Kinebohのブログ一覧

Unexpected warmer days are lasting since yesterday, it's like an early spring. Change of pressures causes such a remarkable thermal transition so incredibly. Probably, First Spring Wind must blew 3 days ago. Flowers preparing spring season must have frightened. Blooming timing would be enhanced this year. Early cherry blossom and plum will make haste to bloom.

There is a term Tele-Photo Ratio in the lens design R/D field. It is a ratio that the length of the distance from the anterior surface to image sensor were divided by the actual lens focus distance. The smaller value than 1, the shorter the finished length would be. It must be a good Gospel for the most of the photographer who wanna carry less burdenning. But, things aren't going so well, such kind of modification in designing steps invite much discrepancy, difficulty in correction aberrations. As most of the buyers want to be free from inconvenience caused by the bulk, consumers want to buy smaller and cute one as the newer models.

The engineers in R/D must have been obliged desperate effort by the thoughtless and unreasonable requests. When you violate basic principles, problems arise somewhere, and you have to somehow work around them, so unnecessarily. This results in compromises and compromises---leading becoming worse.

However louder the new announcement might be done in the Website, the newer model does not always overcome the performance of the old model in all the aspect. Consequently, photographers must be obliged to make good decision especially who have some strange desire in his or her deeper part of their heart.

One the other hand, same kind of phenomena is recognized on wide angle lenses. Frontal extension is done to compensate several aberrations, it is called as Retrofocus design. Increasing the glass reflective surfaces does not invite acceptable result, however coating technology might have made progress.

Physical minus fuator never disappears. Fundamental principle cannot be ignored, otherwise unexpected failure might occur without an exception, no matter how someone notice or not.

In Scientific field, Data-backed results, not Emotion, are the priority.

(R/D: Research and Development)

The closest distance is so designed at 1m on Leica old interchangeable lenses some of the later model was 0.7m. On the other hand, those for SLR body were so done at 45cm on standard lenses. Range finder construction had some disadvantage on close distance because of paralux and measuring accuracy. These are why 1m closest distance was designed. Other rangefinder cameras were same as Leica.

I make it a rule to make this disadvantage into advantage without any irreversible modification, just an additive of an adequate extension tube. For example, Summitar extended 20 mm anteriorly could establish infinity focusing with its fuselage collapsed, without fuselage extension as normal use.

Then what will happen when the barrel was extended with extension tube? Yes, more close up shooting would be possible, 23cm distance like a macro lens!

As I show here, all the collapsible lenses could be utilized their performance shown here if an adequate length extension was applied, interesting don't you think?

Whenever I come across with some reports or impressions on old lenses especially made by Ernst Leitz Solms GMBh, I mourn and lament. The condition of object are not always well settled and maintained, they were not estimated their original and innate capability and potentials.
Mold and dust particles causing cloudiness and peeling of the edge lacquer can lead to poor image quality and the occurrence of flare and ghosting.
Consequently, we should restore them as original condition if we try to know their potentials fairly, of course the best care must be paied especially not to wipe out delicat and sbtle coating layer---difficult for layman.
The subtle differences in spherical aberration correction should be discussed under fair and correct establishment of any conditions. It is not an area that amateurs can easily enter.

Cold air pressure comes down from the Western Continent and cold weather are lasting in our country these days. On frozen road surface must be paid attention. Once start to slip all the vehicle fall into uncontrol.

My photo shooting hobby is inhibited this coldest season. Newly obtained equipment, Elmar 90mm/f4.0-Black lacquer painted no coating, Summitar 50mm/f2.0-square iris shape and M Rokkor 40mm/f2.0-similar with Summicron M 40mm/f2.0.

When it get warmer and the flowers bloom, things get busy.