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Old September 19th, 2006, 01:11 AM   #31
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sorry for asking too much......i'm looking forward to buying a 35mm adapter because i'll be shooting my feature in thailand........is it possible if someone can post up a 720/24p or 25p .m2t file......i really want to see the results in HD (without the modifications of conversions, color correction, etc.)
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Old September 22nd, 2006, 10:42 PM   #32
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Quote:
Originally Posted by Robert Castiglione
Ok, here is some footage shot on HD111 and the Letus.

Sorry, they are rather dull. I will have a bit more time in the coming week to post some more shots.

Both at HDV30p using Paolo's TruColour 3.

Letusfocus indoors is with 85mm nikkon. Use of small practical light from the left and the key light is in fact the sunlight from the right through a large window. Cant recall what I used for Letushousemess.

Please forgive the state of my sitting room as evidenced by Letushousemess. The banana was delicious.

Anyway two shots to satisfy the Letus hunger out there for a couple of days while I get my act together and post some proper shots.

Indoors you are losing a stop of light and as stated by others. It is of course therefore essential to light properly indoors but we want to do this anyway so it is not an issue.

There are two main issues that are "concerns" at this stage. The first regards the the Nikon/Canon interchangeable mount at the front of the letus. This is not sufficient to adequately hold the lens securely. However, more importantly is the issue of whether you can actually see the ground glass while doing any kind of camera moves. It may be that I just need to play around with backfocus a bit more so no concluded judgments at all yet. I will post some more shots shortly and say a lot more about this device.

The links:

http://homepage.mac.com/rcastiglione/letusfocus.mov

http://homepage.mac.com/rcastiglione/Letushousemess.mov

Rob
When I tried to play, Quicktime indicated it needed a plug-in, could you indicate which one it is? Thanks.
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Old September 25th, 2006, 06:31 AM   #33
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Hi,

I hear that HD camcorder can actually capture the grains on a GG even when the GG is vibrating. Does Letus HD100 have this problem.
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Old September 25th, 2006, 12:04 PM   #34
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Alex.

There are a couple of grain artifacts which turn up. You will see them on SD and HDV.

One is caused by use of a high shutter speed sufficient to freeze the groundglass texture. This will be seen as a frame to frame random sandpapery looking texture or a grubby smeary look depending on how frozen the groundglass texture has become.

This random texture may mess up the image through giving the codec too much detail to play with and it will take a short cut and soften the image in order to preserve frame rate.

Another is caused by video noise in the camera itself. It seems most imaging devices on video cameras generate some random noise. It becomes most evident when gain levels are brought up in low light conditions but apparently it is apparently always there lurking in the background.

One thing groundglass based image relay devices do when set up properly is to confer a soft uniform image where we want it. With no longer a place to hide in the generally complex and detailed background of a small chip image which remains fairly sharp even if out of focus, video noise can become more evident.

In low light conditions it can become very evident.

This internally generated "grain" will be observed to be very fine on SD and even finer on HDV but also very sharply defined. Grain from the groundglass itself, in many appliances will not appear as sharp and often will be of a coarser texture.

Video gain noise will be found across the entire image, though in lighter areas it will be harder to see. It remains sharp and not modified by brighter high points of light in the same way grain on a groundglass is.

It is also independent of shutter speed/frame rate and is governed by gain settings.

Aesthetically, is is not always a bad thing and might be evident in the same circumstances which cause grain in motion film imaging, lowlight, high speed film stock, forced processing.

Because the nature of these adaptors is to lose some light and low budget operators are more likely not have access to adequate lighting, it is also more likely cameras wearing relay devices will be set to operate in a manner to aggravate internal video gain noise and "grain" artifacts will consequently be more often observed in an image more prone to show them.

There is a more professional way of talking about this subject. Trouble is I can only pass on my observations in layman's terms. Be doubting of my comments here.
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Old October 3rd, 2006, 10:31 AM   #35
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Sorry, but need to bump this. Which quicktime plug-in is needed to view video?

Plus any new review/info on Letus for the HD100?
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Old October 9th, 2006, 07:24 AM   #36
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slight diversion of topic, but... I am used to using the hand grip on the HD100 stock lens, so how does it work when the letus is attached - where do you hold/support the camera? Does anyone make a grab handle or similar which can be mounted next to the letus for support? and what about the record and return buttons? I'm a little concerned that, without the hand strap the whole thing could easily just slip out of my hands and off my shoulder to destruction...
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Old October 9th, 2006, 10:52 AM   #37
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Best practice is going to be to use a tripod. The Letus direct relay model for the HD100 should not be used to support the camera weight or the camera to support the Letus. You might need to investigate bridgeplate and rods assembly and a substitute handle mounted off the rods support.

For handholding, you may need to change hands over the habit you normally used with the JVC, right hand for the SLR lens and run button, camera on right shoulder as before, left hand holding the camera from overhead by its carry handle Bolex filmcamera style. - Ungainly, awkward but quite steady with practice.
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Old October 10th, 2006, 11:20 AM   #38
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Quote:
Originally Posted by Joe Carney
Sorry, but need to bump this. Which quicktime plug-in is needed to view video?

Plus any new review/info on Letus for the HD100?

I just did a little review over at the HD100 list last week.
It's probably still on the first page.

I'm an early adopter of the Mini35 and had a Letus built because of the potential ease of use versus the Mini.
Did a good deal of tweaking and testing with a Putora chart and getting just the right setting to maintain resolution versus the FUji lens as well as the cleanest backgrounds with shallow DOF.

Very succesful after a couple of days of testing and setup.
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Old October 10th, 2006, 11:30 AM   #39
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Quote:
Originally Posted by Bob Hart
Best practice is going to be to use a tripod. The Letus direct relay model for the HD100 should not be used to support the camera weight or the camera to support the Letus. You might need to investigate bridgeplate and rods assembly and a substitute handle mounted off the rods support.

For handholding, you may need to change hands over the habit you normally used with the JVC, right hand for the SLR lens and run button, camera on right shoulder as before, left hand holding the camera from overhead by its carry handle Bolex filmcamera style. - Ungainly, awkward but quite steady with practice.
With a quality AIS lens in the 20 to 50mm range (pretty much where you want to stay given the 1.9 factor), you're not really adding much more length or weight beyond the standard Fuji lens, so it's fine to mount the Letsu HD100 without rods. There is no practical way to handhold it like this though. You certainly want to use a tripod unless you're going to set it up on rods as Bob suggests

Over different projects we did use the Mini35 handheld as it is a permanent rod setup, but it also weighs about twice what the HD100/Letus setup weighs.

Bottom line is that it works great on a tripod where, honestly, you're going to want to work mostly with this level of production (shallow dof) and do your moves with pan, tilt, on a small dolly or jib arm.
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Old October 11th, 2006, 03:07 AM   #40
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You can mount the Letus35 XL and HD100 flip relay versions to the cameras without rods and the Canon will handhold as it normally does as it has a permanent handle where the lens grip and the standard JVC HD100 lens or ENG cams have one. The JVC loses it with the removal of its own lens.

It is true the Letus35 assembly does not in itself add extra harmful weight to the HD100 lens mount. However, the relay lens used in back of the Letus35 relay versions is a load bearing component in this arrangement. It was not designed to be a load bearing component but is unlikely to fail structurally.

However, unless the weight of the Letus35 appliance is supported, changing backfocus using the relay lens focus ring is awkard and the mechanism binds. Backfocus cannot be conveniently done with the camera on shoulder except if the camera op is three handed.

Unless the Letus is supported, focus adjustments to the SLR lens may also introduce unwanted movements of the image due to compliance in the structure in the immediate neighbourhood of the relay lens and the relay lens itself.
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Old October 11th, 2006, 07:40 AM   #41
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It's true that most shots would be supported in some way. But I like the freedom of being able to grab a quick shot handheld, if not making it a whole stylistic choice to shoot handheld (maybe with a focus puller if necessary). It's interesting that one of the clips used as an example on the Letus site is of a wholly handheld shot in a radio studio, thats the kind of flexibility I'm looking for.

Just another brief diversion away from topic however... can someone explain to me the implications of the 1.9x image magnification factor, I'm not great on film lenses so can someone explain - does that mean that a wide lens will be less wide, and a telephoto will be even more telephoto as a result of using the Letus?
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Old October 11th, 2006, 09:43 AM   #42
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[QUOTE=Bob Hart

It is true the Letus35 assembly does not in itself add extra harmful weight to the HD100 lens mount. However, the relay lens used in back of the Letus35 relay versions is a load bearing component in this arrangement. It was not designed to be a load bearing component but is unlikely to fail structurally.>>

Yeah, it's a pretty close coupled arrangement that would take a lot to fail there I would think

<<However, unless the weight of the Letus35 appliance is supported, changing backfocus using the relay lens focus ring is awkard and the mechanism binds. Backfocus cannot be conveniently done with the camera on shoulder except if the camera op is three handed.>>

I actually find this to be an accidental plus in the design.
There is no focusable relay on the mini35, just an adjustable iris.
You should only have to adjust the focus/backfocus on the relay once when you attach it, but because it's there by the iris there's a regular chance that you could accidentaly hit it and throw it out of focus.
The slight downward pressure keeps the relay focus ring secure while shooting, and placing your hand under the main body gives enough gentle support to adjust it if necessary.

<<Unless the Letus is supported, focus adjustments to the SLR lens may also introduce unwanted movements of the image due to compliance in the structure in the immediate neighbourhood of the relay lens and the relay lens itself.[/QUOTE]>>

Haven't had this issue.
What are you using to support yours Bob?...specifically what piece to adjust to the proper height when attached to the rods?
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Old October 11th, 2006, 09:54 AM   #43
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Quote:
Originally Posted by Paul Jefferies
It's true that most shots would be supported in some way. But I like the freedom of being able to grab a quick shot handheld, if not making it a whole stylistic choice to shoot handheld (maybe with a focus puller if necessary). It's interesting that one of the clips used as an example on the Letus site is of a wholly handheld shot in a radio studio, thats the kind of flexibility I'm looking for.>>

Well you can certailny hand hold it in apinch...I did shooting with it yesterday.
It's just not something you would want to do without a better setup...it's not ergonomic to say the least

<<Just another brief diversion away from topic however... can someone explain to me the implications of the 1.9x image magnification factor, I'm not great on film lenses so can someone explain - does that mean that a wide lens will be less wide, and a telephoto will be even more telephoto as a result of using the Letus?
>>


Take a calculator and multiply the focal length of the lens you want to use by 1.9 and that's the actual FOV you will get.

That's why I built a kit of 20mm, 24mm, 35mm, and 50mm.
With the Letus HD, they become 38mm, 45mm, 66mm, and 95mm.
I would have gone with an 18mm but they're not fast enough.
You can get by with a f2.8, but you absolutely want the extra stops of a f1.4 for critical work...the best you can get is f/2 with a 24mm.

Basically the wide end is a bit of a challenge witht he speed and multiplication issues, but for a direct to camera upright adaptor it's a reasonable compromise. the 20mm 2.8 AIS is the best glass you'll get for your wide end.
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Old October 11th, 2006, 11:30 AM   #44
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(Haven't had this issue.
What are you using to support yours Bob?...specifically what piece to adjust to the proper height when attached to the rods?)

Actually, on reflection, the normal movements of handheld work will likely bury any movement introduced by any flex in the camera/Letus combination. I am probably being excessively fussy.

The two specimens I have had dealings with -

One was for a HD100 and was supported on a purpose built Cavision rods system which has a little strap which goes under the Letus body, simple and effective.

Another was for an XL2/XLHI. For this, I cobbled up a solid support piece which went onto the rods of an existing teleprompter support which is very generally similar to how the Cavision worked. The rods were 12.7mm (1/2 inch) and the centres were 60mm apart.).

In my version the solid support completely surrounds the front tube on the Letus and clamps to it with a compression screw. It is a stable arrangement.

However, the real world quickly proved the solid support to be inconvenient as the camcorder cannot be quickly dismantled from the rods and the Letus.

I will be changing this to a cradle and overhead strap arrangement which should be nearly as solid but capable of being broken down instantly which is what the client needs to happen.

For the teleprompter support, XL2/XLH1 base to top of 1/2" rod vertical distance is 52mm. From bottom of front Letus35 XL Flip tube to top of 1/2" rod vertical distance is 38mm.

The XL camcorder family of camcorders has the lens centreline offset a considerable distance to the left as viewed from back of camera. My dimensions for this offset meaurement are not valid as the teleprompter was discovered to have been received incorrectly assembled which put my measurements out by about 8mm.

For an XL1 mounted to a tripod hole in dead centre between the two rods plus the misalignment I built onto, as viewed from the rear, the horizontal distance from the right outer edge of the right 1/2" rod to right outer edge of the Letus35 XL flip front tube was 21mm.

This was the centre point of the range of flex the camcorder/Letus combination permitted. This distance would come back to between 28mm - 32mm on a correctly assembled version but don't take my word for it on this one.
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Old October 11th, 2006, 10:51 PM   #45
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delete post please
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