Mattebox and EF Lenses

[Kevin Martorana]

Ok...so dumb question of the day.

I wasn't sure where to post this....so since many of you are using the Canon7D in a cinema mode...I thought you might have some answers.

I recently purchased a P&S Technik Mini 35 adapter. I'm can use both PL and Canon EF lenses.

So...with EF lenses...How is every one dealing with focus ? The focus dials on these EF lenses are very small. They're basically designed for auto focus. AND...since most EF lenses are not INTERNAL focus...the lens zooms in and out.

GREAT...how do you deal with this on the mattebox ?

Also..I purchased the SNAP! gear set from Indisystems. indiSYSTEM - SNAP! gears Set

So I assume you allow room for the lens to move in and out of the mattebox. My mattebox is a Chroziel 450-10. Where would I get any kind of baffling to cover around the different EF Lenses...that would also allow it to move ?

16x9 inc says they have a product that does that....but they're not instock.

Any suggestions on how you guys are using these lenses...and matteboxes successfully would be of great help.

THANKS !

[Peer Landa]

Originally Posted by Kevin Martorana

Ok...so dumb question of the day. [...]
So I assume you allow room for the lens to move in and out of the mattebox. My mattebox is a Chroziel 450-10. Where would I get any kind of baffling to cover around the different EF Lenses...that would also allow it to move ?

Not a "dumb question" at all -- I've more or less had the same problem ever since I got my Century mattebox, and have partially solved it with different hacks (foldable rubber lens shades, etc.) but I'm now at a point to try solving it once and for all. So I'm thinking of perhaps trying one of the Zacuto donuts: Universal Donut - Zacuto

-- peer

[Barry Nolan]

Kevin,

Chrosziel makes the a donut, Chrosziel AC-450-22 Flex-Ring Flexible Step-Down Ring (110:50-85mm) sold at B& H for just this purpose. Works for lens diameters from 50mm to 85mm.

B&H # CHSDR5085
Mfg. # AC-450-22.

It’s $112.95. An awful lot for a donut. I also use the 450 matte box and use generic step up rings to fill the hole. A lot less expensive.
I’ve made adapter plates so I can use the 450 matte box system on all my Video and DSLR cameras.

As for the focus problem, I believe most of the hard core Cine Videographers are using older manual focus lenses for just this very reason. I’m a retired Motion Picture Cameraman and over the years I have collected a large amount of Nikon manual lenses.
There are a lot Nikon to EOS lens adapter available so I was able to use all my Nikon lenses.
Motion Picture lenses have different gearing on the focus mechanisms requiring more turning to focus. The focal distances are also put on the left side of the lens rather then the top for the benefit of the camera assistant.
For your focus problems possible a smaller focus drive gear will make it a little better.

Hope this helps,

Barry

[Olof Ekbergh]

The Canon 24-70 f2.8 L has the same problem it moves in as you zoom out opposite from most lenses, and different from other L zooms.

I just treat it as if I am changing lenses when I change focal length, and just slide the matte box to the proper position. It is faster than changing the lens, and pretty easy to do. I think it is always a good idea to have your matte box filters as close to the lens as possible.

Just don't forget to move the filter out of the way before moving barrel out or you can scratch the filter easily, if you use a hard step ring this is not a problem, but knickers (fabric donut) can be.

[Kevin Martorana]

Thank everyone for the insight to this problem !! I appreciate the suggestions.