DIY Reflector/Compound camera lens? at DVinfo.net

Wayne Morellini · December 28th, 2004, 05:15 AM

Hi,

I am doing preliminary research into using a reflector lens, like what is use in refelctor telescopes, as a conventional camera lense. My reasoning is to get better image per cost, and a lot more light gathering power than normal lense. There is the possibility to do a compound lens, using bother reflectors and normal lenses, instead.

The problem is that I don't know much about lens systems and need some advice on how things work, problems and suitabilities.

One thing that occurs to me is that all the reflector lenses for cameras I have seen, and telescopes of course, are telescopic. It appears that a normal angle lense should be possible, but are there real problems against this?

If anybody really knows their stuff please let us know.

Some very basic stuff on how reflector works:
http://science.howstuffworks.com/tel....htm/printable

Thanks

Wayne.

Bob Hart · December 28th, 2004, 06:52 AM

Perhaps look up Maksutov-Cassegrain and Schmidt-Cassegrain, with or without the -.

From the little I know and it is very little, you deny yourself ability to control exposure via a lens iris when using these types.

Slightly off this topic, the older photocopiers have a reflector lens which you can do some weird stuff with but the image path through the lens to a focal plane is not along the same axis to the rear but projected back out through the front.

Wayne Morellini · December 29th, 2004, 01:10 PM

Thanks Bob. I'll look at that in the new year, I just spent all night trying to get this computer to do what it should ;(

Would putting the iris after the mirror and before the image plane be able to solve the Iris problem?

Thanks

Wayne.

-----Further questions

I wonder how they go on zoom, focus and DOF?

I see some designs with the lense out the side and some with the lense out the back, I wonder what the compromisers are.

Régine Weinberg · December 29th, 2004, 01:34 PM

Dear Wayne
take it this way It can be done,
it was not the need to do it
as for short focal the lenses are compact
for extrem telephoto there
is an economocal need
as it is much cheaper as to have 20 or more lenses.
for a 50mm I do not know
there are lenses 1.4 or even 1.1 leica 35mm

Wayne Morellini · December 31st, 2004, 10:14 AM

I have had a prelliminary look at mirror prices, and I think it might be possible to do a much cheaper and lighter lense of cinema quality in small volume, or home made. So instead of spending thousands, for us it might be hundreds, also the lite design is good for any handheld, portable, or low light use ;) But again, the compromises of a mirror lense are what will sink or float that that dream. Unfortunately, as most people are away, we will probably have to wait weeks to get a propper discussion going, so I might have to do another post then.

Wayne Morellini · January 6th, 2005, 12:11 PM

Well I am making progress on the subject ("mirror lens" works better than those search terms) but research is proving difficult as I am dizzy at the moment.

It's exciting, it looks like I can resolve most, if not all, the problems of the mirror lens (with zoom and aperature). I have a few leads on some things, and one of them is the solution I was going to implement anyway. I'm sure that with the other optical ideas I have been developing I could do some interesting things.

I'll see how I go, but I am starting on a very low cost laser projector project again, so I am going to deviate to that.

Thanks

Wayne.

December 28th, 2004, 05:15 AM	#1
Wayne Morellini Inner Circle Join Date: May 2003 Location: Australia Posts: 2,762	DIY Reflector/Compound camera lens? Hi, I am doing preliminary research into using a reflector lens, like what is use in refelctor telescopes, as a conventional camera lense. My reasoning is to get better image per cost, and a lot more light gathering power than normal lense. There is the possibility to do a compound lens, using bother reflectors and normal lenses, instead. The problem is that I don't know much about lens systems and need some advice on how things work, problems and suitabilities. One thing that occurs to me is that all the reflector lenses for cameras I have seen, and telescopes of course, are telescopic. It appears that a normal angle lense should be possible, but are there real problems against this? If anybody really knows their stuff please let us know. Some very basic stuff on how reflector works: http://science.howstuffworks.com/tel....htm/printable Thanks Wayne.

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December 28th, 2004, 06:52 AM	#2
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	Perhaps look up Maksutov-Cassegrain and Schmidt-Cassegrain, with or without the -. From the little I know and it is very little, you deny yourself ability to control exposure via a lens iris when using these types. Slightly off this topic, the older photocopiers have a reflector lens which you can do some weird stuff with but the image path through the lens to a focal plane is not along the same axis to the rear but projected back out through the front.

December 29th, 2004, 01:10 PM	#3
Wayne Morellini Inner Circle Join Date: May 2003 Location: Australia Posts: 2,762	Thanks Bob. I'll look at that in the new year, I just spent all night trying to get this computer to do what it should ;( Would putting the iris after the mirror and before the image plane be able to solve the Iris problem? Thanks Wayne. -----Further questions I wonder how they go on zoom, focus and DOF? I see some designs with the lense out the side and some with the lense out the back, I wonder what the compromisers are.

December 29th, 2004, 01:34 PM	#4
Régine Weinberg Major Player Join Date: Jan 2004 Location: Bordeaux, going to Bangkok, 2011 Posts: 232	Dear Wayne take it this way It can be done, it was not the need to do it as for short focal the lenses are compact for extrem telephoto there is an economocal need as it is much cheaper as to have 20 or more lenses. for a 50mm I do not know there are lenses 1.4 or even 1.1 leica 35mm

December 31st, 2004, 10:14 AM	#5
Wayne Morellini Inner Circle Join Date: May 2003 Location: Australia Posts: 2,762	I have had a prelliminary look at mirror prices, and I think it might be possible to do a much cheaper and lighter lense of cinema quality in small volume, or home made. So instead of spending thousands, for us it might be hundreds, also the lite design is good for any handheld, portable, or low light use ;) But again, the compromises of a mirror lense are what will sink or float that that dream. Unfortunately, as most people are away, we will probably have to wait weeks to get a propper discussion going, so I might have to do another post then.

January 6th, 2005, 12:11 PM	#6
Wayne Morellini Inner Circle Join Date: May 2003 Location: Australia Posts: 2,762	Well I am making progress on the subject ("mirror lens" works better than those search terms) but research is proving difficult as I am dizzy at the moment. It's exciting, it looks like I can resolve most, if not all, the problems of the mirror lens (with zoom and aperature). I have a few leads on some things, and one of them is the solution I was going to implement anyway. I'm sure that with the other optical ideas I have been developing I could do some interesting things. I'll see how I go, but I am starting on a very low cost laser projector project again, so I am going to deviate to that. Thanks Wayne.