Davetrials Posted May 20, 2007 Report Share Posted May 20, 2007 say u have a fish lense 11mm to 17mmor a zoom lense 70mm to 200mmWHAT THE f**k DOES THE MM BIT STAND FOR!!!!!!!!!!i have no idea. Quote Link to comment Share on other sites More sharing options...
Has anyone seen my shoe? Posted May 20, 2007 Report Share Posted May 20, 2007 Millimeters?so 10 to the -3 of a meteror 0.001 of a meter Quote Link to comment Share on other sites More sharing options...
MikeCottTrials Posted May 20, 2007 Report Share Posted May 20, 2007 i dont think he means what are millimetres, surely you mean what is the measurement of Quote Link to comment Share on other sites More sharing options...
Has anyone seen my shoe? Posted May 20, 2007 Report Share Posted May 20, 2007 Cant take anything for granted with Dave Quote Link to comment Share on other sites More sharing options...
Dr. Nick Riviera Posted May 20, 2007 Report Share Posted May 20, 2007 MM = Millimetersfocal length is shown in millimeters.lower the focal length, wider the lens effectively. Quote Link to comment Share on other sites More sharing options...
Davetrials Posted May 20, 2007 Author Report Share Posted May 20, 2007 i dont think he means what are millimetres, surely you mean what is the measurement ofyea obvioslybut what is it measuring, what on that that lense is 10mm Quote Link to comment Share on other sites More sharing options...
chrishayton Posted May 20, 2007 Report Share Posted May 20, 2007 yea obvioslybut what is it measuring, what on that that lense is 10mmok i think i could be wrong but it could be lens length. from shutter ( sensor film whatever. to the front element. however that doesnt work as a 10 mm lens obviously isnt 10 mm. ask mike, he ll know Quote Link to comment Share on other sites More sharing options...
ScotchDave Posted May 20, 2007 Report Share Posted May 20, 2007 My Dad explained this to me years ago, if I remember right; the numbers are the ranges of focal lengths as when you focus a lens you are effectively tuning the focal length. Quote Link to comment Share on other sites More sharing options...
Rob_P Posted May 20, 2007 Report Share Posted May 20, 2007 Excuse me for sounding like an asshole. But why does it matter?You worry wayyy to much about this sorta crap dave lol. Quote Link to comment Share on other sites More sharing options...
Davetrials Posted May 21, 2007 Author Report Share Posted May 21, 2007 well people are saying lense's to me and ive no idea what the f**k there on about,shut up and answer the question. Quote Link to comment Share on other sites More sharing options...
Tomm Posted May 21, 2007 Report Share Posted May 21, 2007 Quote Link to comment Share on other sites More sharing options...
BONGO Posted May 21, 2007 Report Share Posted May 21, 2007 But, a 17 - 200mm lense doesn't have a focal limit of 20cm does it!! Quote Link to comment Share on other sites More sharing options...
Joe Papasnap Maher Posted May 21, 2007 Report Share Posted May 21, 2007 Dave really are a gay? Like Rob said, whats does it matter, just go and take some photos u homo Quote Link to comment Share on other sites More sharing options...
BONGO Posted May 21, 2007 Report Share Posted May 21, 2007 nah f**k this. I'm with dave on this. If you are gonna spend a lot of money on something, it' better to understand how it works, why it works and have a good general understanding about it. I don't like owning something without knowing as much as possible about it.Anyway, it's a f**king forum. There are thousands of questions you don't give a toss about knowing the answer to, but dave does want the answer to this, so either help, or leave the thread alone to let him get the answer...Not being funny about it like, but just cos you don't give a shit about the answer, doesn't mean it's wrong to want to know.Bongo Quote Link to comment Share on other sites More sharing options...
Tomm Posted May 21, 2007 Report Share Posted May 21, 2007 But, a 17 - 200mm lense doesn't have a focal limit of 20cm does it!!I guess the number of lens elements has something to do with it - I.e. the calculations are based on if there was only one element (like in the picture) whereas most lenses have several bits of glass in them?EDIT: And yeah I'm with Bongo on this one, it's not exactly dumb to want to know what something means. Quote Link to comment Share on other sites More sharing options...
Joe Papasnap Maher Posted May 21, 2007 Report Share Posted May 21, 2007 LOL. Aww, sorry dave my bad.I do find your camera topics amusing. 1) Because i dont know the ansers to your questions, beacuse i pay interest in the TECHNICAL aspects of cameras and 2) Beacuse Your dave.. The one and only Dave.You know i love you really.Must bear In mind though, i was sorting through 670 photos took in 1 hour at the baftas yesterday, until about 2am last nightm then had to get up at 5, to carry on sorting and have them sent before 6. So im still abit grouchey lol.I should go take a sleeep Quote Link to comment Share on other sites More sharing options...
Davetrials Posted May 21, 2007 Author Report Share Posted May 21, 2007 WOOT that pic kinda made it a bit clearer. bngo raised a valid point though.. Quote Link to comment Share on other sites More sharing options...
Has anyone seen my shoe? Posted May 22, 2007 Report Share Posted May 22, 2007 That picture only applies to having a single peice of glass in the lens, most modern lenses have more then that.I think my fuji S5600 has 3 just as an example. Quote Link to comment Share on other sites More sharing options...
Davetrials Posted May 22, 2007 Author Report Share Posted May 22, 2007 oh bugger..so no one on this forum knows why then? Quote Link to comment Share on other sites More sharing options...
Davey Posted May 22, 2007 Report Share Posted May 22, 2007 oh bugger..so no one on this forum knows why then?Surely google has the answer? If I understood anything about photography I'd look for you but I'd only make a numpty out of myself!Davey Quote Link to comment Share on other sites More sharing options...
BONGO Posted May 22, 2007 Report Share Posted May 22, 2007 The focal length is a basic optical property of any lens, and the most important one to a photographer. The simple way to think of the focal length is to think of it as a numerical value, expressed in millimetres, which represents how much of a given scene (the coverage area) a lens can take in.Focal lengths for Canon SLR lenses range from ultra-wide (14mm) to incredibly long telephoto (600mm and 1200mm). The typical range of an affordable lens or lenses is from 28mm to 105mm or so.Why, then, these strange values in millimetres? Why not indicate the angle of view taken in by each lens instead? Well, partly for historical reasons and partly for practical reasons. The technical description of focal lengths is rooted in the mathematics of optics - it’s the distance between the focal plane and the rear nodal point of the lens, given infinity focus. How this bit of Martian translates to the field of view depends on the size of the imaging area being used, which can be different between 35mm film cameras, APS cameras and some digital cameras. And as for practical reasons, the focal length of a lens is an innate property of the lens, but the actual coverage area of the scene depends on the size of the image format used.So note that crucial point - all the examples I gave above are for a 35mm film camera or full-frame EOS SLR only. If you were to use a 28mm lens on an APS camera or a digital camera with an image sensor smaller than that of 35mm film (ie: most digital cameras sold today) then you would have a much narrower field of vision than if you were to use the same lens on a 35mm film camera.The same focal length system is used to describe lenses for other types of cameras as well, such as medium format cameras. But the area taken in by a lens on a medium format camera will be totally different from that of a lens of the same focal length on a 35mm camera, because the area covered by medium format film is considerably larger.I knew all along. Seriously dave, the FIRST link on my FIRST google search gave me this john...THE GURU... Quote Link to comment Share on other sites More sharing options...
F-Stop Junkie Posted May 24, 2007 Report Share Posted May 24, 2007 It's all a bit of relational values rather than anything actually specific or interesting. As Bongo said, it's simply the distance from the film (or sensor) plane to the rear nodal point of the lens. It's not important, but an interesting bit of trivia.Now, for a bonus point, can any one a) say where F numbers come from, and why aperture values are called stops? Quote Link to comment Share on other sites More sharing options...
Tomm Posted May 24, 2007 Report Share Posted May 24, 2007 F numbers are the focal length of the lens divided by the diameter of the aperture. Not sure about stops. Quote Link to comment Share on other sites More sharing options...
RobinJI Posted May 25, 2007 Report Share Posted May 25, 2007 The way I understand it from what bongo said and comon sense, it is the distance from the rear nodal point of the lense* and the image sensor. Obviously a 300mm lense couldnt physicaly fit that length in it, but the length of the lense could be compressed by adding a second lense within it, that will focus the light in earlier.N = Rear nodial point of the lense:So I guess kinda like this, both setups would be called the same length lense, but the lower one would be more compact. Quote Link to comment Share on other sites More sharing options...
Tomm Posted May 25, 2007 Report Share Posted May 25, 2007 Yeah that's what I was talking about when I was on about the number of elements Quote Link to comment Share on other sites More sharing options...
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