gtownby Posted April 9, 2007 Share #1 Posted April 9, 2007 Advertisement (gone after registration) Had the M8 ordered in November but cancelled when Leica announced the filter fix. Now, with all the good images posted, I can live with the IR filters, especially if FW 1.10 does what it promises. But my first lens would likely be the 35 mm summicron. What is the heck is the "backfocus" problem that some people ascribe to this and some other fast asph lenses? Does this only mean that one must re-focus after changing the aperture, or is the problem more than that? As my question indicates, I really do not know what backfocus is. Thanks. --Gordon http://www.gordonownby.net Link to post Share on other sites More sharing options...
Advertisement Posted April 9, 2007 Posted April 9, 2007 Hi gtownby, Take a look here Backfocus for Dummies? . I'm sure you'll find what you were looking for!
ho_co Posted April 9, 2007 Share #2 Posted April 9, 2007 Gordon-- "Backfocus" means that the lens focuses further away than the rangefinder shows. Example: You focus on an object 6 feet away, but the lens focuses, say, 6 ft 4 in away. Theoretically, with most lenses focus may shift a bit as you stop down, but that is compensated by increased depth of field. So there should be no need to refocus after changing aperture. Some forumites seem to think all members of a certain class of lenses have a backfocus problem; others feel it is definitely not all but perhaps a very small sample of that class of lenses. The 35/2 is in any case less likely to show the problem than the 35/1.4. Next issue of LFI is supposed to address the matter. E Puts has already talked about it (Testreports). I wouldn't worry about it. --HC Link to post Share on other sites More sharing options...
j. borger Posted April 9, 2007 Share #3 Posted April 9, 2007 Get the lens .... do not drive yourself nuts in advance or with all kind of rulertests and enjoy shooting real life content .... too much thinking and testing will kill the enjoyment ... . Start testing ONLY if your real life pictures show problems or unexpected behaviour! Just my 2 cents ............. Link to post Share on other sites More sharing options...
egibaud Posted April 9, 2007 Share #4 Posted April 9, 2007 I had a 35mm summilux that was back focusing. I read and post many messages here, some will tell you to adjust the range finder, other that the lens has no problem etc. My advice is, do not touch your range finder as what you will fix for one lens will be worse for another one. I eventually sent returned my 35lux but luckily as I had only one lens I change my mind from buying 35lux and 75 cron to 28 Elmarit 50 Cron and 90 Elmarit. If you can, go to the shop and try the lens, it is what I did and I also tried a 35 cron, focusing was perfect. I would have bought it if I had found a 75cron too. Eric Link to post Share on other sites More sharing options...
andym911 Posted April 9, 2007 Share #5 Posted April 9, 2007 I have had no focussing issues at all with any of my older lenses (35 cron 2nd version, 50 lux from 1970, 28 elmarit) but I just purchased a new 35 cron asph and it has this problem. At 1 meter if focuses about 5 cm behind e.g 1.05 meters wide open.It is a pain but now I know it I am just nudging the focus a bit to compensate and am getting sharp focussed results. When I get round to it I will send it in for adjustment.It is not unusable..just frustrating. I will not try any self adjustment of the range finder as I am notoriously clumsy and incompetent with anything smaller than a garage door. andy Link to post Share on other sites More sharing options...
tashley Posted April 9, 2007 Share #6 Posted April 9, 2007 Unfortunately it is more complex than this: the classic behaviour for a backfocussing 35 Lux or cron (and the cron is less strongly afflicted) is for the centre of the frame to move OOF as you stop down, until you are saved by DOF at f8. However the peripheral area of the frame, (imagine about 2/3rds of the whole frame excluding the centre third) will remain sharp. I won't re-open the arguments here but I have had two new 35 luxs and one cron and they all exhibited this behaviour, as have the lenses of a lot of people who have posted here. Others have examples that don't do this. But the key fact is that if you get one that does, Solms will not fix it because they regard its behaviour as normal. They will almost certainly exchange it though. Whoever above said 'don't touch your rangefinder' is most likely right: unless focus is off with all lenses, or with your 35 wide open (at which aperture they are designed to focus perfectly) then your RF is most likely correctly adjusted. Nuff aid: I'm off to take some pictures! Tim Link to post Share on other sites More sharing options...
gtownby Posted April 9, 2007 Author Share #7 Posted April 9, 2007 Advertisement (gone after registration) OK, got it! Thanks so much for the time. This is an amazing forum. I don't think any other camera company has anything that offers so much public information/opinions. I'll keep you all posted . . . --Gordon http://www.gordonownby.net Link to post Share on other sites More sharing options...
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