mdominic20

Here's some tips, based on my experience with the sharpness tweak:
I'm not sure if this is the case with every lens, but with mine, it was possible to adjust the sharpness without even removing the brass tabs.
Just by loosening all 6 screws, but leaving the tabs in place, it created enough rotational play in the front optic for me to fine-tune the sharpness. This is because the holes in the brass tabs are ever so slightly bigger than the screws, so you have a little room for rotation.  For me it was just enough. 
Once you find the sweet spot, simply re-tighten the screws.  No glue needed.  Be careful that the act of re-tightneing the screws doesn't nudge the optic. This took me a little while to get right.  Once everything is tight, check the image again to make sure it's still sharp.
As Tito says in his video, it's easiest to judge the sharpness using a long lens at (or near) infinity, and stopped down to 4 or 5.6.  In my case,  I could never get a sharp image with the Kowa and taking lens at infinity.  I had to focus both lenses slightly less than infinity to get a super sharp image. 
This is very important, especially if you are using a single-focus solution.  Don't blindly trust the infinity marks on your Kowa or your taking lens.  You might be able to get a MUCH sharper image by adjusting them slightly under infinity.  I'm sure this will vary from lens to lens.
Hopefully this helps!
 

i finally got a hold of a minolta 100-500 and compared directly it to my tokina 0.4.  setup was a gh4/contax zeiss 50mm @ f2.8/iscorama 36.  
tokina focus range: 3.8' to 8.9' (measured to the diopter)
minolta focus range: 4' to 10.5' (measured to the diopter)
field of view (at the same distance): minolta was about 1-2 degrees wider than the tokina. 
sharpness/overall image quality: identical
i was surpised that the tokina was able to focus that far out (seems like mine is closer to .37 than .40).  i was also surprised the minolta was able to stay sharp all the way down to 4'. 
so the minolta gives you another 1.5' of range at the far end, a slightly wider FOV (which is always handy), and you only lose a couple inches on the close end.  all things considered, i think i might be selling my tokina at some point.
 
 
 

Here's some tips, based on my experience with the sharpness tweak:
I'm not sure if this is the case with every lens, but with mine, it was possible to adjust the sharpness without even removing the brass tabs.
Just by loosening all 6 screws, but leaving the tabs in place, it created enough rotational play in the front optic for me to fine-tune the sharpness. This is because the holes in the brass tabs are ever so slightly bigger than the screws, so you have a little room for rotation.  For me it was just enough. 
Once you find the sweet spot, simply re-tighten the screws.  No glue needed.  Be careful that the act of re-tightneing the screws doesn't nudge the optic. This took me a little while to get right.  Once everything is tight, check the image again to make sure it's still sharp.
As Tito says in his video, it's easiest to judge the sharpness using a long lens at (or near) infinity, and stopped down to 4 or 5.6.  In my case,  I could never get a sharp image with the Kowa and taking lens at infinity.  I had to focus both lenses slightly less than infinity to get a super sharp image. 
This is very important, especially if you are using a single-focus solution.  Don't blindly trust the infinity marks on your Kowa or your taking lens.  You might be able to get a MUCH sharper image by adjusting them slightly under infinity.  I'm sure this will vary from lens to lens.
Hopefully this helps!
 

Here's some tips, based on my experience with the sharpness tweak:
I'm not sure if this is the case with every lens, but with mine, it was possible to adjust the sharpness without even removing the brass tabs.
Just by loosening all 6 screws, but leaving the tabs in place, it created enough rotational play in the front optic for me to fine-tune the sharpness. This is because the holes in the brass tabs are ever so slightly bigger than the screws, so you have a little room for rotation.  For me it was just enough. 
Once you find the sweet spot, simply re-tighten the screws.  No glue needed.  Be careful that the act of re-tightneing the screws doesn't nudge the optic. This took me a little while to get right.  Once everything is tight, check the image again to make sure it's still sharp.
As Tito says in his video, it's easiest to judge the sharpness using a long lens at (or near) infinity, and stopped down to 4 or 5.6.  In my case,  I could never get a sharp image with the Kowa and taking lens at infinity.  I had to focus both lenses slightly less than infinity to get a super sharp image. 
This is very important, especially if you are using a single-focus solution.  Don't blindly trust the infinity marks on your Kowa or your taking lens.  You might be able to get a MUCH sharper image by adjusting them slightly under infinity.  I'm sure this will vary from lens to lens.
Hopefully this helps!
 

Here's some tips, based on my experience with the sharpness tweak:
I'm not sure if this is the case with every lens, but with mine, it was possible to adjust the sharpness without even removing the brass tabs.
Just by loosening all 6 screws, but leaving the tabs in place, it created enough rotational play in the front optic for me to fine-tune the sharpness. This is because the holes in the brass tabs are ever so slightly bigger than the screws, so you have a little room for rotation.  For me it was just enough. 
Once you find the sweet spot, simply re-tighten the screws.  No glue needed.  Be careful that the act of re-tightneing the screws doesn't nudge the optic. This took me a little while to get right.  Once everything is tight, check the image again to make sure it's still sharp.
As Tito says in his video, it's easiest to judge the sharpness using a long lens at (or near) infinity, and stopped down to 4 or 5.6.  In my case,  I could never get a sharp image with the Kowa and taking lens at infinity.  I had to focus both lenses slightly less than infinity to get a super sharp image. 
This is very important, especially if you are using a single-focus solution.  Don't blindly trust the infinity marks on your Kowa or your taking lens.  You might be able to get a MUCH sharper image by adjusting them slightly under infinity.  I'm sure this will vary from lens to lens.
Hopefully this helps!
 

Thanks guys!
 
So if it doesn't say "MC," it might be single coated or it might be multicoated.  That ebay listing looks nice, and definitely looks single coated.  The price seems a little crazy though, compared to other lenses I have seen being sold. 

Thanks guys!
 
So if it doesn't say "MC," it might be single coated or it might be multicoated.  That ebay listing looks nice, and definitely looks single coated.  The price seems a little crazy though, compared to other lenses I have seen being sold.