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Tito Ferradans

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Posts posted by Tito Ferradans

    The Diopter Thread.

    In: Cameras

    Posted

    My guess would be these are 86mm threads, with a pressure clamp, for wide angle lenses. About the strength, Century Optics makes them +2 and +3.5, so, it's a bit too much, but someone might be interested.

    http://www.ebay.com/itm/170612887809

     

    Sigma +0.5 72mm - this one is interesting since it's a low power, but has this dreadful bayonet ring. I though about buying it, since it's very cheap, and trying to fit into a 72mm UV filter, without the glass. If someone is up to the task, go ahead!

    http://www.ebay.com/itm/290901672382

    Rehousing LA7200. Help needed!

    In: Cameras

    Posted

    Yeah, I already did some stuff with google sketchup, but the program has some serious problems when dealing with round things. They're not perfectly round, as that would consume too much processing power, and that's not sketchup's purpose. :P

     

    It must be CAD, in order to be directly transfered to a CNC machine, or 3Ds Max.

    Selling lenses!

    In: Cameras

    Posted

    Ended up upgrading the set of the Century, and after a long mental fight, decided to let the Kowa go to someone else's happy home. Both lenses come with a lot of extras to avoid any more shopping to get them working. After they arrive, you're ready to go and shoot whatever you want.

    I accept Paypal, the taxes are on me!
    PM me, or send me an email: ferradans@gmail.com

    1 - Century Optics Bayo for GL1. (1.33x stretch, focus through)
    This was originally a bayo mount, unable to use with our loved threaded lenses. I got a step up ring "stuck" into the bayo slot, so it's transformed into a 52mm mount and very very safe. It's not a permanent mod. The lens can be switched back to bayo if you want, just unscrew the back and remove the step-up ring.

    The front element has a few cleaning marks in one of the borders, but they don't affect the image. It comes with front and rear caps.

    I also adapted a 77mm thread on the front - kind of rude, but it's safe and can be removed - for attaching filters/diopters. I'm providing a pair of very rare Spiratone 77mm diopters, with low strenght: +0.25 and +0.5. This combination of low strength and big size is very valuable when working with anamorphics.

    Also included is a Series 9 77mm adapter and retaining ring, +1 and +3 Series 9 diopters (in pouches), and, finally, a 77-62mm step down ring for the Sigma +1.6 Achromatic diopter - in original jewel case. Achromatic diopters have much higher image quality, therefore, are also greatly seeked by anamorphic shooters.

     

    And, when you though there was nothing more that could possibly fit here, I'm putting in two extra "anamorphized" primes. A Helios 44 58mm with f/4 fixed oval aperture, and a Pentacon 29mm f/4 fixed oval aperture as well. Both with M42 to EF adapters, M42 rear caps and front caps. The Pentacon comes with a rubber hood and a step-down ring 55-52mm to allow use with the Century. Both lenses have pouches.


    US$1300 + shipping

    http://www.eoshd.com/comments/gallery/album/28-century-optics-bayo/

    2 - Kowa Bell and Howell (2x stretch, double focus)
    Sadly, I'm letting this wonderful lens go. It also comes with everything you need to start shooting. Lens in great shape, no scratches, no fungus, nothing. Crystal clear glass. Very little dust inside, which is common for a lens this old. I bought it a few months ago, when I was starting into anamorphics and now will have to let it go, because I can't make good use of double focus, and gotta make room for the LOMO.

    This kit includes the original front and read caps, as well as the original lens pouch, but also Redstan front and rear clamps (62mm rear, with a locking ring that won't let the lens fall while you align it, 72mm front) and extra front and rear caps for the clamps, to keep the lens ready to shoot, and safe, at all times. I'll also include a lot of step up and down rings to make the clamp fit into any taking lens filter thread (49, 52, 55, 58 and 67mm).

    The diopters included here are a rare Tokina 72mm +0.5, in original jewel case, and four Vivitar 72mm (+1, +2, +4 and +10) in a filter pouch.

    US$1500 + shipping

    http://www.eoshd.com/comments/gallery/album/40-kowa-bell-howell/

    Rehousing LA7200. Help needed!

    In: Cameras

    Posted

    some more information and details of what I had in mind. I've stopped developing due to lack of time! If anyone has any insights over this, please, speak. hahaha.

     

    whenever I find a friendly engineer, I'll update this!

     

    la7200-pg1.jpg

    la7200-pg2.jpg

    la7200-pg3.jpg

     

     

    Select-o-matic Iscorama

    In: Cameras

    Posted

    Iscoramas really convince you that 'in focus' means 'in focus'! Damn, that's sharp. This machine is beautiful! Don't even know what it does, but these colors made me think it was CGI. :P

     

    I prefer the first CC option, since I'm more of a blue guy, than a greenish fellow. hahaha

    The Diopter Thread.

    In: Cameras

    Posted

    To help our friends having trouble getting close ups for their LA7200, there are a few options below.

     

    Angenieux +0.3, 82mm

    http://www.ebay.com/itm/121097575147

     

    Unknown Diopter for Angenieux Lens, 108mm

    http://www.ebay.com/itm/251232033300

     

    Tiffen +0.5, +1, +3 , +5, Series 9 and a bunch of adapters
    http://www.ebay.com/itm/321107468006

     

    Tiffen Photar +3, Series 9
    http://www.ebay.com/itm/380297498220

     

    Tiffen Photar +4, Series 9

    http://www.ebay.com/itm/110451883842

     

    Tiffen +1, 105C

    http://www.ebay.com/itm/400440410462

     

    Tiffen +0.5, 138mm

    http://www.ebay.com/itm/190827528672

    The Diopter Thread.

    In: Cameras

    Posted

    In the end, we never stop talking about these suckers across multiple threads, so I'm gonna try to compile as much information as I can into this one.

     

    As in most cases, diopters are cheaper than anamorphics, I ended up with a lot of them, from multiple brands and multiple performances. The key was never go where everyone else is trying to find. Got the classics too, but that was luck.

     

    Anyway, let's go to the undeniable favorite: Tokina +0.4 Achromatic diopter. My only complain about it is: why aren't you bigger?! My first lens was the LA7200 and I took quite a while to find the 105mm.

     

    The next lenses all had different thread sizes. I could filter the Hypergonar on 77mm or 86mm, the Kowa with 72mm, Sankor 72mm too, Isco 54 at 95mm or 86mm and had a plan of an alternative 86mm front for the Lomo Squarefront, which didn't go through. Anyway, if I started to look for all these sizes of diopters, I'd go broke.

     

    My salvation were the Series 9 filters. If someone isn't familiar with these, they come as unthreaded glass, that you put into an adapter that can range between 67mm and 86mm. That pretty much covers all lenses. I got adapters for 72, 77 and 86. The glass itself has around 83mm diameter.

     

    Tiffen Series 9 filters are not in production anymore, so you can pick them off cheap ($1-10), even though they're not so common. The adapters are a bit harder to find.

     

    After that, I went crazy on other brands as they showed up with decent sizes. Got 77mm Spiratones +0.5 and +0.25 for $6, 86mm +0.6 Fujinon, 72mm +1.25 Fujinon, 95mm +0.25 Pentax (for the 135-600mm Pentax Zoom), 82mm +0.75 Canon (1300H), etc, all very cheap. Some of them are real heavy, and I don't know if they're achromatics or single elements.

     

    The advantage of the bigger ones is, less vignetting, even when you go wide, and, the sharpness is increased, since you don't get corner areas.

     

    Finally, I found a couple 4.5" ones (around 114mm), that require special adapters, like Series 9. These adapters are impossible to find! I'm making a couple myself, as I trust threads more than tape. :P

     

    EDIT Dec 07, 2014

     

    Why Look for Low Powered Diopters

     

    There's a common question going around, of WHY fraction diopters are better than full numbers, so I'm addressing that here too. Rich has a good explanation too >here.

     

    As you can see below in the math section, the numbers correspond to certain maximum and minimum focus distances. When it comes to anamorphic lenses, what is the most common minimum focus distance? Something between 1.5m and 2m (or 5 to 7 feet, imperial scale).

     

    Iscoramas have 2m minimum focus. Kowas, Sankors and most dual focus projector lenses are set to 1.5m minimum focus. For most shots, this distance is greater than the distance you want to put between the camera and your subject, which leads to being unable to focus properly - also, it's a pretty messed up distance for working indoors.

     

    What a +0.4 or +0.5 diopter does is turn this "near 2m minimum focus distance" into "near 2m MAXIMUM focus distance" (see math below, seriously), allowing you to frame and shoot freely indoors and much closer to your subjects. If you want extreme close ups, then you need to have stronger diopters, but a +0.5 is a key tool for "standard" shots.

     

    Achromats are also better, but they have their own explanation below too.

     

    Focus and Anamorphic Compression

     

    Another thing that relates directly to diopters is the lens compression. Most of our 1.5x or 2x stretch lenses only have that proportion when focused to infinity. Things change when you twist the focus ring. As you get closer to minimum focus, the less compression you have. 2x lenses tend to go towards 1.7x or 1.8x, Iscoramas get very close to 1.3x. 

     

    When unsqueezing your footage, this compression disparity can make shots look different from the rest of the footage, as if it was shot with a different lens. In a technical level, it really was a different optical path.

     

    Using diopters you get rid of using the shorter distances on your focus ring and keep your compression constant throughout the shots.

     

    DISCLAIMER: I don't know how this relates to baby anamorphics, and this CERTAINLY does not affect focus through lenses since you don't change the distance between the anamorphic elements.

     

    //EDIT.

     

    Strength measuring:

     

    Fujinon: The first number is their maximum focus distance, the second number is the thread size. For example, a 16086 reaches 160cm at infinity (+0.6) and has 86mm thread. 190101, 190cm at infinity focus, 101mm thread.

     

    Canon: The newest series (250D and 500D) measures in millimeters their maximum distance. 250mm equals +4 and 500mm equals +2. The "D" stands for Double element. The older ones use the same measuring, 1300H = 1300mm, +0.75. There's also a 900H, 105mm, which is a like +1.1.

     

    When nothing is marked on it, good luck with testing the thing. It's usually not hard, but most of them have information lying around the web.

     

    Thread size:

     

    As well as regular threads, some are marked with a C after the number (mostly 86C, 95C and 105C), that means the thread on this filter is coarse, 1mm pitch. Our regular (fine) threads have .75mm pitch. There are adapters for these too, like the one below, from 86mm fine to 86C.

     

    http://www.ebay.com/itm/350325079425

     

    Minimum and Maximum focus distance:

     

    Just realized that I haven't explained the math relating diopter strength and maximum focus range! Since most anamorphics perform better when focused closer to infinity, a diopter gives great help in "faking" it optically. A close up filter "sets" infinity just a couple meters/feet away, so anything BEYOND that certain point will be IMPOSSIBLE to focus.

     

    Of course, this will NOT follow the lens' focus marks. Infinity on the lens now equals the diopter maximum focus distance.

     

    Now, the numbers:

     

    S = diopter strength (+0.5, +0.6, +1, +2, etc)

    MaxFm = maximum focus distânce, measured here in METERS

     

    MaxFm = 1 / (S)

     

    Ha! I bet you expected something waaaay more complex, right? Some examples are never bad, so let's get to it. I'll use +0.5, +1.25 and +2 as sample strengths.

     

    MaxFm = 1/(0.5) = 1/(1/2) = 1 x 2/1 = 2 meters

    MaxFm = 1/(1.25) = 1/(5/4) = 1 x 4/5 = 0.8 meters

    MaxFm = 1/(2) = 1/2 = 0.5 meters

     

    If you live in a country where imperial scale prevails over the metric system, you just gotta do a quick fix to the expression.

     

    S = diopter strength (+0.5, +0.6, +1, +2, etc)

    MaxFf = maximum focus distânce, measured here in FEET

     

    MaxFf = (3.3 / S)

     

    Same examples from above, now in feet

     

    MaxFf = 3.3/(0.5) = 1/(1/2) = 3.3 x 2/1 = 6.6 feet

    MaxFf = 3.3/(1.25) = 1/(5/4) = 3.3 x 4/5 = 2.6 feet

    MaxFf = 3.3/(2) = 3.3/2 = 1.6 feet

     

    Regarding minimum focus distance, I'd say anything closer than half maximum focus distance is gonna look pretty bad already. With high power close ups (+2 and up), I'd say anything closer than 3/4 of your maximum focus distance is gonna be pretty bad already.

     

    Of course, this "minimum focus distance" image quality has A LOT of influence from the anamorphic. Also, achromatic diopters will improve almost everything you could imagine.

     

    Since I've just mentioned them, here's a list of achromatic diopters, with their strength, manufacturer, price range, etc.

    http://fuzzcraft.com/achromats.html

     

    Price range:

     

    Just for checking, here is a list of the most common lenses and their outgoing price.

     

    Tokina +0.5 72mm - $150

    Kenko +0.5 72mm - $90

    Tokina +0.4 72mm Achromatic - $350

    Kenko +0.3 105mm - $350

    Canon +2 72mm Achromatic - $100

    Sigma +1.6 62mm Achromatic - $20

    Angenieux +0.25 82mm - $330

    Kinoptik +1 82mm Achromatic - $530

    Foton-A +1 or +1.25 - $900 (GONE!)

    Tiffen +0.5 to +2 138mm - $50 and up

    Tiffen +0.5 to +5 Series 9 - $1-50

    Tiffen/Kodak Series 9 Adapters - $20-40

    Tiffen +0.5 to +2 4.5" - $10-50 (RARE)

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