FX1/Z1 + Letus35(A)

[Anthony Bristol]

Hi All,

I recently received my Letus35A from Quyen and am suffering the same problems as described by other members of this board when using with Sony FX1/Z1, i.e. Not being able to zoom right into the GG to avoid its edges without losing focus.

I am hoping this thread could become place for Z1/FX1 owners and prospective buyers to discuss the Letus rather than a multitude of new threads regarding the same issue.

Here is a frame for example:

http://www.anthonybristol.com/images.../static_gg.jpg

I measure it as 169 Horizontal pixels lost. Zooming in post solves the problem, but it's not really acceptable as a permanent workaround due to a loss in resolution, however small.

Am I right in thinking all we need is a wider GG to solve this issue? Or is there some combination of distance adjustment inside the unit that would work? I have tried moving the GG closer the to camera, didnt do much except for distortion as seen here:

http://www.anthonybristol.com/images...odin_letus.jpg
(Yes it gets REAL dirty in there)

Here is a picture of the unit with the Z1:

http://www.anthonybristol.com/images...z1_letus35.jpg

(That's a Vivitar Series 1 105mm F2.5, the result of a mad week on Ebay which also included; 28mm F2.8, 50mm F1.8, 50mm F1.4)

Another question for Letus owners, how do you get it to fit tight on your camera and have the GG aligned so that it is horizontal? If I tighten mine all the way it ends up 45 degrees off axis. Leaving it loose results in wobble when focusing (especially with the 105mm, *must get rods*) and if I hit max or min focus and keep going a touch too far it spins the letus on the thread of the step down rings.

I have shot some test footage of the Z1 and the Letus which I'll post if I can figure this H.264 codec out, at the moment it's making the picture really desaturated, and the aspect ratio is outta whack :\

Regards

[Quyen Le]

For aligning the unit, you should:
-Put it on your camera tightly
-Loosen the screw on the opposite side of the battery holder (72mm version doesn't need to do this step)
-Pull the adapter from the camera then put it back in using the LCD to align the unit.
I will work on the issue of GG. The problem I faced with DVX100 is top and bottom and not the sides, so the current large GG is only taller, not wider. I think the HD camera use 16:9 and this cause the problem? If that's the case, I will widen the GG instead.
Z1/FX1 owner with letus35A please email me and I will schedule for a replacement, thanks.

Quyen

[Anthony Bristol]

Thanks for your response Quyen,

The HDV CCD's are indeed 16:9, so they do shoot quite a bit wider than the 4:3 cams such as the DVX100. The wider GG should work fine in my opinion.

Your directions for adjusting the adapter worked a treat! Cheers :D

[Cody Dulock]

bigger GG means you need a bigger lens generally. so lets say you use a medium format screen... you would have to use a medium format lens i would suspect, but im not completely sure on this because i havent tested it yet.

[Bob Hart]

I think those cams have a doubler function which increases the zoom. I don't know if this is a digital doubler or is an actual optical doubler. If it is digital, then there might be some resolution loss.

In the demo cams I have had time to see, the doubler seems to time out but may hold in if the tape is running. For the short period I was able to handhold my own device up to the demo cam with the 7+ dioptre crudely handheld in place, the edge of the 24mm x 18mm frame can just fit on the far end of the normal zoom range or at the close end of the doubled range.

[Anthony Bristol]

Cody: Other 35mm adapters are functioning with standard 35mm lenses just fine it seems. The lenses certainly aren't the problem, just the GG size in this case.

Bob: I do believe there is absolutely no digital zoom on the Sony HDV cameras.

Here is some Z1 + Letus35A footage I shot quickly today. And yes, that is oregano ;)

h.264 - 640 x 360 - No CC, zoom by 5% to get rid of GG.

Lens: Vivitar Series 1 105mm F2.5 Macro

http://www.anthonybristol.com/video/smoke2.mov

[Maheel Perera]

Anthony,

I think Cody’s reasoning is correct. No matter what the size of the GG is. The 35 mm lenses are designed to cover the rectangular picture area using the center portion of the image. If one uses a bigger GG the relay lens will see outside the required area and gets a vignette. The only way to get the image without vignette is zooming to get the entire 35 mm frame, which the 35mm lens is designed to cover.

[Matthew Groff]

Originally Posted by Bob Hart

I think those cams have a doubler function which increases the zoom. I don't know if this is a digital doubler or is an actual optical doubler. If it is digital, then there might be some resolution loss.

Bob, the doubler function you speak of is the focus assist and while it doubles the size of the center of the screen in order to aid focusing it does not affect anything that is recorded to tape so unfortunately would not help.


mg

[Yasser Kassana]

Oregano my ass!! Anthony - have you given your letus35a back to quyen?

[Ben Winter]

Why not just add fake vignetting to cover up the GG edge? It would a more rustic and genuine feel to your films :)

[Anthony Bristol]

Yasser, That was indeed oregano, fresh from Portugal on a stick :) I have not sent mine back to Quyen because I had begun shooting a short with it, despite the small errors I would like to finish the shoot (next week) then send it back for repair. I got a new one of these http://cgi.ebay.co.uk/NEW-MANFROTTO-...QQcmdZViewItem for £30 inc delivery. Will leave a report about how it performs, i am not sure if it will work to support the letus but the wobble when focusing is an issue, especially with the macro lens.

Ben, the vignetting would be a bit OTT for me. I am a digtal art student at university in the UK, my tutor (video artist) is wholly against making digital look like film in a big big way. Using the letus might stump him as I cant see much too complain about, but artificial vignetting will no doubt start a riot.

[Anthony Bristol]

Early morning in Frensham Ponds. A fleck or two on the GG but otherwise ok. Shakiness attributed to big lens, no support and very very numb fingers.

H.264 - no CC - Z1U + Letus35A + 105mm F2.5

http://www.anthonybristol.com/video/frensham3.mov (23mb)

[Wayne Kinney]

Some of the best letus footage i've seen i think, very clean and crisp.

[Yasser Kassana]

Anthony me and wayne were playing with the Z1 and letus the other day - please can you tell me how you resolved the issues you had at the beginning?

[Anthony Bristol]

Thanks Wayne, I think it could be a little sharper, my focusing skills arent the greatest at the moment. This is the first time I have used my new Z1(U), having previously been using my universities camera, so there is some tweaking to do with picture profiles and whatnot.

Yasser, I haven't resolved any of the issues with the Letus itself. It still has a chip on the condenser or whatever that piece of glass next to the GG is called, and the GG hasnt grown wider I'm afraid, so a simple zoom with the Cineform plugin (PZR) by about 5% sorts out the GG in frame issue.

I have assigned the underscan feature on the Z1 to one of the assignable buttons so I can see exactly what i will get on my NLE (ppro1.51) at the touch of a button. A handy feature for checking the Letus is aligned correctly without zooming. Or I use the shot transition and store the correct zoom and focal lengths to A incase I knock the zoom ring or rocker during filming.