Backfocus - how hard is it on lex / brevis

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dadoboy

Well-known member
I'm considering the purchase of a 35mm adapter, either the Letus Extreme or the Brevis. I don't intend to use it for feature film making, just low budget shorts and music videos but nevertheless, a focus puller will be employed. Being a 1st AC myself, proper lens calibration and back focus integrity is important to me.

Can anybody comment on the ease of collimating the Extreme vs the Brevis? I heard that the Extreme is more difficult to make adjustments to backfocus. The Brevis has its "Micro Collimation" feature, but is that just some marketing gimmick? I'm also aware that Zacuto has a modified LEX Elite that allows greater flexibility in back focus, however I'm not willing to spend the many hundreds of $$ for this added feature if Brevis already has it built in.

As well if anybody has used the Minolta mount on either adapter, I'd like to know how sturdy the flange is. I'll be using primes only, so a lot of lens changes.

Much appreciated. I suppose I could wait to see what the new Scarlet specs are, but doubtful it would support a Minolta MD mount.
 
Brevis system is much better than on the LEX.

The only dowbnsie of the Brevis is that you do have the remove the lens between adjustments ( which is a downside if you are using lenses that have different collimation themselves) , but the adjustments themselves are very fast and easy. You simply turn a ring behind the lens that is on a fine screw base. As you turn it in and out it changes the collimation distance. It is a good system.

At least on my unit Lex unit ((I only know it for Nikon) is basically an attempt at a quick fix for a "non system". It works best if you have to pull the lens away from the unit. Then you have to screw out three adjustment screws that just push the mount away from the unit. Getting all three screws exactly the same distance is not as easy at it sounds and its a bit of a pain. It does work however so its not awful. If however you need to bring the lens closer to the unit, you need to open it up and push & pull some very very wanky pins that seat the screen. This is a lousy method and I think its just luck that I got mine flat to the film plane at all.

As I understand it the Letus Ultimate has a very good system that will adjust with the lens on in the field but it is pricier of course.



Lenny Levy
 
The major problem with an "on-the-fly" collimation system has already been documented by folks having flex/movement issues with it.

This is why our system is physically "locked" apart from the adjustment mechanism. This in turn guarantees that the mount remains 100% solid once adjusted :-)
 
Letus Extreme can be adjusted, its not too hard, but it is not a quick process (especially if the GG comes from the factory out of wack).

I have only used Nikkor mounts - the flange is very sturdy.

Jason
 
The Brevis is really easy and fool proof. No screws to mess with. You can even mark it for each lens so you know where to line it up at when you change each lens out that has a different back focus.
 
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