Home-made Lens: Critique & Advice Please!!

[DaveW]

Jason See:-

http://en.wikipedia.org/wiki/Achromat

http://en.wikipedia.org/wiki/Apochromat

DaveW

[rjlittlefield]

...something I certainly have never thought of - magazine pages! Sounds good, but especially contrasting colours, ideally black + white??

For evaluating CA, black + white is best. The reason I suggested "screened gray-scale photos" is that they are actually composed of little dots of pure black ink. The dot size changes depending on dark gray versus light gray. The edges are generally quite crisp, and since there are no colors except what's added by the lens, CA is easy to see. Magazines printed on glossy paper are much better than newspapers. Newspaper ink tends to have fuzzy edges.

but for now it's fun experimenting

Experimenting is also a great way to prompt questions that lead to understanding. Getting a box of miscellaneous lenses to play around with was one of the best investments I ever made.

You'll probably be amused to hear that the way I started in macro (about 45 years ago) was with an Argus C3 35 mm rangefinder camera, shooting through simple magnifying lenses. Feedback was a lot slower then, what with taking a week to send film off to get it developed. So I really had no choice but to do a lot of predicting, based on simple theory and what I could see by eye. It was a valuable learning experience.

Of course I also upgraded to an SLR and bellows as soon as I could scrape together the funds. You can only learn so much by beating your head on a brick wall!

--Rik

[Jason G]

...yep, like it hurts for example !!

That's a good idea RE the black pixels, then maybe check CA vs. focus by supporting the paper at differing angles...

Thanks again, and the box of lenses does sound interesting

Take care,

Jason

[lothman]

Hi All,

I have a Fuji S5600 prosumer with a 310mm zoom lens. Whilst it does have a Macro mode, I often have to crop on-camera to get in close to an insect, for example. I then decided to have a bash at making my own Macro lens...

Hi Jason,
years ago I had a Fuji S602 and made a macro-converter from a slide projector lens:

I tried an old slide projector lens - a Leitz Hector F=100mm 1:2,5. Use a lense faster than 2,8 otherwise vignetting might occur. You can get that type of lenses rather cheap on ebay, might be you have to buy a whole slide pojector ;-) Do a search for the Leitz Colorplan or Supercolorplan.

For a proper adapting to the tubus I had to machine the lens housing on a lathe. Therfore I disassembled the lens. .

So 4 lenses in 3 Groups:



I shortened the housing at both ends and machined the right end to fit in an empty filter. I glued the empty filter with silicone. To avoid vignetting as far as possible you should get the lens as close as possible to the lens of the camera. Attention don't scratch the lenses due to collision.



This type of lens has IMO several advantages over the SLR-Lens solution.
- great lens diameter
- cheaper
- no moving parts like apertur and focus ring
- should be designed for fix/open aperture and reversed use
- but usually no filter thread, therefore harder to adapt

and a larger working distance (about 72 mm in my case), which gives you the chance for good illumination.



at full zoom (200m for the Fuji S602) I got an imagewidth of 16,5 mm:



And to give you an idea for the DOF a pic of 2 matches at full zoom. The lower one I split in half to get a second layer for proofing DOF (about 1,5 mm). The pic was taken at f=11, the grid on the paper is 5 mm.



I hope this useful for some of you. Klaus Schmitt from macrolenses.de gave me the link to this wonderful forum. After some days of lurking I thought it's time to contribute ;-)

Best regards
Lothman

P.S.: This pic was taken with a similar setup and a Minolta Dimage A2 at 200mm:

[Planapo]

lothman,

Hello and welcome!

This is a very interesting report on lens building, thanks for sharing!
And the picture of this coccinellid is looking awesome, especially the punctate structure of the elytra!

You wrote about the beetle pic:

P.S.: This pic was taken with a similar setup

So, do I get this right that the ladybird was photographed with that self-made lens that we see above or what was the "similar setup"? You´ve aroused my curiosity now!

--Betty

[lothman]

So, do I get this right that the ladybird was photographed with that self-made lens that we see above or what was the "similar setup"? You´ve aroused my curiosity now!

--Betty

With "similar" I meant it was also a slide projector lens. It was not the Hector described above but a Zeiss Super Talon 2,5/90, giving some more magnification due to the shorter focal lenght. But IMO there is no need for Zeiss/Leitz other manufacturers are also OK.

[rjlittlefield]

Lothman, let me add my thanks and welcome you to the forum!

Your setup does great work and your description is very clear and detailed.

Very helpful!

--Rik

[Jason G]

Wow, V. detailed post! Love the ladybird! Real food for thought there Loth!!!

[Cyclops]

Lothman, thats a fabulous piece of lens work there!!

[Aynia]

Lothman...that is an amazing looking ladybird.

As for your set up, I can only be amazed at the "diy technology" used.....

Welcome to the forum.

You will fit right in.

[lothman]

Just to show another possibility of adapting I'll show a pic of the converted Zeiss Super Talon 2,5/90. I turned an aluminium ring with a 49 filter thread on a lathe and fixed the shortened slide Projector lens with a hex-screw, so the axial position of the lens can easily be changed/optimised (as close as possible to the cam).

[Jason G]

Afternoon Lothman,

I've just run a quick search on Amazon and just seen a cheap hand-held slide viewer - the type with a battery-powered bulb. Would the lens be CA-free or not, or is the lens of a slide projector made differently?

[lothman]

I've just run a quick search on Amazon and just seen a cheap hand-held slide viewer - the type with a battery-powered bulb. Would the lens be CA-free or not, or is the lens of a slide projector made differently?

As far as I know your hand held slide viewer has a normal single emlement loupe and therefore is not very well suited as a lens attachments (similar to a cheap singleelement CU-lens).

The lenses in a slide projector have several lenses are coated and are for shure much better corrected than such a hand-held slide viewer and give a higher magnification.

Regards Lothman

P.S.: There are loupes for slide viewing out ther with an achromatic lens or even with aspheric lenses. These elements do also quite well used as a macro attachment, but they are >50$

[g4lab]

Slide viewer lenses don't have to magnify as much as projector lenses, and usually are not even achromats. So no, that would not do the trick. They are essentially single lens magnifiers.

Projection lenses are easily obtained these days from flea markets.
You can also still find 8 and 16mm movie camera lenses, that are also excellent, although these are not as common as they used to be, they are still around. Those lenses usually are shorter focal length (ie. higher magnification) than projection lenses.

The Leitz Colorplans are superb. I used to have a Leitz slide projector, and it really threw a gorgeous image. I traded it away once upon a time, but considered keeping it to use as an illuminator. In addition to the Colorplan projective, it had a gorgeous condensor ,consisting of two aspheric lenses, that looked like half an egg. So if you have to buy a whole projector don't forget to salvage the condensing optics.

I like all our new digital gear, but back in the day , a Kodachrome slide was hard to beat.

[Jason G]

Right, thanks for that!! So, now I know what my next purchase'll be