Philip Forrest

Do some google searching for lens design, crown glass, flint glass, refractive index, raytrace. Focal point, nodal point. Go down the rabbit hole.

Phil Forrest

Only some rays would pass through the lens at the aperture but you wouldn't have a real convergence. You're creating a lens that will not draw a sharp image at all since the 28mm nodal point is very different than the 18mm nodal point. It won't focus, even if you could swap the front groups. What you might try instead is get a Kodak Retina Reflex and swap lenses around on that. All of the optical groups between the leaf shutter and the film plane are the same and all the groups in front of the shutter are designed to work with them. The rear optical unit has its own focal length and nodal point. Designing the front optical units to work with them is how they did it. You could do it with the rear of the 18mm Nikkor, but you have to have a lens design in mind, have to know what kind of glasses you're using and where, have a raytrace program, and then you'll be able to see what your aberrations will look like. Try not to destroy those nice Nikkors. Get some bargain basement lenses or garbage lenses from a thrift shop, take them apart and see what they do. 

Phil Forrest

I'm thinning the herd of my collection by quite a bit, and have the following 16mm gear for sale:

Bell & Howell Filmo:

70A with Taylor Hobson 1" f/3.5. This camera has been converted to run 1R film by machining the film sprockets and by removing one pulldown claw from the shuttle. I plan on replacing the sprockets with 1R versions this week. Shutter assembly has been cleaned and lubed. This camera runs well at 16 frames/second, as the friction felt in the governor has disintegrated in the last 90 years, so 8 f/s isn't available. Viewfinder in the door is clear, clean and bright. The lens is in very good condition, clean, no scratches, no fungus, good aperture blades. Camera includes folding later style winder key. I should probably just keep this one because it is that much fun. Point and shoot 16mm. $100.

70E. This camera has been converted to run 1R film by replacing the film sprockets with later types and by removing one pulldown claw from the shuttle. The viewfinder in the door is clear, clean and bright. This camera runs strong and consistent for 56 seconds at 16 frames/second. Camera includes folding winder key. $125.

70DL that has been converted to 70DR. This camera is the chassis of a 70DL that has had the shutter front plate and assembly changed to a later 70DR. This shutter plate is the type with a slip-in filter slot. Turret is the proper 70DR geared turret with the cutout notch for the filter. Film door is 70DR. Finder is very clear, clean, and bright. Camera runs strong and steady for 55 seconds at 16 frames/second. This camera has an interesting 1/2" alloy plate attached to the base which adds an additional 3/8" tripod socket as well as the 1/4x20. Camera includes folding winder key. $100.

Kodak K-100 Turret. This camera is amazing and just keeps going. It runs for 1:39 at 16 f/s, and 1:11 at 24 f/s on a full wind. The clockwork is very stable through the whole run. The viewfinder has some flecks of dust inside but for composition is still very bright and clear. There is some superficial chrome pitting on the turret but otherwise the camera is in great shape. I'm selling it with the 25mm and 50mm viewfinder objectives, as well as a proper cap for the other objective port. I will sell this with two K100 C mount caps and one generic. I would prefer to sell this camera with a trio of lenses, **15mm f/2.5 Cine-Ektar, **25mm f/1.9 Cine-Ektar II, and **50mm f/1.4 Soligor TV lens (lens descriptions below.) $140 camera only, $280 with lenses.

Somewhere around here I have a Bell and Howell 240 (not EE). This is a C-mount camera. This ugly beast runs strong and loud for over a minute at 24 frames/second. Viewfinder is good. Loop former works well. No corrosion. It's really clean, just not my cup of tea. $45.

Lenses:

Angenieux 17-68mm f/2.2 Reflex. This lens is in amazing condition with proper front and rear caps, and series filter adapter. Reflex viewfinder is in very good condition. Everything adjusts properly, nothing too tight or loose. Lens is clean and clear. Small amount of dust inside, no scratches, marks or fungus. Aperture is good, no oil on the blades but still has clicks. Single coated. I used this with the Filmo 70E (above). $165.

Bell & Howell Super Comat 1" f/1.9.,C-Mount. This is the older version that could fit inside a ping pong ball. Tiny lens in good shape. Focus is smooth but has a touch of helical thread lash. Aperture is good, still clicks. Glass is clean and clear of fungus or marking but there is a bit of dust. Single coated. End of the barrel, where the threads are is slightly dinged up but it doesn't affect mounting Series IV adapters. $35.

Wollensak Cine-Raptar 1" f/1.9, C-Mount. Also a very small lens and incredibly well built. Focus is nice and smooth but a touch on the tight side. Glass has a bit of dust but is otherwise prefect. Single coated. Aperture is smooth with no clicks. Blades are good but every other blade has a smear of oil.  $35.

**Kodak Cine-Ektar 15mm f/2.5, S-Mount w/ S-C adapter. This lens is a really good shooter. All of the Cine-Ektars up to 50mm have rare-earth glass and this one is not an exception. It is slightly yellowed as a result but the image it draws is very sharp with nice falloff. Glass has dust but is otherwise  perfect. No fungus or marks. Single coated. Focus action is very smooth and precise. Aperture ring is smooth with no clicks. This lens comes with an aftermarket S-C mount adapter. The C mount threads on this adapter are tight but once seated properly, this does not effect the lens performance. NOTE: THIS LENS CANNOT BE USED ON REFLEX BOLEX. $85.

**Kodak Cine-Ektar II 25mm f/1.9, C-Mount. This lens is not pretty but it draws a fantastic image. The alloy barrel is discolored from age, so it's dull aluminum. Lens focusing is smooth but a bit tight. Rare earth glass is slightly yellowed. Glass has a bit of dust but is otherwise in excellent condition. No marks or fungus. Single coated. Aperture clicks are still there and the aperture blades are clean and in good condition. $55.

Kodak Cine-Ektar 25mm f/1.9, S-Mount. Lens is in very good condition. Glass has no marks or fungus but does have some dust. Rare earth glass is slightly yellowed. Single coated. Focus is smooth. Aperture moves smoothly with no clicks. I actually prefer this one to the Ektar II, as I think the handling is better. Both are great shooters though. This lens does not come with an adapter but I could possibly sell one, if needed. $60.

**Soligor 50mm f/1.4 Television lens, C-Mount. Lens is in overall good condition. Small amount of dust inside but otherwise clear with no fungus. Front element has some edge coating marks plus a very fine scratch towards the outer edge. Multi-coated. It draws a very nice image and I used it for quite a bit on my GX85. Focus is buttery smooth. Aperture has positive clicks. Aperture blades are clean. $50.

MST Perfectone motor for Bolex REX4/5. 24 frames/second, 60hZ, 12v. This motor came with my camera, with no cords nor battery pack. It looks like one of the mounting screws is missing as well. I have no way to test it, so I'm throwing it out there for $100 OBO.

I can entertain offers for any or all of the above stuff. I'm located in Philadelphia, PA and can arrange local pickup within reason. If anyone wants me to shoot some stills with the lenses for sale, I can do that upon request. I'll send along and post images of the gear for sale as I get time to do so. I'm still slogging through the last week of my Masters Degree, so I don't have much time to set up lights and take product images.

I prefer to ship to the lower 48 states but we are an international community, so I'm open to shipping overseas as well. Shipping will be via USPS Priority Mail with full insurance, tracking, and signature confirmation. All prices include shipping to CONUS.

Thanks all.

Phil Forrest

This camera and lens are SOLD.

My K100 turret is incredibly stable and runs really long. I haven't used an accessory motor, only the internal spring wound motor. 

Phil Forrest

That's great footage, Roger. Thanks for your service. I was a Navy combat photographer with the Seabees during our initial invasion of Iraq and a year after. Did a deployment to Fallujah in the fall of 2004. Good to see another military cameraman here.

Phil Forrest

I think I was mentioning it on goodwill because that is a place to look. I saw a Sachtler ENG setup go for a couple hundred bucks there last year. But since I didn't see the model of the Vinten heads, although shipping was insane because the trio were like 20lbs total, I'll send you this link.

https://lmgtfy.com/?q=+heavy+duty+tripod+head

Phil Forrest

A trio of Vinten heads just went for like $60 on goodwill a couple days ago.

Phil Forrest

I have seen this on a bunch of my lenses. 1" Super Comat, Angenieux 10mm, a few others. On all these lenses, there is no provision to adjust the rotation of the lens in relation to the turret, so I thought it may have been a feature. It hasn't affected the use of the lenses, but it also means that every time I change a lens, I have to realign the threads to ensure I can see the focus/aperture index marks. That said, I also think that over 40-60 years, the metal may have just changed. Threads may be applied using an adhesive and/or heat to allow the thread to shrink as it cools onto a lens flange assembly. It's a lot cheaper to make a bare tube then add the thread to it later, than it is to cut the threads to locate the focus/aperture index marks for every lens.

Phil Forrest

I had this problem as well with my RX4. Someone had jammed the eyepiece in too far, which made it stick AND cracked the adjuster ring with the screw in it. I had to completely dismantle the eyepiece assembly and clean it (as well as the reflex finder) to get the ground glass into focus. I'll be getting that piece replaced when it goes in for service soon. Good luck.

Phil Forrest

Jon,

For telecentric lenses, such as the 17-35, you shouldn't have to stop it down. The difference between RX lenses and those which are not is in the exit pupil of the lens. All 35mm SLR lenses will have an exit pupil far enough away from the prism so as to not be affected. The reason for this all is that the light rays are hitting the prism and film almost exactly perpendicular. This is the reason that lenses over 50mm were never corrected for this, as Bolex must have surmised that with long focus lenses, the light rays hitting the prism and film would be straight on. With shorter focal length lenses, the exit pupil is closer and the light rays hit at varying degrees, like a shallow cone. Digital rangefinders like the Leica M8 and M9 are plagued with this problem which causes a dramatic color shift around the edges with some wide angles. This is the reason Leica has moved to larger, longer telecentric lenses since the introduction of the generation of lenses after the M9. The exit pupil of any Nikon SLR lens on an adapter will be very far from the prism and so won't be a problem. You could use any Nikkor and it will work perfectly, with no softening of the image, regardless of the maximum aperture. 

To answer your recent wide angle question, the Switar 10mm RX, Cinegon  10mm, and Cine Navitar 12.5 are good lenses wider than 16mm.

Phil Forrest

Jon,

What kind of range are you looking for in a Nikkor zoom? The problem you're going to encounter is that all the 35mm camera constant aperture zooms (by any brand) are going to be heavy. The 17-35 f/2.8 is excellent and very large. Pretty dark for a reflex. The old AF-D 18-35 is very light but has a variable aperture f/3.5-5.6. The 20-35mm f/2.8 is one of the very best and the older brother of the 17-35, also heavy. The uncommon 25-50 is a little heavy but a constant f/4. Too dark for a reflex. You can't put G lenses on a C mount camera because you can't control the aperture, so you need older AF-D, AiS or Ai lenses. The 70-200 f/2.8 and 80-200 f/2.8 are very heavy, put a lot of torque on the lightweight mount and they are really dark for that focal length and weight. You should have any of these lenses I mentioned well supported. 

In a nutshell, you can have lightweight or constant aperture zooms in the NIkkor range, but not both. The fastest zoom you'll find that you have control over the aperture will be f/2.8. 

Once you decide on your lens, you're going to find that every one of them exhibits focus breathing. It doesn't bother still photographers. you may want to have your aperture rings serviced to take out the hard clicks.

Just a few things to think about.

Phil Forrest

I'm wondering if there is a fix for the eye relief of the reflex viewfinder. I wear glasses to correct astigmatism, I'm heavily left eye dominant (right eye is much worse) and I'm finding that I have to really mash my glasses up to the eyepiece of the 10x viewfinder on my REX 4. I'm sending it out soon for overhaul and if there is a fix for this to add eye relief to the exit pupil of the viewfinder, I'm wanting to get this done. I've been a still photographer for 20+ years and I've always just moved my eye around the viewfinder. Some cameras are better than others as well. These last few years I've been shooting with a couple Filmos and I don't worry about eye relief as much since the viewfinder is only used for composition (and the eye relief is pretty decent.) The reflex viewfinder of the Bolex is a completely different animal though, but since I'm used to using a reverse Galilean VF as on the Filmo, I may just use the reflex as a quick focus confirmation than close it up and shoot through the octameter (isn't this what Bolex had in mind anyway?) If anyone has any recommendations, I'd be grateful. I scoured the forum and there aren't any posts specifically addressing this issue.

Thanks all,

Phil Forrest

Simon,

Thanks, I had not thought to contact them directly. I've been completely stonewalled by still camera manufacturers like Nikon, when doing work on those cameras, so going directly to Bolex wasn't on my mind. Again, many thanks!

Phil Forrest

I just got a REX 4 from a friend and it needs the washer/s and screw which fix the turret to the shutter plate of the camera. If anyone has a set they can sell me, I'd be very grateful.

Thanks all,

Phil Forrest

Some lenses say RX on them. Some have "For Bolex" or "For Bolex RX" on them (flange area sometimes.) Angenieux lenses for RX say "Special P" on them. I think Som Berthiots say "H16 RX" or "RX". That said, it's not as simple as a label either. I'm going through this same issue, as I just got a REX 4. It comes down to the exit pupil and the nodal point of the lens itself. There's a few good threads here on the forum describing this and they link to a few pages which go into the lens design specifics even better.

Your 10mm is a retrofocal design, so it will put the exit pupil farther away from the film plane than a true 10mm (which would nearly touch the shutter since the registration of C-mount is 17.526mm.) I say go give it a try. It's one of the lenses that I've been searching for because I love Schneiders, and even if there is some astigmatism wide open, I'd still happily use it, personally. 

Phil Forrest

13 minutes ago, Richard Boddington said:

Like I said.....let's use the same methods to predict the stock market and the weather.  Why is it that "mathematical models" will accurately predict how many people get infected by a virus, but they lack the ability to predict the weather or the stock market?

R,

I don't want to pick a fiight but do some research into how accurate weather predictions are for ON STATION. I used to be a meteorologist in the US Navy and the lowest 48 hour prediction acccuracy we ever had in my 5 years as a "weather guesser", was 96%. Doing the weather on a ship, moving across a dynamic surface that affects weather itself is extremely difficult, and many ships do it every single hour of every day. Do you know how we know? The ships aren't missing. As for you thinking that weather can't be forecast, after 48 hours, accuracy goes down logarithmically. Past 96 hours is 50% prediction rate. This is for on station, not 2 miles or 10 miles away.  If you live right where a weather station is and you have access to the data (and you do because it's all public) then you don't have cause to complain. Weather is science; dynamic, difficult science but still predictable. Disease transmisssion is also science, within given margins of error. The stock market is pure human nature which is completely erratic.

Phil Forrest

50mm is a bit of an intermediate focal length between the standard 25/75 kit. They are out there and certainly not all as expensive as you've seen. Look for Schneider Xenon, Cine-Nikkor, Cine-Velostigmat, Cine-Raptar, Cine-Anastigmat.  Those manufacturers are Schneider, Nikon, Wollensak, and Kodak. Zeiss, Fujinon, Canon, Taylor Hobson, Cooke, Kowa, Bausch & Lomb, Pentax (Cosmicar), Elgeet (Navitar), Yashica and others. Lots of good FSU leses as you know from using a K3.

Phil Forrest

How long of a focal length are you looking to shoot? Inexpensive and good quality lenses are available up to 152mm or 6". 

Phil Forrest

Bubonic Plague, AKA black death is a bacterial infection spread by fleas. It can't and shouldn't be confused with any virus. There are still cases every year in the southwest USA.

Phil Forrest

C mount Cooke lenses are really good but climbing in price. The Combat line from Bell and Howell was made by Taylor Hobson so there is Cooke lineage there. Angenieux lenses are superb and came stock with the later DR/HR/KRM. Wollensak Raptars are really good. From my still photo work (I've been a still photographer for over 25 years) I love the look of Schneider lenses. The Xenon and Xenar lenses are awesome. I would trade my set of Angenieux (10/1.8, 25/.95, R17-68/2.2) and Cine-Ektars for a fast set of 10/25/50mm Schneider in C mount. One other limitation of SLR lenses is click stop aperture that can be really variable due to the auto-diaphragm linkage. Those lenses may not be able to replicate a stop from shot to shot even though they may get close. Just another thing to think about. If you can't find a Filmo locally, hit me up when this pandemic winds down. 

Phil Forrest

People will do ANYTHING to make sure their children are fed. Really. There is no limit to what a person will do in order to provide for their family. 

Phil Forrest

One thing to remember, since there is only 3 months of epidemiology on this novel virus, is that there is NO GUARANTEE of resilient immunity. Yes, there is an immediate immune response, but that may be short lived. We can only hope there is immunity, but as it stands, you can still catch the same cold twice in a year. 

Phil Forrest

The shuttle in the E is also for 2R. It needs to be either replaced with one from a later camera or modified. 

I like the 70E, don't get me wrong, but why not try a later Filmo with a turret and the ability to hand crank / rewind? The only reason I have my 70E is because I got it from goodwill for $14. I really bought it because it had a Cooke Kinic on the front. The camera was all gummed up from years of non-use and had to be overhauled. By the time you find a 70E (which are way less common than the later DE/DL/DR), have it overhauled and modified for 1R, you're looking close to the price of an older reflex Bolex, but you still have the most basic of Filmos besides the 70A (the 70A is just pure fun by the way).

C mount lenses aren't very expensive and you don't have to worry about your SLR/C adapter being off at infinity so you'll get better focus since SLR lens scales are not printed for fine focus but for DOF calculation. They usually don't have the finer gradation of distances that cine lenses do. Plus, you can get much wider if you want, easily down to 10mm. You may like your 24mm Canon, but unless it is the f/1.4L, it won't be any better than many of the very commonly available 1" and 25mm C-mount lenses out there. My slowest 1" lens (not counting the lens of the 70A) is f/1.9 and my fastest is f/.95.

A Filmo with an SLR lens hanging off the front is a somewhat ungainly beast, whereas with 3 different focal lengths, they are very portable and pretty easy to use once you get the hang of it. 

Phil Forrest

You could possibly switch the film door from a 70DE/DL to work on the 70E to give you the different finders but you're looking at more expense and the possibility of the door not fitting. Each door was fit to each body as they all should have matching #s. I doubt putting a heavy lens on a Bolex would be good either. Another problem is that with the really fat adapters, you can't fit more than one lens on the turret often. I had this problem and gave up wanting to fit any SLR lenses to a Filmo. I have a Kodak Cine-Anastigmat 50mm f/1.6 which is amazing but even that is too wide to fit on the turret with any other lenses beside a tiny 1" TTH Cooke Kinic I have. And that 50mm lens is a motion picture lens, so it's slightly smaller  and still won't fit (made for Cine-Kodaks like the K, K100, and the Special which had no or larger turrets with angled flanges to fit their lens line.) I only mentioned the E because it is probably the only one that you could confidently hang a larger reflex zoom off of.

Another thing is that the E is a 2R camera that needs to be converted to run 1R film. If you were here in the states, I'd say borrow one of my Filmos to really try it out before you jump in. I'm just a hobbyist who likes to shoot and repair any broken camera I can get my hands on, so I don't have any professional film MP experience. 

Phil Forrest