Brevis vs. Letus35A
 

Since my recent acquisition of two new adapters, I think I am in a unique position to do a direct tat-for-tat shootout between the Brevis and the Letus. Both of these that are in my possession are the latest and greatest from Quyen and Dennis, and although one costs twice as much as the other I'm sure some people would like to know how they perform from a person's POV first-hand.

I'm busy at college but I can give initial impressions before I set up my tripod next week and do resolution charts, test shots and the like.

The Grain on both units is minimal, but there is definately more in Quyen's Letus. The Letus GG diffuses more however which can be a good thing as the bokeh is better. Neither adapter can be used static.

There is no vignetting with the Brevis. There is more with the Letus but you need to adjust the Plano-convex lens to an acceptable distance depending on the lens size of your camcorder. Even after adjustment I was experiencing vignetting.

I discovered something interesting. The Letus uses an achromat of much lesser power than the Brevis, probably to keep cost down, meaning your camcorder cannot zoom in as much. To compensate for this, the Letus uses a much bigger focusing plane, meaning the GG extends outside of where the image begins to falloff from the edge of the lens. This works fine for longer lenses 50mm+ but for wide angles vignetting becomes a serious issue.

The Brevis on the other hand, uses a standard-size focusing plate about the same size as a true 35mm SLR film plane in conjunction with a very powerful, very expensive achromat. This allows you to zoom into this smaller plane. Albeit you might be getting less "field of view" and therefore less DOF in this situation, but this is how the image is supposed to look like anyway.

I won't go into details about it because it doesn't deserve more than a couple sentences, but the Letus experiences chromatic aberration and the Brevis just doesn't. At least none that is easily visible anyway. Maybe towards the edges of the image I see a little, but you'll see that a lot in real movies anyway. I think it's a characteristic inherent in all lenses.

Noise.The Letus35 has become silent. Nill sound. Nothing. My previous version made a slight buzz, but you literally have to look at the switch position or peer inside to tell if it's running. Not even joking.

The Brevis, on the other hand, has a very powerful vibration unit. You can feel the vibration through the camcorder handle when it's screwed on. It's that powerful. You don't even need the indicator light to know it's on. I wouldn't be surprised if the TSA confiscated the watertight Pelican case the Brevis ships in if it turned on accidentally during transportation and somebody heard/felt it vibrating. It's definately audible, a small hum/buzz in the background. If you've got this screwed onto a camera that has a microphone right above the lens (like most cameras do) you can forget about using the onboard mic. The small hum goes away when you pull away more than about a foot but for a distance of 2 inches like an onboard camera mic, you're pretty much hosed.

The Letus has replacable batteries. The Brevis does not. Convenient when you don't want a silly box attached to the outside, and it definately makes the unit look sleeker, but not so convenient when you run out of battery power and need juice fast. Although you shouldn't run out because I hear the Brevis runs 22+ hours on one charge.

The Letus came with shoddy depth of focus placement. I know! I was surprised too. Quyen isn't usually that sloppy. But sure enough, I peered into the viewfinder the first time to find that half of my image was in focus while the rest wasn't. The GG was installed on a slant! I had to open up my unit and readjust it myself on-set. A real pain.

The Brevis is a tank. If you're a demanding professional I wouldn't trust your image to anything else. The Letus wouldn't stand up to half of what the Brevis does. I know you may not think that's a selling point, you're probably thinking "oh well I take care of my equipment, I don't need to pay for durability, I'll just be careful with it." Well ladies and gentlemen, @#*( happens. The only question is when.

The Brevis imaging adapter
Pros
* Bulletproof
* Great image
* No chromatic aberration or barrel/pincushion distortion
* Rechargable internal battery
* no vignetting, true 35mm image
* Big oscillation movement reduces grain
* All black/carbon fiber construction is sleek!
* Modular design, totally dust-proofed and sealed (unscrew the achromat, you get a metal plate with a glass window between you and the GG)
* Comes with a serious, rugged Pelican case
Cons
* Heavy/bulky (what adapter isn't? you're adding another lens for @*(#'s sake)...well, heavier than the Letus anyway.
* Overly powerful vibration, vibrates camcorder
* Battery can't be replaced/replenished immediately
* Bokeh is meh. Sort of greasy but amazing light-loss performance and Dennis ships a different, swappable focusing screen soon that allows options!

The Letus35
Pros
* Lightweight-ish
* Use Nikon and Canon FD lenses!
* Amazing bokeh, totally film-like. Great diffusion
* External battery pack allows immediate replacement on-set if drained
* Quieter than molasses in January. I guess that comparison doesn't really make sense but I'm guessing molasses doesn't make too much noise so it sort of works.
cons
* Diffusion and bokeh is at the expense of light-loss performance.
* Not as precisely made
* External battery pack is bulky and unsightly
* No indicator light
* Grain is easily apparent at even slightly higher shutter speeds or slightly higher apertures (probably because of the grain's diffusion)
* Distortion, vignetting, aberration, oh my! Even at optimal positioning, the PCXL still induces unavoidable distortion. Chromatic aberration is also very visible. This is with the upgraded 72mm achromat.

All tests were done with my FX1. I'll be back within a week with test frame grabs and movies.

Hi Ben very interesting write up. Good to read stuff like these in the forum.

Letus35A is pretty outdated I believe, the LetusXL v2 has almost none of the issue you mention but it only works on the Canons.


ash =o)

It also wouldnt be a fair comparison as the XL version is a relay setup that mount directly to the Canon body. I am just comparing screw-on vibrating adapters. The Letus35A may be "outdated" as in it hasn't been updated in a while but it's still the only adapter available from Quyen that non-Canon XL owners can get and the only vibrating adapter out there other than the Brevis.

we order two letus35 and while the device is really smart the way it is built, i was a bit deceived by that final work.
there is a lot of dust left inside, mainly aluminium powder.
the glue work is awful. I think he is not using a glue gun, but a bazooka gun.
the distances are ok, but not perfect, so the focus at infinity is sometime impossible, and position of condenser must be sometime reworked.
I do not like the strange idea to include a rectangular GG and condenser.
You need then to adjust the position of the adapter versus camera, while using a circular GG and condenser would have been not only more practical, but also easy to build.
The original GG definitely needs a replacement.
So if you are looking for an adapter ready out of the box, i would not advise this product (while for some it could work as is). If you can take some time to clean and enhance it, it is definitely a good deal.

we order two letus35 and while the device is really smart the way it is built, i was a bit deceived by that final work.
there is a lot of dust left inside, mainly aluminium powder.
the glue work is awful. I think he is not using a glue gun, but a bazooka gun.
the distances are ok, but not perfect, so the focus at infinity is sometime impossible, and position of condenser must be sometime reworked.
I do not like the strange idea to include a rectangular GG and condenser.
You need then to adjust the position of the adapter versus camera, while using a circular GG and condenser would have been not only more practical, but also easy to build.
The original GG definitely needs a replacement.
So if you are looking for an adapter ready out of the box, i would not advise this product (while for some it could work as is). If you can take some time to clean and enhance it, it is definitely a good deal.

The LetusFlip Enhanced I believe is the latest 'screw on' version. This will work with most cams and I beleive solves most of the problems you mentioned in the older A model.

Great read though Ben, very detailed.

Yes, great writeup. I have the Letus35A. definately not ready to go out of the box. I've since cut out the achromat since my camera, DVC30, can focus on the screen without it (big improvement without it). I can also zoom in enough on the screen so I get no vignetting. I don't care how much you clean it, dust gets in somehow. Still, I got it for a great price, image looks great.

My mind was already made up....but this was a great review. I wonder with the Brevis' rechargeable battery having such a long endurance, if the powerful vibrator mentioned is only as mentioned when the battery is at or near full charge. Maybe at "half charge" the review about the vibration would be different. Ben, What was the battery's charge status during your review? (or did you use the AC charger/adapter?) Could this be a possible factor?

Does the vibration from the Brevis affect the image quality? If it vibrates the camcorder, are you seeing it also in the final image?

The battery was at full charge so yes this is a possibility...also the falloff of a Lilon battery (which I am assuming this is) is usually linear so this supports your theory.

No it definately doesn't vibrate that much. You can just feel the rumble if you hold the handle of my FX1. I don't mind it.

Awesome write-up Ben, thank you. I was always planning on going with the Brevis and this just sealed my decision.

Yes good write up, though you commented more on the design of the two units than a comparison of the image quality... NOW, I'd love to see someone compare these adapters to the mighty P+S Technik. It's my impression that many of the much cheaper adapters can match the Technik in image quality (thought I haven't seen much footage from it).

So the question is, exactly how overpriced is the Technik?

The problem is that PS will never come down in price. It will always be overpriced and the first out there. We just need to concentrate on making lower prices unit that match that quality.

I would echo what a few have said in this string, the version of the Letus used in the test is an older model. I've owned two different Letus models, including the newest Flip Enhanced and let me tell you, if you own a Canon XL2, it is a great adaptor. Quyen addressed many of the problems on the earlier model and the fact that it connects directly to the XL2 body is a huge bonus.

I've used the LetusXL Flip Enhanced for a music video and have now used it in 4 broadcast political commercials and it is great. Clients love it.

The Letus flip was great until I got my HVX, at 720p you can see every bit of grain on the gg as it just does not vibrate enough to disperse the grain. The Brevis is very well put together and polished as a product. I'm waiting on the filp module now...Dennis:) I wish Quyen would upgrade the glass as my Letus Flip is collecting dust.

Yeah, and same time having exactly same quality issuses than cheaper ones.

I've not used the Brevis, but have used the PS many times & the Red Rock adapter several times on features and music videos. Firstly, I can totally agree with the statement that quality matters. I was shocked at the lack of control and adjustability and repeatabilty in the Red Rock unit. The PS has far fewer of those limitations, and is much more bullet proof. And more importantly, the PL mount adapter on the PS is -great- compared to the Red Rock. At least that's my findings. I'm very interested in the Brevis as it seems to have better build quality and a positive and repeatable connection chain between camera body and lens. I just wish they too had a PL mount adapter so I could use good Zeiss superspeeds without the slr lens breathing.

Ben, thanks for posting that review. I'm always looking for ways to improve the adapter, and feedback like this is very important. The noticeable threshold of vibration is pretty much directly correlated with dampening mass...meaning heavy cams like the HVX will "feel" a great deal less than cams like my GS400. You can increase dampening mass by just using the rails and rails adapter, which works very well with my setup. Having said that, we are working on bringing down oscillation amplitude, with a corresponding increase in frequency...

We'll be stocking the first of the interchangeable diffuser kits in about 2 weeks which I'm guessing will inspire a flurry of creativity :-)

We do have a PL mount by the way. I just haven't posted it on the catalogue yet. It's not cheap :-(

Sorry for "hijacking" this thread ;) .. but what about the Go-35 Pro? What kind of achromat does it use? The only thing I know is that it's using a pure static GG... but does anyone know the quality of the achromat used? Is the bokeh ok/good? How much light loss?

Jeez it's really getting harder and harder to follow all those different 35mm adapters currently out there especially since every one of them seems to be improved/changed/replaced by a new revision every week! *sigh* :-/
Although the M2 is really one of the weaker ones in terms of quality it has one "advantage" (really, I'm not kidding ;o) : it's design was not changed since they started selling it!
Of course this means: hey bad, it's not being improved.. but from a consumer/user point of view it's sort of an up side too... you know what you get and that it's not totally "worthless" and outdated 2 weeks later....... :(

Soeren, the Brevis basically went from the beta design, to the Rev2. Every change was motivated by user feedback and field testing to make it extremely durable, (go ahead and drop it if you like!), as user friendly as possible, completely portable, and still offer uncompromised image quality. It will not be changed as far as design goes anytime soon. We'll just be adding mounts, diffuser options, and the flip module. These are all designed to be modular...meaning they will work with all of the Rev2 adapters. For that matter, a DVX100 user who purchases the adapter, then upgrades to an 82mm HD cam, will need to change nothing except for an 82-72 step ring. We already have 2 diffuser options in production, and likely one more in short order.

Dennis, I know.. I already wanted to explicitely exclude your adapter from my rant. :-D
The Brevis is currently the only really promising adapter (besides the Digi35 - especially for european users - but it's still sort of vaporware) ... so if I currently was to buy one I would certainly get the Brevis. Nevertheless the Go-35 Pro sounds interesting too.. but I haven't seen or heard much (tech specs/info) about it yet.. so that's why I was asking. The newly posted test shot looked good... but I need more info. :)

Btw Dennis do you still ship with the RR (HD) achro or any news about your own achromat?

Ah, the achromats. Stay tuned.

I’m not sure the M2 is one of the weaker ones in terms of quality. You say this based on what? Image quality? Build quality? The build quality seems to be one of the best, certainly better than the Letus line and some of the new stuff popping up every week on the “whatever35 let’s make a penny” bandwagon. The only ones to compare to the M2 in build quality are the Brevis and SGpro.
Image quality same thing. Besides the SGpro and Brevis not much else to compare.
But I know what you mean about losing track with so many options coming out every week. What was a frustrating lack of option situation back when the P+S was the only way became an annoying race for making a buck over desperate young “independent filmmakers”. It seems there’s now even a 100 bucks adapter option out there. Jeez, might as well just buy a broken SLR for $5 off ebay and shoot through the viewfinder.
The thing about M2, Letus and SGpro is that they have been here from the beginning, they have helped to develop the whole affordable market and the products and not just jumped in when it has proved to be profitable offering more of the same.

I could really do with some help.

I want a 35mm adaptor for my z1/ a1.

I am torn between them all. I want quality/affordability

I like the idea that the Brevis will have a flip module coming out for it. Will it be soon and will it just be on new models or will it work on one I buy now. Also how long do they take to arrive generally. The sgpro lead time is almost 2 months.

Thanks

Phil,

The SGpro lead time is currently 1 month (ship Beginning of November).

Phil, the upcoming flip module will work with existing units.

Hi Greg, Any latest news on your HVX seeing grains with the Letus flip? Is this still a problem and do you think this is a problem inherent with all HDcam when used with vibrating GG like the Letus or other Adaptors? Thanks.

Where do I order any of these later version adapters?
I mean, Letuse35 website doesn't even show LetusXL and go-35 hopefully will be running soon.
some of the adapter websites need apdates as well...

If anyone's interested in learning about the Go35, just email me. My girlfriend leaves for Japan in a week, and with the time alone I've got coming to me, I intend to update the site with a ton of info.

Meanwhile, if you're interested in asking anything: info@go-35.com

I'm currently accepting pre-orders for October 6th release date of a new revision of the adapter -- features a diffuser with even less grain than the beta and early release units. The pre-orders come with a 10% discount, incidentally, provided you reserve yours by October 1st.

For Soeren and others -- the Go35Pro uses a high quality coated achromat. Light loss is just under two stops, maybe close to 1.5. Grain is, with good exposure, pretty much non-existent up to f/4.0 for first gen. HDV cams (e.g. FX1); for DV cams like the DVX, I've shot up to f/11 on a sunny day and looking over the footage haven't noticed much difference between that and f/2.0 footage from the same shoot.

Bokeh, while subjective, I would say is as close to film as you can possibly get with the Go35Pro. I have a series of shooters who confirm this, having had a lot of film shooting under their belt.

Victor, all the Brevis stuff is found under my signature. We've found the forum there great for sharing info on the adapter, including an owners section for more in depth product detail.