Kinebohのブログ一覧

The performance of Minolta MD Macro-Rokkor 100/4 was tested at Kyoto the day before yesterday, excellent resolution of texture was proved as I had expected. In spite of a marvelous performance, most of the photographers must have deserted because old Minolta lenses of shorter flange-back value, 43,5mm than Canon EOS and 46,5mm Nikon Digital bodies in addition to SONY alpha 44,5mm. There should be no idea to adopt 43,5mm flange back MD lenses onto longer FB digital body, so our common sense on this point leads us to a miserable conclusion.
Though this 0,5mm shorter flange back value than EOS mount standard might be some decisive flaw not to be controlled, so not a few MINT conditioned MD Rokkor lenses appear at an incredibly cheap price in the jank market, 1/10 to 1/20. It would be unwilling phenomena for the factory lens designing engineers once who had been at the forefront, because they must have made desperate efforts to produce Minolta MD Rokkor lenses 30 to 40 years ago. The technology to correct most of the aberrations were established at that time already and now the way to obtain the best answer for lens designing is known instantly by computerized calculation how ever complicated and difficult formulae might be. So, recent lens tastes are the almost the same between lens makers, because the answers are the same obtained by computer analysis. The difference of the way of expressing were found in silver salt period apparently, this is why I prefer older lenses than modern ones. 100mm/4 Macro Rokkor is one of my most favorite one among Minolta lenses while silver salt film period.

Malfunction on the rear transfer clutch in BC7 SUBARU Legacy LSi US model has recovered completely, no strange tight corner braking effect is observed since a month ago just after availing all the replacement parts for the maintenance, how come? 6 years interval used lead battery 75D23L has ended it's life because of lack of capacity, head light becomes darker when starter motor is activated, and the voltage comes to higher in relatively charging period of time. In addition, special shaped clip to keep frontal grill in position must be ordered, 6 pieces in total. Wheel alignment and constructive axle geometry must be checked again, I feel some left side tendency while straight running. Set-back, swung rear end, uneven wheel bases, frontal camber error or it's value on rear axle leading to causing thrust angle?

97th Hanging scroll mounting exhibition was held at Kyoto Cultural Museum last Sunday, the engineer group is very active in repairing old and ancient Japanese National Treasures, so their technology shown there was nothing but some ultimate technology. The end processing of their works are great and above words. They are now all busy for the preparation works of Ise Jingu in Mie Prefecture. I could hear by chance about a piece of special technical recipe from the representative of the group who is my friend that the glue is made from boiled flour powder and mature the material as long as 10 years to obtain adequate and flexible physical property avoiding cracks on the surface according to wound-surround procedure. And the works with natural glue are inhibited while the rainy season because of it's physical property conflicting with too much humidity. It is an unique and secret technique that was transmitted from generation to generation for hundreds of years.

A connected Canon EOS bayonet mount on Minolta MD Macro Rokkor 50/3,5 was replaced. The metal part applied was from some jank zoom lens with 2,0mm thickness, so flange back was extended 2,5mm forward. As a matter of fact, too much anterior displacement of lens element made it impossible to adjust on infinity position, this is why I replace the meta bayonet mount into my ordinary way with utilizing a plastic body cap part as usual. The epoxy resin adhesive that had been already applied there was relatively easy separated by heating with alcohol torch. Original Minolta bayonet nail was reduced 0.70mm thickness avoiding mirror box hitting. Thanks to this procedure, the infinity position was acquired safe for this MD Macro Rokkor close up lens. Now I have finished long desired modifications of old lenses into modern Digital EOS mount.

Careful observation on Canon EFS lens has proved the reason for incompatibility on ordinary EOS body except Kiss models. The lens back of EFS is so short as to be hit by the mirror movement and the posterior lens element is protected by a rubber ring designed intentionally for safety in case of error. The most posterior glass comes back when the zooming operation of widest 18mm position. By setting some stopper at safer position not to interfere mirror movement and removing protection part, it might be possible to set on ordinary EOS body if vignetting does not exist, I do not feel any necessity to do that because of insufficient picture quality though lighter and smaller zoom system is attractive. My son deserted this first generation Kit standard zoom lens included in Kiss body. Probably, the lens designing engineer in Canon factory must have made incredible efforts to invite this EFS lens system inviting several design changes into existing EOS mounting system.