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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Parafocal EF zoom?

PC Greene

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For less than a Cooke etc?

Thank you,
 
Nothin huh?
 
Canon 70-200 Gl optics version. 6000 USD parfocal
 
Let me be the one that breaks the ranks here :
EVERY 35mm format lens is designed as parfocal (not parafocal BTW). They vary from one copy to another and vary in back focus due to workmanship/ tolerances/QC factors. On top of that cameras flange vary all over hell and gone since there are no standards and everyone is an expert ;-)
No lens design is going to solve that.
You don't need to look at lens designs- look much closer first- like put some effort in correctly adjusting your lens back focus and camera flange.
Putting on a flame proof suit now....
 
I thought OP wanted an EF zoom. Canon 24-70 2.8L is parfocal
 
Jacek we've gone over this before regarding my inquiries if Optotron could offer "zoom & focus intelligent linking" to make non parfocal (thanks) lenses so. Our back focus is well set, im not sure what you're suggesting regarding flange (adjust for every lens change? No thanks) PL zooms are perfectly parfocal & EF are simply not lol.

Thank you,

Let me be the one that breaks the ranks here :
EVERY 35mm format lens is designed as parfocal (not parafocal BTW). They vary from one copy to another and vary in back focus due to workmanship/ tolerances/QC factors. On top of that cameras flange vary all over hell and gone since there are no standards and everyone is an expert ;-)
No lens design is going to solve that.
You don't need to look at lens designs- look much closer first- like put some effort in correctly adjusting your lens back focus and camera flange.
Putting on a flame proof suit now....
 
Jacek we've gone over this before regarding my inquiries if Optotron could offer "zoom & focus intelligent linking" to make non parfocal (thanks) lenses so. Our back focus is well set, im not sure what you're suggesting regarding flange (adjust for every lens change? No thanks) PL zooms are perfectly parfocal & EF are simply not lol.

Thank you,
I rest my case haha
 
What do you mean you "rest your case" Jacek?

You state every lens is designed as parfocal when virtually no EF mount glass actually is.

I have to say I find communicating with you challenging my friend :rolleyes:

Thanks to those who answered the OP. Leica R seems like the best path for us currently...


Let me be the one that breaks the ranks here :
EVERY 35mm format lens is designed as parfocal (not parafocal BTW). They vary from one copy to another and vary in back focus due to workmanship/ tolerances/QC factors. On top of that cameras flange vary all over hell and gone since there are no standards and everyone is an expert ;-)
No lens design is going to solve that.
You don't need to look at lens designs- look much closer first- like put some effort in correctly adjusting your lens back focus and camera flange.
Putting on a flame proof suit now....
 
What do you mean you "rest your case" Jacek?

You state every lens is designed as parfocal when virtually no EF mount glass actually is.

I have to say I find communicating with you challenging my friend :rolleyes:


Thanks to those who answered the OP. Leica R seems like the best path for us currently...
I mean that you don't even know what the back focus on your lens is and the flange depth on your camera but you already decided which lenses are or aren't parfocal. I.E you are an expert.
I do this for living.
I conceived , designed, built and manufacture peripherals that utilize these features and have tested and repaired lenses for for 25 years before that.
Sorry -parafocal won't fly here haha ;-)
 
The Canon FD 35-105 from Eddie Lens Doctor in EOS mount...worth a look...very small and light weight. Eddie refurbs zoom to be parfocal too (as it was orginally out of factory).

best
 
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