picts taken by friends and family and have found the larger physical dimensions the better the final show -- i have one friend that has a 50 widescreen and we could see the difference between shows that used his picts full size from his camera 99% of them were 2272/1704 - the exif data does not show his dpi but they ranged between 196 kb to 2.08 mb and were the resulting show 238 images was 270 meg with the music-- i also made shows that i resized to 1024/768 - experimenting has shown me go for the big original image when i put a show together now it's final show place is on a tv -- the computer is just a tool to get it there -- when i used a Hassleblad -- i looked at every scene and said to myself how will it look as a 16 x 20 or larger picture -- -35 mm the decision was not greater than 11 x 14what would i lose in the enlarging process -- would i have to print it borderlessthe bigger image of the medium format film gave one a whole lot of leeway in making the final printI think the biggest decision when working with pictures that will be going thru a computer is unless it is absolutely necessary -- dont shoot verticalsyou will have to experiment - what may be your cup of tea is vinegar to somebody elseken Quote Link to comment Share on other sites More sharing options...
alrobin Posted October 12, 2004 Report Share Posted October 12, 2004 Hi, Ron,As usual, Ken said it very well. I use lower-res for a lot of my images as I know that I will never get around to making large prints from most of the images I shoot for digital slide shows, for instance.However, if there is any doubt about the way I will eventually use the image, or if I am shooting with large prints in mind, I will use the maximum resolution available.One reason for using a higher resolution is where severe cropping will be required - and one does not always know for sure about this until one is preparing the images for a show. Often I crop just to get two images to line up properly for that "third-image" effect, or just to have certain areas in each image in a pleasing juxtaposition with each other.If there is any doubt about the use you will be making of the photos, go to a higher resolution. And always try to edit "down" in photoshop or other image editor. i.e. in your editing start with a higher resolution than you ultimately need. Also, it can be problematic if you try to edit low-quality jpegs. And if you have to go back and re-edit, try to use the original image, whether it is a jpeg or a lossless image.One further point, it is confusing to refer to digital images in terms of "dpi". "Dpi" is reserved for printing - it really has no bearing on the quality of images as viewed on a monitor or with a digital projector. All that is required is the size of the image in pixels and the jpeg quality - if they are jpegs. Quote Link to comment Share on other sites More sharing options...
Ken Cox Posted October 12, 2004 Report Share Posted October 12, 2004 I will add if people are interested seeing the difference in pictures of varying sizebuy an AGFA Lupe 8xprint a picture in bw at various picture size and print to fit page sizethen look at the edge detail with the lupeyou will see the differencethe lupe is a phoyograher's best friend -- a must have in all your working rooms and in camera bag -- for locating the sliver you got in your finger while getting in a precarious position to get "the shot"ken Quote Link to comment Share on other sites More sharing options...
Gérard de Lux Posted October 12, 2004 Report Share Posted October 12, 2004 I always use the highest resolution (i.e. 3000x2000) at the shooting stage, even for pictures thoretically taken for PTE shows, because you never know if these pictures won't be needed for another purpose (what would happen if the National Geographic people see your show and wish to make a special edition with some of your pictures ? ).After selection and copy of those needed for the PTE show (the originals are kept in separate safe places), I resize them to the desired size (I always make a version at 1280 px wide and one at 900 (*)), then make the final adjustments or retouching and save the resulting image in jpeg with an average quality factor of 60%.(*) why another version at 900 px wide : just for exchanges via e-mail or the internet, to reduce the overall size and also because many people still do not have monitors/processors able to cope with large size pictures when the pace of the show is very rapid - but this will change !As Al said, forget about 'dpi' which are only used for printing, and always use the actual dimensions in pixels. If you want, I have two pages (in English) on this topic of dpi, image size and compression, with numerous examples, starting here. Quote Link to comment Share on other sites More sharing options...
Ronniebootwest Posted October 12, 2004 Author Report Share Posted October 12, 2004 Informative and helpful replies, thankyou fella's! Interesting to note that you all seem to prefer the larger resolution in spite of the storage space. You have probably got big (gigabyte) hard drives. I accept that I have confused ppi with dpi - you would think I'd know the difference by now wouldn't you. I will get there one day.I'd be interested in seeing a demo of your experimenting with hi/low res shows Ken. Can you point me to a couple of slide shows, or maybe I shouldn't be so lazy and just produce a couple for myself.Please do keep on responding, we will all learn from these replies.Ron West Quote Link to comment Share on other sites More sharing options...
Gérard de Lux Posted October 12, 2004 Report Share Posted October 12, 2004 Storage space costs not that much nowadays (I recently bought a 120 GB external hard drive, fast and 'cheap'), but I can garantee that 'lost' pictures is a real disaster.When I say 'lost' pictures, I mean very good pictures of not common subjects, ones that you'd like to see enlarged after some cropping; you can't do it with low res pics... but you don't know at the time of shooting that these will be the 'pictures of the century' ! I recently had an extensive 'portfolio' (12 pics, plus interview) published in a French big photography magazine, and I can tell you that the editors were very demanding as far as quality was concerned (they were even quite worried that my pictures were jpegs and not tiff or raw ! but they went out well) Quote Link to comment Share on other sites More sharing options...
Ronniebootwest Posted October 12, 2004 Author Report Share Posted October 12, 2004 I do realise that to print a large photograph will demand high resolution, but remember that my original question was about the resolution required for on screen presentation. PTE requires a file size to be quite small and the resolution would therefore need to be low. I believe that the accepted norm is just 72.It is also worth pinting out that most desktop (injet) printers will only require a resolution of 300 - anything more that that would be a waste. Is this right or wrong?Ron West Quote Link to comment Share on other sites More sharing options...
Gérard de Lux Posted October 12, 2004 Report Share Posted October 12, 2004 Yes, as I said, for PTE shows image sizes corresponding to the usual screen resolutions (1024x768 or 1280x1024) are sufficient as far as the final image is concerned.But what I say is that it is much safer, at shooting stage, to use a resolution (image size) as big as possible because one never knows what the future uses of the pictures might be. Even only for a simple slideshow, if one has to crop the image or take only a part of it, the result will be good if the original size is big enough.Again, forget about 72 ! This a 'dpi' value which is absolutely of no relevance for screen where only size in pixels matters ! I think that this is clearly explained and illustrated on this page and the next one.[Edit] : you don't have to believe me but it is easy to make the experiment yourself. Take a picture of yours. Then, without changing its width and length in pixels, make a copy at 10 dpi and another one at 1000 dpi. And look, on the screen, if you see any difference... Quote Link to comment Share on other sites More sharing options...
Ken Cox Posted October 12, 2004 Report Share Posted October 12, 2004 2272/1704 Ron as i said pte has no problem picts that were this size and +- 2 mb in sizeKen Quote Link to comment Share on other sites More sharing options...
Conflow Posted October 13, 2004 Report Share Posted October 13, 2004 Hi Ronnie,Just got your EMail, I shall get around to a reply tomorrow-There's a little confusion in this 'thread' - you refered to the resolution of standard Monitors as 72 or 96 (you're not the only one confused by this)No,thats nothing to do with Resolution - its simply the "Refresh Rate" of the visual imageper second on the Monitor,ie:- 72 FPS or 96FPS. Whereas a 625 Line TV is 25.FPS/Interlaced.The "Resolution" of a 16" PC.Monitor would be 1024 x 768 x 16.7million Pixels - its quite vast.In fact a 4.OMeg/Pixel Camera is 'Ludicrously puny' in resolution compared to the Monitor -Also the very best 'Digital Camera' will come nowhere near the resolution of a Good Monitor -In reality Al and Ken are quite correct in going for the best 'Camera Resolution' they can get.Don't forget when the 'Image' is downloaded it is in JPeg Format not Bitmap - so the Camerais already imposing a 10:1 compression on the 'Image' (due to storage space restrictions).So the greater the 'Camera resolution' the better the PC.Image will be -Now if you compare a 'Digital Camera' to a good 'SLR Film Camera'- there is no contest.The reason is very simple - Where Al and Ken would be restricted to 6-7 Meg.Pixel per Imagethe 'SLR Camera' would be running at TeraPixels per Image, because the Image is taken onFilm at 'atomic particle level'. The only restrictions being Film Speed, Light, Lens, and f.Stop.That's not to denegrate the 'Digital Camera' - it has many use features - but for Hi-Qualityprinted Imagery the Film Camera can not be beaten - YET !Brian.Conflow. Quote Link to comment Share on other sites More sharing options...
Conflow Posted October 13, 2004 Report Share Posted October 13, 2004 Ron and all who read my last PostRon, I owe you an apology - when I read your Post and you mentioned 72 or 96 resolution.I took that up incorrectly. Because there was some confusion I assumed that you were alluding to Monitor Size and display rate where in fact you may have been refering to 'Pixels per Inch' of Photo Resolution. In that case you were perfectly correct -Indeed 72 Pixel/Inch for a Windows PC. and 98 Pixel/Inch for a Mac are the quoted figures -Whereas, the Monitors 'Frame Repetition Rate' is from 70Fps -100Fps (Frames per Sec).However that does not detract from a Monitors performance which is vastly superior to thatof a Digital Camera, and the bigger the 'Camera Resolution' the better the image on Screen.OOOooopps, Sorry about that !!Brian.Conflow. Quote Link to comment Share on other sites More sharing options...
alrobin Posted October 14, 2004 Report Share Posted October 14, 2004 The "Resolution" of a 16" PC.Monitor would be 1024 x 768 x 16.7million Pixels - its quite vast.In fact a 4.OMeg/Pixel Camera is 'Ludicrously puny' in resolution compared to the Monitor Brian,I'm afraid I have to beg to differ with this description. The resolution of the 16-inch monitor, in order to compare with the camera, is only 1024 x 768 pixels, or less than 1 Megapixels, whereas my D70 is capable of 6.1 Megapixels - much greater than the monitor. The "16.7 million" you mentioned is pixel "depth", representing colour and intensity, and is related to the limit in the number of bits (24) which can be assigned to this task. Each of my camera's pixels can also be "resolved" into many different levels of colour and intensity - 48, in fact, or 16 bits per colour channel. Thus there are 1.7 x 2^21 different elements of information, compared to only 1.3 x 10^13 for the monitor. Hope my math is OK. Quote Link to comment Share on other sites More sharing options...
ContaxMan Posted October 14, 2004 Report Share Posted October 14, 2004 I'm with Al on this - Could we please kill this 72/96 rubbish once and for all. On a monitor it's the number of pixels that counts not how many per inch/rod/pole/perch/angstrom/nanometre/cm/metre/mile - OK I think I've made my point. Sorry to rant but it confuses so many... Quote Link to comment Share on other sites More sharing options...
Ronniebootwest Posted October 14, 2004 Author Report Share Posted October 14, 2004 Hi Contaxman! My you are getting all het up about this 72/96 thing - calm down, 'it's only a commercial'.I am not sure that we should kill of this theory though, after all most of us tend to assume that 72 id the right thing to go for on a PC. In fact, I have several CD tutorials (from well respected authors) that suggest that this is the setting to use in photoshop when preparing a slide for a show in PTE.Perhaps you can offer your reasons for thinking that we should 'kill' the idea. I would just like to get it clear in my mind.Ronnie West Quote Link to comment Share on other sites More sharing options...
ContaxMan Posted October 14, 2004 Report Share Posted October 14, 2004 It's easy, really. VDUs and the like display pixels. My (typical) screen has dimensions of 1024 pixels by 768 pixels so that's all I need to know. An image of this size will fill the screen. My monitor is nominally 17 inches. My laptop is 13 inches. My old machine 14 inches. A friend has a monitor of 23 inches. But the 1024 x 768 pixels image will fill the screen on each one exactly. If you look at photoshop/photoshop elements image size dialogue, you'll see that the inches/cm bit comes at the bottom in document size & that's exactly where it belongs. If I'm intending to print then I need to know about this. But all that matters on my monitor/projector is what it says at the top - pixel dimensions. Quote Link to comment Share on other sites More sharing options...
alrobin Posted October 14, 2004 Report Share Posted October 14, 2004 I have several CD tutorials (from well respected authors) that suggest that this is the setting to use in photoshop when preparing a slide for a show in PTE.Ron,It's just a different way of adjusting the resolution in an image editor (e.g. photoshop). But Roger is 100% correct in stating that in reality, monitor image sizes have nothing to do with print dpi. Period! It doesn't matter how many tutorials there are out there that state differently, the fact remains that to set the resolution of an image for showing on a monitor or digital projector, one has merely to specify the number of pixels in each of the two dimensions. Of course, all these measurements are indirectly related, in that for printing, you would want to have a large pixel size to start with, and then also set the print dimensions (here dpi comes into play), as there is a direct relationship between the dpi and the number of "i's" (or print size). However, it is confusing to speak of dpi when referring to screen resolution. It's almost like asking a used-car salesman how many miles per fence-post a prospective automobile gets on a gallon of petrol! Or in ordering a load of firewood, determining the size of the load by asking the salesman how many loads it would take to encircle the earth by setting each piece of wood end to end. Quote Link to comment Share on other sites More sharing options...
Gérard de Lux Posted October 14, 2004 Report Share Posted October 14, 2004 I fully agree with ContaxMan ! But I'm a bit disappointed that this matter comes up again when I had hoped that everything was clear from my web page indicated above despite all the efforts I made to write it and have it translated into English (only joking).But if you don't believe me, may be that you'll believe a quite famous author, Wayne Fulton, who has an excellent website and a book called "A few scanning tips", and where you'll find this page which explains things probably better than I do... It's called 'Say No to 72 dpi' ! Quote Link to comment Share on other sites More sharing options...
ronwil Posted October 14, 2004 Report Share Posted October 14, 2004 For the record, I opened Gerard's web page fourteen months ago now and found it so useful that it is on my list of favourites so that I can refer to it quickly, whenever I wish. Thanks Gerard.Ron [uK] Quote Link to comment Share on other sites More sharing options...
ContaxMan Posted October 14, 2004 Report Share Posted October 14, 2004 Yes - Gerard explains it very well - with examples. And Wayne Fulton's "Scantips" is a mine of information - should be compulsory reading for anyone getting into digital imaging (whether by scanner or not). Quote Link to comment Share on other sites More sharing options...
Ken Cox Posted October 14, 2004 Report Share Posted October 14, 2004 Ronnieseehttp://www.scantips.com/no72dpi.htmlthis has been brought up many times and others have agreed with Wayneken Quote Link to comment Share on other sites More sharing options...
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