The moon taken with homemade lens

newarts · 10-27-2009, 08:46 AM

Originally posted by wildlifephotog

Super shot there Nick.
I used something similiar years ago.

It is a telescope for a lens. The diopter goes at the business end. And the teleconverter at the camera end. One paper tube fits inside the other for a slide focus adjustment.
You can build a pretty fair telescope from a +1 diopter and eyepiece from a binocular or reading glass.

Nick's idea to use a teleconverter to couple the objective lens to the camera is a good one.

These, plus bellows + suitable black tube should be an easy way to construct long telephoto lenses. I assume that achromatic close-up lenses should be used.

How is the image edge quality & distortion in such a setup?

Dave in Iowa

wildlifephotog · 10-27-2009, 09:00 AM

Usually very good. You are basicly making a telesope with a 2X barlow attached. The better the glass, the better the end result.
A +2 diopter has a focal length of .5 meter, or 19.6850 inches. The longer, the better CA control you'll have.

stormcloud · 10-27-2009, 10:47 AM

Originally posted by wildlifephotog

Usually very good. You are basicly making a telesope with a 2X barlow attached. The better the glass, the better the end result.
A +2 diopter has a focal length of .5 meter, or 19.6850 inches. The longer, the better CA control you'll have.

sorry if i'm being obtuse but i dont know much on the technical side of lenses but does that mean when assembling a DIY lens/telescope that you need the the teleconverter 0.5 from the objective lens?

wildlifephotog · 10-27-2009, 12:17 PM

Due to manufacturing tolerances, I'd start a little further away and adjust the focus tiil it is perfect. The 19.6850" is the nominal distance.

nick c · 10-27-2009, 01:20 PM

Here is what's left of the lens.

It was made as an experiment, not for serious use. I will probably build a better one later from something more solid than construction paper. The moon picture was not taken with the K1000 is this picture, but with my K2000. I removed the macro lens to use for macros, but it used to be taped the the front.

The close-up lens used was a 52mm +2 diopter "Sigma achromatic macro lens".

With a 30mm diameter aperture stuck to the front the lens was at f33. The aperture didn't really make any difference in image quality. It was just as good wide open at f20.

The formula for calculating focal length is:

1000 _____ = focal length
# of diopters

The formula for calculating the f stop is:
focal length (mm) = f stop
aperture diameter

I was really surprised at how good homemade lenses can be.

The contrast of this lens was pretty bad probably because the long tube of paper wasn't completely black. Foccussing was also very difficult because of how long the tube was.

newarts · 10-27-2009, 02:01 PM

Quote:

The close-up lens used was a 52mm +2 diopter "Sigma achromatic macro lens".

I think maybe that's a 1.6 diopter lens (but I haven't measured it.)

hinman · 10-27-2009, 02:10 PM

Originally posted by nick c

Here is what's left of the lens.

It was made as an experiment, not for serious use. I will probably build a better one later from something more solid than construction paper. The moon picture was not taken with the K1000 is this picture, but with my K2000. I removed the macro lens to use for macros, but it used to be taped the the front.

The close-up lens used was a 52mm +2 diopter "Sigma achromatic macro lens".

With a 30mm diameter aperture stuck to the front the lens was at f33. The aperture didn't really make any difference in image quality. It was just as good wide open at f20.

The formula for calculating focal length is:

1000 _____ = focal length
# of diopters

The formula for calculating the f stop is:
focal length (mm) = f stop
aperture diameter

I was really surprised at how good homemade lenses can be.

The contrast of this lens was pretty bad probably because the long tube of paper wasn't completely black. Foccussing was also very difficult because of how long the tube was.

PentaxForums and I are so grateful for your experiment. I am going to bug my good friend Dadipentax who may be interested in this 1000mm setup that cost like a coffee. I can ship him one of this and he can save the rest for his daughter's college fund. This will be LBA with a scientist twist. Love it! I am giving you a big Bravo.

Warmest,
Hin

nick c · 10-27-2009, 02:25 PM

Originally posted by newarts

I think maybe that's a 1.6 diopter lens (but I haven't measured it.)

It may be. I just looked at it and it doesn't say how many diopters it is. I guess I just assumed that because when I foccussed it at infinity it was approximately 500mm away from the camera.

**dadipentak** · 10-27-2009, 02:29 PM

Originally posted by hinman

PentaxForums and I are so grateful for your experiment. I am going to bug my good friend Dadipentax who may be interested in this 1000mm setup that cost like a coffee. I can ship him one of this and he can save the rest for his daughter's college fund.

Warmest,
Hin

I may never forgive you, Nick for giving Hin the chance to tweak me like that!

I wholeheartedly second the Bravo!

nick c · 10-27-2009, 02:36 PM

Originally posted by newarts

How is the image edge quality & distortion in such a setup?

Dave in Iowa

Distortion was hard to measure since it was a 1000mm lens. However, there wasn't very much, definitely not enough to be noticable. Edge quality was about the same as in the middle (not that great, but for a close-up filter as a lens its not bad)
The main issues with image quality were getting the picture in focus (because the lens was so long) and lack of contrast (probably because my paper wasn't completely black).

Jonson PL · 10-27-2009, 02:37 PM

I’m officially impressed. Great shot and great work

**Ex Finn.** · 10-27-2009, 02:40 PM

Very nice!, I need to rethink my approach for moon shots.

Cheers. Mike.

newarts · 10-27-2009, 03:02 PM

Originally posted by nick c

It may be. I just looked at it and it doesn't say how many diopters it is. I guess I just assumed that because when I foccussed it at infinity it was approximately 500mm away from the camera.

I've seen it specified at 1.6. It is a pretty good lens I think.

Do you have any tricks for blackening optics tubes? a candle maybe?

Blue · 10-27-2009, 03:13 PM

You just make mirror lenses obsolete for moon shots for the cost of a cup of coffee.

**pacerr** · 10-27-2009, 03:21 PM

Nick, you obviously don't understand that the whole point of this photography thing is to spend hundreds, if not thousands, of your local money-units to produce such images! This frontal attack on the world economy may not go unpunished if you persist in this rebellious manner.

Well done, sir!

H2

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10-27-2009, 08:46 AM	#16
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by wildlifephotog Super shot there Nick. I used something similiar years ago. It is a telescope for a lens. The diopter goes at the business end. And the teleconverter at the camera end. One paper tube fits inside the other for a slide focus adjustment. You can build a pretty fair telescope from a +1 diopter and eyepiece from a binocular or reading glass. Nick's idea to use a teleconverter to couple the objective lens to the camera is a good one. These, plus bellows + suitable black tube should be an easy way to construct long telephoto lenses. I assume that achromatic close-up lenses should be used. How is the image edge quality & distortion in such a setup? Dave in Iowa

10-27-2009, 09:00 AM	#17
wildlifephotog Inactive Account Join Date: Nov 2008 Location: USA Posts: 924	Usually very good. You are basicly making a telesope with a 2X barlow attached. The better the glass, the better the end result. A +2 diopter has a focal length of .5 meter, or 19.6850 inches. The longer, the better CA control you'll have.

10-27-2009, 10:47 AM	#18
stormcloud Senior Member Join Date: Oct 2009 Posts: 232	Originally posted by wildlifephotog Usually very good. You are basicly making a telesope with a 2X barlow attached. The better the glass, the better the end result. A +2 diopter has a focal length of .5 meter, or 19.6850 inches. The longer, the better CA control you'll have. sorry if i'm being obtuse but i dont know much on the technical side of lenses but does that mean when assembling a DIY lens/telescope that you need the the teleconverter 0.5 from the objective lens?

10-27-2009, 12:17 PM	#19
wildlifephotog Inactive Account Join Date: Nov 2008 Location: USA Posts: 924	Due to manufacturing tolerances, I'd start a little further away and adjust the focus tiil it is perfect. The 19.6850" is the nominal distance.

10-27-2009, 01:20 PM	#20
nick c Junior Member Join Date: Aug 2009 Posts: 29 Original Poster	Here is what's left of the lens. It was made as an experiment, not for serious use. I will probably build a better one later from something more solid than construction paper. The moon picture was not taken with the K1000 is this picture, but with my K2000. I removed the macro lens to use for macros, but it used to be taped the the front. The close-up lens used was a 52mm +2 diopter "Sigma achromatic macro lens". With a 30mm diameter aperture stuck to the front the lens was at f33. The aperture didn't really make any difference in image quality. It was just as good wide open at f20. The formula for calculating focal length is: 1000 _____ = focal length # of diopters The formula for calculating the f stop is: focal length (mm) = f stop aperture diameter I was really surprised at how good homemade lenses can be. The contrast of this lens was pretty bad probably because the long tube of paper wasn't completely black. Foccussing was also very difficult because of how long the tube was.

10-27-2009, 02:01 PM	#21
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Quote: The close-up lens used was a 52mm +2 diopter "Sigma achromatic macro lens". I think maybe that's a 1.6 diopter lens (but I haven't measured it.)

10-27-2009, 02:10 PM	#22
hinman Veteran Member Join Date: Oct 2006 Location: Fremont, CA Photos: Albums Posts: 3,473	Originally posted by nick c Here is what's left of the lens. It was made as an experiment, not for serious use. I will probably build a better one later from something more solid than construction paper. The moon picture was not taken with the K1000 is this picture, but with my K2000. I removed the macro lens to use for macros, but it used to be taped the the front. The close-up lens used was a 52mm +2 diopter "Sigma achromatic macro lens". With a 30mm diameter aperture stuck to the front the lens was at f33. The aperture didn't really make any difference in image quality. It was just as good wide open at f20. The formula for calculating focal length is: 1000 _____ = focal length # of diopters The formula for calculating the f stop is: focal length (mm) = f stop aperture diameter I was really surprised at how good homemade lenses can be. The contrast of this lens was pretty bad probably because the long tube of paper wasn't completely black. Foccussing was also very difficult because of how long the tube was. PentaxForums and I are so grateful for your experiment. I am going to bug my good friend Dadipentax who may be interested in this 1000mm setup that cost like a coffee. I can ship him one of this and he can save the rest for his daughter's college fund. This will be LBA with a scientist twist. Love it! I am giving you a big Bravo. Warmest, Hin

10-27-2009, 02:25 PM	#23
nick c Junior Member Join Date: Aug 2009 Posts: 29 Original Poster	Originally posted by newarts I think maybe that's a 1.6 diopter lens (but I haven't measured it.) It may be. I just looked at it and it doesn't say how many diopters it is. I guess I just assumed that because when I foccussed it at infinity it was approximately 500mm away from the camera.

10-27-2009, 02:29 PM	#24
dadipentak Site Supporter Join Date: Jul 2008 Location: Baltimore, Maryland Photos: Gallery Posts: 11,590	Originally posted by hinman PentaxForums and I are so grateful for your experiment. I am going to bug my good friend Dadipentax who may be interested in this 1000mm setup that cost like a coffee. I can ship him one of this and he can save the rest for his daughter's college fund. Warmest, Hin I may never forgive you, Nick for giving Hin the chance to tweak me like that! I wholeheartedly second the *Bravo!*

10-27-2009, 02:36 PM	#25
nick c Junior Member Join Date: Aug 2009 Posts: 29 Original Poster	Originally posted by newarts How is the image edge quality & distortion in such a setup? Dave in Iowa Distortion was hard to measure since it was a 1000mm lens. However, there wasn't very much, definitely not enough to be noticable. Edge quality was about the same as in the middle (not that great, but for a close-up filter as a lens its not bad) The main issues with image quality were getting the picture in focus (because the lens was so long) and lack of contrast (probably because my paper wasn't completely black).

10-27-2009, 02:37 PM	#26
Jonson PL Veteran Member Join Date: Dec 2006 Location: Copenhagen Photos: Gallery Posts: 1,842	I’m officially impressed. Great shot and great work

10-27-2009, 02:40 PM	#27
Ex Finn. Site Supporter Join Date: Nov 2007 Location: Southern Maryland. Espoo. Kouvola. Photos: Gallery \| Albums Posts: 7,975	Very nice!, I need to rethink my approach for moon shots. Cheers. Mike.

10-27-2009, 03:02 PM	#28
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by nick c It may be. I just looked at it and it doesn't say how many diopters it is. I guess I just assumed that because when I foccussed it at infinity it was approximately 500mm away from the camera. I've seen it specified at 1.6. It is a pretty good lens I think. Do you have any tricks for blackening optics tubes? a candle maybe?

10-27-2009, 03:13 PM	#29
Blue Moderator Site Supporter Join Date: Jun 2008 Location: Florida Hill Country Photos: Gallery \| Albums Posts: 17,377	You just make mirror lenses obsolete for moon shots for the cost of a cup of coffee.

10-27-2009, 03:21 PM	#30
pacerr Loyal Site Supporter Join Date: Jan 2008 Location: Paris, TN Photos: Gallery \| Albums Posts: 3,349	Nick, you obviously don't understand that the whole point of this photography thing is to spend hundreds, if not thousands, of your local money-units to produce such images! This frontal attack on the world economy may not go unpunished if you persist in this rebellious manner. Well done, sir! H2