kenneth_smith7 Posted January 30, 2014 Share Posted January 30, 2014 <p>I hate to be one of those sharpness fanatics, but I'm a bit disappointed with the corners of this lens @ f/11 in my landscapes. I bet I could focus a tad closer, hyperfocal, and bring the lower branches/grasses into sharp, but after quite a few experiments I still find those corners a bit soft. Any thoughts? Am I expecting too much from this lens? My research claimed greatness, especially over the older f/3.5. I suppose it could be a bad sample, but I'll admit it's usually operator error. I should add that this is not an enlarger issue, as I'm looking at the negs.</p> Link to comment Share on other sites More sharing options...
User_502260 Posted January 30, 2014 Share Posted January 30, 2014 <p>Do you think the lens needs to be looked at? My widest lens in the 6X7 format is the 50/4.5 Zenzanon for the GS-1. It seems sharp everywhere. At f/11 you might be closing down a little too much. Are you using any kind of filter with the lens? </p> Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted January 30, 2014 Author Share Posted January 30, 2014 <p>My choice of f/11 was found after laboring over many negatives and listening to others. It's the sweet spot. However I can't see any difference at f/16, personally. No loss there, and I might start using it for depth of field reach. I don't print over 16x20 anyway. Besides the center is fine, it's these corners that start to go ever so slightly. I've shot one scene at all apertures to compare. Theres no gain for shooting at f/8.<br> As for filters, a protective Hoya SMC UV. No harm in that. I seriously doubt the lens needs to be checked, as everything is in order, no rattles anyway. </p> Link to comment Share on other sites More sharing options...
john_wiegerink1 Posted January 30, 2014 Share Posted January 30, 2014 <p>All lenses are not created equal and it is possible you got a dud, but I have enough Pentax 6x7 lenses to know or at least think that duds are not common. My 55mm f4 second version is a very good lens and I don't think I need to look further. Having said that, yours might be different. A good test to see if you have an alignment problem within the lens is to find a large brick build and get far enough away to be near infinity focus and shoot wide open to f16 and see what thew corners look like. Make sure the camera is level and perpendicular to the building, which means you might have to find a building with a little hill next to it to setup on. If your corners are a little soft at wide-open that is expected, but by f8 the corners should certainly be equal to the center. If not, then you might have a faulty lens. If you didn't buy this lens new then you have no idea of its track record and it's possible it could have been disassembled for cleaning or repair and not assemble right. I really have never heard anything really bad about any of the three versions of the 55mm's. JohnW</p> Link to comment Share on other sites More sharing options...
WJT Posted January 31, 2014 Share Posted January 31, 2014 <p>Wow, it is hard to imagine you thinking the 55 f4 is soft; mine is excruciatingly sharp. I consider it to be the best lens that I have (out of six lenses). I do have a 45 f4 that suffers from chromatic aberrations in the corners on high contrast subjects and yet others have said that their 45's are great. It might be worth having your lens looked at by a tech. Regards.</p> Link to comment Share on other sites More sharing options...
dougmiles Posted January 31, 2014 Share Posted January 31, 2014 <p>John alluded to his "second version".... so this raises the question whether yours, Kenneth, is first or second. The first version, 1979, was only on the market for 7 years before being replaced in 1986 by the second version. Both are 55mm f/4.0 but the second version has one fewer element, so the optics are different. Both are reputed to be excellent... I have both but haven't done any rigorous tests. But the fact it was replaced so quickly raises the possibility the performance was improved.<br> The 1979 version has the lens ID lettering around the front element within the filter ring. The second has this ID info on the beveled front edge of the focusing ring.</p> Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted January 31, 2014 Author Share Posted January 31, 2014 <p>I had to copy and paste John's reply into Word to read it, because there was a Samsung ad into half the text. Having ads is one thing, but this won't allow a delete. Nice.<br> I've got the second version. It's sharp, not excruciatingly sharp, which sounds wonderful, pardon me, but just wonderful. I shoot 5x7 to get my sharpness kicks, so I wish this was up there, but really my 90mm Takumar is better than the 55.<br> I did a mess of testing a few years back when I got it (ebog) and I felt confident enough to keep it. Since then it did hit the ground hard one time, enough to shatter the filter, but all else seemed fine. Now I'm wondering if I did it in.<br> But what exactly could go wrong with the internals if the glass is lodged in place? If it wasn't in place then why is 98.5 % of the image sharp?<br> I think I might just need to stop assuming infinity focus is best. I did a number of experiments where I brought my focus ever so slightly back and that did help, so I' guess that's all I can do. I don't want to stick someone else with this and go lens hunting. Launching into all that squinting through a loup thing again when really it could be I need to focus differently than normal. Am I learning or going down a dark alley?</p> Link to comment Share on other sites More sharing options...
d_purdy Posted January 31, 2014 Share Posted January 31, 2014 <p>Kenneth, when an ad is covering some of the text, at least on my computer, you can just refresh the browser page and get a different ad that probably doesn't cover the text.</p> <p>I have the later version of the 55 f4 and I just went and looked at an 11x14 print I have framed on the wall and clearly there is not the least fall off in any corner. If there is it is so microscopic that I can't see it. I never stop all the way down with any lens. <br> Dennis</p> Link to comment Share on other sites More sharing options...
john_wiegerink1 Posted January 31, 2014 Share Posted January 31, 2014 <p>Ken, it doesn't take but a fraction of a millimeter/inch to throw a lens off. Usually a drop like you had will render one side or two comers out of whack, but not all four corners. You are finding out something I had to find out for myself also. That is "do not rely on the infinity lens setting or racking your lens all the way in" for infinity focus. When I bought my first 35mm slr I ran around just taking picture of distant scenes by setting the lens on infinity. I could never understand why the slides never seemed as "tack" sharp as the closer shots. After about two years of wondering(I was young and stupid) I finally did some testing and found my beautiful Miranda Sensorex was focusing past infinity by a good long shot. Lesson learned the hard way. Now I check all my lenses and most are not dead on at infinity. Lens manufactures usually leave a little room for hot/cold expansion and contraction so watch out. You might have just found your problem with the infinity focus setting. Let us know what you find 'cause I'm curious and I'm sure others are too. I bet you don't have infinity focus issues on your 5x7! JohnW</p> Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted January 31, 2014 Author Share Posted January 31, 2014 <p>Thanks for the replies fellows.<br> The last, reluctant, test was after the fall. I wanted to make sure I didn't cave in this beautiful monster, and it was my famous "Tiniest Newspaper Print Collage" ( TNPC) to a 30x40 mount board. Focus is around three and a half feet. And the results were perfecto to the edges. Not infinity though. Three and a half feet. <br> In the field however.... that's what I'm crying about. Being a wide angle lens I imagined infinity would be the best way to grab trees in the middle and background, and aperture would take care of all the bramble in the foreground. And center foreground it does, but not to the corners. So therefor, I'll make a point to help the aperture by tapping the focus in a bit. If that doesn't do it, I might sell with a cavet added to let the less obsessive have a great lens cheap.</p> Link to comment Share on other sites More sharing options...
john_wiegerink1 Posted January 31, 2014 Share Posted January 31, 2014 <p>After re-reading your initial post I see you haven't really tried using a hyper-focal distance setting and therefore focusing before the infinity setting on the lens. Maybe the whack is not letting the lens focus all the way to infinity? I have bought a few lenses for the cheap just because the owners could not focus to infinity. Of course if it stops focus slightly before and is stopped down to f11 then it should be sharp across the negative. I had to reset the focus tubes on the lens and now they work find. There are so many variables it's hard to tell which is the problem. Focusing before infinity or focusing after or just plan soft on the corners???? I'd still guess the lens is focusing slightly after infinity, but who knows. Good luck and like I said, keep us informed. JohnW</p> Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted January 31, 2014 Author Share Posted January 31, 2014 <p>Well I can clear one thing up at least. I don't look to the lens markings for distance focus/infinity. I focus with the swing up magnifier on the main subject, which is usually infinity because the lens is wide. Back where the main body of the subject resides is always infinity, so I have a tendency, especially if I'm working fast, to just rack it to the lazy eight ( infinity ) and shoot. Now however I'm going to focus closer because those nasty corners keep slipping away from me. At least I hope that's the answer. </p> Link to comment Share on other sites More sharing options...
allan_jamieson2 Posted January 31, 2014 Share Posted January 31, 2014 It's been a few years now since I sold my Pentax 67II and lenses but I did have during my medium format days two versions of the 55mm lens. First one was the f3.5 version which was a mistake by mail order quickly traded in for an f4 mk I version, I used that lens for many years professionally and took probably thousands of images with it, all sharp and mostly using the hyperfocal markings on the lens barrel, f11 was that lenses sweetspot but set to the markings for f8. It even survived being dropped into a river once by accident with both caps on, one very quick grab from the river bottom and left it in a towel for a few days and it was fine. Great lens and the mark 2 version is supposed to be sharper but frankly I wouldn't worry too much as either version will give excellent images in the right hands but it does help knowing how to handle the Pentax 67/ II carefully as it does need a careful hand and good tripod/ head to get the best results if taking landscape images. i always locked the mirror up and then pressed my palm down on the prism before taking the image with a cable release but then I was using fairly slow shutter speeds, great cameras but with a few interesting quirks! Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted January 31, 2014 Author Share Posted January 31, 2014 <p>Thanks for the attention. I'm a mirror upper too of course and dampening instead of cable release.<br> I also dropped a lens into a river. It popped out of a clasped Nikon case from a rock hop maneuver, the Nikkor 20mm f/4 non AI . Went into that famous Yosemite River ( Merced? ). Couldn't even find the thing. Freezing too.</p> Link to comment Share on other sites More sharing options...
steve_rasmussen Posted February 1, 2014 Share Posted February 1, 2014 <p>I'm betting that it is your lens that is flawed, either from dropping it or possibly it came that way from the factory. The damage cause is more likely. </p> Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted February 1, 2014 Author Share Posted February 1, 2014 <p>We'll see tomorrow. I had a great field day with it today, Saturday, cold and snowy, and took six rolls of Acros. I noticed that infinity was farther away than I thought. There was always a need to tap it closer, then closer still if I wanted the details at the bottom corners. I see that the hyperfocal scale is considerably generous, and I have to say, I don't believe it. But all that aside the negs tomorrow will tell if it's operator error or lens, and I'm inclined to bet on operator at this point. Usually is.<br /> I also decided to shoot it at f/16 as ALL my tests at f/16 were indistinguishable from f/11, the purported sweet spot. I use a 20x loupe to check these things and I see no difference with this lens.</p> Link to comment Share on other sites More sharing options...
allan_jamieson2 Posted February 1, 2014 Share Posted February 1, 2014 <p>I did use f16 occasionally if I really needed to get everything in focus from near to far and like you say, it was always pretty good but if you don't need that range, then f11 is plenty good enough for most things. I've got a D800 now and with that camera f8 is optimal in most lenses before diffraction starts to bite, although I do use smaller apertures as and when I need to. There are no absolutes in photography, if something works well for you and you get good results, why worry!</p> <p>But, if you can you should try to borrow another copy of the 55mm f4 to compare yours with because it should give you good results easily and if it doesn't, maybe it needs serviced or replaced. The mark one copy that I had was exceptionally good and hopefully someone else is enjoying it now and still taking good images with it.</p> Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted February 2, 2014 Author Share Posted February 2, 2014 <p>The lens is fine. Great in fact. I was too in the habit of assuming infinity focus was best, not thinking it out, and instead I should always be using hyperfocal distances. All of these were focused half way between infinity and and the first distance marking of ten feet. That placed it way closer to me than I ever would have thought. I had some kind of "wide angle" thinking that was all wrong. Now I'm focused pretty close in, but the sharpness goes all the way back. Bravo. The scans are a little weak, but my loupe shows great detail throughout. The film was Acros @ 64 developed in Rodinal 1:100 @ 68 14 min. The scans received 50% sharpening. What a relief. What a beautiful lens.</p><div></div> Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted February 2, 2014 Author Share Posted February 2, 2014 <p>Here's another.</p><div></div> Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted February 2, 2014 Author Share Posted February 2, 2014 <p>One more for kicks.</p><div></div> Link to comment Share on other sites More sharing options...
john_wiegerink1 Posted February 2, 2014 Share Posted February 2, 2014 <p>Ken,<br> Those results look like crap! I'm sure somebody on this forum will be glad to take that dog lens off your hands. Haha! I'm really glad you got the bug fixed and now you can press that release with confidence. Taking pictures with the lens as before would be like taking a scoped hunting rifle hunting and never sighting the scope in. Not much confidence in bringing home the game that way. Plus, you'd waste a lot of shots. JohnW</p> Link to comment Share on other sites More sharing options...
kenneth_smith7 Posted February 2, 2014 Author Share Posted February 2, 2014 <p>John: How did I not know this? I'm spossed to be edukated.</p> Link to comment Share on other sites More sharing options...
john_wiegerink1 Posted February 3, 2014 Share Posted February 3, 2014 <p>Ken: Me too! I done gradgyated from the 6th grade. My Pa only only got to the 4th. Now that's highly edukated in my book. Have fun, JohnW</p> Link to comment Share on other sites More sharing options...
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