New Flipping Adapter

kyle.presley

kyle.presley

Well-known member
Hey guys,
I am in the process of designing a 35mm adapter, similar to Quyen's. However, the flipping unit will not lose as much light as Quyen's. I will be using a roof prism instead of a pentamirror, which I believe is the reason for the excessive light loss. Also, I plan to use a zero-grain (yes, zero) static ground glass.

My question to you guys is: is there still a market for a static adapter? A flipping adapter (with some light loss)? What would you pay for it? (Supposing there is little to no chromatic abberation or vignetting?

Keep in mind, this adapter is still in it's wee stages of developement and I don't know if it will even be commercial yet. I guess that will depend on you guys.:thumbsup:

I am calling it the CineField35.
 
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Wait, there's zero grain but it still diffuses properly? Must be a good material. Any hints to what it is? I'm using a diffuser that has extremely little grain, none that I've been able to detect, but I don't dare say it is grainless.

I wish you the best with this. Sounds like an intriguing idea. A static adapter that flips with little light loss. I'd expect people would pay at least $500 for it.
 
Yes, I think there's a market provided:-

1. It maintains the Letus35 price-point or better
2. Less than 1.5 stops of loss, better if less than 1 stop

If you can do these two, and still have good bokeh and have the product look good and have it well built, you'll basically kill the market for all the adapters that are non-flipping and have above 1-stop of light loss.

Daniel Wee
 
There should be very little light loss with this gg. Not sure about the bokeh just yet. I will let you know when I get the thing put together.
 
If you produce a professional unit that actually works, reliably, solidly, is precision made, and delivers a right-side-up image, with sharp imagery and no added grain, you can expect people to pay upwards of $1000 for it, depending on how well made it is.

If it's a one-off knockoff made in your garage (or, more accurately, looks like it was) then the $500 price point is probably more appropriate.
 
Exactly, it could be the best working adapter ever, but if it has a shoddy design and is held together by duct tape, super glue and pipe cleaners and looks like a 3rd grade science experiment, dont expect anyone to trust it/want it.
 
Thanks for the feedback everyone. I will keep you posted as more info becomes available. I have some interesting and VERY unconventional design ideas, as to the minimumization of light loss.
 
What is the best (price within reason) 72mm diopter to use? This is what will make or break the adapter I think.
 
the redrock is Phenominal. however Wayn kinney just got his hands on some Custom ones.... they are OUT OF THIS WORLD. IVe seen Proof! he makes the SGpro. give him a PM see if he can help you.
 
Sounds good Kyle. Make sure you're ready with your unit before you let everyone in on your design. You could be on to something really hot. Count me in if it's well made.
 
Just an update: I am working on the prism system. I have found a particular prism that flips the image AND keeps the lenses line of sight on the same plane. That is to say that unlike the mini35 and the Letus35 FE's line of sight offset ( the video lens above the slr lens), the cinefield35 will have the SLR lens and the video lens on the same plane, which will be a little more pleasing to the eyes and improve light loss.
 
"I have found a particular prism that flips the image AND keeps the lenses line of sight on the same plane."


Dove-Prisms.jpg



Yes the dove prisms, very very expensive, especially when going to sizes beyond 30.00 mm in width. I've been looking into this for some time now and with the r&d I've done, it's not a bad idea, but with all of the newer 35mm/image converter models (and lets not forget the RED CAMERA) coming out it's a draw. Good luck, keep us posted on the progress!
 
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Well, it's not a dove. A dove erects the image vertically, not laterally. I have one that reverts vertically and inverts laterally: a full 180 degree turn. No supplier stocks this particular prism, so they will be custom, but they do exist. It is siimilar to the Schmidt pechan prism used in the movietube, but doesn't bend the light through a 45 degree angle.

If you are looking for a large dove prism twocik, the surplusshed.com has some large ones for about 30 bucks, They seem like they might work for your application. Here's the URL: http://www.surplusshed.com/pages/item/l1833.html
 
Kyle, for a full size image adapter, the image size must be maintained throughout the optical path...meaning a large and very heavy prism. This is why you won't find a non custom variant available in mass production to manage the task. There are also phase considerations for roof type prisms.

Given the loss inherent in extended optical paths, and ease of digital inversion/reversion, the flip concept loses some attraction. That's not to say that we are not going release our version, but suspect many will opt not to use it.
 
Just wait till you see it. It's not that big, or that heavy.


You said that there is loss inherent in extended optical paths, but keep in mind that light travels faster through glass than through air. Lightloss will be nill.

When you say image size, are you refering to aperture of the prism? The light path will be 17cm or less, because it goes through multiple "folds", so overall the prism will be compact, but the actual size of the image will be smaller because of the length of the light path. Nothing a good macro can't correct.

Yes, like I said, it is custom.
 
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You will have phase issues with an abbe-koenig type config...but you probably already know that.

Either way, a very worthy project.
 
Thanks. I hope I can just get it off the ground. If nothing else, I plan to provide a generic image flipper that can be used on most 35mm adapters out there as a third party accessory.

By the way, I love EVERYTHING I have seen from the Brevis. Just terrific. Keep up the great work.
 
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