Letus Relay for EX3
 

This morning I received from Hien Le of Letus, the B4 pro relay and very excitingly the long awaited EX3 relay for Letus adaptors.

It's really nice. F1.5, a little bit shorter than the Pro relay, certainly longer than the Compact relay. It looks really neat on the EX3.

i will try it out for the first time on a shoot tomorrow. Can't wait. Will report back!

please let me know how much light loss it is vs letus ultimate attached to the stock lens and if the image is sharper.

thanks!

Phil.


If you get time in your busy schedule, will you do a little experiment for me.

Offer up by hand or jig the appliances together on rods if you can, the EX3 relay with Letus Extreme attached, to a 2/3" camera. You may not be able to get back far enough into the B4 mount as the EX mount lugs may foul on the sides. If this happens can you just hold a piece of paper behind the relay lens as a screen at the focal plane (sensor position) and measure the diameter of the image area. An 18mm circle drawn on the paper will make this easier.

I'm interested in seeing if the wider full frame of the Extreme groundglass can be relayed by the 1/2" lens to the 2/3" sensor without the corners going soft or brightness falling off.

If the 1/2" lens will do this, it might not be a big engineering deal to cross-configure the EX3 relay with a B4 mount so users can have that option.

You may bring in a side. If you can get a clean frame top to bottom then a recentered Extreme should work in this configuration to the SI2K. Chances are, being fine tuned to the EX3 the 1/2" relay will go slightly soft in the corners to 2/3" or even vignette.

SGBlade ...
 

Phil,
The SGBlade ... will the relay fit?

Hi dean mate! How are you?

No it won't fit without serious mods.

Got some more pics up of it

Philip Bloom Blog Archive More pics of EX3 Letus Relay

Will try Bob!!!

Oh ... well ...
 

Will have to look into that relay to lens connection! How does it attach?
I'm doing well ... thank you very much. Just got off a couple of corp. gigs shooting SD. I'm still playing with the EX3 ... waiting for the SGBlade. Hope to get some zeiss primes in front of the blade!
all the best ... let me know when you are in Tokyo again.

newbie alert
 

okay why do you need this with the Letus adapter... I;m a little confused about the purpose.

micheal

Google it.

You don't need it. Almost all of the 35mm adaptors on the market bolt up to your cameras current lens. But with some cameras, like the EX3 for example, you can remove the lens from the body. So Letus built a replacement for your camera's lens that mates perfectly to their 35mm adaptor, they call it a "relay lens". This comes with some advantages. Because it's not a zoom lens they can use very little glass inside. This means that the relay lens is shorter than the EX3 lens, which helps with the balance of your rig over the tripod. In the case of the Letus rely, the image is sharper (less glass inside) and it has a lower f-stop than the factory lens, which helps make up for some of the inherent light loss that comes with using a 35mm adaptor. Finally, if you frequently switch between shooting with and without an adaptor, it makes the switch easier. Really the only negative with a relay lens is the additional cost. Letus hasn't announced the cost of the EX3 version yet. We're all hoping it's not too astronomical.

I did a web commercial last week with Suresh Kara of DocuMovie using the EX3/ Relay/ Ultimate and it was AWESOME.

here is my blog with some pics. We will be releasing the spot very soon for you to see.

Philip Bloom Blog Archive Shooting a commercial spot on EX3/ Relay/ Letus Ultimate

here are two screen grabs. Go to the blog for more!

Footage looks great Phil! Very sharp! I'd love to purchase a new relay for our EX3, but I'm still crossing my fingers that the price will be "affordable"....what ever that means.

What is your current logic for running the Ultimate "snorkel up" instead of down? I haven't tried that configuration yet.

no real advantage to snorkel up, just personal preference...i do think it is going to cost this relay. Having both the pro b4 relay and ex3 relay in my hands and there is little difference in quality. ex3 one is a tad shorter and different mount, but is also f1.5. I would expect it to come in around the 4k mark, maybe less.

It's a lot of cash but this is a high quality piece of glass. When you hold it you can feel the money in it's weight...The cinevate one is much cheaper, i haven't seen it and it may work on all adaptors. It is rather long though...

I'm curious as to how it performs without the flip? Flips on some brands reduce CA and increase sharpness, but also add a stop or more.

Does removing the flip increase light and sharpness? Can you even remove it?

the letus is one solid piece of milled aluminum. you cant remove it. Also the total light loss of the ultimate with its flip is just half a stop and it suffers no CA and as you can see has cracking sharpness. Have a look at Ultimate with B4 relay on pdw700 grab here...

I seem to remember Letus saying that they were surprised to find that their flip actually added sharpness. (I'm just repeating what they said) The Letus Ultimate that Phil is using is a one piece design. You can't use it without the flip, and I don't think the relay is designed to be used with anything other than Letus adaptors.

it's weird. Cinevate and Letus both say flip enhances image but it seems the flip on the Blade isn't quite as good as shooting without it on the ex1/3. don't understand!

It's very nice, no doubt. I'm keen to keep the whole setup as short and light as possible for Steadicam work. The Cinevate relay is massive compared to the Letus EX3, but I like the light weight of the Brevis. Perhaps the Letus EX3 relay and the new MP.2 Brevis might work well together, if the can mate properly?

i do believe inter species mating is not possible with the ex3 relay...

Isn't it something to do with the acromatic (spelling) lens they made to perfectly match to the EX1/EX3? When I was shopping for adaptors, that's what steered me to the Letus and Cinevate adaptors over the others.

But yeah, I don't know how it works either.

You've got to be THRILLED with the footage you're getting with that relay. (very jealous)

You going to NAB in April in Las Vegas? I'm planning to attend for the first time in many years. Off of your recommendation, switching to the EX3 and Ultimate has rejuvenated my interest in videography. I've been going nuts researching and shooting as much as possible. Thanks Phil.

That is a tragic loss to biodiversity :(

yep going to NAB. Decided today and booked my tickets!

You going to be a the Sony, Letus or Zacuto booth? Do you know if they are going to even have booths?

if anywhere will be at zacuto. But am a free spirit! Letus as far as I know won't be there, but they will have their gear on the zacuto stand

Well maybe I'll lucky and bump into you.

Okay, not back to the topic of this thread....

So the EX3 relay has a iris and focus rigs, but no zoom....right?

Drop me an email when out there, or phone. Always good to meet people off the forums. Also there may be a DVinfo gathering like there was last year.

The Ex3 has no relay. That is what keeps it short, unlike the cinevate relay. Downside is academy frame size of 24x16mm rather than 36x24mm which is what you get our of SLR lenses. What Hien decides to do about this is anyones guess but two different relays would be my choice. I am very unlikely to use PL lenses on my EX3, maybe on the B4 and would prefer a full frame relay for the ex3...

Sorry, but you totally went over my head with your comments.

1) So "relay" is another word for "zoom"? So the EX3 relay lens (which doesn't have a relay) will not have a zoom function. Right?

2) I don't know the significance between academy and 36x24mm (35mm?). Does this mean that our 35mm lenses will not be their true focal lengths? So a 24mm will be like a 35mm? I hope that's not the case.

I don't have your phone number, so I'll email you when I get to NAB. A DVInfo Net meeting would be great. But I'm especially interested in talking to others who use like equipment and especially those who use them professionally (to make a living).

phone number is on my website...


The relay is essentially a prime lens, a fixed focal length lens. Not a zoom lens. Cinevate are making a zoom relay but it is very long.

Yes, the relays currently being made by Letus are for Academy size frames, that's 24x16mm. The reason being is they are cropped for use with PL lenses. PL lenses are essentially movie camera lenses. If you look at a piece of 35mm film when it goes through a stills camera it it horizontal, but when it goes through a movie camera it is vertical hence a smaller image. 35mm movie lenses are designed to project a smaller image. If the fixed focal length of the relays was set for 35mm still lenses what would happen with a PL lens on it would be a large vignette. So they have decided to go with the PL size Academy frame as they believe people who will be shelling out for a relay will use cinema lenses. I disagree. Certainly this could be the case on the B4 but maybe not so on the EX3.

So hopefully they may have more than one type of relay coming out for the EX3. This one and one for full frame still lenses...

Keep your fingers crossed!

So what's the negative with using Academy frame size relay with a 35mm SLR lens? Not as sharp? Bright? (sorry if these are newbie questions)

you hit the nail on the head earlier. A multiplication factor of 1.5x so you wides aren't as wide, your long lenses are a bit longer etc...

That would suck! What size is the opening of an Ultimate mounted on an EX1/EX3 lens? In other words, when you zoom in the least amount possible. Is it pretty close to 1:1? My 17x35mm seems pretty darn wide on the Ultimate/EX3.

Sorry for all the questions but this is a very helpful conversation......well at least for me. I would assume there are other people reading this as wel.

pretty much...yes losing part of the wide end of lens isn't great...

Well you need to use some of that huge amount of influence you have (now that you're a household name) and get Letus to make 2 versions. hehehehehe

See you at NAB.

Yes, to reiterate Mitchell's question: without the relay and the Extreme on an EX-1/3 set to about Z70-74, are we closer to the Academy or Full Frame size? I guess I could put a lens on a 35mm camera to check, but my DSLR is not Full Frame, either.

B

had to take down video. sorry!

To muddy the water further....when I frame up the Letus Ultimate my zoom is around 40 (maybe 42-45.....I know it's 40 something). The Extreme is 70 something. That's a big difference. Maybe the opening of the Ultimate is different than the Extreme?

Mitchell


The spinning disk on the Ultimate is quite small and has to be for some very practical reasons. So also was the disk in the older P+S Technik Mini35-300.

The motion picture image frame size was adopted by P+S it seems to keep the faith with DPs intuitively accustomed to their cine lens choices.

The Ultimate is likewise intended as a professional tool for such operators.

Those of us who play with the alternative adaptors or home-build are less inhibited and experiment. If something goes wrong and we pick up an edge or an artifact we don't go out and slash our wrists because there is less at stake.

As a tool intended for professionals, the Ultimate has to be both reliable, predictable and conform to an accepted standard. Re-shoots for technical failure are not an option longterm.

A person with an infectious contagion only takes one bite at your chocolate bar and its all gone for you. Likewise for the professional level appliances. One stuff-up and consequent bad press and its all over.

The Le brothers are being exceptionally conservative and careful with this one, a courageous development in these financially straitened times.

As for hacking the relays to the SGBlade, there are a few things at play for a reasonable chance of a successful consummation.

1. The optical distance from groundglass to front of relay lens has to be about the same or within the adjustable focal range of the lens.

2. The condenser element between the groundglass and the relay lens may have to be of similar power and diameter, otherwise bads like edge softness, hot spot or even hot corners around a dark ring may occur.

3. Wayne ( and he needs to slap me over the ears here if I am wrong ) I recollect has traditionally gone for a larger groundglass area and more solid bokeh using a coarser groundglass diffusion and restoring apparent sharpness by using the larger image area.

Therefore his groundglass may not resolve as sharply as the Letus Ultimate for the same smaller motion picture frame area the direct relay is confined to. He has a new optional groundglass offering which may permit this.

Wayne's flip adaptor seems to be a bit shorter, more like the Brevis. To get the correct distance from groundglass to front of relay lens may require a longer bridgepiece between the front of the relay lens and the rear of Waynes flip adaptor.

As for the comment of improved apparent resolution through a flip adaptor, I have also observed this. It is related to the longer optical (folded back on itself) distance between the groundglass image and the camera which allows the use of a less powerful dioptre in the relay path for a given size of appliance. The angles of incidence are less severe. The problems of edge softness are reduced. If the optics and prisms/mirrors are of good quality, it is a win all the way.


Benjamin.

If you are framing Z70 on the Extreme, you are probably in academy frame size on the groundglass. Are you having to zoom so far in to avoid picking up a side edge? If you are, chances are your Extreme received a damn solid clout during its journey and the prism has been shocked slightly to left and forwards against the rubber wedge retainer which retains the compound prism against a centre support spine and the rear face of the enclosure.

There is a quick hack based on my adjustable centricity mod that I can give you to restore centricity to within manufacturer's limits if this has happened but it requires you to have good dextoral skills, a clean working environment and the necessary tools. Parts required, scizzors, tweezers, maybe a throwing dart, (or splinter pick, scriber or saftety pin) and a sheet of quality thick printer paper or plastic lens shim of similar thickness. You assume all risks of damage-failure of the appliance.

Also, what are the measurements on your mounting setup to the rails system. I can give you the correct dimensions for the EX1 on the original Letus rails kit, not the new one or the Zacuto.

relay hack ...
 

Good to hear there may be a way to hack the letus EX3 relay for SGBlade! I been wonder about this since it came out. I'm willing to give it a try anyway!

This has been my experience too, with just buying the separate Letus flip adapter. I have an old Letus35a, which had condenser and achromat. I bought a flip adapter, and was able to eliminate both from the 35a when I added the flip adapter.

Dean.


If you want to eliminate some of the guesswork and have any 35mm Nikon prime lenses and your SGBlade is already mountable along with your EX3 on a rails/rods system, there is a bit of a test you might do. I am assuming your SGBlade is a flip appliance. If it is not, then what spills onto the page below is useless comment to be ignored.

Try taking the EX3 lens off after you have got everything aligned and centred on the rails, get a 35mm Nikon prime if you have one and offer it up by hand into the space between the camera and back of SGPro. YOu will need to have the camera hooked up to a good monitor to see what you are doing.

Set the focus of the 35mm prime in midrange, say about 8ft.

To avoid shorting out any hotpins in the EX3 lens system, tape over the conductors inside the EX3 mount orifice before you go shoving a wild lens in there. It WILL be hell expensive to repair. Take extreme care not to let any part of the rear of the Nikon lens clash with the transparency in back of the EX3 mount orifice. It WILL be hell expensive to repair.

As a starting point, there may need to be about 8mm between flange face of the Nikon lens and flange face of the EX3 mount, maybe closer, maybe furthur. If you know the flange to focal plane "in-air" spec for the EX3 lens then you can calculate this distance. The Nikon lens system is 46.5mm for the F-Mount.

If the difference is additive, not subtractive, then you can't use the Nikon for the test and get a valid result.

My guess is you will need about 18mm - 24mm of space between the rear of the SGBlade and the front of the 35mm Nikon.

This is all rough guesswork on my part, no science inolved at all.

If you can get an acceptable image to the EX3 through this mess, you may be in with a chance with the Letus EX3 relay.

You would have to have a bridgepiece machined for the rear to go into the front of the relay lens, which appears to be the same Letus simple shoulder and clamp screw arrangement. The front would have to be machined to fit the rear mount system of the SGBlade. I do not know what that is.


Please do not ascribe any authority to my suggestions. All risks are your own. No use in sueing me as I am near to bare-ass broke and my debts will be of no use to you.

Bob ...
 

When I receive my Blade I will give this a try. Not to worry ... I'm a grown up. I wouldn't dream of bringing suit against you for things you suggest !!