Kinebohのブログ一覧

2 pieces of donor, Konica EE Matic 40mm/2.8 were destroyed because of the intention of lens survival. As smaller as possible and as lighter as possible were the basic concept for the first time and the weight 80 gr was attained with some ugly appearance a bit. Almost of the cylinder fuselage parts made of brass material were removed for the purpose mentioned, losing focusing ring, iris controlling ring and decorative name plate including mechanical shutter construction. Because the resultant shape does not make a good impression to others, determined I to try another attempt based on a different concept, keeping it's original appearance on different circumstance with the least modification. As it's original focusing system was inside of it's lens cylinder, putting it with satisfaction of requirement, accomplishment of infinity position was not so difficult task for me even if the original lens body is obliged, not to be changed. Only the mechanical shutter mechanism removal resulted into the body weight owes at 160 gr as a matter of fact. Helicoid releasing stop position for the latter model was enlarged angularly intending more close up shooting from 900mm to 650mm. No performance difference was observed between them, very natural result going without mentioning.
Triplet lens design & construction provides clean, clear and transparent imaging on the digital sensor, Barrel-shaped distortion, field curvature, corner image flow and bignetting are observed in exchange. From a different point of view, such kind of disadvantage could be made use of different purpose and effectiveness, making only center portion outstanding. Though recent sophisticated designed autofocusing lens with high price covers all the disadvantages at all like a ideal in a instruction book, I would take former ones. The cheaper equipment, the more fun for geriatric.

A lens hood set on Konishiroku Hexanon 48mm/2.0 was re-fabricated to fit well as long as possible under the condition of infinity focusing helicoid position and iris at the most closed diameter. The length of hood is the most important requirement to avoid unnecessary light noise at any time, transparent and clear picture is desired only when indispensable condition is satisfied. This concept does not accept any other opinion however sophisticated lens coating technology might be invented. It's internal surface was carefully reinforced with Non-reflective blanket. The lens is the most favorite one because of it's superb performance if compared with recently manufactured standard lenses. Focusing procedure is done by not an electrically controlled stepping motor but my own finger with my surely corrected optical signal into my brain. 6 elements in 5 group designing of this small lens is well corrected 5 aberrations, I have no complaint on this point. Only 160 gr weight makes it possible to be selected as the first choice whenever I go out for shooting. The history of this Hexanon had been mounted on Konica Auto S-Ⅱ old range finder camera. All the unnecessary parts when used on mirror-less camera was removed thoroughly including iris indicating ring except showing mark only on 5.6 position. The rate of iris opening that affect on focusing depth leading to "Bokeh" is recognized actually peeping in EVF before shooting, so iris opening indication numerically is not always necessary, the picture on the back monitor shows everything. Also, straight focusing hericoid mechanism is removed for the convenience and the reduction of mechanical slipping resistor. Rotating helicoid focusing attitude does no harm on the procedure. As a conclusion, I desire nothing more on this pretty lens and I would like to continue this as long as my hobby would last from now.

Cool & refreshing morning we have in Osaka, it's the first time this season, in spite of hottest daytime yesterday. The heat in the daytime would be reduced gradually day by day and rain after rain. I'll be more active in shooting photos seeking the object wherever it will be. I must the specific opportunity to be checked my work, making multiple pieces of 5 pieces.
New comer arrived from a conscious seller in Yahoo Auction, Minolta MD Zoom 28-85/3.5-4.5 at the lowest price 100 yen. The item looks used reasonably but handled with best care, no mark of mold was found or scratches, it means the lens has been used continuously under the Sun ultraviolet lay. Consequently, I will continue this lens without any discrimination leading to the intention of the former user. From the wide range 28 to the actual requirement of telephoto side 85 with good performance means that no more desire is hoped if this Zoom Lens is equipped on the camera body no matter how it is a silver salt film body or Digital one.

Several 85 mm focal length lenses have been produced by Minolta, Varisoft Rokkor 85 mm/2.8 has some outstanding situation among them, the performance of adjustable rate of the correction in Spherical aberration. Though there is a easy way to control it by inserting holed plate on the light source, Minolta's Varisoft lens is designed with different way, forming the adjusting lens module at the most posterior part of the construction, the module moves antero-posteriorly as long as 8 mm when adjusted actually. As the focusing performance and the change of aberration correction are completely some different phenomena, two types of helicoid construction are designed in tandem, this is why it has longer cylinder fuselage length. As the rate of Aspherical aberration drifts according to the iris opening condition, the distribution of correction should be done with the deeper consideration on the interactive relations, it requires most difficult and professional like keen observation at all, yes, it is so difficult as to make me enthusiastic emotionally. At that time, over half a century ago, the engineers in Minolta's researching and development had enthusiastic energy to make us excite ultimately. Now, we can see their efforts by utilizing Digital Imaging format so easily without employing exaggerated professional measuring devices and equipment, we are living now in the fantastic paradise world.

As for my surprise I could have bid and no competitor appeared on the item, Tokina SZ-X 630 60-300/4-5.6 Zoom lens was obtained at only 100 yen. However cheaper price it might be, any instrument and device and machinery should be handled gently enough to perform it's potential and capability, this is my way of dealing them. Recently, young engineer sometimes has an different idea and treats it off-handle leading to loosing accuracy. Anyway, this new comer lens would be handled with best care so long as I am in this world.
The seller told me, "This is quite a new one without any used history, so take it to the shooting site, only once is enough!". Because I could take his intention by this sentence, I would report the result of the shooting in very near future rewarding his thought.
Comparison of 300mm lenses, Minolta MC Rokkor -HF 300/4.5, Minolta MD Zoom 100-300/5.6 and Tokina 60-300/4-5.6. Weight distribution and center of gravity balance with camera body is good for avoiding camera-shake.