27 janvier 2007

Mini 35? Movietube? Redrock!

Le mini35 de P+S Technik est un système astucieux qui permet d'adapter des objectifs "nobles" (qui servent sur les caméras 35mm ou les réflex photo) sur quelques petites caméras DV/HDV. Résultat: les optiques grand angle sont respectées, et surtout la notion de profondeur de champ fait son apparition sur un format où d'habitude "tout est net".
Il peut sembler ridicule d'équiper une caméra semi-pro (DV ou HDV) d'un ensemble optique deux fois plus lourd et plus cher que ladite caméra. Après tout, pourquoi ne pas assumer les limites du format?
J'étais donc de ceux qui regardaient cet adaptateur comme un joli gadget, ingénieux mais hors de prix. D'autant plus que les premières versions du système "bouffaient des diaphs" et faisaient du bruit - un dépoli tourne comme une toupie pour rester invisible.
Or voici que les Texans sortent le Redrock M2. Leur version d'entrée de gamme est non seulement beaucoup moins chère (environ 500$ contre 10'000$ pour le mini35), mais elle recueille pas mal de suffrages chez les cinéastes. Un tel système sur une bonne HDV rend la profondeur de champ abordable.
Le magazine Showreel a publié un papier de fond sur les nouvelles caméras HDV testées par l'équipe image de la série TV 24. Rayon caméras, la JVC sort gagnante. Rayon adapteurs ciné, c'est le Redrock qui tire le mieux son épingle du jeu.
Je vous laisse lire l'article complet. Je vous reproduis ci-dessous le passage sur les adapteurs ciné.

Cine adaptors

Taylor Wigton: Regardless of how great the off-the-chip quality of these cameras is, until the problem of poor optical performance is resolved – and as long as the physical limitations of a tiny chip equate to near infinite depth of field – a lot of pros, particularly those working in drama, are going to steer clear of them. The ideal situation would be for there to be a healthy market in dedicated 1/3in chip lenses, and hopefully this will come. But for the time being, the only viable solution is to use better quality optics designed for S16 or 35mm stills and cine cameras.

There are a number available, and even though they may not be optically perfect, they are also likely to increase in quality daily. With the prevalence of 1/3in HD cameras, cine adaptors are likely to be used by anyone from prosumers to top cinematographers.

The three units we brought on set for our second round of tests were: the Movietube from South London Filters in the UK, the P+S Technik Mini35 and the Red Rock Micro M2. We had previously looked at the Cinemek (Guerilla 35), but in the form we saw it, it still needed work.

When attaching these units to the front of the cameras, it is worth noting that the cameras’ existing lenses (where required) remain at a fixed focusing distance (basically, they are used to focus the image that passes through the 35mm lens on to the ground glass inside the cine adaptor, then on to the 1/3in CCDs. This means all focusing 'in the field' is carried out on the cine or SLR lens you use, so weaknesses in focusing control inherent in the lenses supplied with the cameras is no longer an issue. Similarly, because the supplied lenses don’t change focal length, this also overcomes any breathing issues. However, I don't want to oversimplify the cine adaptor situation, as they can require some training to get the best results.

Movietube: The most impressive unit from a construction standpoint is the German-made Movietube supplied to us by South London Filters in the UK. It looks like it was made by the same team who constructed the ArriCam series of 35mm cameras. The Movietube uses a patented static film screen rather than ground glass, and it seems so well protected that you feel it would take a shoulder-fired missile to crack it open and get dust and hair into it. The Movietube is a 35mm adaptor that can only be used with fixed lens cameras at this point, making it suitable for the Sony Z1 and Panasonic HVX200. When a 35mm lens is attached, the iris has a minimum stop of T5.6 before the ground glass can be seen, making it a solid yet limited system (although I know Rodney would rarely stop down further than this). I would happily combine this with the HVX200 at 60fps if I were shooting a commercial or music video and wanted both shallow DOF and high frame rates (as the HVX offers variable frame rates). I would also use it in any environment where there was a possibility of being knocked about.

The current limitation is that the Movietube would not allow me to use the entire range of T-stops, so while I could achieve a shallow DOF (at T1.2 the DOF is a focus puller-challenging 2in), it would be difficult to shoot wide DOF shots using the same optics.

Mini35: At $10,000 without 35mm lenses or any accessories, I was certain the P+S Technik Mini35 would be able to demolish even 2/3inch HD cameras. Like the Movietube, it has the advantage over the other adaptors of shooting an upright image, whereas with the other two the viewfinder (and footage) has to be flipped. This isn’t that much of a problem to overcome, though, and hopefuly the camera manufacturers will add ‘flip’ functions to their cameras sooner rather than later.

The Mini35 was kindly loaned to us by Eric MacIver of Indie Rentals in LA, who also supplied us with a set of Zeiss Superspeeds to test with the Movietube. Given how impressive the HDV images alone were proving themselves to be – even without the results pouring in from Canon XL H1’s HD-SDI-out, which bypasses the MPEG2 encoder and sends out 4:2:2 10bit HD at 100mbs – the first year of 1/3inch HD was looking menacing when you put the P+S Technik into the picture.

We did find one or two issues, though. First, you have to be aware that the Mini35 loses quite a bit of light. In addition, with the HDV signals we could detect the oscillating movement of the ground glass grains – this swirling was most noticeable in the dark areas of the frame, but becomes discernible in the lighter areas the further the lens is stopped down. This was evident even before we captured to tape, as we were looking at live component-out images, so we fervently hope P+S can fix this – and soon.

M2: This $500 unit was something of a shock. Who would have thought an engineering genius from Texas could design and set in motion a patent for his M2 adaptor that is actually quite suited to drama – and which is designed to work with old Nikon and Canon SLR lenses, of which there are legion sitting round the world gathering dust since the advent of digital photography, but which still feature exceptionally good optics?

The Redrock M2 is the only 35mm cine adaptor that exhibits a nearly lossless resolution and no image degradation, as there are no visible grains to throw a wrench into the MPEG2 HDV encoder. There is no artifacting and no soft edges.

The M2 can be notched down to T16, and I have even closed down to T22 with a Nikon 80-200mm SLR lens. No grain visible, no breakdown from MPEG and grain battling it out, and no visual loss of resolution.

Site Redrock M2 http://www.redrockmicro.com/micro35.html

J'ai utilisé le Redrock sur quelques tournages depuis. Mes réflections se trouvent ici.
Dernier film en date tourné en Redrock, avec grandes photos tirées du film: ici.