eudemian Posted July 12, 2007 Share #1 Posted July 12, 2007 Advertisement (gone after registration) I was disappointed with some photo's taken at a party that I decided to investigate my Noctilux and its focusing. I set the camera on a tripod and shot these reference photo's from just over a meter away. The only difference between each shot is the focal length used, camera stayed stationary. The following 7 shots are at the focal lengths from 1 through to 8. These first five shots are 1 through to 4. I am after some explanations about the results obtained because they confuse me, there may be a logical pattern here but I cannot work it out. I focused on the hair trigger symbol in the centre of the target. 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/28784-noctilux-and-focusing/?do=findComment&comment=303842'>More sharing options...
Advertisement Posted July 12, 2007 Posted July 12, 2007 Hi eudemian, Take a look here Noctilux and focusing. I'm sure you'll find what you were looking for!
eudemian Posted July 12, 2007 Author Share #2 Posted July 12, 2007 These last two shots are from 5.6 and 8 I will leave my thoughts about this till I have some expert advice from forum members. Tom 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/28784-noctilux-and-focusing/?do=findComment&comment=303849'>More sharing options...
wattsy Posted July 12, 2007 Share #3 Posted July 12, 2007 The only difference between each shot is the focal length used, camera stayed stationary. The following 7 shots are at the focal lengths from 1 through to 8. These first five shots are 1 through to 4. I presume by focal length you mean aperture? If so, your results demonstrate the well known tendency of the Noctilux to 'focus shift' (the plane of focus moves) as you stop the lens down. This is a characteristic of the lens and there's nothing that can be done about it. I haven't examined your results too closely but it looks like your Noctilux is also back focussing a little (a different issue that can be fixed) and this tends to exaggerate the effect of any focus shift. Link to post Share on other sites More sharing options...
Eoin Posted July 12, 2007 Share #4 Posted July 12, 2007 I'm not sure what the scale is in that chart, but if we take the scale to be cm your Nocti is back focusing by 2cm at f:1. This seems to be pretty consistent up to f/:4. After that, f:5.6 to f:8 where the depth of focus seems to mask the issue some what. Link to post Share on other sites More sharing options...
Peter Branch Posted July 12, 2007 Share #5 Posted July 12, 2007 I assume that the rulers are at an angle of about 45 degrees. If this is the case then the focusing error is of the order of 14mm at 1,000mm and f/1.0. The lens is backfocused like almost all the examples on the forum. I suspect that these lenses are optimised for film where, because film always bowed, the lens will have been set slightly further back into the body. We are talking approximately 5 hundredths of a millimeter i.e. 0.05mm. (Assume actual focal length of Noctilux is 52.4mm and the image plane to object distance is 1,000mm. Then, if it were in focus, the lens would be moved by 3.067mm from the infinity focus position. If it is focused on 1,014mm then the lens is moved by 3.020mm. Difference 0.047mm. For the purists I know that this is an approximation because I have not taken into account the distance between the entry and exit pupils of the lens, but it is good enough for this purpose.) The performance of the lens which your pictures illustrate is the classic behaviour of the Noctilux. One can look at it in two ways. If one stops down then for a given focus point at f/1.0 the image will appear most out of focus at f/2.0. With further stopping down the image appears to improve at the focus point due to the rapidly increasing depth of field. On the other hand the actual point of best focus continues to move backwards, but at a much reduced rate, after f/2.0. The M8 is a much more sensitive and analytical tool than any of the film M cameras and these effects are much easier to both see and to replicate. They were always there and well known to those interested in the subject. Link to post Share on other sites More sharing options...
wlaidlaw Posted July 12, 2007 Share #6 Posted July 12, 2007 When I sent my Noctilux back to Solms after they had done their "interesting" service and coding, I specifically asked them to optimize it for the M8. Now my back focus at 1m and f1.0 is less than 5 mm and zero at 5 meters. It deteriorates a little at 10 meters to about 10-12 cm and then is accurate at infinity. I presume it was just too difficult to get this highly corrected lens to focus totally linearly. The back focus increases as you stop down but the focus point always stays within the DOF. I would recommend that anyone sending a Noctilux back to Solms, asks them to optimize it for the M8, as I would guess it will still be good enough for film bodies, even allowing for film bowing. Did Contax have a problem between their normal SLR bodies and the RTSIII, which sucked the film onto a porous ceramic plate with a small vacuum pump, to hold it dead flat - same scenario. Wilson Link to post Share on other sites More sharing options...
wlaidlaw Posted July 12, 2007 Share #7 Posted July 12, 2007 Advertisement (gone after registration) For anyone who wants to see a very clear explanation of the consequences and design difficulties of film bowing, have a look here - interesting and readable like most of Dante Stella's articles. Dante Stella Also covers the Leica/Konica flange to film distance question well (Konica lens prices rise on eBay next week?) Wilson Link to post Share on other sites More sharing options...
eudemian Posted July 12, 2007 Author Share #8 Posted July 12, 2007 First, thank you for all the replies, I was in a rush this morning and of course I meant aperture not focal length. I suspected the back focus problem, how is it possible to fix this, could I ask the dealer to do this for me or is it my responsibility? Is there any strategy one could adopt shooting to overcome this back focus? I still think it is weird behaviour, the focus seems to jump at f 2. I really want to use this lens at f1, or 1.4 so do you think it is a little soft at these apertures? Again, thanks for the help and advice, my education proceeds apace. Tom Link to post Share on other sites More sharing options...
wlaidlaw Posted July 12, 2007 Share #9 Posted July 12, 2007 First, thank you for all the replies, I was in a rush this morning and of course I meant aperture not focal length. I suspected the back focus problem, how is it possible to fix this, could I ask the dealer to do this for me or is it my responsibility? Is there any strategy one could adopt shooting to overcome this back focus? I still think it is weird behaviour, the focus seems to jump at f 2. I really want to use this lens at f1, or 1.4 so do you think it is a little soft at these apertures? Again, thanks for the help and advice, my education proceeds apace. Tom Tom, I think the Noctilux is a bit soft wide open and the contrast is quite gentle also, which tends to accentuate any focus softness. However it is generally considered to be less soft than the previous f1.2 version and the f1.2 Canon 50mm. I took some landscapes at dusk the other night at f1.0 and in comparison to the Biogon 35, which from f2.8 upwards is very sharp and at all apertures, very high contrast, the Noctilux photo has a quite different look. It is a bit like images taken with my 1950's Summitar. However, even if you just go to f1.4, the Noctilux crisps up a lot. I think you just have to accept that there are compromises inherent in having an f1.0 lens, not least the amount of muscle you put on carrying it around on the M8. I am going to see over the next few months how much I use it and my other 50mm lens, the tiny collapsible Elmar-M. If I find that every time I have the wrong lens on the body, I will sell them both and buy a 50mm Summilux. I will also have a Voigtlander 35/1.2 for low light situations, if DHL ever get round to delivering it. Mind you I have now found out that Foto-Mundus did not post it last Tuesday as they told me they had. It was not posted until the Friday - a touch economical with the truth. Wilson Link to post Share on other sites More sharing options...
stunsworth Posted July 12, 2007 Share #10 Posted July 12, 2007 I have a Nocti and a 50mm Summicron. If I were buying today I'm sure I'd go for the ASPH Summilux instead of those two - expecially given the stratospheric price of the Nocti these days. In fact I could probably sell them, buy a new Summilux and make some money on the deal. The only thing that stops me is that the Nocti has such a unique look <grin> Link to post Share on other sites More sharing options...
jackal Posted July 12, 2007 Share #11 Posted July 12, 2007 how do you know that it is accuarelty focused on the hair trigger ??? with the noctliux the throw is so long that you can focus on something, twiddle the ring a touch and then it still looks focused and you cannot see any difference comapred to how it was before my noctilux does not back focus, and i suspect that many others don't either Link to post Share on other sites More sharing options...
alex7075 Posted July 12, 2007 Share #12 Posted July 12, 2007 To all of you who will eventually sell their Noctilux, please take a look at my ad in the proper section of the forum: I badly seek one! Link to post Share on other sites More sharing options...
Peter Branch Posted July 12, 2007 Share #13 Posted July 12, 2007 ........I still think it is weird behaviour, the focus seems to jump at f 2. I really want to use this lens at f1, or 1.4 so do you think it is a little soft at these apertures?...... Thomas, What you have is a lens that was never intended to be used at f/1.0 when focused at 1.0m. If any compromises had to be made, and there certainly were many with this lens, then the designers would not be particularly concerned about the performance with these settings. If nothing else it is almost impossible to focus accurately, certainly hand held, at these apertures and distances as the slightest movement will require refocusing. If the camera and lens are sent to Leica they may be able to get a slightly better result but I would not bet on it. One has to understand the tiny distances which are involved here and the extreme sensitivity of the M8 to “errors”. It is a bit like suddenly finding that the lens is being used with film that has the recording capability of microfilm and is also perfectly flat. More than 30 years ago when this lens was being designed nobody would have imagined its use in such circumstances. It was intended for use with films like Tri-X and HP4 which have quite different characteristics and within the limits we are discussing were certainly never flat. It concerns me that so many people seem to regard the Noctilux as the most desirable lens to go with an M8. Don’t please get me wrong I understand the thrill of owning and using such a specialised and exotic item, I owned one for 6 years – but it is a 30+ year old design with characteristics better suited to film cameras and even then one has to accept a lot of compromises. It can be bettered in almost every respect by the more modern designs. It is currently being praised for its “special look” frankly if I wanted a “bottle bottom” look I would not get it by paying for a Noctilux. I used mine on the M8 for 6 months and then sold it. Link to post Share on other sites More sharing options...
carstenw Posted July 12, 2007 Share #14 Posted July 12, 2007 I find that I like the pictures taken with the Noctilux at 1m at f/1 to be some of the best ones! I think the copy I am borrowing focuses correctly wide open, but might focus a bit wrong stopped down a little. I haven't tested it rigorously, but I think that wide open it focuses fine at all distances. Link to post Share on other sites More sharing options...
eudemian Posted July 12, 2007 Author Share #15 Posted July 12, 2007 I must thank all of the replies so far, it is really helping me to understand this lens. I know test shots of targets are boring I just wanted to get to grips with the behavior of the lens and thought this was the best way to isolate one aspect of the character of the lens.. I am astonished at its low light abilities, it seems to be able to suck any available photons that are lurking in the murk and magnify and extend and enhance them, so I am keen to use that ability and to get better focus, or at least the optimal focal precision that the lens will deliver. I didn't think using this lens would be an instant hit unlike the 75 Summicron, so I am going to soldier on and tame the beast. Tom Link to post Share on other sites More sharing options...
ho_co Posted July 13, 2007 Share #16 Posted July 13, 2007 Tom-- I'm not a Noctilux owner, so my comments are more general. 1) Others have found back-focus problems with various lenses wide open. According to Erwin Puts (Testreports), focus should be accurate with all Leica lenses at all distances when wide open. Leica can adjust this. (Tim Ashley had a similar problem with his 35/2; it took some effort from his side getting Leica to see the problem, but they were then able to correct it.) 2) The same Puts article recommends a test by focus bracketing. Sean Reid has described the procedure, as does Holger Fehsenfeld at http://www.l-camera-forum.com/leica-forum/leica-m8-forum/28152-m8-noctilux-focus-problem.html#post294786. 3) In a recent forum post which I can't turn up at the moment, Carsten Whimster mentioned having a discussion with a Leica tech in Berlin, in which if I recall correctly the tech said that some of Leica's lens test procedures may not be adequate for the M8 and are being looked at with an eye to improvement. 4) Since I don't know the Noctilux, I'm bothered by what I see as cyan fringing at the upper right edges of the rulers in your f/1.0 image. Is this part of the Noctilux' design, or could it indicate some misalignment? 5) I am amazed at the amount of effort you made assembling your test chart. You may find the one at http://www.focustestchart.com/focus21.pdf somewhat easier to use. (If you try it, remember to turn the camera to vertical for ease of use--an idea that naturally occurs to old-time rangefinder users but is sometimes overlooked by newcomers. ) --HC Link to post Share on other sites More sharing options...
rondeb Posted July 13, 2007 Share #17 Posted July 13, 2007 I'm STILL looking forward to my Noctilux and, may I say, that must have been one really exciting party! Best, Ron Link to post Share on other sites More sharing options...
eudemian Posted July 14, 2007 Author Share #18 Posted July 14, 2007 Ok Ron I get the gentle jibe, just to prove that I don't just shoot silly targets here is one of the shots at F1 that left me thinking what am I doing wrong. In the light of this discussion I now understand that noctilux is soft in this region and perhaps this is its character and it may suit some subjects. I focused on the face but the necklace is in the sharpest focus so I guess probably operator error and a little backfocusing. The colour and contrast on this jpg do not match in any way the original, I am not sure why, but anyway I will post it and hope for the best Tom 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/28784-noctilux-and-focusing/?do=findComment&comment=305608'>More sharing options...
carstenw Posted July 14, 2007 Share #19 Posted July 14, 2007 Howard, actually the talk with the Leica mechanic about quality control was told to me by Holger. I also talked to him, but mostly about other things. Tom, do you use the 1.25x Loupe? I find that without I can't consistently focus it. Moving subjects are also hell. Get the focus close, then sway your body the last bit before you shoot. Link to post Share on other sites More sharing options...
wlaidlaw Posted July 14, 2007 Share #20 Posted July 14, 2007 Howard, actually the talk with the Leica mechanic about quality control was told to me by Holger. I also talked to him, but mostly about other things. Tom, do you use the 1.25x Loupe? I find that without I can't consistently focus it. Moving subjects are also hell. Get the focus close, then sway your body the last bit before you shoot. I also recommend Carsten's technique. With the Nocti, swaying your body is a whole lot easier than tweaking that last little bit of focus ring. In addition to the 1.25x magnifier, I also use a Leicagoodies STEER knobbly sleeve on the focus ring, which helps together with my 3M rubber thumb knob on the back of the M8. It all makes it easier to hold the M8 with the right hand while you focus with the left, given the over 1Kg weight of M8 and Noctilux. Wilson Link to post Share on other sites More sharing options...
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