P67 120mm soft focus lens

Discussion in 'Medium Format' started by dave_cheng|1, Jun 25, 2005.

  1. There has not been many posts about this p67 lens on photo.net so far.
    Nor can I find it in elsewhere either. Since I have this lens I
    thought to share my recent experience about it here.

    Frankly I am a little frustrated in using it. I have not
    been able to capture any images (mainly people shots) with main
    object sharp in focus and soft everything else. The degree of softness
    of the out of focus area can be controlled by the aperature opening.
    The wider the aperature the softer it will be. The problem is the in
    focus object (face of people as an example) is getting too soft and
    appears like out of focus when I want all out of focus area to be
    softer by widening the aperature.

    At f5.6 the softness effect looks really good but the main object
    looks like out of fucs too. At f8 the lens is losing the softness
    and yet the main object is not sharp enough. By f11 the softness is
    mostly gone then the main object looks in focus too.

    Is it because I did not use it correctly or what? Between f5.6 and
    f8 the softness of out of focus background looks really nice. You
    won't see that kind of softness from regular lenses. The problem
    is the in focus main object is never sharp enough. This is especially
    the case when shooting pictures of people with head to toe all
    included in the frame. The background is soft and good but the people
    looks out of focus. I don't know about head shots. I seldom shoot
    head shots. The focal length of this lens is too short for head shots.

    I did have good results in using it as a closeup lens. It focuses
    really close. And it focuses beyond infinity (meaning you can turn
    the focus ring passing the focus point of infinity). When closing down
    the aperature the background will be still very soft and the softness
    (maybe it should be referred to as bokeh) is still plenty soft. At f11
    the image in the prism of my 67II is still plenty bright. Shooting
    flowers as an example the bokeh is something not seen from regular
    closeup lenses. I had a shot of flower that has a building in the
    background. The building is so soft that you basically will not notice
    it but its shape is still intact as a building. The lens has a minimal
    aperature of f22. It would be fantastic if it gets to f32 or f64.
     
  2. Hi Dave,

    There was a two-part article on the 120mm soft focus lens in "Pentax Family" no.51. The first part is attributed to "R&D Office Asahi Optical Co." and includes this statement: "The degree of softness is controlled by the aperture stops - the smaller the aperture the sharper is the picture image. In other words, the lens has two aspects - one is the soft effect over an aperture range of f/3.5-5.6 and the other sharp depiction over a range of f/11-22."

    The second part of the article is written by photographer Kimio Tanaka. He includes the following statement: "The soft focus effect is almost nil around f/8 and depiction becomes as sharp as regular lenses over the aperture range f/11-22." Later, under the heading "How to focus with Pentax Soft lens", he writes: "The focus tends to be a little behind the in-focus point. In other words, the actual point of focus on the film plane is a bit behind the best focus point even if you focus on the focusing screen of the camera. Its principle is a little complicated but, in short, the human eye is dazzled by the flare of the soft-focus lens. Critical focusing is an unexpectedly indispensable factor in the use of a soft-focus lens. If it is not fully focused, a flare-combined picture is not attractive".

    Tanaka then goes on to describe three ways to achieve best focus: "The easiest way is the use of correction lines engraved on the lens barrel. As the focus point differs with the aperture stops, stop down the aperture to the desired stop for taking pictures. Be sure to use a matte portion of the focusing screen. Then, turn the focusing ring to the correction line indicator. (The diagram here shows two white correction lines, the left one labelled "resolution weighted", the right one, nearest the orange standard line, labelled "contrast weighted".) The other way is to stop down the aperture to f/11 (the finder field will be a bit dark) and then return to the working aperture which should be within a range of f/3.5 to f/5.6. I myself like this method best and I used it all through the picture-taking this time. Still another way is to find out the focus point at which the contours of the subject image are the sharpest. The sharpest point inside the flare makes the focusing difficult."

    The article includes a nice full-page waist to head soft-focus photo in B&W of a model wearing a dark sheer dress against a white background.

    A text box rephrases the three methods. If you need more detail on this, let me know and I'll type it out.

    Hope this helps.
    Rod
     
  3. Dave, I remember you having problems with this lens in the past. It may not be capable of doing what you want to accomplish. It sounds like you want to keep the background soft while keeping your main subject fairly sharp. The 120mm at wider apertures is so uncorrected for aberrations that keeping anything in your frame close to sharp will be a problem. Soft focus lenses will not be sharp when wide open and are designed to truncate the marginal and zonal rays using the diaphragm to reach any degree of sharpness. Sharpness is not what they are seeking though. If you are looking for more sharpness wide open and the bokeh you seek, try a faster lens that is better corrected (165mm f/2.8 or 150mm f/2.8 Takumar).
     
  4. Rod, thank you very much for your post providing the three focussing
    methods in using this lens. I believe I have actually done all three
    although I have not seen the article before. I have a downloaded copy
    of the user manual of this lens. It has the description of the first
    two methods. The third is what I mostly do after I gave up the first
    two methods. This lens is indeed very difficult to use. I believe
    my near sighted eyes make it even more difficult. As you said correct
    focussing is critical to using this lens. Without that the lens simply
    produces useless images. I completely agree with that. The problem
    is I have not been able to get even one image that I am satisfied.
    I will try very hard again with another roll of film and try the first
    two methods again, especially the first.

    Steve, I have a 165mm/2.8 lens. I could not get the bokeh I want from
    it even fully opened. The 120mm does give the bokeh I was looking for.
    The problem is I can not get the main object sharp enough. I am not
    expecting it to be as sharp as regular lenses. It should be a little
    soft still. An image produced by a soft focus lens in a right situation should look like superimposing two identical images, one
    being very sharp but the other very soft. The result is a reasonably
    sharp main object with very nice soft background of everything not
    seen from regular lenses. This kind of images are very popular in Japan. Most potraiture images on Japanese magazines are like that.
    Strange enough I have never seen one like that in any US magazines.
    The focal length of this lens makes me believe that it is made for the
    purpose of producig images like that.

    I have a collection of an example image that will describe it perfectly. But I believe it is a copyrighted work of a Japanese photographer. I am afraid that I can not post it here. Is it OK to post a size reduced one just for a few days then remove it by you?
    The image will show very clearly what I am talking about. I have
    tried almost half a dozen roll of films yet could not produce
    anything close. I wonder if the lens is capable of that or it is my
    failure in focussing correctly that I should blame.

    Nevethless, this lens can focus as close as 1 foot. It may be used
    as a closeup lens with a very interesting bokeh not seen from any
    reqular lenses.
     
  5. Dave, you can post an example of the type of shot you have described. Some of the super fast lenses produced for 35mm cameras can give a really shallow DOF and the type of soft background you are looking for. Maybe the 105 f/2.4 used wide open can give you something close to what you are seeking? Unfortunately, medium format does not have f/1 lenses.
     
  6. Just one example of using this lens ( NUDE):
     
  7. Hi Dave,

    Here are the extra details from the article by Tanaka I mentioned above:

    "Focus correction method 1: Standard line (in orange) and two focus correction lines (in white) are indicated on lens barrel...After focusing operation, turn the focusing ring to left to align a dot coincided with the standard line to the focus correction line. The correction line at left is for a maximum of resolution (larger flare with sharply focused core) and the line at right for a maximum of contrast (the shadow around the image and lesser soft effect).

    Focus correction method 2: Stop down the aperture to f/11 and focus on the focusing screen. Then, set the aperture at the picture-taking stop (f/3.5-5.6). The corrected position of focus for the aperture range of f/3.5-5.6 coincides roughly with the on-finder focus position at f/11." !!

    Sorry, he doesn't elaborate on the third method he described earlier.

    The editor preceded these comments with : "Pentax engineers have tackled unknown specifications. We are proud of its superb performance. It is a mysterious lens that haunts you more, the more you use it intensively. To make the best use of it requires a bit of knowledge and skill." !!

    Best of luck! Regards, Rod.
     
  8. Steve, I have a 105mm/2.4 lens. It may give shallow depth of field but it does not produce the softness effect of a soft focus lens like the 120mm. Look at the photo at the bottom. The background is something not regular lenses can produce. But the 120 can. Look at the flare around the highlight spots around the hair and the skirt of the girl. Only soft focus lens can produce that. The overall sharpness of the image is soft but is still quite sharp. I believe the Pentax 120mm is designed for shots of this kind. But I have not been able to prove it. Rod, thank you so much for your effort to post the details of Tanka's article. The editor's note is really interesting. "It is a mysterious lens that haunts you more, the more you use it intensively. To make the best use of it requires a bit of knowledge and skill." Yes, this lens is still a mysterious one to me after shooting half a dozen rolls through. I have not produced any image that is what this lens is meant for. For method 1, if I understand it correctly, I should simply focus and get a sharpest image on screen then turn the focusing ring to the left (to bring the focus point closer to me) to line up with either one of the white lines on the barrel. I have done it many times to no success. The first step (focusing on screen) is the key. I probably did not get it right. Will have to try it again. See the attached photo for an example image that I am hoping to produce with this lens.
    00CgyP-24367584.jpg
     
  9. Rod, thank you very much again for bringing in Tanka's article. I really
    hope to see more , a lot more, of articles like that brought in by
    members.
     
  10. Mikhail's photo is an example of a softfocus lens image. The problem
    is it looks like an image out of focus. Just look at the hair of the girl in the image. I don't see the sharpness desired.
     
  11. Dave, another way to achieve what you are trying to do, is to use a telephoto. I have taken some portraits with my 400 Takumar nearly wide open of a girl fishing in the tropics. She is fairly sharp while the background is similar to the picture you have posted. Using minimum focus distance of the lens really softens the background nicely.
     
  12. Steve, I do not have a 400 Takumar but I have a 200. With the 200 I couldn't get anything like that. If you look closely at the highlight you will see flares that softfocus lenses are known to create. I have seen quite some images of the like so I can immediately tell if one is created by a softfocus lens. I am glad that P67 system has a softfocus lens. But I could not achieve the effect I want with it. Look at the next image and see the bokeh with this lens. I don't think (although I am not sure) P67 135mm Macro lens has this kind of bokeh. The problem with this image is the main object is not sharp enough. Look at the trunk of the trees covered by flares from the bright clouds. I feel this lens can be one for a lot of creative images. It would be perfect if I can make the main object sharper.
    00ChJ8-24377684.jpg
     
  13. Dave, it looks like good bokeh and good sharpness is almost impossible to achieve at the same time... You may try some old lenses, like Heliar or Apo-Lanthar, attached through the helicoid adapter. It will be a bulky device, but the bokeh these old lenses can give you probably will be impossible to get with the modern lenses...
     
  14. One more nude (sorry!) - the example of Heliar 150mm F 4.5 (aperture was about 8), attached to my Pentax-67 via the helicoid adapter. You can see how gental is this lens...
    Delta-400, two flashes with umbrellas.
     
  15. Mikhail, thank you for your replies. Your 2nd photo looks fairly sharp. I can sense a little of the effect of softfocuss lens on it.
    It's an interesting lens. Keep the good work out of it!!!

    The first photo I posted is an ideal photo that I like to produce. First, it has the unique bokeh. 2nd, it has flares from the highlight spreading into the shadow area producing the unique softness. 3rd, the overall object is still sharp.

    The 2nd photo I posted has the bokeh but does not have the kind of glow of flares from the highlight. It is reasonably sharp but would have been sharper if a closeup lens was used. The reason there is no
    obvious flares is because I had the aperture set to f11. That gave me the sharpness needed but then the flares were lost.

    Rod, I took my camera with the 120 lens out and practiced focusing today. I concentrated on the focussing method one. I watched the change happening when turning the focus ring to left a little after the lens is focused on the screen. The bokeh has a bit of change causing the main object in focus to stand out more. I can observe the change without checking the white lines on the barrel. That's very cool. I used to pay too much attention to the details trying to focus.
    I really don't need to do that. Just focus, turn the ring to left
    and observe the change of bokeh. I will see if the images on film will
    come out right next time.
     
  16. Dave, one more hint with the soft-focus 120mm lens - try aperture 4.5-5.6-6.3, not 3.5-4 ( too soft). I regularly set 5.6, sometimes 8.
    Regards,
    Mikhail
     
  17. After a long search found the optimal method of focus. This method is tested on a working aperture of 5.6. Leads us to a small aperture 11.0. Next, open up to 5.6 and turn the focus ring to the right by one division (the distance between two scratches etched on the lens). It is advisable to make a double, turning the lens has one division (total distance between the left turn white Valium and a red mark on the right), and turning the ring to the right. Take especially desirable when shooting at close range.
     

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