Letus Extreme and...

[Robb Cox]

Originally Posted by Phil Bloom

the ex1 kit for the extreme makes edge to edge sharpness perfect and almost completes reduces vignetting meaning you can actually zoom out quite wide on the GG

Hey Phil, what Z number (approx) can you zoom out to? Still a few weeks to wait for my Letus to be delivered...

Cheers

[Steve Cahill]

I went from 80 to 76 with the fix. I probally could go further but I left a little margin for any falloff NOT to appear.

[Piotr Wozniacki]

Phil,

1. What exactly is the specifics of the PL and/or OCT19 lens mounts, which are much more expensive than the other mounts, and when would I need them?

2. What would be your recommendation on a matte box that could be used with BOTH the Letus system, and direct on the EX1?

[Seth Bloombaum]

Originally Posted by Piotr Wozniacki

1. What exactly is the specifics of the PL and/or OCT19 lens mounts, which are much more expensive than the other mounts, and when would I need them?

PL is a standard mount system for film cameras. Cinematographers may have a selection of PL mount lenses they'd like to use. Note that the RED camera is available with a PL mount. In my neighborhood, shooters will perhaps use the phrase "a set of cine primes", meaning, a set of PL mount lenses in fixed focal lengths.

I'm not so familiar with OCT19, but I believe it is a 35mm film mount originated in Russia or eastern Europe.

So, when you'd need them, of course, is when you have some cine lenses to mount to them.

[Piotr Wozniacki]

OK, so I ordered the Letus Extreme bundle, and with the "Rush delivery" option, too...

I'd like to have at least one good lense ready when it arrives. Being unexperienced, I wouldn't like to take chances by digging on eBay and alike - but buy a brand new Canon FD or Nikon, manual focus, fixed zoom lense.

Please advise which would be most useful for a newbie like me, i.e. most flexible in general application? 50mm? TIA!

[Sean Seah]

50mm is good for focusing on say.. someone's face. 85mm is good for half/full body and 35mm is good for closeups, eg a ring. 135mm would be even better for full body but the price is higher. Please correct me if I'm wrong. Primes are great becuz they can have a good bokeh (background blur in laymen) while keeping the subject sharp. The F stop is critical as the DOF adapter loses some light so the bright the prime lens r, the better. The price is of cse higher. IThe recommended starters kit are:
1. 35mm F1.4 (not sure of the F stop) most exp of the 3
2. 50mm F1.4
3. 85mm F1.8

I have the 50mm only but it is a hell of a diff bet the F1.4 and F1.8. Go straight for the recommendations that others have trail n tested. EX owners r really lucky to have folks like Phil who has spent a lot of time & $$ and willing share his knowledge with us =)

Hope this helps n please correct me if I'm wrong.

[Mika Tertsunen]

Originally Posted by Sean Seah

50mm is good for focusing on say.. someone's face. 85mm is good for half/full body and 35mm is good for closeups, eg a ring. 135mm would be even better for full body but the price is higher. .

Mmm, would I suggest that the figures are upside down. You need to walk away quite a bit to get a standing person in frame with the 135mm.

[Piotr Wozniacki]

Using the EX1's peaking function, I am focusing the camera on the Letus GG (without a lense attached, of course) - how uniform is the peaking supposed to be with the new achromat, optimized for the EX1? Can anyone post a picture of the peaking in the camera's LCD, perhaps using zoom at Z70, Z75 etc? Because mine is not uniform at all; I'd like to compare with what others are getting.

Also, a Letus newbie question on some practical aspects of its use with the EX1: once focussed on the GG, do you leave your EX1 in fully manual zoom and put some tape on the ring to fix it, or do you leave the servo engaged so that it's not accidentally bumped thus loosing the gg focus?

[Kaya Hacaloglu]

Hello,

I have just ordered the letus bundle along with rods and a Canon adapter. My brother owns about four Canon lenses, 2 - 35mm, 1 50mm and 1 zoom lens..Saves me from buying new lenses and will help my learning curve as I will be experimenting with DOF.

I'm confused, what is exacly the Zacuto support, which also bundles with the Letus Extreme ? I'm not sure if I was in need of this one, or will the system that comes alongside with the Letus do allright? I use an old VX2000, DVX100a and am looking forward for the EX1 in the near future.

Regards

Kaya

[Steve Cahill]

I never have gotten peaking across the entire field of view with the LetusEX.

Focus on the ground glass w/o the lens attached and Sony lens zoomed, using the expanded focus mode as well should get you critical focus. Try focusing not just on the center of the GG but a 1/3 of the way in on the GG either right or left. One thing that is most important is that the LetusEX mount is secured to the Sony's threads, tighten the allen screws that attach to the letus .

Make sure that the Nikon mount is secure as well. When you re-attach the lens makes sure things do not move again this includes lens changes as well. Tape down the camera's focus, retest the focus again with the lens attached to the Letus and use the expanded focus again with the lens wide open, re-check focus. The new Nikon mount I got the screws losened-up on the mounting flange and I had some issues as well until I locktite the screws.

I recently discovered one of the allen screws on the adpater to the Sony Lens was not making contact, so the whole Letus EX had a bit of play with the camera and I only discovered it when I pushed the Letus power button on, the whole unit moved forward ever so slightly (thickness of a piece of paper) and got out of focus, even with the Zacuto rail system. So there is room for errors, so beware. Getting the focus set and secured should be checked through out the shoot and with lens changes.

There are challenges with using this setup, and until you flush them out, then you can get the results you expect.

[Piotr Wozniacki]

Thanks Steve for the hints.

I also have one more question, very naive one - please bear with me:) I never had to do with manual lenses before, and I'm surprized none of my 3 Canon FD lenses (28, 50 and 85mm) is able to focus at infinity when full open. I guess it's related to the limited DOF (and I'm talking full open iris), but just wanted to make sure it's normal.

The back focus adjustment procedure for the Letus (described on the flyer attached) is about focussing with short distances; also when trying to pull out the lense mount ring from the Letus, the infinity focus gets even softer.

Again - is it normal?

[Sean Donnelly]

Doesn't sound like it. Back focus problems are most easily seen with a wide lens focused at infinity with the aperture open. That is when the depth of focus (the area behind the lens that is sharp) is shallowest. If you can't get infinity to be sharp with a 28mm, your flange depth is off. Sounds like it probably isn't much, but I bet if you focus on an object at a medium distance (10-15 feet) the lens markings would not match.

-Sean

[Piotr Wozniacki]

Originally Posted by Sean Donnelly

Doesn't sound like it. Back focus problems are most easily seen with a wide lens focused at infinity with the aperture open. That is when the depth of focus (the area behind the lens that is sharp) is shallowest. If you can't get infinity to be sharp with a 28mm, your flange depth is off. Sounds like it probably isn't much, but I bet if you focus on an object at a medium distance (10-15 feet) the lens markings would not match.

-Sean

With the iris max open, I cannot get infinity focus with either of my lenses - not jus the widest (28mm). Closing iris to some 5.6-8 makes it possible to focus at infinity. So, is the problem with all 3 lenses (less probable), or the Letus? How do I adjust this (the lens mount ring is all the way in; pulling it out makes focussing at infinity even worse).

[Sami Sanpakkila]

I think this might be a problem Philip Bloom mentioned some time ago. Im just guessing though!! If it is you have to move the GG a couple mm forward or backward. But Philip can chime in if Im totally out of limb here!

[Phil Bloom]

replied to this on my thread. It's a ground glass position issue. It's tricky to fix but doable

Instruction are on the Letusdirect site