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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 :)

Anyone shoot any film with the 18-50?

Mike Prevette

Mike Prevette

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HERITIC! I'm sure you all are screaming. In my world film is still a viable option for some projects, so I was wondering if anyone with the 18-50 has turned some 35mm over with it. Results?
 
CrewPix.com said:
I haven't rolled film thru it, but I have looked at the lens on a Super35 (TV) Arri 435 and can confirm that it does not vignette.
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Hi,

Has anyone tested how accurate the T stop marks are?

Stephen
 
Stephen Williams said:
Hi,

Has anyone tested how accurate the T stop marks are?

Stephen
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Hi Stephen,

Century Optics use to have an intergrating sphere for "T" stopping lenses. I don't know if they still do, but mayby someone in L.A. could look into that. I would think a massed produced "T" stop ring on the zoom would be more than close enough.
 
chuck colburn said:
Hi Stephen,

Century Optics use to have an intergrating sphere for "T" stopping lenses. I don't know if they still do, but mayby someone in L.A. could look into that. I would think a massed produced "T" stop ring on the zoom would be more than close enough.
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Hi Chuck,

I would have thought so myself, but in view of collimation issues reported on this site I would want to know for sure.

I am sure it's good wide open but what about T5.6 that is probably the sweet spot?

Stephen
 
Billy.Summers said:
...and no witness marks...:umm:
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Hi Billy,

Adding witness marks by hand is time consuming. With the £ worth over 2 USD's I am not surprised, as those Sigma lenses are rehoused in England. I would have thought it could have been done cheaper elsewhere at at least as good (if not better) quality.

Stephen
 
Billy.Summers said:
...and no witness marks...:umm:
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CAN I GET A WITNESS! LORD ABOVE!

Really? No witness mark? I got a couple of grease pencils you can have Billy. lol

That's kind of wierd. Since the whole lens has new external shells all the had to do was make either the aperture or witness mark ring adjustable and it could have been part of the assembly procedure.
 
Hi Chuck,

I think the T stop has a witness mark, it's the focus distances that are slightly open to interpretation.

Stephen
 
Any good rental house should have a device to test the accuracy of T-stops.

Often they don't advertise the fact because they don't want to deal with the angry mobs when the T-stop accuracy of most cine-zooms is revealed. Make friends with a lens tech at a place like Panavision.
 
it's actually quite simple to do with a lightmeter probe and a grey card.
 
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