dhessel Posted August 9, 2013 Share Posted August 9, 2013 I am new here and want to say hello before getting into it. I've just got my Kowa shooting on a Mark II and I cannot get it to focus wide open or anywhere near wide open. I can only get soft focus at f6.3 and higher. I have tried it on several lenses including a Canon 85 mm 1.8 and all show the same problem. If I get something focus as close a possible the defocused parts of the image that are beyond the focal point appear to be skewed to the left. I am wondering if maybe the optics are out of alignment a little bit. I had a giant ISCO projection lens that displayed similar artifacts and the front and back lenses were slightly off, visually it doesn't look like the Kowa is and I can look through the back of it and it looks sharp to my eyes. Any advice on what might be going wrong? Thanks. Quote Link to comment Share on other sites More sharing options...
Paulio Posted August 9, 2013 Share Posted August 9, 2013 I assume your familiar with the dual and minimum focus aspects of the kowa that could be causing softness, sounds like there is something wrong with the lens. Quote Link to comment Share on other sites More sharing options...
dhessel Posted August 9, 2013 Author Share Posted August 9, 2013 It appears so, I disassembled the lens so I could adjust the focus and rotate the front element independent of the rear. Doing so I was able to get near perfect focus using my 85 mm at 1.8. At this point I am not sure if its an issue with just the rear or the front since the front appears to have more than 1 piece of glass. Can anyone confirm if that is the case with the front piece. Thanks. Quote Link to comment Share on other sites More sharing options...
Gábor Ember Posted August 10, 2013 Share Posted August 10, 2013 Your problem is that the front and rear glass elements are not aligned to each other properly. It is enough to adjust only the front part or only the back. I don't have a kowa but it looks as simple as a Sankor or Sun so there should be only 2 glass groups. I had the same problem with my sun and adjusting the front glass (rotating it so that the image was sharp) solved it. You can usually use a caliper to rotate glass elements. Quote Link to comment Share on other sites More sharing options...
dhessel Posted August 10, 2013 Author Share Posted August 10, 2013 Thanks for the advice, this one is a little trickier. Some I have done have some screws that you loosen and then you can rotate the rear element. This one has a tube that wont allow them to rotate independently. Looks like I may have to rotate the rear glass. It appears to be mounted on a threaded ring with 2 notches in it, any advice on how to rotate that? Quote Link to comment Share on other sites More sharing options...
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