new LEX achromat worth it or not?

does anyone know how to adjust back focus on the new nikon mount? i've got the screws out but i'm not sure what to do from here. i must be an imbecile...
 
wartez said:
does anyone know how to adjust back focus on the new nikon mount? i've got the screws out but i'm not sure what to do from here. i must be an imbecile...
Click to expand...

Well i bit the bullet & ordered the new achromat & new nikon mount :)

Your not an idiot! lol. I'd like to know the exact same thing & i don't even have it yet.

I hope it's all worth it. Freight is a killer buying all these add - ons.

Regards,

Ben
 
The screws are used to set the back focus distance. You set up a focus chart, measure off a predetermined distance (3 or 4'), set your still lens for that focus distance then adjust the mount to the inner flange of the LEX until the focus chart is in perfect sharp focus, edge to edge. In my experience, this is pretty hard with the old mount, MUCH easier with the new mount.

The only proper way to do this is with a lens collimator but you would have to go to a camera rental/repair shop that has a collimator and do it there. Doing it by eye is possible but not as precise as using a collimator.

This article pertains to Super 8 but idea is the same for your setup. http://lavender.fortunecity.com/lavender/569/lenscollimation.html

Dan
 
Dan,

Do you HAVE TO adjust the backfocus? (Will the NEW mount work fine when you first get it) ...With the old mount i currently have i've just attached the prime lens and shot.

Regards,

Ben
 
benandaim said:
Dan,

Do you HAVE TO adjust the backfocus? (Will the NEW mount work fine when you first get it) ...With the old mount i currently have i've just attached the prime lens and shot.

Regards,

Ben
Click to expand...

Hi Ben:

If you are shooting with a prime, issues with the back focus not adjusted will be that the lens may not focus to infinity and if you are using your lenses focus markings, they will not match. In other words, you may use a tape measure to measure off 10' and set your lens to 10' and you may be still out of focus.

If you are using a zoom lens, when you zoom into the farthest zoom length to set focus, then zoom back out, your lens will go out of focus.

All of these issues seem like a big deal to me but depending on your skills, eye, tolerance for slightly out of focus footage, may not be as big of an issue to you.

Dan
 
puredrifting said:
Hi Ben:

If you are shooting with a prime, issues with the back focus not adjusted will be that the lens may not focus to infinity and if you are using your lenses focus markings, they will not match. In other words, you may use a tape measure to measure off 10' and set your lens to 10' and you may be still out of focus.

If you are using a zoom lens, when you zoom into the farthest zoom length to set focus, then zoom back out, your lens will go out of focus.

All of these issues seem like a big deal to me but depending on your skills, eye, tolerance for slightly out of focus footage, may not be as big of an issue to you.

Dan
Click to expand...

Hi Dan,

I've never measured focus before ...with a tape or markings. I just attached the lens and started shooting. The only issues i've had have been with edge softness. Does this mean the new mount will be different out of the box to the one i currently have?

Regards,

Ben
 
benandaim said:
Hi Dan,

I've never measured focus before ...with a tape or markings. I just attached the lens and started shooting. The only issues i've had have been with edge softness. Does this mean the new mount will be different out of the box to the one i currently have?

Regards,

Ben
Click to expand...

Hi:

The new mount will not change edge focus per se, unless on your present mount you have the mount mounted to the unit crooked. The optimized achromat kit is what will supposedly remedy soft edges.

I have the Nikon mount, it is better than the stock mount but I feel that you also need the optimized achromat kit, I am getting one.

Dan
 
LOL.... i didn't even know you could put the mount on crooked. Shows how much i know ha ha. How do i ensure i'm putting the mount on correctly?

I ordered both the mount & the optimization kit aswell.
 
Am i stupid or..? When i zoom out, i still get the picture slightly "off centre" with the new achromat. I thought this fix would be included... What have i missed?
 
It doesn't correct for that. It solves the edge sharpness issues (largely), but not the HVX's off-center imager problem.

I wonder if they corrected that in the 200a. Gonna find out soon...
 
Look who's getting an upgrade...200a, huh? Will you do any side-by-side comparisons that are not posted in some weird codec?


J
 
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