andybarton Posted April 19, 2012 Share #21 Â Posted April 19, 2012 Advertisement (gone after registration) Next step... it could be that the DMR and the EXIF don't recognise the focal length... Getting there by a process of elimination Link to post Share on other sites More sharing options...
Advertisement Posted April 19, 2012 Posted April 19, 2012 Hi andybarton, Take a look here EXIF information on DMR. I'm sure you'll find what you were looking for!
psquared Posted April 20, 2012 Share #22  Posted April 20, 2012 Here are a couple of pictures. The first one is of the DMR LCD when I displayed INFO of a picture taken with the 35-78/2.8. It clearly identifies the lens as 35-70mm. However, there is no focal length info in the EXIF. The second picture is the DMR picture with EXIF intact. The DNG file must contain the zoom lens info somewhere, but it's obviously not in the standard location.  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/1224-exif-information-on-dmr/?do=findComment&comment=1988385'>More sharing options...
gautier Posted April 20, 2012 Share #23 Â Posted April 20, 2012 Thanks a lot for this test ! I can forget the management of zooms in my script... Link to post Share on other sites More sharing options...
graeme_clarke Posted April 20, 2012 Share #24 Â Posted April 20, 2012 There seem to be some interesting disaparities! Â Page 68 of the DMR Instruction Book (English section) indicates data from ROM lens data will be recorded but not for some ROM zoom lenses. It doesn't mention the two I have, the 21-35 and the 28-90 and neither communicate aperture data. Data from the primes are recorded though (100, 180, 280), and aperture figures doubled when the 2X ROM converter used. Â Just have to live with it! Â Best wishes, Â Graeme Link to post Share on other sites More sharing options...
psquared Posted April 20, 2012 Share #25 Â Posted April 20, 2012 It doesn't mention the two I have, the 21-35 and the 28-90 and neither communicate aperture data. Â Probably because of variable maximum aperture on these zooms ... Link to post Share on other sites More sharing options...
masjah Posted April 20, 2012 Share #26 Â Posted April 20, 2012 But, for both the 21-35 and the 28-90 zooms, the "correct" aperture is transmitted by the ROM chip to the camera viewfinder. Link to post Share on other sites More sharing options...
AbbeyFoto Posted April 20, 2012 Share #27 Â Posted April 20, 2012 Advertisement (gone after registration) But, for both the 21-35 and the 28-90 zooms, the "correct" aperture is transmitted by the ROM chip to the camera viewfinder. Â This is true of my 28-90 and I have had to adjust my reading of the aperture setting on the lens e.g f4 is one stop less than the maximum for the current focal length - but just what is the aperture for 27mm? No idea. So I give up worrying about it? f5.6 is two stops off maximum - if shutter looks ok go for it. Not ideal but otherwise a nice lens so I put up with it. Â My 21-35 is "I'm off on a long weekend Friday" lens which is back to Leica for the third time. Link to post Share on other sites More sharing options...
psquared Posted April 20, 2012 Share #28 Â Posted April 20, 2012 But, for both the 21-35 and the 28-90 zooms, the "correct" aperture is transmitted by the ROM chip to the camera viewfinder. Â You're correct, John. Nevertheless, the information does not get to the DMR for some reason. Link to post Share on other sites More sharing options...
andybarton Posted April 21, 2012 Share #29 Â Posted April 21, 2012 The aperture in the viewfinder is transmitted by the cam on the lens, isn't it? Link to post Share on other sites More sharing options...
masjah Posted April 21, 2012 Share #30 Â Posted April 21, 2012 The aperture in the viewfinder is transmitted by the cam on the lens, isn't it? Â Andy, no, if it's a ROM lens, it comes from the ROM chip. This is how it can give the "true" aperture with a ROMmed variable aperture zoom lens. There's some sort of position sensor in the lens which is connected to the lens ROM chip. Â Also, if you mount a ROM 2X converter on the camera, and then mount a non-ROM lens on to that, there is no aperture indication in the viewfinder. Presumably this is because, whenever the camera sees a ROM chip, it automatically takes the aperture information from that, and not the cam. And of course, at the other end, with the non-ROM lens, nothing is being sent to the other end of the converter ROM chip for it to process and pass on to the camera. Link to post Share on other sites More sharing options...
masjah Posted April 28, 2012 Share #31  Posted April 28, 2012 Andy, no, if it's a ROM lens, it comes from the ROM chip. This is how it can give the "true" aperture with a ROMmed variable aperture zoom lens. There's some sort of position sensor in the lens which is connected to the lens ROM chip. Also, if you mount a ROM 2X converter on the camera, and then mount a non-ROM lens on to that, there is no aperture indication in the viewfinder. Presumably this is because, whenever the camera sees a ROM chip, it automatically takes the aperture information from that, and not the cam. And of course, at the other end, with the non-ROM lens, nothing is being sent to the other end of the converter ROM chip for it to process and pass on to the camera.  Andy, on thinking more about this, I might well be wrong. What I observed is also consistent with the nominal aperture still being taken from the 3rd cam, and just the information required for the camera's own software to convert to the true aperture being transmitted by the ROM chip. Link to post Share on other sites More sharing options...
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