Guest #12 Posted October 23, 2011 Share #41 Posted October 23, 2011 Advertisement (gone after registration) ......It's the correct way to put it, and '15/3.5' just is the abbreviation thereof. I dislike the excess use of abbreviations which is rude against the reader. When I quote someone's text then it will become part of my text which I don't want to contain unnecessary abbreviations ... or typos. So I will correct these... You're missing the whole point of quotation marks, which is that you don't change anything. Including what is, or what you think is, an error. Otherwise, anything one writes, in or out of quotes, is useless. Not sure why 15/3.5 is an abbreviation and 15 mm 1:3.5 isn't. Link to post Share on other sites More sharing options...
Advertisement Posted October 23, 2011 Posted October 23, 2011 Hi Guest #12, Take a look here Hyperfocal scales on Lenses and crop factor cameras (M8). I'm sure you'll find what you were looking for!
lct Posted October 23, 2011 Share #42 Posted October 23, 2011 +1 Link to post Share on other sites More sharing options...
Jeff S Posted October 23, 2011 Share #43 Posted October 23, 2011 Quotes containing typos/errors, but which are transcribed as originally presented, are followed by [sic]. Of course one can still debate whether there was a typo or error in the first place. Jeff Link to post Share on other sites More sharing options...
lct Posted October 24, 2011 Share #44 Posted October 24, 2011 « It is impossible to overemphasize the importance of meticulous accuracy in quoting from the works of others. » (Chicago Manual of Styles, 16th edition, 13.6). Link to post Share on other sites More sharing options...
pico Posted October 24, 2011 Share #45 Posted October 24, 2011 Here's an experiment. Using an 8x10 camera, a 4x5, 6x6cm, 35mm. Use the same lens on each, say a 14" lens. Stop it down to a physical aperture of 8mm. Take a picture of a subject from the same location with all three with the principle subject at 40'. Include objects to infinity. Do not adjust the distance to the subjects. Then develop and cut down the films to the centre - 35mm full frame. Print to the same dimension. Show me the difference in DOF. Link to post Share on other sites More sharing options...
SJP Posted October 24, 2011 Share #46 Posted October 24, 2011 Don't need to do the experiment the result will be the same in all cases, obviously. The thing in the woodpile is that on a MF camera you tend to use the whole film area, as is the case on a cropped sensor camera. Then you run into different behavior, a 28 mm lens on the M8 "looks like" a 35 mm on full frame due to the crop factor. In that case the DoF markings are off - roughly by the crop factor. The digital era provides an additional incentive for pixel peeping so the rule of thumb is 1 stop on the M9 and 2 stops on the M8 to get the required DoF "correction". Link to post Share on other sites More sharing options...
lct Posted October 24, 2011 Share #47 Posted October 24, 2011 Advertisement (gone after registration) Don't need to do the experiment the result will be the same in all cases, obviously... But the DoF calculations will be quite different... At least if i understand well Pico's post above. Did he refer to a 350mm lens open at f/44 really? Link to post Share on other sites More sharing options...
lct Posted October 24, 2011 Share #48 Posted October 24, 2011 ...the rule of thumb is 1 stop on the M9 and 2 stops on the M8 to get the required DoF "correction". I don't know for the M9 but zero stop works well for me on the 5D, and one stop on the M8.2. Link to post Share on other sites More sharing options...
SJP Posted October 24, 2011 Share #49 Posted October 24, 2011 I don't know for the M9 but zero stop works well for me on the 5D, and one stop on the M8.2.Sure, I agree with that if you take a standard viewing condition as the criterion (viewing distance is the same as the diagonal of the image as was agreed a long time ago). The additional 1 stop is for those that insist on inspecting 100% crops to make sure that they spent their hard earned money wisely. Personally I usually just consider wide open (lens dependent) & f/5.6, or similar, as a binary choice. Maybe sometime I will be good enough to really make use of a controlled depth of field but so far composition and focusing anything at all is more than enough challenge:rolleyes: Link to post Share on other sites More sharing options...
SJP Posted October 24, 2011 Share #50 Posted October 24, 2011 But the DoF calculations will be quite different... At least if i understand well Pico's post above. Did he refer to a 350mm lens open at f/44 really? Dunno, the main component is chop the film back to standard 35 mm size and then print on the same size paper. In that case the optics is identical => same result by definition. Link to post Share on other sites More sharing options...
luigi bertolotti Posted October 24, 2011 Share #51 Posted October 24, 2011 Here's an experiment. Using an 8x10 camera, a 4x5, 6x6cm, 35mm. Use the same lens on each, say a 14" lens. Stop it down to a physical aperture of 8mm. Take a picture of a subject from the same location with all three with the principle subject at 40'. Include objects to infinity. Do not adjust the distance to the subjects. Then develop and cut down the films to the centre - 35mm full frame. Print to the same dimension. Show me the difference in DOF. NONE... and you can leave apart the pysical aperture... Link to post Share on other sites More sharing options...
mjh Posted October 24, 2011 Share #52 Posted October 24, 2011 But the DoF calculations will be quite different... No, they would be the same since all the relevant parameters – focal length, distance, aperture, and image size – are the same. He was using sleight of hand to make you believe that image size was not the same when of course it is: The image size used for the eventual prints is always 36 x 24 mm. The use of different sizes of film just served as a distraction. Link to post Share on other sites More sharing options...
ho_co Posted October 24, 2011 Share #53 Posted October 24, 2011 But when we enlarge the negatives in the thought experiment to print them all at, say, 8 x 10 inches, we will see different depths of field (due to the different enlargements), won't we? Link to post Share on other sites More sharing options...
lct Posted October 25, 2011 Share #54 Posted October 25, 2011 Enlarging or cropping won't sharpen a blurred image miraculously folks. Let's take Pico's example if i understand it well. With a 350mm lens at f/45 (if any) on a 8x10 camera, focusing on a subject matter situated at 10 meter distance will generate a DoF of 29m from a near limit of 5.84m to a far limit of 34.8m. If we look at an object situated at 25m for instance, the latter will be sharp accordingly. Now let's look at the same object shot with the same lens on a 35mm camera. Instead of 29m the latter has only 2.16m of DoF from a near limit of 9.03m and a far limit of 11.2m. Then the object situated at 25m will be blurred and we can well enlarge or crop the pics as we like, the latter will remain blurred at the end of the day. All this to repeat what i thought we agreed about: a smaller capture medium generates less DoF with the same lens and more DoF with an equivalent one. http://www.l-camera-forum.com/leica-forum/1728743-post104.html Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/164202-hyperfocal-scales-on-lenses-and-crop-factor-cameras-m8/?do=findComment&comment=1825609'>More sharing options...
Erik Gunst Lund Posted October 25, 2011 Share #55 Posted October 25, 2011 Enlarging or cropping won't sharpen a blurred image miraculously folks.Let's take Pico's example if i understand it well. ...... IMHO you failed to understand Pico's example... The same lens, not an equivalent lens... Link to post Share on other sites More sharing options...
SJP Posted October 25, 2011 Share #56 Posted October 25, 2011 In Pico's thought experiment he is using a 8x10 film and at the end is cutting the negative size back to standard 35mm dimensions. In that case all the stuff you chop off is superfluous, it doesn't exist. After the clipping of the negative you get exactly the same negative as with a 35mm film, ergo the DoF is the same. Link to post Share on other sites More sharing options...
Erik Gunst Lund Posted October 25, 2011 Share #57 Posted October 25, 2011 Yes also same CoC Link to post Share on other sites More sharing options...
luigi bertolotti Posted October 25, 2011 Share #58 Posted October 25, 2011 But when we enlarge the negatives in the thought experiment to print them all at, say, 8 x 10 inches, we will see different depths of field (due to the different enlargements), won't we? His example spoke of "cutting the negs to 35mm"... undoubtly an odd way to throw away a precious 8x10 film plate... but ok, the mental experiment is correct... a series of 35mm sized films with exactly the identical image (supposed, which I am not 100% sure, that you can find the same film in 8x10 and 35mm...) Link to post Share on other sites More sharing options...
mjh Posted October 26, 2011 Share #59 Posted October 26, 2011 His example spoke of "cutting the negs to 35mm"... undoubtly an odd way to throw away a precious 8x10 film plate... but ok, the mental experiment is correct... It’s both correct and totally pointless – several 35 mm negatives exposed with the exact same parameters will obviously show the same images. As I said it is the rhetorical equivalent of sleight of hand – first making it look like the experiment involved different image sizes, then cutting everything down to 36 x 24 mm to make sure the different negative sizes are irrelevant. This is like a stage magician mumbling strange words and waving his magic wand, purportedly in order to make the ball in the box disappear – but actually just distracting from the fact that he had palmed the ball before and it was never in the box to begin with. Link to post Share on other sites More sharing options...
SJP Posted October 26, 2011 Share #60 Posted October 26, 2011 Oy, Michael! I am disappointed you forgot the smoke and the rabbit out of the hat part of the story. Link to post Share on other sites More sharing options...
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