Dom Jaeger

You need to make sure the lens is both centred and aligned to the collimator beam. As you go wider the IHI image will get dimmer and hazier, so you need to adjust the intensity of the light source depending on the focal length (and the aperture of course.) With very wide lenses (on my Chroziel collimator under about 10mm) it can be hard to make out a clear IHI image, but 15.5mm should be OK. Using a narrow spectrum green light source will give a sharper image, but a white source will be brighter. Sometimes it helps to view the IHI image in a darkened room. Obviously if the back-focus is out the IHI won't be visible until you're in the close vicinity of infinity. If there is an issue with the lens, such as decentration of elements, the image will be fuzzier, but this is something you should pick up on projection.

Hi Kate! So you were asking about checking infinity on a zoom.. Well, first you set the zoom wide open at the long end, and adjust the focus to infinity going off the IHI (not the focus scale). Then you go to the wide end and adjust the back-focus to centre the H. You may then need to go back to the long end and fine tune where infinity is on the focus barrel. If it doesn't line up with the index mark the focus scale needs adjusting. Going back to the wide end, the H should remain within the bars as you go through the zoom range. Check it in both directions, as there can be a bit of play in the zoom mechanics. The graph of how far the focus drifts in both directions (measured in back-focus adjustment) is called the zoom curve, and manufacturers will generally have tolerance specs for it, but without getting too technical if the H remains within the bars (or just overlapping one side) the focus should be OK. If it drops out too much the lens needs servicing. As a general rule if the collimator back-focus adjustment you made at the wide end is more than about 0.01mm the zoom needs back-focus adjustment, usually done by re-shimming under the mount. The shorter the focal length, the more critical the back-focus. By the way, it's a good idea to regularly check the collimator lens mount with a flange depth gauge and re-zero it if necessary. I check mine every time I switch it on. Regarding making a separate index mark for focus shift, I've only done it very occasionally for picky assistants who complained about discrepancies. Because it can change depending on the distance it can be more confusing than helpful sometimes.

With anamorphic lenses the anamorphic elements (the ones with cylindrical curvature rather than spherical) need to be perfectly aligned in their azimuth, ie in the plane of their horizontal compression. Any rotational misalignment and you get what you're seeing. Even the tiniest misalignment can dramatically reduce sharpness. Without professional optical tools it can be tricky and time-consuming to re-align them properly, almost impossible if there are more than 2 misaligned anamorphic elements. If the person who "cleaned" it only removed one anamorphic element, say the front or rear one, then it will just be a case of needing to rotate it so it lines up optically with the rest of the lens. You'd need to check it on a camera or projector each time you make an adjustment.

Why would someone sell off an essential part of a functioning camera to supply you with a spare part? Any number of Bolex service providers should have spares like this, or try Bolex themselves.

One of the forum rules here is that you use your real name. You might have noticed that all the responses to your question were from actual people rather than anonymous pseudonyms or companies. It's not strictly enforced by the moderators, but tends to be self-regulated by forum users. Quite a nice, civil etiquette. :)

It's mostly a problem associated with high-speed lenses, where it's hard to correct all the aberrations at full aperture, causing a slight shift in the plane of best focus. Past about f/2.8 the depth of field covers the discrepancy, but if the shift is large enough it can be a problem going from say f/1.2 to f/1.8. Within the tolerances of back-focus distance you can set a lens to one side of the tolerance to minimise how noticeable the shift is. So for example you might go from 0.01mm under to 0.015mm over as you stop down. With a collimator you'll also find that the frequency band of the light source may shift the focus on some lenses. A narrow spectrum green source (theoretically mid-range) might give you a different infinity point than a broad spectrum white source. But lenses are curious objects, highly scientific in their design and specifications, yet also quite subjective in that they create images that are judged aesthetically. Collimators and MTF measurements are very handy in checking specs and comparing between lenses but they don't tell you what the image actually looks like. So while I rely on a bench collimator and MTF machine for a lot of things, I use a projector/collimator to really assess how a lens is performing, and where best focus might actually be. With focus shift issues it allows you to see just how much softness stopping down really causes, and how far you can push the back-focus tolerance when the lens is wide open to compensate for it. On some lenses I've marked a different focus index mark for when they are used wide open, but it tends to shift further at close focus.

If you're setting the meter to a faster exposure time it will give a reading that would overexpose the film, so you need to increase the ISO to compensate. In Rafael's case, he sets his meter to a slower time and decreases the ISO to compensate. A T stop (T standing for transmission) is an exposure adjustment to the f stop, adjusting for the light that is lost passing through the lens. The amount lost depends on how many glass to air surfaces (lens elements) there are and how good the coatings on those elements are at stopping reflections and light dispersion. Going by similar zooms from that era, the f/1.8 6-66 would be about T2.1, so losing around 1/3 of a stop. The simplest thing then would be to set the meter to 24fps (1/48 sec), giving you a reading that would underexpose by about 2/3 stop, and with a further 1/3 stop in transmission loss, you'd need to compensate by increasing the reading one full stop. So with the meter set to 24fps you could either set the ISO to half its actual value, or just open the lens up a stop more than the meter reads. Easy! Always good to shoot a test too, and like Christopher said, experiment with it.

Whitehouse A/V have an Arri to CP mount adapter that will let you use most lenses in Arri Standard or Bayonet mount: http://www.whitehouseaudiovisual.com/Mount_1.html Just be careful with wide angle lenses that protrude too far back and may hit the mirror. I've also heard of CP adapters for Nikon stills lenses, and there were likely others. There were also of course a number of lenses that could be ordered in CP mount - mostly Angenieux zooms, and the fast Ultra T primes made by Kowa, which are pretty close to the 16mm Zeiss Super Speeds in quality. But being news cameras they invariably came fitted with zooms, so I'd say finding CP mount primes might be tricky. The Angenieux 5.9mm with interchangeable mounts may have had a CP version, which would be a good wide angle. Regarding the mirror, the 170 degree mirror/shutter was a half-moon shape, with no smearing issues. Earlier models had bow-tie mirrors, 144 and 156 degrees versions. They reputedly caused smearing in certain lighting conditions with certain lenses, particularly the larger angle 156 degree one. Whitehouse have a photo of that model for sale, which you could compare to yours: http://www.whitehouseaudiovisual.com/CP-16R_Camera_Package_1.html If your camera has smaller gaps and larger mirror wedges, it's the 144 degree version. The T on cine lenses stands for transmission, being an f stop that is adjusted to compensate for light lost passing through the lens itself. Early zooms in particular lost quite a bit of light due to the many elements and primitive coatings, so for more accurate exposure T stops were developed. Some early Angenieux zooms have both f stops and T stops marked, one in white, the other in red. The T stop will always be a larger number (or smaller equivalent aperture) than the f stop. So for example while the geometric aperture (widest f stop) is usually written on the lens barrel or front ring as a ratio, say 1:2 (being f/2), the widest T stop marked on the iris ring might be T2.3.

The aperture is part of the gate, once it's removed you're left with a larger area bounded mainly by baffles. I'd say a 14mm wide sensor could fit in that gap. The mirror/shutter would still cover it. The viewfinder should also just cover it, provided it's centred to the sensor. You'd need a custom ground glass made up though.

A "Super 16" 2x anamorphic projection lens? Not sure that makes sense unless you wanted to shoot or project something in 3.3:1 aspect ratio. Ordinarily you'd be cropping the sides of a R16 frame to 1.2:1 to project a 2.4:1 image. A quick google found this "Fumeo 16mm Super Anamorphic" on ebay: http://www.ebay.com/itm/Fumeo-16mm-Super-Anamorphic-2x-44541-/251101819580 Is that the one? Like a lot of 16mm anamorphic projection lenses the lens manufacture would have been outsourced, it's quite possibly a Kowa, branded as Fumeo (like those made for Bell & Howell, Elmo etc). That particular one has a rather long barrel, I would imagine it will porthole when used with even a moderately long focal length. Probably anything under 40mm won't work. With projection anamorphics the rear element size will give you some idea of how wide you can go with your taking lens (and how large the taking lens itself can be), but you need to experiment with them really to find the limitations. A projection lens with a large rear element and short barrel tends to allow for the widest angle, but even the best-suited ones will often porthole when used with a 'standard' focal length taking lens (25mm for 16mm format) or wider.

Can't say I've found much on the net, lots of misinformation though! I enjoy Roger Cicala's blog at http://www.lensrentals.com/blog, some interesting articles in there, but not much on cine lenses (or this particular question). There's a great French site on older lenses at http://dioptrique.info/sommaire/sommaire.HTM which is worth using an online translator to explore. But the best info I find is in good old fashioned books - and often the old ones are the goodies. Kingslake's "A History of the Photographic Lens" or Cox's "Photographic Optics" are two of my favourites, both written by lens designers. The problem you'll find is that most ray diagrams simplify the path of light going through a lens, just showing rays travelling parallel to the lens axis or passing through a focal or nodal point, and only depicted as a 2 dimensional cross section. In reality, every point from a focussed object within the field of view of a lens is sending a cone-shaped multitude of rays through the glass elements, each one being bent and spread into separate wavelengths only to be re-focussed again out the back of the lens to a point (or close to a point) on the image plane. With a wide open aperture, all these rays need to be corrected, leading to combinations of aberrations (3rd order, 5th order, 7th order etc), but as the aperture closes the cone of rays from each point becomes narrower, reducing the complexity of correction required, and increasing the clarity of other points near the focus plane. So you get more depth of field, and a sharper image. But the entire image is still visible because rays from each point are still passing through the lens, just through the inner zone of the aperture.

With any zoom the front focus (controlled by the focus ring) is more critical at the long end, while back focus (the distance behind the lens where an image forms) is more critical at the wide end. The back focus is always set at the wide end, so if it is correct (and the corresponding flange depth of the camera is also correct), when you focus at the long end and zoom all the way out to the wide end, the image should be sharp. But with a non-parfocal stills zoom the focus will drift during the transition from zoomed all the way in to all the way out. And/or the focus may shift a little depending on which direction the zoom ring is turned. Stills lenses have larger mechanical tolerances than cine lenses, less fine adjustability and less stringent quality controls, so it could be that the back focus is a bit out, as well as having the focus drift or shift through the zoom range. But as Mark mentioned, focussing at the wide end then zooming in is not a good test. Even with a parfocal cine zoom, it can be hard to focus by eye at the wide end and zoom in to a perfectly sharp image.

Well they're different focal lengths, so yes they have different spatial distortion. If you think about it, to perfectly match a S16 25mm image you'd need to use a S35 25mm lens, and crop a S16 frame out of the middle. But to get the same angle of view on different sized formats you need to use different focal lengths, which have different characteristics in terms of how they render spatial depth.

It's also dependent on what format the lens was designed for. You can't get a wider angle of view by putting a lens on a larger format camera if the image circle won't cover it. Since lenses are designed and optimised for a particular format, you could make an argument that in terms of mechanical design the angle of view is built in, even if someone chooses to crop the image circle (and thus reduce the angle of view) by using the lens on a camera with a smaller sensor/film gauge than it was designed for.

That's actually a very good question, James. Without getting too technical, my understanding is this - the front element (or front group of elements) gathers the basic image, in terms of an angle or field of view, limited of course by the basic construction of the lens and its focal length. The rest of the glass is concerned with correcting out aberrations, and focussing the image at the focal plane. At the plane of the iris the light is travelling in such a way that rays from the entire image are passing through more or less at every point, so reducing the diameter of the opening only diminishes the amount of light passing through, rather than cutting into the image itself. Some people believe that stopping down only uses the centre of a lens, but this isn't really the case. The front and rear elements are always passing through light all the way to their outer edges, no matter the stop. Greg's analogy of a "funnel" is a good one. As mentioned, reducing the aperture also affects depth of field, depth of focus, and control of certain aberrations. It can also sometimes cause a slight focus shift (particularly in high speed lenses). Too small an aperture introduces diffraction.

Don't know where you'll find information other than Sachtler parts drawings like this: Pretty easy to dismantle, if the break pads inside aren't worn too bad you can just give them a clean and tighten up the screws/locknuts to the point where the leg no longer slips. Otherwise get new bits from Sachtler (or Vitec who now owns them as well as O'Connor).

Hi Gregg, we usually charge AU$390 for a full service, including checking lens collimation. Given the time it takes it's far from being a money spinner for the company, but we're pretty committed to keeping film an option for filmmakers down under. It tends to be mainly experimental filmmakers here who still shoot film, occasionally students, and a lot use Bolexes because they're affordable. Professionals in Australia (or at least the producers) seem to have all but forgotten film still exists. Funny thing is, when someone does have the balls to shoot on film, they invariably scoop up all the industry awards, and their careers take off. Go figure. Thanks Jean-Louis - I'm a Bolex novice next to you, so if it gets your approval I'm a happy man!

For all the Bolex lovers out there I documented a service procedure on an RX5. As mentioned in the blog, it is not a guide for servicing your own Bolex (and I've deliberately left out a few parts), but hopefully it's of interest to some people. At the very least it should demonstrate that putting a few drops of oil on the bearing pivots is not giving your camera a service. Send it to a professional! And long live film.. http://cinetinker.blogspot.com.au/

It's in the article: "You format the XR Capture Drive either for ARRIRAW or for ProRes. SxS PRO cards have not been forgotten. An adapter with a single slot accommodates an SxS PRO card. (SxS-1 and SxS PRO+ cards are not compatible with Alexa.)"

Arri just announced an upgrade to allow internal ARRIRAW recording, using an XR module that replaces the existing SxS card holder. It will only add 8mm to the width of the camera. The XR drives will record 55 minutes of ARRIRAW at 24fps, be able to record up to 120 fps, and have a data rate of 6.7 Gigabits per second. An adapter will still allow for SxS PRO cards to be used for ProRes. A new Alexa XT range will have the module built-in, all with 4:3 sensors. http://www.fdtimes.com/2013/02/20/arri-alexa-xr-and-xt/

It's probably OK without a support on a PL mount camera, as long as the camera doesn't get jolted. You'd definitely want to remove the zoom from the camera during transport (which was always the professional procedure in the past, but lately I've noticed people transporting cameras with lenses attached - yikes!) Add a clamp-on matte box and filters and you'd be pushing it. Personally I'd recommend a support, but I tend to err on the safe side.

You can find a B8 manual here: http://www.intervalometers.com/pdfs/2003-bolexb8.pdf The B8SL was a simplified version with only one speed and a more basic viewfinder, but included a built-in lightmeter. A manual for the D8LA (which will include information about the meter) is here: http://www.apecity.com/manuals/pdf/bolex_D8LA.pdf A reproduced test report, which includes lots of information specifically about the B8SL is here: http://www.pathefilm.freeserve.co.uk/cel8/cel08.htm And lastly, if you want to pull it apart for lubrication, I wrote an easy-to-follow guide for lubricating pocket Bolex cameras, which you can find here: http://cinetinker.blogspot.com.au/

They're all good really, not much between them optically. The 7-81 is actually about the same size and weight as the 7-63, maybe even a little thinner. The main drawback to the Angenieux is that it loses light at the long end, it's T2.4 until 50mm then T3.5 to 81mm. Focus marks are also a little haphazard on the feet scale ( ie 3'6" then 5'6" then 8' etc). It breathes more than the Canons, but not badly, nothing like the Zeiss 11-110 for example. If you're considering buying one, get whichever one has been the best maintained. With older zooms, condition is more important than anything. For that reason renting can often be a safer option, particularly if a whole feature depends on the one lens.

Should be OK in cameras that don't have too much torque driving the claw or registration pin. I'd be a little wary of running it through pro cameras like an SR3 or 416 (especially at high speed), but S8 cameras, Bolexes etc have claws that are either spring-loaded or will slip under pressure. Fuji's Single 8 system used a polyester base. I've heard stories of Estar stock destroying Mitchell movements though.

You've gotta look further than REDuser for all your news Keith! :P http://cinescopophilia.com/red-vs-arri-inc-micheal-bravin-court-case-settled-dismissed-with-prejudice/ http://nofilmschool.com/2013/02/red-sues-arri-sony-lawsuit-f65-f55-f5-camera/