How many of you ever attempted to remove all the elements from a complicated zoom ... and lived to tell the truth?
Case in point: Vivitar 28 - 105 f3.5 - 4.5: this monstrosity has 15 elements!!!
What initially made this so frustrating was the fact that, although spanner slots were on the rear element casing, the obscene amount of pressure needed to budge this set was monumental. Mere maximum pressure was not enough. I had to place a screwdriver into one of the slots and hammer with all my strength to (finally, after multiple tries) get it loose.
Then the fun really started. In the rear, there are TWO element sets. After getting the lid off of the first, the elements were reluctant to leave their abode. THEN, all five came cascading down, ruining the careful alignment order and individual direction!. Then, more of the same with that inner set, which contained three more elements.I had ALL the elements ... but the order and direction?
Luckily, most elements align according to how the metal casing is constructed: they have to fit perfectly, without wobble. But there still are countless ways to order these and I invented new four letter words in getting this accomplished.
It is Sunday morning at 8 AM. I worked on this for SIX hours yesterday and, today, after a needed night sleep, worked for THREE AND A HALF more. Almost ten hours to set right a $20 lens. (And some people think that I am intelligent!!!!)
There are many configurations whereby the lens is ALMOST sharp, but there are tell-tale signs of misalignment when you have halos at the far corners. We KNOW that wide open there will not be tack sharpness in the corners, but we also know that those corners have to be at least reasonably sharp wide open. Two stops down, I can finally say that I 'have a lens' in that it 'justifies' the whole day of work.
NOTA BENE: Always be obsessive when taking apart one of these types of lenses. You will save much time and will not have to require Merriam Webster to modify its lexicon with the colorful terms that you newly invent. - David Lyga
Case in point: Vivitar 28 - 105 f3.5 - 4.5: this monstrosity has 15 elements!!!
What initially made this so frustrating was the fact that, although spanner slots were on the rear element casing, the obscene amount of pressure needed to budge this set was monumental. Mere maximum pressure was not enough. I had to place a screwdriver into one of the slots and hammer with all my strength to (finally, after multiple tries) get it loose.
Then the fun really started. In the rear, there are TWO element sets. After getting the lid off of the first, the elements were reluctant to leave their abode. THEN, all five came cascading down, ruining the careful alignment order and individual direction!. Then, more of the same with that inner set, which contained three more elements.I had ALL the elements ... but the order and direction?
Luckily, most elements align according to how the metal casing is constructed: they have to fit perfectly, without wobble. But there still are countless ways to order these and I invented new four letter words in getting this accomplished.
It is Sunday morning at 8 AM. I worked on this for SIX hours yesterday and, today, after a needed night sleep, worked for THREE AND A HALF more. Almost ten hours to set right a $20 lens. (And some people think that I am intelligent!!!!)
There are many configurations whereby the lens is ALMOST sharp, but there are tell-tale signs of misalignment when you have halos at the far corners. We KNOW that wide open there will not be tack sharpness in the corners, but we also know that those corners have to be at least reasonably sharp wide open. Two stops down, I can finally say that I 'have a lens' in that it 'justifies' the whole day of work.
NOTA BENE: Always be obsessive when taking apart one of these types of lenses. You will save much time and will not have to require Merriam Webster to modify its lexicon with the colorful terms that you newly invent. - David Lyga