Can I use 16mm cine lenses with the Letus Extreme and EX3? at

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Old March 23rd, 2009, 11:55 AM   #1
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Can I use 16mm cine lenses with the Letus Extreme and EX3?

I'm shooting a graduation piece for some students in West London next weekend, on the EX3.

I'd like to use film lenses, as it's quite an ambitious drama, and would benefit from a much reduced depth of field.

We've had to dispense with the idea of using 35mm cine lenses due to cost, but I may be able to get a set of PL mount 16mm lenses for free.

I'm totally new to using these adaptors, so I want to know what the issues are with using 16mm lenses with the Extreme. Is it right that I'll have to zoom in on the picture on the ground glass to fit the frame? Is this a total pain or is it just what you have to do, and otherwise harmless...?

Using stills lenses is obviously more affordable than the 35mm cine lenses, but I don't want to make life difficult for the focus puller.

Any thoughts or experience shared would be great. Thanks,

Jamie Kennerley
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Old March 24th, 2009, 04:52 AM   #2
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Skip the 16mm lenses.
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Old March 24th, 2009, 05:05 AM   #3
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16mm lenses do not work with 35mm adaptors like letus or mini 35

they do work with the jvc adaptor and may be others

you should be able to find 35mm lenses at film schools etc. at low or no cost

but be aware that shooting 35mm is VERY different from video work much more demanding and time consuming
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Old March 25th, 2009, 01:06 AM   #4
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I don't want to be a parade rainer but there is a reality here you cannot escape, - preparation time.

Any groundglass adaptor requires the operator to have considerable practice with it before taking on a serious project which consumes a little of the valuable lifetime of everyone involved.

You are not going to get there in three days and that irreplaceable piece of everybody's lifetime may yield a substandard result people are disappointed with if you try.

This will happen because you will be so pre-occupied with trying to wrangle the groundglass system that other essential little tricks and finesses will become neglected.

This time round, use your EX3 camera bare and beautiful. You have a half inch sensor and you can get some shallow depth-of-field effects if you sit off from the subject with the lens on the longer end of the zoom.

My personal preference would be to forget about shallow depth-of-field and separation of subject from background with focal effects unless it is absolutely critical.

Your project will look better if the other quality adding is attended to like camera-friendly faces, good composition, lighting, locations and of course the story matters.

Don't be lazy. Move the camera to match your close-ups and reverses. Watch your eyelines. Don't adjust the frame with the zoom just because you can but move the camera to get the perspectives right.

If you do decide to use the Letus, a Nikon 50mm and Nikon 85mm f1.8 or f1.4 should be sufficient for your selective focus effects. Shoot the rest direct-to-camera because you will run out of time otherwise.

Shoot backup coverage of the same shots without the adaptor. When setting up relay focus and framing, use an underscanning monitor. The LCD viewfinders are just not good enough. If you can get hold of a resolution chart with blocks of parallel lines which show differing resolutons, use this chart when setting relay focus. Always set your relay focus with the camcorder lens iris at its widest, then close it back to preference for the actual take.

When setting your relay frame, for best apparent resolution, you want it as wide as you can get it without vignetting or edge/corner brightness falloff. The underscanning monitor will enable you to do this without an edge coming into the image frame. An edge may otherwise be undetected in the viewfinder but found in the playback image. Zooming out until the optical path edge is just on edge of frame then zooming in about 10% is a ballpark solution but not ideal.

When focussing on the subject, use a Siemens focus pattern on a fullsized printer page alonside the subject when setting up as a focussing aid. Eyematching is just not good enough, especially when using a groundglass system.

You likely have already been taught better on this subject so ignore my suggestions if they go over old ground.

Last edited by Bob Hart; March 25th, 2009 at 01:48 AM. Reason: corrections
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Old March 25th, 2009, 10:46 AM   #5
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Not being a parade-rainer Bob. I want to hear that it's not as simple as popping the adaptor and lenses on because it scares into making some serious decisions! Although, despite an almost universal suggestion not to do it, I think we are actually going to go ahead.

I have a crash course booked in with the hirer, and an assistant who's worked with this set-up before. I also realise it's a different world to shooting with a stock lens, but I have recently come out of about 5 years of shooting stop-motion series on film, so I'm not un-used to having to work in a detailed way but quick and efficient way.

Thanks for the advice Bob. I know you've been working with adaptors for a long time, so I take all your pointers on board.

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Old March 25th, 2009, 12:59 PM   #6
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If you have an assistant who is going to sweat over the relay framing and backfocus and leave the camera operator free to concentrate on framing and setting up then that is a good move.

This is definitely not a one-man-band job for a first up. Don't be tempted to have your camera assistant/adaptor-wrangler do double duty as a boom swinger.

Your assistant may have been around adaptors long enough have have got the "shoot everything wide-open novelty" out of his system.

Best if you can have the widest aperture lenses f1.4s if you can find them trhat you can get hold of so that you keep headroom under f5.6. This is the generally accepted limit on groundglass imaging before artifacts appear. You might get away with f8 or even f11 with a longer lens but the chances are you will encounter an artifact.

You will not see artifacts on a camcorder LCD screen. You will also not see if the groundglass motor has not been switched on, hence the larger monitor recommendation.

If the lens is a f1.4 then at f2.8 you will be closer to a sweet spot than a f2.8 lens shooting wide-open. F2.8 to f3.5 is a good safe zone. Some f3.5 lenses especially the wider ones may artifact or exhibit brightness falloff.

Your stills lens kit should hopefully include 14mm, 20mm, 24mm, 28mm, 35mm, 50mm, 85mm.

Longer lenses can be handy outdoors. The Sigmatel f1.8 135mm can be a good lens. The Nikon f1.8 105mm is pleasing if you can still find one.

Try to avoid zooms unless you want it for a dynamic effect. There are a few good ones but anything which is not f2.8 constant through the zoom range is likely to waste your time.

Try to do the old traditional Kodak box camera rule of thumb and shoot outdoors in morning or afternoon with the sun lower and behind the camera. Midday with sun high overhead tends to cause high contrasts and sometimes an artifact. Against the light is not so good.

If you are going to use ND filtering to bring light levels down outdoors, examine using a mattebox and ND filters. This will reduce groundglass flare and help preserve contrast rather than having the in-camera ND drop an overexposed groundglass image.

However do not do more than about one f-stop of added ND filtering as there can be a problem with infrared getting through the filter and causing a reddish colour cast in the blacks. If you have a true-cut IR filter then you can go deeper with your added NDs.

Contrary to what some will tell you, you may use the camcorder zoom for a small amount of dynamic effect. Be prepared though for a softer image. The furthur you zoom in on the groundglass, the softer it gets.

In keeping with the value adding you aspire to with groundglass imaging, avoid using on-camera mikes except for a reference track if you are recording double-system. The more recent adaptors are fairly quiet but may produce some noise to on-camera mikes.
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Old March 31st, 2009, 11:00 AM   #7
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I've been using a DOF adapter for about 9 months. I'm still quite a newbie to all this, so my advice is pretty basic. But here's what I've learnt based on my limited experience:

-- If you can't get 35mm cine lenses, then I guess your only other alternative are SLR lenses. The cheapest (but oldest) you'll find are Canon FD lenses.

-- Your rig will be substantially heavier. Unless it's staying on a tripod, you will probably need a shoulder mount support system.

-- Depth of field will be extremely shallow so will you need a decent monitor. Don't rely on the LCD screen or viewfinder, it's too small for critical focussing. Also consider how you're going to mount and power this monitor onto your rig.

-- Once you've focussed and zoomed in onto your groundglass, lock your focus and zoom rings down. Use PVC or masking tape. Trust me, you will always accidently nudge them.

-- Don't forget to switch off image-stabilization. The stock lens will try to stabilize against the shaking ground-glass and the resulting image will appear twitchy.

-- Always try to leave the ground-glass motor on all the time throughout the shooting day. Bring spare batteries with you. If you keep switching it off between takes, you will accidently forget to switch it back on again on a few occassions. And you'll be kicking yourself in the editing room.

-- Be prepared with the light-loss, especially when shooting indoors in the UK. Even though the DOF adapters only have 0.5 stop light-loss, depending on your camera, you could lose an additional (approx) 1.5 stops for zooming in onto the ground-glass. I've had to use 6dB (and even 12dB) Gain when shooting indoor scenes that rely on natural lighting.

-- For your SLR lenses, keep it below f5.6, otherwise you'll start to see artifacts from the moving ground-glass.

-- Keep your shutter speed below 1/250, otherwise you will start to see artifacts from the moving ground-glass.

-- Be wary if you are using the camera's internal mike or if you are mounting an external mike onto the camera. Depending on the mike's sensitivity settings, you will probabaly still pick up the noise of the ground-glass motor.
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Old March 31st, 2009, 07:27 PM   #8
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All very good hints and best practices.

On switching the groundglass motor on and leaving it on, I have some reservations about that practice.

A called checklist which includes "adaptor" + "on" is my personal preference. (Ie., "camera" - "rolling", "adaptor" - "on", "sound" - "speed".) It soon becomes habituated and second-nature.

Although Quyen and Hien who make the Letus Extreme, have used dropping resistors and lower power on their vibrator motor to bring it into, or closer to a continuous duty rating, leaving it switched on will obviously increase general wear and tear in the motor and other moving parts.

With the benchmark P+S Technik Mini35 and Pro35, I would not do this to either. The groundglass carrier ballbearings are fairly bulletproof but the motor bearings and drive belts are wearing parts with finite service lives.

It is a matter of personal preference, one benefit versus the other.
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Old April 4th, 2009, 03:13 AM   #9
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I've been shooting with a Letus Ultimate adaptor since January 10th. Andy and Bob are right on the money with this. But I don't think that should discourage you. I LOVE the look the adaptor brings to my footage. I've gotten all kinds of complements from my peers since I've started using it. Comments like "you didn't really shoot that....did you?"

It sounds like you're an experienced shooter, so you will just have to put your thinking cap on for the first few times you use it. Then you'll get used to it and it will become second nature. I made some "mistakes" during this learning process but I never lost any footage or had to reshoot anything and all my shoots were paid shoots. (threw myself into the fire so to speak)

BTW, the EX3 viewfinder is fantastic. I don't have much trouble focusing, especially if I used extended focus, and that's shooting wide open most of the time due to shooting indoors. Yes, an external monitor would make it easier, but I think the EX3 is one of the few cameras were you can get away with using an adaptor without an external monitor. But eventually you'll probably end up buying one along with a follow focus. I haven't done this yet, but it's close to the top of my list. (right behind the soon to be released Letus EX3 relay lens)
Sony EX3, Canon 5D MkII, Chrosziel Matte Box, Sachtler tripod, Steadicam Flyer, Mac Pro, Apple/Adobe software - 20 years as a local videographer/editor
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