Hi guys,

With the advent of so many different mini35 type products hitting the market, I thought I might propose an additional anamorphic adapter.

I have been seriously pondering manufacturing these things to sell (I'm not particuarily looking for profit so I can pretty much keep the cost as low as feasible). Certainly in 16:9 and perhaps 2.35. Now my question is, before I get too much farther in my thinking, would anyone be interested in this sort of thing? My current design would mount between the lens mount of the 35mm rig and the 35mm rig allowing you to use the same adapter for still photography as well if you so chose. Should I persue this more? I'm definitely going to be getting one for myself just curious if anyone else was interested.

Well I am definitly interested in something like this. I still don't fully understand how the rear system works though. I have been trying to figure out a front mounted system, but I haven't had any luck as of yet. Do you know what the problems are with the front mounted systems. Thanks!

Hi Keith,

For more information on how these work check out my post here:

http://www.dvinfo.net/conf/showthread.php?s=&threadid=38190&perpage=15&pagenumber=1

Sixth down or so. Feel free to ask questions as well!

The idea doesn't seem to be all that popular. I suppose a fully functional working model would be requisite to spark any real interest. Still, I'm just wondering if it would be worth my time to order a few extra while I'm at it.

Anyway... I hope to have a fully functional prototype done soon. When I do you can most certainly expect footage! Theoretically this adapter would work with any mini35 system though different lens companies would require slightly different anamorphics. I'm focusing on Nikon at the moment.

I personally would be totally interested. I'll definitely follow the progress.

Just like everything else on here, I think alot of people would be more interested in it once there's footage to see. I've been toying with the idea of using a cylinder lens for a front anamorphic, but i couldn't find out if there is a way to calculate the magnification factor of these lenses. Basically what I am trying to figure out is a way to make something like the century optics one that could fit in front of the 35mm prime lens, like an add on wide angle, but so far I haven't been able to figure too much out. Anyone have any ideas on what kind of lenses are in something like the century optics adapter? Like this...

http://www.centuryoptics.com/products/dv//133x/133x.htm

It seems to me that there has to be a way to make something like this for alot less than the price they're asking for their anamorphic. Something that could thread onto the front of the lens and fit different 35mm lenses.

Either way I'm looking forward to finding out whatever you come up with Aaron and I'll be more than happy to help where ever i can.

The site of the century optics lens says it has a wider view, so does this mean the lens is thicker in the middle or narrower?

If there is an optic expert amongst us, could he make a calculation on the curve we need? Or maybe someone has the real thing and measure it.

I really think if you bend a flat piece of acryl glass and make a construction with a real glass lens filter, fill it up with water, it would work. The only thing I need is the curve, or an estimate to get testing.

I'd definitely be interested if it was feasible and not incredibly expensive--most of us shooting with a mini35-type adapter in place will be going to widescreen, and having to crop PLUS any sharpness loss inherent to the 35 adapter means that you're losing a lot of resolution--a good anamorphic would help re-gain some of that. So yes, I'd be interested... if it works!

Ocar, yes the lens is indeed thicker in the center. Much like this:

http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2108&search=1

I could run some calculations if you would like. You would need to tell me what brand lens you use though and anything else you can find with regard to the optics contained in the lens.

Keith, the magnification factor depends on the interaction of two optical elements. It's not a 100% straightforward topic and the magnification changes depending on the distance as well. If you want an adapter for a 35mm lens that goes on the front I suggest getting ahold of a 16mm anamorphic projector lens. These can usually screw onto the front of a 35mm lens. The only downside is that both the 35mm lens and the anamorphic would have to be focused separately. If you do go this route look for a 1.75x lens though. A 2x will give you a very wide image 2.66:1 or so.

Ryan: if it works indeed! I'm actually not worried about getting it to work. I know it works and I can predict the aberrations that the lens might have before constructing it (by working with lens design software). The only question is: "how much would you be willing to pay for such a piece?" You could do this very cheaply but the image quality would suck. You could also do this very expensively which isn't necessary either.

im interested. pricing?? is it already mounted in a threaded type application or is going to be bayonet style?

Aaron I am interested. Let me know when you have a working model.

Aaron, the lens is a (photographic) cosinon (auto MC)
F=1,7 f=50mm
no. 756105

That's what it says on the front. I know it's a cheep one, but it is very smooth and light in focusing, that’s why I use it.

If you could calculate something, I would be very happy. Even with a rough estimate, so don't make much work on it.
I’ll also be following this tread, so maybe I’ll end up buying your lens anyhow.

Oh, and is it possible to have a step wider than 16:9? Or would the lens be too thick for a rear lens.

Hi Cody,

Heres the dillema. A bayonet style adapter would be preferable I think. The problem? This would extend the focal length of your lens slighty.

I could make it as an internal lens but that would require installation and would mean I would have to make many different versions.

The only other option is to have one end be bayonet mount and the other replace the mount used in the 35mm adapter. This is how this is usually done with film cameras. While it would still require an installation it would be much simpler (theoretically). My goal is to make this as easy to use as possible (for my own sake if nothing else!)

So... I have some thinking to do about actual housing. The lens system is ready to go though.

Ocar, what diameter is your lens?

You can have the compression be whatever you would like! Would you prefer a different aspect ratio?

If you mean the diameter of the 35mm lens: 3,2mm is the front lens, the front filter ring is 48mm. The rear lens is 2,5mm.

If you mean the lens I will be making, it will be 48mm.

2.35:1 aspect ratio is what I'd want.

Thanks.

Alright, I'll see what I can churn out :D. It may take a day or two as I have other things going on as well right now.

As for demo footage - Expect some fairly soon! Week or two perhaps.

Aaron, I too would be quite interested in your adapter, as it would be a very nice upgrade to the micro35 I plan to purchase/build as soon as possible.

About the price, I guess anything under $500 would be considered OK, from my point-of-view. Based on the street price from the Panasonic DVX100's anamorphic adapter, I don't think you could easily justify many more bucks than $500, because a "rear system" doesn't have as much glass (AFAIK), and doesn't weight as much as a "front" system... Of course, should you need extra income after a while, you could also make an updated super duper PRO version of your adapter, with no optical distortion at all (even at full wide, and full telephoto), titanium case, lifetime warranty, PL mount, and so on... And sell those for $4000 each, which will sound like quite a good deal for the PRO-market. But, don't forget to test your system with us (the DIY market segment) first :)

My 2 cents...

Anyway, keep us informed on your progress, as you are making something many people accross the world would be interested in, including, pehaps, the real "mini35" and "movietube" guys :)

Thanks Emmanuel :)

My plan is to keep this as cheap as possible. Any actual profit will be a bonus in my eyes. It can be rather expensive to have custom lenses manufactured (which is a must for this sort of project). I'm just trying to gauge the general price range people are willing to spend so I can adjust the design to be maximally efficient for a target price range!

I think the price point sort of depends on what 35mm lens mounting system becomes somewhat of an accepted and widespread system. For example, if James' Micro 35, which costs less than $100, does end up being very high quality, then you'll have a very hard time selling a $500 adapter to go anamorphic... In this situation I'd think it would have to come in at or under the $300 pricepoint... my 2 cents.

Excellent point. Perhaps a few quality options and varying price points would be best.

Aaron,

How versatile could we expect this to be? For instance, I have a full line of minolta primes (28, 35, 50, 85, 100, 135), plus a sigma 28-200 zoom (all in minolta mount). Would I be limited in what lenses I could use with your adapter? Would I expect to only be able to use a certain range of f-stops? Some of my lenses go all the way down to f1.4. I would hate to lose the lower stops in order to go anamorphic. Would I lose my close-focusing ability? Again, some of my lenses come as close as 12 inches in focusing. I would be willing to lose a little, but I don't want to go out to 3 feet like some of the front anamorphics.

Also, I would be looking for a 1.25x anamorphic. Would this be possible?

If I could have the 1.25x, use all of my lenses at all or most of their f-stops, still be able to focus pretty close, and have no chromatic abberation, I would probably pay $600.

Aaron,

By the way, have you considered an anamorphic lens behind the ground glass; in other words, between the ground glass and the video camera?

It seems like it would make the whole thing a lot easier for you to make, since you would only need to be able to focus on one plane: the ground glass. The lenses in front could do their own thing, uninhibited by the anamorphic process happening on the other side of the groundglass.

Do you know of reasons why this would not work?

Hi Justin. I don't have 100% solid answers for some of these questions yet but here is what I expect:

1) You should be able to use any prime or zoom lens you wish so long as they all have the same mount.

2) You would not be limited in the range of f-stops you can utilize. You WILL loose light though (this varies with the compression desired etc) - how much is yet to be seen. In any case, there should be no restriction on the ability to choose a specific f-stop.

3) I *believe* you should be able to retain the ability to focus up close. I don't see any reason why this would be affected. Something to test for sure.

Chromatic aberration is one of my main concerns and I will try to deal with it as best as possible.

Why a 1.25x? It could be done, just curious as to the reason for the specific compression :).

Aaron,

The Reel Stream Andromeda (also known as Juan's Mod) produces an image that is 990 DV pixels tall by 1546 wide. A 1.25x anamorphic will give me a 16:9 image.

Ah, ok! Maybe a means of changing the compression via some ring/lever would be a useful feature as well then.

You could do that?!!

In that case, I would want one to go from 1.25-1.66. Then I could have 16:9 and 2.35. Woo-hoo!!

The lever/ring would, of course, need markings and the ability to lock down somehow.

Oh yes, it's possible :). I don't know how much more it would cost. It's something I'll definitely look into though as I am sure others would find it of use as well.

Okay so here's the one thing that i'm not understanding. I know I'm stuck on the front mounted anamorphic, but it just seems like it would be easiest to mount/remove.

If it were a lens mounted with a rear filter ring to thread onto the front filter threading of the lens... why wouldn't it give the same compression on different lenses? I mean there are add on wide angle lenses that fit on standard 35mm lenses right? I mean those have a set magnification. Why would it be any different for an anamorphic lens.

Sorry, I just don't understand the difference. If someone could explain, that would be great.

Keith, the front anamorphic could be easier to mount/remove - you are right. However, if done correctly, the rear would not be any harder. One option is to have bayonet mounts on either end of the adapter so you would merely snap the adapter onto the 35mm mount and then the lens onto the adapter. The downside is you would have a slight increase in focal length.

Anway, on to your question:

Such a lens would indeed give the same compression regardless of which 35mm lens you used it on. The problem is that you would have to have a very large adapter to cover most of the diameters that 35mm lenses use. These can range anywhere from 45mm diameter to 90mm etc. It would just make a front system more complex to use, larger, and more expensive.

For a quick summary of the benefits and downsides to each type:

Front Anamorphic Disadvantages:

- Causes the lens to have two focal planes; one for each axis. Because of this you have to play around with both focal planes so they are both in focus at the same time. This can severly limit the ability to choose a specifc aperture and/or focal length for creative purposes (which partially defeats the purpose of a 35mm adapter in the first place).

- Can cause strong horizonal and/or vertical flare due to the lens shape and proximity to direct sunlight. Some people like the effect but it can also be rather annoying to have a huge flare across th entire screen from a light in the corner of the room.

- Very few matte boxes are designed to work with square lens shapes. Also, the wider anamorphics can cause severe vignetting unless you have a very, very wide mattebox.

- Limit your close focusing abilities due to multiple focal planes.

- Filters are harder to come by

- Need an adapter which can fit many different lens diameters. This causes the need for a very large diameter lens (and consequently more expensive/slower).


Rear Anamorphic Disadvantages:

- Out of focus points can become squarish instead of round. Some people find this to be bad others don't even notice. The amount varies. This effect can be seen in films such as "Apocalypse Now"

- More light loss. At least a 1/3 of a stop for 16:9 and more for higher compressions such as 2.35:1 (at least 2/3 of a stop)

- Depending on the mechanical design, could possibly extend the focal length of your lens slightly.

- Actually looses vertical field of view to create tha anamorphic image. Much like cropping the image in post but done optically so you don't loose res. This isn't a problem for most people as they would have cropped in post anway (again no resolution is lost only vertical field of view).


Front Anamorphic Advantages:

- Out of focus points are always oval in shape (note: not round as you would get with a straight 35mm spherical lens). Some prefer the stretched oval shape.

- Extends your view by approx 33% for a 16:9 adapter. This can be both good and bad actually. It can cause some strong barrel distortion at times.


Rear Anamorphic Advantages:

- Easy to use when made correctly. Just a simple piece between your lens and the body.

- Does not suffer from the strong artifacts that can plague front adapters in terms of distortion and flare.

- No need to have an adapter that can fit many lens diameters as it mounts to the rear.

- You can keep using your current matte box and accessories.

- Smaller, lighter, less expensive


I hope I remembered everything... I may update this if I realize I forgot something!

In any case, I think the rear has many advantages which make it more attractive. This is, of course, just my personal assessment.

Thanks for the info. Things are making alot more sense now. I know I don't know alot about how these systems work, but I'll help out with whatever i can.

Aaron, do you think it's possible to make either a front or rear mounted anamorphic conveter with a combination of existing lenses (cylinders, etc) or do you think the adapters would have to have custom made glass?

I know this tread is mostly setup for the pricing enquiry, but I have a technical suggestion or question.
I pointed out to make the lens shape of a clear lens filter and bend the anamorphic curve with a acryl (or other flexible) glass. This would be made waterproof on all edges. Now I suggested filling it up with water, but for the obvious risks I'm wondering if there is something within our reach to fill it up with something that will harden and turn it to a solid matter.

And Aaron, will the curves be different for a front or a rear lens?

Keith: Custom glass is the only really viable option. I've looked around at the various stock pieces on the market but there are very few of the right size and none with much quality for this purpose. Custom glass is also necessary to get the correct aspect ratio. It's absolutely imperative to get this correct or the adapter becomes useless!

Ocar, I honestly don't know. I haven't looked at materials such as you describe. One thing to keep in mind though is that you won't be able to make an achromat easily that way. This could be bad or acceptable depending on how critical of your footage you are.

I'm not sure about the differences in curve. Will get back with you one that one.

Ok just a quick question about design preference.

Would you guys rather see a small, compact adapter which increased the focal length of your lens or a longer adapter which maintained the focal length as it should be? Both are possible - I'm just trying to judge what people would find more useful. I know what I personally would go with but that doesn't mean a whole lot :D

EDIT: Also, what lens types are most people going to be using? (Nikon, sigma.. etc)

If a focal increases, would that mean the GG has to be closer to the 35mm lens or further away? (probably a stupid question)
Most people probably have much work or no space left if the GG needs to move to the 35mm lens.

No movement of the ground glass would be required. The design would however, make your wide angle lens become effectively longer making it harder to achieve wide angle. It would mean that the ground glass is farther away from the lens (due to the adapter taking up space in there). There is a way to get around this but it requires a longer adapter (counter-intuitive but it does work).

I'm guessing that we're talking about an increase like this:

20mm lens -> 45mm lens

Personally depending on how much the difference is in size between the two, I would prefer an adapter that keeps focal lengths the same. Most of the stuff I shoot and am planning on shooting requires alot of interiors so increasing the focal length of the lenses wouldn't help me out much with that.

My 2 cents.

Not much response like I was hoping for but I'm going to go with the longer version. It may be larger but I just can't stand the notion of having an adapter that adds to my focal length when I don't want it to.

Will keep everyone posted.

Aaron, what size will it be. I think people need to know to check their equipment first. I don't really like the focal length increasing too. Do you think the lens I'll be making, will have a larger focal length?
Again, don't do too much work on calculating the curves for my lens, I'll make a few different prototypes anyway, so I'll be able to adjust it then.

I'm still interested in the anamorphics. I was just curious if aaron or anyone else might be able to point me in the direction of how they work optically (books, websites, etc). I mean i know the purpose of them and the basics. I just wonder how you are going about actually designing how to make one.

Keith, there are some decent introductory optics tutorials online. It's a pretty heavily math oriented field so you will need to know a bit. For books that take an easier approach (not totally mathless - you can't do it, but less math intensive) you might consider looking for the book "Practical Optical System Layout" by Warren J. Smith. It even has a chapter on getting the most out of stock lenses! I'm quite lucky actually. I have access to some very powerful, industry leading, design software which helps. You still have to understand what the math means, how to calculate etc but the computer runs the actual calculations and can even optimize a design for best output given a set of specifications.

Edit: Ocar, depends on what sort of lens you are attempting. A front mounted adapter shouldn't have this problem. Will post more later.

Aaron, I'd first want to try a rear lens, because of the advantages you pointed out. But if I end up having too little space inside the camera (I also have a thick condenser lens) I would attempt a front lens.
I hope it doesn't effect the curve of the lens whether it's front or rear mounted?

Shaw, how's this going?

thanks
Frank
fomoDVXpal

Goin alright. I've had to put the project on hold temporarily but I'm gearing up again to bash away at it. Hopefully I'll have some footage soon!

wow. can't wait

actually, something came to mind.

if i want to keep the video DOF, can i simply remove Dan (or whoever) 35mini system and still maintain 16:9?

in other words will it shoot with JUST your adapter?

if so, will the zoom function?

Good question. The short answer is, unfortunately, no.

It is/will be designed to mount to a 35mm mount. You would have to find a way to mount this straight to your video camera if you wanted to do this. About zoomthrough.. I can't say. It would depend heavily upon your camera since it isn't designed for this purpose.

Still making progress. Slowly but surely.

>>>It is/will be designed to mount to a 35mm mount.<<< and project that anamorphic image on a GG !

Whatever the format you shoot, will be the same (3:4, 16:9)
The image will be squeezed though on that format.
Keep it up Aaron. Good idea.

Hi Aaron,

Haven't seen any new posting's on here for a while and was just wondering how you are progressing with the adapter?

Cheers

Robert

Yep things are progressing :).

It's taking a while as there are so many variables but I'm slowly getting there. I'll hopefully have some decent information to post by the end of the month.

Things are going well.

However, I'm putting this project on hold. With the new HVX200 and the uncertainty of the cheap 35mm market I'm going to bide my time for a while. I need money for a new HD camera after all and I can't afford to do both! ;)

Too bad you have to put this on hold.

By the way, have you seen my tests on the water prisms? (three threads down, currently)
I'm surprised, as you were when starting your project, that there aren't many people interested in anamorphics.

Anyway, I'm looking forward to hear you put it back -off- hold.