The Letus35 Redesigned :) at DVinfo.net

Ben Winter · January 18th, 2006, 04:19 PM

Ok, maybe not "redesigned," more like "shortened"...

I wanted less light loss so I ordered a Beattie a while back. Even though it still hasn't come, I wanted to get rid of the achromat as well--so I took it upon myself to shorten the Letus body enough so the GL2 could focus on the GG right smack up against the lens.

Pictures:
http://www.frozenphoenixproductions.com/misc/letus/

THe white thing is a PVC thing I found at Home Depot--they called it a "soil converter" or something like that--used to connect PVC to cast iron pipes or something. Not really sure. Anyway it was five dollars and with a bunch of small screws I was able to fit it together.

The ground glass vibrates maybe half a millimeter from the mount that connects it to the body of the camera.

The best part? If I want to go back to my original Letus, all I have to do is unscrew everything and put it back together. I just drilled a few extra holes :)

Does it work? Well, no. I don't have my Beattie yet, so there's mass vignetting everywhere (even in my raccoon wounds!). Other than that, it fills up the frame fine, and vibrates normally.

Took me about 3 hours worth of work and $7.68.

Cheers,
Ben

Quyen Le · January 18th, 2006, 05:46 PM

Nice Ben, it should work fine with beattie focusing screen.

Quyen

Leo Mandy · January 18th, 2006, 07:52 PM

Ben I think you were a 35mm adapter in another life. Great job pushing the boundaries!

Ben Winter · January 18th, 2006, 09:33 PM

Haha--thanks for the comments. B&H just emailed me and told me that the Intenscreen will be here Monday. I'll post screengrabs as soon as I can.

BTW I tried glueing the PXCL from my Nikon D Screen overtop the GG and the the plate barely vibrated--even less so with 3 AA's. Wonder why. Oh well--back to the drawing board on that problem.

Dmitriy Uchakin · January 18th, 2006, 09:55 PM

Sounds like an improvemnt in terms of weight of the adapter and not needing to use support rods. Looking forward to see your results. Do you by any chance know the dimensions of the intenscreens? Are they any bigger than nikon D ones. I am thinking of getting a beattie to go inside the thorlabs tube. Just not sure if it will fit in there.

Thanks.

Andy Gordon · January 18th, 2006, 10:09 PM

You can get a small Beattie or a large one, small one is about the same size as a nikon D. I got a large second hand one from B&H for $30, it was about 3" x 5" I think. It comes in two parts, fresnel and GG. I glued each part to some 50mm dia pvc pipe and power sanded the edges back till I had a 50mm dia screen (with some 50mm pipe either side). that fit inside another pvc pipe 56mm dia. Bit of a nightmare to sand it without scratching it cause dust etc really clings to the grooves in the fresnel. In the end I scratched it trying to clean it but the results were worse than I was getting with optosigma. It still had a hotspot so I needed a 120FL condensor with it, the grain was worse, and it didn't diffuse enough. So I'm back to the double optosigma. That was with a takumar 1.4 lens and a GS400.

Alain Bellon · January 18th, 2006, 10:33 PM

Andy, does the fresnel go between the 35mm lens and the GG screen, or does it go after the screen?

I have a Nikon screen and it has a PCX lens that goes after the screen. (actually its a PCX that is ground on the flat side).

Bill Porter · January 19th, 2006, 01:32 AM

Ben, nice job. Good for you for continuing to tinker. Keep it up!

Note: get this out of your system now as it will be harder to get away with it when your girlfriend gets older or you get married.

But what the heck are raccoon wounds?

Michael Maier · January 19th, 2006, 05:44 AM

Quote:

Originally Posted by Andy Gordon

You can get a small Beattie or a large one, small one is about the same size as a nikon D. I got a large second hand one from B&H for $30, it was about 3" x 5" I think.

3x5 inches or cm? Inches sounds a little big. You need a big pipe to fit that in.

Ben Winter · January 19th, 2006, 08:16 AM

Quote:

But what the heck are raccoon wounds?

lol. It was a Family Guy reference. Popular at my school right now.

Quote:

get this out of your system now as it will be harder to get away with it when your girlfriend gets older or you get married.

Haha! It's hard enough with a mother--I can only imagine...

Quote:

Originally Posted by Alain Bellon

I have a Nikon screen and it has a PCX lens that goes after the screen. (actually its a PCX that is ground on the flat side).

Are you referring to the Nikon D Screen? In which case it's actually two separate pieces of glass (ground glass, then condenser lens) fitted together in a metal bracket. You can take them apart, they're only kept together with four screws and a little glue.

3x5 is a little big for inches. Maybe centimeters.

Alain Bellon · January 19th, 2006, 01:57 PM

Quote:

Originally Posted by Ben Winter

lol
Are you referring to the Nikon D Screen? In which case it's actually two separate pieces of glass (ground glass, then condenser lens) fitted together in a metal bracket. You can take them apart, they're only kept together with four screws and a little glue.

I was talking about the Beattie. I have a Nikon one with the GG and the PCX.

I assume the setup is the same, since a Fresnel lens just acts the same way as a PCX lens.

Ben, have you tried making a thin-film plastic screen? I would be curious as to what kind of results you get from it with your current setup (which looks fantastic btw, congrats to both Quyen and and yourself).

Michael Maier · January 19th, 2006, 02:16 PM

It kind of looks like a plastic version of the MPIC, for much cheaper.

Quyen Le · January 19th, 2006, 02:25 PM

Hey, don't tickle Dan, he will cough. I thought about beattie focusing screen and shorter distance but just don't want to copy Dan's work. Nice job Ben, I hope Dan has no problem with you modifying the Letus that way.

Quyen

Michael Maier · January 19th, 2006, 02:30 PM

I don't think it would be copying from him anymore than everybody has P+S in a way or another. If you think it would make your adapter better, I would do it. They look different and have different approaches to the construction and different ways of moving the GG, so I don't see what's the problem.
About having a problem with modifying the Letus that way, nobody can control what your customers will do after you sold them the thing.

Mark Wisniowski · January 19th, 2006, 04:17 PM

Quote:

Originally Posted by Michael Maier

About having a problem with modifying the Letus that way, nobody can control what your customers will do after you sold them the thing.

I completly agree. Ben keep doing what you're doing, and post your results :) I always look forward to your findings.

January 18th, 2006, 04:19 PM	#1
Ben Winter Trustee Join Date: Jun 2005 Location: Hollywood, CA Posts: 1,675 Images: 1	The Letus35 Redesigned :) Ok, maybe not "redesigned," more like "shortened"... I wanted less light loss so I ordered a Beattie a while back. Even though it still hasn't come, I wanted to get rid of the achromat as well--so I took it upon myself to shorten the Letus body enough so the GL2 could focus on the GG right smack up against the lens. Pictures: http://www.frozenphoenixproductions.com/misc/letus/ THe white thing is a PVC thing I found at Home Depot--they called it a "soil converter" or something like that--used to connect PVC to cast iron pipes or something. Not really sure. Anyway it was five dollars and with a bunch of small screws I was able to fit it together. The ground glass vibrates maybe half a millimeter from the mount that connects it to the body of the camera. The best part? If I want to go back to my original Letus, all I have to do is unscrew everything and put it back together. I just drilled a few extra holes :) Does it work? Well, no. I don't have my Beattie yet, so there's mass vignetting everywhere (even in my raccoon wounds!). Other than that, it fills up the frame fine, and vibrates normally. Took me about 3 hours worth of work and $7.68. Cheers, Ben __________________ BenWinter.com

January 18th, 2006, 05:46 PM	#2
Quyen Le Major Player Join Date: Jun 2005 Posts: 356	Nice Ben, it should work fine with beattie focusing screen. Quyen __________________ Affordable Adapter http://www.adapterplace.com

January 18th, 2006, 09:33 PM	#4
Ben Winter Trustee Join Date: Jun 2005 Location: Hollywood, CA Posts: 1,675 Images: 1	Haha--thanks for the comments. B&H just emailed me and told me that the Intenscreen will be here Monday. I'll post screengrabs as soon as I can. BTW I tried glueing the PXCL from my Nikon D Screen overtop the GG and the the plate barely vibrated--even less so with 3 AA's. Wonder why. Oh well--back to the drawing board on that problem. __________________ BenWinter.com

January 18th, 2006, 10:09 PM	#6
Andy Gordon Regular Crew Join Date: Mar 2005 Location: Perth WA Posts: 103	Beattie You can get a small Beattie or a large one, small one is about the same size as a nikon D. I got a large second hand one from B&H for $30, it was about 3" x 5" I think. It comes in two parts, fresnel and GG. I glued each part to some 50mm dia pvc pipe and power sanded the edges back till I had a 50mm dia screen (with some 50mm pipe either side). that fit inside another pvc pipe 56mm dia. Bit of a nightmare to sand it without scratching it cause dust etc really clings to the grooves in the fresnel. In the end I scratched it trying to clean it but the results were worse than I was getting with optosigma. It still had a hotspot so I needed a 120FL condensor with it, the grain was worse, and it didn't diffuse enough. So I'm back to the double optosigma. That was with a takumar 1.4 lens and a GS400.

January 18th, 2006, 10:33 PM	#7
Alain Bellon Regular Crew Join Date: Jan 2005 Location: LA Posts: 130	Andy, does the fresnel go between the 35mm lens and the GG screen, or does it go after the screen? I have a Nikon screen and it has a PCX lens that goes after the screen. (actually its a PCX that is ground on the flat side). Last edited by Alain Bellon; January 19th, 2006 at 12:12 AM.

January 18th, 2006, 07:52 PM	#3
Leo Mandy Major Player Join Date: Dec 2004 Posts: 749	Ben I think you were a 35mm adapter in another life. Great job pushing the boundaries!

January 18th, 2006, 09:55 PM	#5
Dmitriy Uchakin Regular Crew Join Date: Dec 2005 Posts: 48	Sounds like an improvemnt in terms of weight of the adapter and not needing to use support rods. Looking forward to see your results. Do you by any chance know the dimensions of the intenscreens? Are they any bigger than nikon D ones. I am thinking of getting a beattie to go inside the thorlabs tube. Just not sure if it will fit in there. Thanks.

January 19th, 2006, 01:32 AM	#8
Bill Porter Major Player Join Date: Mar 2005 Location: Ventura, California, USA Posts: 751	Ben, nice job. Good for you for continuing to tinker. Keep it up! Note: get this out of your system now as it will be harder to get away with it when your girlfriend gets older or you get married. But what the heck are raccoon wounds?

January 19th, 2006, 02:16 PM	#12
Michael Maier Trustee Join Date: Apr 2005 Posts: 1,269	It kind of looks like a plastic version of the MPIC, for much cheaper.

January 19th, 2006, 02:25 PM	#13
Quyen Le Major Player Join Date: Jun 2005 Posts: 356	Hey, don't tickle Dan, he will cough. I thought about beattie focusing screen and shorter distance but just don't want to copy Dan's work. Nice job Ben, I hope Dan has no problem with you modifying the Letus that way. Quyen __________________ Affordable Adapter http://www.adapterplace.com

January 19th, 2006, 02:30 PM	#14
Michael Maier Trustee Join Date: Apr 2005 Posts: 1,269	I don't think it would be copying from him anymore than everybody has P+S in a way or another. If you think it would make your adapter better, I would do it. They look different and have different approaches to the construction and different ways of moving the GG, so I don't see what's the problem. About having a problem with modifying the Letus that way, nobody can control what your customers will do after you sold them the thing.