jackperk Posted February 26, 2011 Share #1 Posted February 26, 2011 Advertisement (gone after registration) I read here talk of the need to have the right setting for the diopter. But I find nothing in the manual not do I understand the diopter, it's options or settings. Can someone please provide a thumbnail tutorial, please? Jack Quote Link to post Share on other sites More sharing options...
Advertisement Posted February 26, 2011 Posted February 26, 2011 Hi jackperk, Take a look here Need guidance on diopters. I'm sure you'll find what you were looking for!
Viv Posted February 26, 2011 Share #2 Posted February 26, 2011 The M9 viewfinder has a power of -O.5 dioptres. If you wear glasses and want to shoot without them, you need a new viewfinder glass. For example, if your glasses have a strength of +1.0 dioptres, you will need a viewfinder glass with a strength of +1.5 dioptres. Leica manufactures viewfinders in a range of plus and minus powers. N.B. A lens with a strength of 1 dioptre has a focal point of one metre from the lens. Quote Link to post Share on other sites More sharing options...
jaapv Posted February 26, 2011 Share #3 Posted February 26, 2011 (edited) In practice the value may vary. The best way to determine which diopter you need is to visit your optician and hold his trial lenses between your eye and the viewfinder, and judge the result. In a pinch the rack of throw-away spectacles at your local chemist will serve. Edited February 26, 2011 by jaapv 1 Quote Link to post Share on other sites More sharing options...
01af Posted February 26, 2011 Share #4 Posted February 26, 2011 For example, if your glasses have a strength of +1.0 dioptres, you will need a viewfinder glass with a strength of +1.5 dioptres. That's nonsense. If your eyeglasses are +1 dpt then you will need a correction lens for the camera's eyepiece of +1 dpt as well. As simple as that. Quote Link to post Share on other sites More sharing options...
jaapv Posted February 26, 2011 Share #5 Posted February 26, 2011 Point being, nobody has eye problems in exact steps of 0.5 diopter. That is why the empirical method works best. Quote Link to post Share on other sites More sharing options...
01af Posted February 26, 2011 Share #6 Posted February 26, 2011 Point being, nobody has eye problems in exact steps of 0.5 diopter. That is why the empirical method works best. That's right but the blanket advice to add 0.5 dpt to the eyeglasses' strength for the eypiece correction lens is just pure nonsense ... as anyone with the slightest bit of common sense can find out by just thinking about it for five seconds. Quote Link to post Share on other sites More sharing options...
Rolo Posted February 26, 2011 Share #7 Posted February 26, 2011 (edited) Advertisement (gone after registration) The M9 viewfinder has a power of -0.5 dioptres.If you wear glasses and want to shoot without them, you need a new viewfinder glass. For example, if your glasses have a strength of +1.0 dioptres, you will need a viewfinder glass with a strength of +1.5 dioptres. Not true. All military gun sight rangefinders and other optical instruments have a standard diopter setting of -0.5. This is to energise the eye for precise viewing. If your spectacles are +1.0 diopter, you need an additional viewfinder lens of +1.0. Do not compensate for the standard -0.5 setting. Edited February 26, 2011 by Rolo Quote Link to post Share on other sites More sharing options...
01af Posted February 26, 2011 Share #8 Posted February 26, 2011 ... have a standard diopter setting of -0.5. This is to energise the eye for precise viewing. "Energise the eye" ...!? Actually, the purpose of the -0.5 dpt pre-set is to place the optical device's virtual image for the eye at a virtual distance of 2 m/6 ft. Do not compensate for the standard -0.5 dpt setting. That's right. Quote Link to post Share on other sites More sharing options...
Rolo Posted February 26, 2011 Share #9 Posted February 26, 2011 (edited) "Energise the eye" ...!? Actually, the purpose of the -0.5 dpt pre-set is to place the optical device's virtual image for the eye at a virtual distance of 2 m/6 ft. Handy in a tank !! Regardless, we agree on the usage. :-) Edited February 26, 2011 by Rolo Quote Link to post Share on other sites More sharing options...
Jerry_R Posted February 26, 2011 Share #10 Posted February 26, 2011 That's nonsense. Really? Why they say so then? http://www.reddotcameras.co.uk/product_info.php?cPath=16_25_58&products_id=829 Quote Link to post Share on other sites More sharing options...
Rolo Posted February 26, 2011 Share #11 Posted February 26, 2011 (edited) Really? Why they say so then?http://www.reddotcameras.co.uk/product_info.php?cPath=16_25_58&products_id=829 He's made that up. It is nonsense. If it was good information, anybody with 'normal vision' would need a correction lens and Leica would have made every camera for dozens of years with the wrong diopter. -0.5 dpt is standard for a good reason. Edited February 26, 2011 by Rolo Quote Link to post Share on other sites More sharing options...
01af Posted February 26, 2011 Share #12 Posted February 26, 2011 Really? Why they say so then? Because they are too dumb to know any better. Quote Link to post Share on other sites More sharing options...
Jerry_R Posted February 26, 2011 Share #13 Posted February 26, 2011 Thx! Quote Link to post Share on other sites More sharing options...
gpwhite Posted February 26, 2011 Share #14 Posted February 26, 2011 In practice the value may vary. The best way to determine which diopter you need is to visit your optician and hold his trial lenses between your eye and the viewfinder, and judge the result. In a pinch the rack of throw-away spectacles at your local chemist will serve. Jack, My advice differs from Jaap's a bit. I have a mild prescription to see better at a distance (-1.5 diopters and have stigmatism-- aspherical retinae, if you will). I have been using diopters on M cameras forever and found that the only way you know which power diopter is appropriate is to try them out. I have not found a useful correlation between the Leica stated diopter power and how well it improves my focus. On the M9, this requirement has gone from important to critical. So I use the -1.5 on the viewfinder itself, but switch up a bit for the 1.25 magnifier (no diopter) and the 1.4 magnifier (-1.0 diopter). It is a lot of fussing compared to the ease of an SLR adjustable viewfinder, but the Leica glass is so darn fantastic, I am obsessed about doing my part to focus correctly. If you shoot the Summiluxes at 1.4 or 2.0 (or use the extraordinary APO Telyt), then precision is the only way around frustration. Peter 1 Quote Link to post Share on other sites More sharing options...
jaapv Posted February 27, 2011 Share #15 Posted February 27, 2011 Another good example that theory and practice don't always match. My (and many others') experience with magnifiers indicates that the diopter correction is less than the naked viewfinder, as mentioned by Peter. Leica insists that there is no difference - in theory. So, with diopters, -these things cost 100 Euro- the best you can do is try before you buy. Quote Link to post Share on other sites More sharing options...
jaapv Posted February 27, 2011 Share #16 Posted February 27, 2011 Jack, My advice differs from Jaap's a bit. [...] I have been using diopters on M cameras forever and found that the only way you know which power diopter is appropriate is to try them out. I have not found a useful correlation between the Leica stated diopter power and how well it improves my focus. Peter :confused:Where do we differ? If they were readily available it might be practical to try them out - but almost all dealers have to order them. So the try-out lenses of the optician are your best bet. Quote Link to post Share on other sites More sharing options...
hoppyman Posted February 27, 2011 Share #17 Posted February 27, 2011 (edited) The information on the Red Dot UK site is actually directly from Leica Camera's own website. <Leica Camera AG - Photography - LEICA CORRECTION LENSES M> Perhaps there has been some confusion when the English content was written. That is only my guess. I agree with the recommendations that your optometrist is the best placed person to assist with selection of any needed correction, including any accommodation factor to be included in the calculation (the eye energising part). If your vision correction is for astigmatism that needs to be taken into account as well. That may be a source of additional confusion I found this link useful to help me to understand some of the terms better. The difference between dioptre and magnification (correction lenses and eye piece magnifiers) is central. Eyeglass prescription - Wikipedia, the free encyclopedia Edited February 27, 2011 by hoppyman Quote Link to post Share on other sites More sharing options...
charles-k Posted February 27, 2011 Share #18 Posted February 27, 2011 (edited) Excellent discussion! I have multi focals, distance correction of +0.25 and near +2.25. When I received the M9, and tried to focus, I was lacking detail to focus on the focus square to be very accurate. I did find then there was a correction of -0.5. How this then translates is not obvious, because in part it will depend, on how well you can resolve detail in the focusing square and does this then compromise your ability to compose in the distance, or do you use the correction of the multi focals in combination. I tried numerous diopters ranging from +1.0 to +2.5, and found +1.0 is my ideal compromise. It really is worthwhile, to test, before investing in too many diopters Once I found the correct diopter, I have now, no problems focusing any lens, any of the lux's ,90mm, or in low light. Edited February 27, 2011 by charles-k 1 Quote Link to post Share on other sites More sharing options...
jackperk Posted February 27, 2011 Author Share #19 Posted February 27, 2011 I also wear bifocals and do not remove them for shooting. If I don't, and if the lower part of each lens in my glasses is for near view and the upper for distance, through which should I be viewing. I assume the upper part. Correct? And as the glasses position my eyes a greater distance from the eyepiece, what complications does that add? Love to hear more from bifocal or trifocal veterans. Quote Link to post Share on other sites More sharing options...
charles-k Posted February 27, 2011 Share #20 Posted February 27, 2011 Jack, this is where it is not obvious, and you must try out for yourself, maybe at an optometrist. I find I use the top part of multi's for composing and focusing and works great! My correction overall with the diopter and mulit's is +1.25. Intuitively it does not seem correct, but it works! I have excellent far vision, with a mild correction of +0.25 for watching TV. Why overall of +1.25, but it works great My suspicion it is a compromise is to correct for near sight vision, which is critical to see full detail for focusing. 1 Quote Link to post Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.