vishwanath_chandrahas Posted January 1, 2011 Share Posted January 1, 2011 <p>I need to know this just out of curiosity. While FX lenses of Nikon can be used both on FX and DX format cameras, why do nikon produce DX lenses which can't used on FX sensors ( I know about vignetting !!) ? thanks</p> Link to comment Share on other sites More sharing options...
frank_skomial Posted January 1, 2011 Share Posted January 1, 2011 <p>Perhaps most DX lenses can be used on FX camera in DX mode, or FX mode with vignetting.</p> <p>Latest FX cameras detect DX lenses and automatically narrow the view by the crop factor, but this feature can be disabled in configuration.</p> <p>Due to smaller circle of coverage needed for DX sensor, the lenses can be made smaller, lighter, and less expensive.<br> However, due to the need to put AF_S and VR optics and electronics in the lenses, the DX lenses are sometimes almost as big as FX lenses.</p> Link to comment Share on other sites More sharing options...
JDMvW Posted January 1, 2011 Share Posted January 1, 2011 <p>For one thing, for quite a while Nikon was in denial about there being any need for the FX cameras (aka, "full-frame" or more properly, 35-mm sensor).<br> As Frank has said, it is possible to take advantage of the smaller format to design lenses that are not only cheaper to build, but that may have other advantages deriving from the smaller area-to-cover.</p> Link to comment Share on other sites More sharing options...
Matt Laur Posted January 1, 2011 Share Posted January 1, 2011 <p>When you say "can't [be] used" on FX (referring to DX lenses), do you mean that the camera won't make a photograph, or that the image projected by a DX lens doesn't cover the entire FX sensor? You say that you know about the vignetting, so it sounds like you already understand the basic issue. As Frank points out, Nikon's FX bodies can sense that you've mounted a DX lens, and will let you shoot to a sub-area (APS-C, or DX-sized) of the larger FX sensor. Or, you can tell it to shoot anyway, and see the entire FX frame, with the vignetting.</p> Link to comment Share on other sites More sharing options...
daverhaas Posted January 1, 2011 Share Posted January 1, 2011 <p>For most focal lengths - there is really not a reason for a "DX" lens - however on the wide angle end of things - if you mount a 10mm FX lens on a Dx body - you are in effect dealing with a 15 degree angle of view - so you're losing the wide part. </p> <p>And just to clarify Frank's remarks - All Nikon FX digital bodies - will automatically determine if you mount a DX lens and shift into Crop Mode - which in effect eliminates the vignetting - but reduces you to a 5 or 6 megapixel camera. And yes - you can disable that feature via menus. </p> <p>Dave</p> Link to comment Share on other sites More sharing options...
vishwanath_chandrahas Posted January 1, 2011 Author Share Posted January 1, 2011 <p>Matt, I did not know that there is a DX mode in D3 or D700 that's why I mentioned DX lenses can't be used on FX sensors (without causing vignetting). Now let us think of my Nikon f100 film camera. When I mount nikon 18-200mm VR DX lens on it, I can see that only area at the center is visible. Is what I see in view finder accurate or is there more vignetting than I can see ? Is metering accurate with this lens on film camera ? does this lens damage the camera? these are some other questions I came up with, after I heard from you guys.</p> Link to comment Share on other sites More sharing options...
dan_south Posted January 1, 2011 Share Posted January 1, 2011 <p>The image projected by the DX lens isn't large enough to cover the entire FX sensor. You'll end up with part of an image in the middle of a black circle.</p> Link to comment Share on other sites More sharing options...
Matt Laur Posted January 1, 2011 Share Posted January 1, 2011 <p>I believe the F100 has a 100% finder, so what you see is what you get, or <em>very</em> close to it!</p> Link to comment Share on other sites More sharing options...
vishwanath_chandrahas Posted January 1, 2011 Author Share Posted January 1, 2011 <p>Matt,<br> F100's viewfinder is 97%. does it mean I get more area focussed than I see or less? </p> Link to comment Share on other sites More sharing options...
Matt Laur Posted January 1, 2011 Share Posted January 1, 2011 <p>That means that the actual image recorded on the film is 3% larger than whan you can see in the viewfinder. So, if you're seeing a bit of vignetting in the finder, you'll see a bit <em>more</em> of it on your negative (or slide, etc). If you were using a non-vignetting lens, you'd still be seeing a wee bit more image on the neg than you're seeing in the finder. 3% isn't much, needless to say.</p> Link to comment Share on other sites More sharing options...
daverhaas Posted January 1, 2011 Share Posted January 1, 2011 <p>Short answer to the "does this lens damage the camera question" is - No. A dx lens mounted on a Film body will not damage the camera - since the electronics are the same. </p> Link to comment Share on other sites More sharing options...
vishwanath_chandrahas Posted January 1, 2011 Author Share Posted January 1, 2011 <p>David,<br> what about the measurement of exposure of a DX lens on Film camera? is it any reliable ?</p> Link to comment Share on other sites More sharing options...
Matt Laur Posted January 2, 2011 Share Posted January 2, 2011 <p>If the camera can support "G" style full-frame lenses, it will also correctly control the aperture on a DX lens.</p> Link to comment Share on other sites More sharing options...
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