18-85mm T2.9 RED PRO ZOOM front lens question?

[JanneJansson]

Hi,

We have just got a 18-85mm T2.9 RED PRO ZOOM at our company here, and It's amazing!

We ordered a Tiffen 138mm round uv filter for front lens protection, but this filter was missing thread. Not sure if this was a -one-off- or if all are like this, but then I started to look closer at the front lens.

By looking close and using a light from below, it looks like the lens already have a thin (2-3 mm) protective glass in-front of another lens behind.

Anyone at red.
Do the lens have a protective, and maybe replaceable front lens? Is it possible to order replacement for this i case of damage?

Thank you!
Cheers

 

[Pawel Achtel]

Sorry this doesn't answer your exact question, but generally people do not use UV or clear filter for protection of professional lenses as many non-professionals do with still lenses. They are just careful.

Extra glass always compromises picture, causes flare, decreases transparency, causes reflections, etc...

Real men do not use protection :clown2:

 

[Stephen Williams]

Hi,

Red seems to have made a mistake. A 138 is a drop in filter, no thread is used.

Stephen

 

[JanneJansson]

cool, thanks

 

[Evin Grant]

Jarred has said that making it a proper 138mm drop in would have made the OD too big for use with the MB20 so they decided to give us the 138mm thread instead of nothing. Hopefully some industrious 3rd party will make an adapter for proper 138mm filters.
But Pawel is correct, you don't want to use an optical flat unless you really need the protection (Flying debris and such).

 

[Jeff Kilgroe]

That said, you should get your self a flat front or clear glass to keep with your lens. I've saved the front element on my Cooke zoom twice in the past 6 months from wind-blown debris.

Not sure what would be the best way to mount it on the front of the RED zoom, once again there seems to be a need for a custom holder of some kind.

 

[Brook Willard]

If they'd wanted to use a 138mm round properly, they could've just had the OD step back down at the end for the MB20. That's neither here nor there, however.

Lenses with excruciatingly expensive front elements [the Cooke CXX comes to mind] often come from rental houses with an optical flat in place for protection's sake. The front element of the CXX is $20,000 to replace [as of the last time I had that discussion... ]. If you can find a 138mm screw-in filter [...], put one on the lens and keep yourself safe!

 

[Pawel Achtel]

The front element of the CXX is $20,000 to replace.

Whaaaaaaat? :w00t:

That is outragous. There is no single lens element worth this much, doesn't matter what.

How do they justify that?

 

[JanneJansson]

Easy fix.
We just woke up our technical workshop guy. As soon he have finished his coffee he will lace out an aluminum ring for us. To get the filter in the ring. We just make a cut in one side, and gently bending it over the filter. The outer diameter is same, so it will fit with MB20.

If more are interested in this fix, I can mail the solidworks file.

Cheers

 

[Perry Ho]

Awesome!

can't wait to see the picture!

Cheers Janne