DVXuser.com : 35mm adapter shootout

There has been a lot of discussion lately by members about 35mm adapters; wondering what was the right one for their needs, seeking other opinions that sometimes sparked debates in forums, and what seems like a new DIY adapter with commercial potential popping up every other week. As such, I decided to coordinate a shoot-out among the manufacturers of adapters that were within financial reach of the average user ... namely, adapters that cost less than $1,000. I immediately contacted Ryan Walters (DVXuser member 235 Studios, f.ka. waltind) to see if he was interested in participating, especially since he's more adapt with the DVX than I am, and between the two of us we would have three DVX100's to shoot with at once (Ryan owns two). He was as eager as I was to see the differences between the units, as well as the pros & cons of each.

There was one requirement for manufacturers to participate; The unit submitted for testing had to be commercially available for purchase by the time this article was posted. The last thing I wanted was for users to get excited about a product that may be stuck in development hell for several more months or longer, and in some cases even changing designs during the course of that time. This weeded out nearly everyone, with the exception of Wayne Kinney's SG35 (http://homepage.ntlworld.com/wayne.kinney/sg35.htm) and Quyen Le's Letus35 Flip (www.letus35.com). We were initially disappointed that we wouldn't have any of the static ground glass (GG) units to test, but were excited nonetheless to be able to put a spinning GG unit and a vibrating GG unit side-by-side and see the results.

I'll first go into the initial feel & onsite feedback of the units, and then post the actual results further down in this article with grabs, links to footage, and measurements ... most of which Ryan Walters was responsible for with regards to consistent parameters, recording of measurements & settings, etc.

The SG35
As I pulled it out of the box it was shipped in, it felt like an absolute tank. Solid and robust, I'd feel safe walking down the darkest of alleys, if I knew I had this within clobbering reach. The rails are metal, and are a snug fit within the shaved & cut, dense plastic framework. I'd wager to say even that they were too snug; so much so that when I wanted to adjust them, I had to resort to using a 5lb sledge hammer to tap them in & out. Sure I could have used a regular hammer, but the sledge was handy.

Before I get into any of the down falls with the SG35, let me say it is a CLEAR winner with regards to light loss. When tested with the unit only (35mm lens not attached as this will vary from user to user), the light loss was only a 1/2 stop. It excelled in the exterior night shots, whereas the Letus35 Flip was nearly useless (more on that later).


SG35 featured with the Canon FD 1.4 50mm lens that was used.	Solid & heavy frame work, with a nice quick release, but could benefit from some refinement.	Batteries are SNUG in place, but could use a housing.

Barrel distortion was evident to a degree, but severe color aberrations appeared in the exterior shots (see below), especially if the camera wasn't stopped down.

While testing for light loss, the unit was directed at a white board and connected to a monitor. On the monitor VERY slight strobing could be detected, presumably from slight imperfections in the GG. This is likely one of the most difficult things to achieve with a spinning GG; perfect symmetry so that there is no out of round/balance both from side to side as it spins, in addition to front & back, which could ever so slightly effect the focus of the camera on the GG. In addition to this, any inconsistencies with regards to the finish of the GG may show visible with strobing or other smearing effects, as we noticed.

Another issue with the SG35 was that the GG was so close to the DVX's lens that we were unable to get all the way inside the GG (so that the edges wouldn't show in frame) and still get a focus. Though the edges of the GG would be outside the TV safe lines, for those who are wanting their work displayed for web or projection screens, they would be frustrated.

In mentioning some of these issues to Wayne Kinney, there are a few things that could be attributed to product shifting during shipping, but most of the other concerns are already being addressed. So much so that Wayne has discontinued manufacturing of the SG35, and will shortly be releasing the SG35 Pro, which is reported to be an improvement in the following:

Obviously the above are radical improvements over the unit we tested, so Wayne has assured us that we'll be able to inspect the Pro version as soon as it's available, at which time we'll look to update this article.

The Letus35 Flip arrived to the shoot-out late, so it was unable to be used on the models we had on set, but we received it in time to test everything else. First, a big thumbs up to Quyen for a major accomplishment. Not only is it an improvement over the original Letus35, as there is no apparent barrel distortion or color aberrations (both of which were problems with the original Letus35), but the image comes into the camera already right side up. This GREATLY improves ease of use during production as there are no monitors to that need to be flipped, and speeds post production because footage doesn't have to be flipped.

While larger and heavier than the original Letus35, to compensate for the mirrors/prism inside the unit, it actually looks nicer. In fact, a LOT nicer. With the well machined curves and styling, one could almost say sexy. The original Letus35 has the typical tomato-can look that so many DIY units have.

With the added curves, some may find it an interesting work around with their rails, but the set of Cavision carbon fiber rails we had on hand worked nicely. In fact, I would highly advise that anyone who ends up with a Letus35 Flip also seek out a set of rails, if they don't already have some. I personally believe it's too heavy, not to mention the added weight of a lens, to allow the long term torque on the DVX that would occur. Cavision makes a nice low cost carbon fiber set that's readily available direct from Cavision, or you can usually find them for even less at EVS or B&H.

Where the Letus35 Flip seemed to excel in nearly all areas (lighter, smaller, uses only 2 AA batteries, no color aberrations, image is right side up, well machined, etc.), it bombed in comparison to the SG35 with regards to light loss. The unit alone brings a light loss of approximately 4 stops, which rendered it nearly useless for exterior night shots where light sources were not able to be controlled and/or well lit.

Another issue with this particular model was that the GG was off center to the right - by quite a bit. In speaking with Quyen about this, he attempted to explain that different cameras can see the GG differently depending on where or how the CCD's positioned. The guy's a certified engineer, so I believe him, yet when we tested this on three separate DVX100a's, the result was the same every time. So while other cameras may differ from the DVX with regards to CCD placement/position, a little more care needs to be placed specific for the DVX. In this case, it's not the GG that's off center, but the last mirror that needs adjustment, according to Quyen.

Since the GG was off center (or mirror was angled incorrectly), it forced us to zoom in even further than the normal Letus35 or the SG35. Doing this actually cut down our field of view, since we were now zoomed into the GG more than necessary. We also discovered, after the fact, that the further you zoom with the DVX the more light is lost. In fact, the additional required zoom was responsible for 1/2 - 1 full stop of light loss. So in all fairness to the Letus35 Flip, if the screen/mirror is properly centered, the total light loss should be about 3+ stops. It's also worth noting that if Quyen has any room to improve with the placement/position of the mirrors/prism, there's potential for additional improvement in the light loss as well, though I'm only speculating.

Another positive note about the Letus35 Flip, is that it comes standard with the Nikon AI / Canon FD metal reversible mount. Some people have stated before that you can't adjust the lens' iris on these adapters, as you need to have it attached to the actual camera body to work, but that's simply not so with Quyen's design. When tested with both a Canon FD mount lens and a Nikon AI mount lens, the iris was fully adjustable on each one, as well as the further refined adjustments you can get inside the DVX itself. However, on a personal note, when I use these adapters, once I've got the camera properly zoomed in & focused on the GG, I lock everything down with black Gaffer Tape. If you look closely, it may not be the prettiest thing to do to your camera, but I don't want to chance having the iris, zoom, or focus accidentally getting changed while shooting.

SG35
Wayne Kinney is really onto something with the SG35 with regards to light loss. Losing only 1/2 of light is just flat out remarkable, to say the least. Unfortunately the rest of the particular unit we tested fell considerably short of our expectations. Since nearly all of our issues with it are supposed to be addressed in the new SG35 Pro version he's preparing for release in the very near future, we're excited to see the improvements and will update or add to this article once we've had a chance to see it. I'm no expert on figuring out where the pound is in comparison to the dollar on any given day (Wayne's unit is manufactured in & sold from the UK), but I do believe the SG35 Pro will be in line with the Letus35 with regards to pricing.

Letus35 Flip
Quyen Le has done something quite remarkable for the indie film maker by creating an affordable adapter that rids the need of having to flip monitors up side down or having to flip footage in post. It's unfortunate that the particular unit we tested appeared to be defective in that the GG (or mirror) was out of alignment, but I believe that if an end user were to purchase from him, and that was the case, he'd make it right as soon as possible. That said, the Letus35 Flip loses a considerable amount of light ... even with the GG/mirror issue corrected, our estimates would be approximately 3+ stops.

In looking at the Quyen's web site, it appears that some of our concern with the Letus35 Flip have already been addressed in an "advanced" version, which has also increased in price by $100, to a total of $700. This is no small sum of change, but Quyen is also reporting only 1.5 stops of light loss with it, as well as an improved GG. I've yet to see this improved adapter, but I'm interested to say the least. If we get a chance to test it, I'll update the results here as well, as I will for the SG35 Pro.

Indie Focus' Geared Follow Focus
Indie Focus was kind enough to supply a geared follow focus for us to test with the 35mm lenses. Ryan Walters was a Beta Tester for Indie Focus, and wrote the following review, which he's updated with his review on the geared adapter: http://www.235studios.com/reviews/235indiFOCUSReview.pdf

I will note that it was difficult to get to work with the SG35, due to the spinning GG box being in the way. Thankfully, the rails were long enough that we were able to invert the follow focus to the other side. It should have worked beautifully with the Letus35 Flip, but the Cavision carbon fiber rails that were on hand did not extend out far enough for the follow focus to reach the lens.

NOTE REGARDING ALL CLIPS & FOOTAGE BELOW: Clips have been saved at 3MBPS for maximum quality and frames have been saved as loss less PNG's. For the clips, and to be kind on the server, please right click & save to view.

Kelly Sharp (left) and Shahna Sanders (right) were kind enough to stand in for us for some quick controlled lighting tests. The Letus35 Flip was unfortunately not on site yet, so we had the original Letus35 as a stand-in. Notice the excessive noise the adapter(s) bring in the right hand side of the clip. The DVX already gets noisy in the blacks, but the adapters really amplify the problem.

The charts completely filled the LCD for testing, but then there's that pesky over scan ... so the charts don't quite fill the frame. However, notice the slight barrel distortion of the SG35.

Specs for the camera distances from both the models and the 4'x3' resolution chart can be located HERE. It should be noted that the meter readings, as listed in the PDF were initially with the 35mm lenses on. A second, more accurate test, was completed after the fact, without the lenses, and is reported above under each adapters' findings.

Also, since the SG35 has a variable speed GG, we captured two different clips of it; one on the low setting, the other on high. We've gone ahead and provided the audio for it, so you can hear how the on camera mic pics up the noise of the GG when on the high setting (audio gain settings were at normal).

Very noticeable in these clips is debris on the SG35 footage. The unit & all glass was cleaned as well as possible, so the only explanation for this is that debris entered the unit/glass while shooting the day/dusk exterior shots. A better sealed unit will be welcomed, which is supposed to be the case with the upcoming SG35 Pro. As for the lighting, no need to comment ... it was late and we just wanted to quickly set this up to see what kind of keys could be pulled with these, even with imperfect lighting.

Special thanks to Wayne Kinney and Quyen Le for providing their units for testing,
as well as to Barry Green for his help on technical Q&A we had during some of the process.