Anamorphics

Aaron Shaw · January 28th, 2005, 11:59 AM

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.

Aaron Shaw · January 29th, 2005, 04:46 PM

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)

Oscar Spierenburg · January 29th, 2005, 05:05 PM

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.

Aaron Shaw · January 29th, 2005, 05:09 PM

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

Keith Kline · January 29th, 2005, 05:55 PM

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.

Aaron Shaw · January 29th, 2005, 09:51 PM

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.

Oscar Spierenburg · January 30th, 2005, 06:27 AM

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.

Keith Kline · January 31st, 2005, 12:04 AM

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.

Aaron Shaw · January 31st, 2005, 01:59 PM

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.

Oscar Spierenburg · January 31st, 2005, 04:42 PM

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?

Frank Vrionis · February 13th, 2005, 09:37 PM

Shaw, how's this going?

thanks
Frank
fomoDVXpal

Aaron Shaw · February 14th, 2005, 11:44 AM

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!

Frank Vrionis · February 15th, 2005, 12:54 AM

wow. can't wait

Frank Vrionis · February 24th, 2005, 04:18 AM

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?

Aaron Shaw · February 24th, 2005, 01:04 PM

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.

January 28th, 2005, 11:59 AM	#31
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	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.

January 29th, 2005, 04:46 PM	#32
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	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)

January 29th, 2005, 05:05 PM	#33
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	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.

January 29th, 2005, 05:09 PM	#34
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	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

January 29th, 2005, 05:55 PM	#35
Keith Kline Regular Crew Join Date: Aug 2004 Location: Akron, Ohio Posts: 153	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.

January 29th, 2005, 09:51 PM	#36
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	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.

January 30th, 2005, 06:27 AM	#37
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	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.

January 31st, 2005, 12:04 AM	#38
Keith Kline Regular Crew Join Date: Aug 2004 Location: Akron, Ohio Posts: 153	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.

January 31st, 2005, 01:59 PM	#39
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	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.

January 31st, 2005, 04:42 PM	#40
Oscar Spierenburg Major Player Join Date: Jan 2005 Location: (The Netherlands - Belgium) Posts: 735	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?

February 13th, 2005, 09:37 PM	#41
Frank Vrionis Regular Crew Join Date: Feb 2005 Posts: 93	Shaw, how's this going? thanks Frank fomoDVXpal

February 14th, 2005, 11:44 AM	#42
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	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!

February 15th, 2005, 12:54 AM	#43
Frank Vrionis Regular Crew Join Date: Feb 2005 Posts: 93	wow. can't wait

February 24th, 2005, 04:18 AM	#44
Frank Vrionis Regular Crew Join Date: Feb 2005 Posts: 93	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?

February 24th, 2005, 01:04 PM	#45
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	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.