[Recovered Thread: 96580]

[seemolf]

Ok, take some flint glass and crown glass.....

.... just kidding!

I was just thinking of all these folks (like me) not having infinite amounts of money.
.. or live at places where delivery costs more than the object.

Cerambyx and others showed us excellent results with the achromatic lenses of stereoscopic microscopes (MBS-10).
None of the expensive achromatic close up lenses could be better!
But these lenses are heavy like the new raynox dcr-5320: around 400g.
This is more than the weight of my camera, even the price is "heavier".

There has to be different glass in my house!!
At this moment my old Revue spyglass 10x40 came into my hand.
I took the front lens (heavy -> achromat?) and tested it.



2* zoom



12* zoom, the ant aphid test



12*zoom, lcd test



Fast mounting with cokin system A

Preliminary results:
- my lens has +6 diopters - 160mm focal length
- 45mm inner lens diameter
- vignetting starts below x2 zoom, could be less with better mounting
- no soft corners
- not as sharp at full zoom as the Olympus a life size, but much better than a single lens close up lens!


Knowing this, some "simple" google actions revealed a german thread from 2003 stating:
There is no reason why simple achromats for cameras are so expensive. These lenses are used in telescopes and spyglass providing an excellent source for homemade achromats! Aha!
Modern spyglasses have a strange coating, but white balance might help. Old Revue (or other) lenses are perfect, they have a normal coating and a big diameter. Diopters are between +5 and +7.
.....and there are two of them. So let's do some stacking ;-)


Any comments welcome

Sven

[Seedubs]

Very interesting, I have some old Binoculars somewhere, could those lenses be utilised? How did you mount it?? Looks like some sort of cokin mount???

[seemolf]

Seadubs,

just try these lenses and test them with a flat object (eg. screen). Achromats are thick and heavy. If there is no corner softness, these lenses will be achromats. Test the sharpness with serveral zoom settings and reduce the lens diameter with a vignette (black paper with a round hole) if you are not satisfied.

Cokin is my first choice to fix new lenses:
http://www.geocities.com/seemolf/tec...sAndTicks.html
Try to fix a lens - even with tape - look at the results and fix it lateron.
Most of the binocular lenses will be achromats, just try it!

Sven

[bayourebel]

Please excuse my ignorance, but what is a cokin system?

Jerry

[seemolf]

Some of us used this modular filter system with their SLR cameras:

http://www.cokin.fr/

There is a modular filter holder with an adapter (in this case 55mm). System A for smaller diameters and system P for bigger lenses. I can use these filters with all of my cameras (old, new, future). Some people think, they don't need it for digital cameras and sell it at fleaby.

There are square filters for all (!) purposes. My best filter is the split gray filter which can be adjusted to match the horizon.

The cokin filter holder is my partner in developing attachments for the FZ5 and A70.

You see some examples for reversed lenses here:

http://www.geocities.com/seemolf/tec...sAndTicks.html

Sven

[bayourebel]

Thanks for the reply, seemolf. I kept seeing referrals to this system, but was not familiar with it. I will look into it some more as I do need some filters.

Jerry

[Seedubs]

I have extracted the following lenses from my old set of binoculars and they appear to be Achromat lenses (2 parts), I have a cokin mount so I will try and compare them to my Nikon 6T, also do you think I could stack the two of them?

Many thanks

[seemolf]

Bingo!
This is an achromat, just mount it and test it.
If the results are promissing, paint the sides black and make some tests with vignettes of ring shape. This additional aperture will improve the results and perhaps even DOF.
Try to stack them and use different zoom levels. The sweet spot is not at 12* zoom. But these lenses will be better than a 10* single lens macro.

Good luck
Sven


...just found a new link:

you should have a look at the threads from lothman at dpreviews:

http://forums.dpreview.com/forums/re...essage=8712942

He uses binocular lenses and slide projector lenses. I have tested slide p. lenses without modifications - I did not like the results.

[Seedubs]

Managed to create a lense using my cokin holder, see below:





Did try stacking two lenses but it didnt seem to work - too fuzzy, anyhow I took a couple of static pictures, firstly one with the Nikon 6T (these pictures have only been resized and saved for web):



And then one with the Homemade lense:



Both were taken on full x 12 zoom (F11 & 1/50), but not too bad really!!

[bayourebel]

I may not know what I am looking at but seems to me the homemade is the better of the two. While I would be proud of both, I really like the second best. Appears that you took the lens completely out of it binocular frame. Is that correct?

jerry